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ClickHouse/CHANGELOG.md
Alexey Milovidov 8dad8ea8c3
Merge pull request #55206 from den-crane/patch-61 
Update CHANGELOG.md  / issue with with a downgrade because of ratio_of_defaults_for_sparse_serialization
2023-10-10 01:39:02 +02:00

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### Table of Contents
**[ClickHouse release v23.9, 2023-09-28](#239)**<br/>
**[ClickHouse release v23.8 LTS, 2023-08-31](#238)**<br/>
**[ClickHouse release v23.7, 2023-07-27](#237)**<br/>
**[ClickHouse release v23.6, 2023-06-30](#236)**<br/>
**[ClickHouse release v23.5, 2023-06-08](#235)**<br/>
**[ClickHouse release v23.4, 2023-04-26](#234)**<br/>
**[ClickHouse release v23.3 LTS, 2023-03-30](#233)**<br/>
**[ClickHouse release v23.2, 2023-02-23](#232)**<br/>
**[ClickHouse release v23.1, 2023-01-25](#231)**<br/>
**[Changelog for 2022](https://clickhouse.com/docs/en/whats-new/changelog/2022/)**<br/>
# 2023 Changelog
### ClickHouse release 23.9, 2023-09-28
#### Backward Incompatible Change
* Remove the `status_info` configuration option and dictionaries status from the default Prometheus handler. [#54090](https://github.com/ClickHouse/ClickHouse/pull/54090) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* The experimental parts metadata cache is removed from the codebase. [#54215](https://github.com/ClickHouse/ClickHouse/pull/54215) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Disable setting `input_format_json_try_infer_numbers_from_strings` by default, so we don't try to infer numbers from strings in JSON formats by default to avoid possible parsing errors when sample data contains strings that looks like a number. [#55099](https://github.com/ClickHouse/ClickHouse/pull/55099) ([Kruglov Pavel](https://github.com/Avogar)).
#### New Feature
* Improve schema inference from JSON formats: 1) Now it's possible to infer named Tuples from JSON objects without experimantal JSON type under a setting `input_format_json_try_infer_named_tuples_from_objects` in JSON formats. Previously without experimantal type JSON we could only infer JSON objects as Strings or Maps, now we can infer named Tuple. Resulting Tuple type will conain all keys of objects that were read in data sample during schema inference. It can be useful for reading structured JSON data without sparse objects. The setting is enabled by default. 2) Allow parsing JSON array into a column with type String under setting `input_format_json_read_arrays_as_strings`. It can help reading arrays with values with different types. 3) Allow to use type String for JSON keys with unkown types (`null`/`[]`/`{}`) in sample data under setting `input_format_json_infer_incomplete_types_as_strings`. Now in JSON formats we can read any value into String column and we can avoid getting error `Cannot determine type for column 'column_name' by first 25000 rows of data, most likely this column contains only Nulls or empty Arrays/Maps` during schema inference by using type String for unknown types, so the data will be read successfully. [#54427](https://github.com/ClickHouse/ClickHouse/pull/54427) ([Kruglov Pavel](https://github.com/Avogar)).
* Added IO scheduling support for remote disks. Storage configuration for disk types `s3`, `s3_plain`, `hdfs` and `azure_blob_storage` can now contain `read_resource` and `write_resource` elements holding resource names. Scheduling policies for these resources can be configured in a separate server configuration section `resources`. Queries can be marked using setting `workload` and classified using server configuration section `workload_classifiers` to achieve diverse resource scheduling goals. More details in [the docs](https://clickhouse.com/docs/en/operations/workload-scheduling). [#47009](https://github.com/ClickHouse/ClickHouse/pull/47009) ([Sergei Trifonov](https://github.com/serxa)). Added "bandwidth_limit" IO scheduling node type. It allows you to specify `max_speed` and `max_burst` constraints on traffic passing though this node. [#54618](https://github.com/ClickHouse/ClickHouse/pull/54618) ([Sergei Trifonov](https://github.com/serxa)).
* Added new type of authentication based on SSH keys. It works only for the native TCP protocol. [#41109](https://github.com/ClickHouse/ClickHouse/pull/41109) ([George Gamezardashvili](https://github.com/InfJoker)).
* Added a new column `_block_number` for MergeTree tables. [#44532](https://github.com/ClickHouse/ClickHouse/issues/44532). [#47532](https://github.com/ClickHouse/ClickHouse/pull/47532) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Add `IF EMPTY` clause for `DROP TABLE` queries. [#48915](https://github.com/ClickHouse/ClickHouse/pull/48915) ([Pavel Novitskiy](https://github.com/pnovitskiy)).
* SQL functions `toString(datetime, timezone)` and `formatDateTime(datetime, format, timezone)` now support non-constant timezone arguments. [#53680](https://github.com/ClickHouse/ClickHouse/pull/53680) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Add support for `ALTER TABLE MODIFY COMMENT`. Note: something similar was added by an external contributor a long time ago, but the feature did not work at all and only confused users. This closes [#36377](https://github.com/ClickHouse/ClickHouse/issues/36377). [#51304](https://github.com/ClickHouse/ClickHouse/pull/51304) ([Alexey Milovidov](https://github.com/alexey-milovidov)). Note: this command does not propagate between replicas, so the replicas of a table could have different comments.
* Added `GCD` a.k.a. "greatest common denominator" as a new data compression codec. The codec computes the GCD of all column values, and then divides each value by the GCD. The GCD codec is a data preparation codec (similar to Delta and DoubleDelta) and cannot be used stand-alone. It works with data integer, decimal and date/time type. A viable use case for the GCD codec are column values that change (increase/decrease) in multiples of the GCD, e.g. 24 - 28 - 16 - 24 - 8 - 24 (assuming GCD = 4). [#53149](https://github.com/ClickHouse/ClickHouse/pull/53149) ([Alexander Nam](https://github.com/seshWCS)).
* Two new type aliases `DECIMAL(P)` (as shortcut for `DECIMAL(P, 0)` and `DECIMAL` (as shortcut for `DECIMAL(10, 0)`) were added. This makes ClickHouse more compatible with MySQL's SQL dialect. [#53328](https://github.com/ClickHouse/ClickHouse/pull/53328) ([Val Doroshchuk](https://github.com/valbok)).
* Added a new system log table `backup_log` to track all `BACKUP` and `RESTORE` operations. [#53638](https://github.com/ClickHouse/ClickHouse/pull/53638) ([Victor Krasnov](https://github.com/sirvickr)).
* Added a format setting `output_format_markdown_escape_special_characters` (default: false). The setting controls whether special characters like `!`, `#`, `$` etc. are escaped (i.e. prefixed by a backslash) in the `Markdown` output format. [#53860](https://github.com/ClickHouse/ClickHouse/pull/53860) ([irenjj](https://github.com/irenjj)).
* Add function `decodeHTMLComponent`. [#54097](https://github.com/ClickHouse/ClickHouse/pull/54097) ([Bharat Nallan](https://github.com/bharatnc)).
* Added `peak_threads_usage` to query_log table. [#54335](https://github.com/ClickHouse/ClickHouse/pull/54335) ([Alexey Gerasimchuck](https://github.com/Demilivor)).
* Add `SHOW FUNCTIONS` support to clickhouse-client. [#54337](https://github.com/ClickHouse/ClickHouse/pull/54337) ([Julia Kartseva](https://github.com/wat-ze-hex)).
* Added function `toDaysSinceYearZero` with alias `TO_DAYS` (for compatibility with MySQL) which returns the number of days passed since `0001-01-01` (in Proleptic Gregorian Calendar). [#54479](https://github.com/ClickHouse/ClickHouse/pull/54479) ([Robert Schulze](https://github.com/rschu1ze)). Function `toDaysSinceYearZero()` now supports arguments of type `DateTime` and `DateTime64`. [#54856](https://github.com/ClickHouse/ClickHouse/pull/54856) ([Serge Klochkov](https://github.com/slvrtrn)).
* Added functions `YYYYMMDDtoDate`, `YYYYMMDDtoDate32`, `YYYYMMDDhhmmssToDateTime` and `YYYYMMDDhhmmssToDateTime64`. They convert a date or date with time encoded as integer (e.g. 20230911) into a native date or date with time. As such, they provide the opposite functionality of existing functions `YYYYMMDDToDate`, `YYYYMMDDToDateTime`, `YYYYMMDDhhmmddToDateTime`, `YYYYMMDDhhmmddToDateTime64`. [#54509](https://github.com/ClickHouse/ClickHouse/pull/54509) ([Quanfa Fu](https://github.com/dentiscalprum)) ([Robert Schulze](https://github.com/rschu1ze)).
* Add several string distance functions, including `byteHammingDistance`, `editDistance`. [#54935](https://github.com/ClickHouse/ClickHouse/pull/54935) ([flynn](https://github.com/ucasfl)).
* Allow specifying the expiration date and, optionally, the time for user credentials with `VALID UNTIL datetime` clause. [#51261](https://github.com/ClickHouse/ClickHouse/pull/51261) ([Nikolay Degterinsky](https://github.com/evillique)).
* Allow S3-style URLs for table functions `s3`, `gcs`, `oss`. URL is automatically converted to HTTP. Example: `'s3://clickhouse-public-datasets/hits.csv'` is converted to `'https://clickhouse-public-datasets.s3.amazonaws.com/hits.csv'`. [#54931](https://github.com/ClickHouse/ClickHouse/pull/54931) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Add new setting `print_pretty_type_names` to print pretty deep nested types like Tuple/Maps/Arrays. [#55095](https://github.com/ClickHouse/ClickHouse/pull/55095) ([Kruglov Pavel](https://github.com/Avogar)).
#### Performance Improvement
* Speed up reading from S3 by enabling prefetches by default. [#53709](https://github.com/ClickHouse/ClickHouse/pull/53709) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Do not implicitly read PK and version columns in lonely parts if unnecessary for queries with FINAL. [#53919](https://github.com/ClickHouse/ClickHouse/pull/53919) ([Duc Canh Le](https://github.com/canhld94)).
* Optimize group by constant keys. Will optimize queries with group by `_file/_path` after https://github.com/ClickHouse/ClickHouse/pull/53529. [#53549](https://github.com/ClickHouse/ClickHouse/pull/53549) ([Kruglov Pavel](https://github.com/Avogar)).
* Improve performance of sorting for `Decimal` columns. Improve performance of insertion into `MergeTree` if ORDER BY contains a `Decimal` column. Improve performance of sorting when data is already sorted or almost sorted. [#35961](https://github.com/ClickHouse/ClickHouse/pull/35961) ([Maksim Kita](https://github.com/kitaisreal)).
* Improve performance for huge query analysis. Fixes [#51224](https://github.com/ClickHouse/ClickHouse/issues/51224). [#51469](https://github.com/ClickHouse/ClickHouse/pull/51469) ([frinkr](https://github.com/frinkr)).
* An optimization to rewrite `COUNT(DISTINCT ...)` and various `uniq` variants to `count` if it is selected from a subquery with GROUP BY. [#52082](https://github.com/ClickHouse/ClickHouse/pull/52082) [#52645](https://github.com/ClickHouse/ClickHouse/pull/52645) ([JackyWoo](https://github.com/JackyWoo)).
* Remove manual calls to `mmap/mremap/munmap` and delegate all this work to `jemalloc` - and it slightly improves performance. [#52792](https://github.com/ClickHouse/ClickHouse/pull/52792) ([Nikita Taranov](https://github.com/nickitat)).
* Fixed high in CPU consumption when working with NATS. [#54399](https://github.com/ClickHouse/ClickHouse/pull/54399) ([Vasilev Pyotr](https://github.com/vahpetr)).
* Since we use separate instructions for executing `toString()` with datetime argument, it is possible to improve performance a bit for non-datetime arguments and have some parts of the code cleaner. Follows up [#53680](https://github.com/ClickHouse/ClickHouse/issues/53680). [#54443](https://github.com/ClickHouse/ClickHouse/pull/54443) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Instead of serializing json elements into a `std::stringstream`, this PR try to put the serialization result into `ColumnString` direclty. [#54613](https://github.com/ClickHouse/ClickHouse/pull/54613) ([lgbo](https://github.com/lgbo-ustc)).
* Enable ORDER BY optimization for reading data in corresponding order from a MergeTree table in case that the table is behind a view. [#54628](https://github.com/ClickHouse/ClickHouse/pull/54628) ([Vitaly Baranov](https://github.com/vitlibar)).
* Improve JSON SQL functions by reusing `GeneratorJSONPath` and removing several shared pointers. [#54735](https://github.com/ClickHouse/ClickHouse/pull/54735) ([lgbo](https://github.com/lgbo-ustc)).
* Keeper tries to batch flush requests for better performance. [#53049](https://github.com/ClickHouse/ClickHouse/pull/53049) ([Antonio Andelic](https://github.com/antonio2368)).
* Now `clickhouse-client` processes files in parallel in case of `INFILE 'glob_expression'`. Closes [#54218](https://github.com/ClickHouse/ClickHouse/issues/54218). [#54533](https://github.com/ClickHouse/ClickHouse/pull/54533) ([Max K.](https://github.com/mkaynov)).
* Allow to use primary key for IN function where primary key column types are different from `IN` function right side column types. Example: `SELECT id FROM test_table WHERE id IN (SELECT '5')`. Closes [#48936](https://github.com/ClickHouse/ClickHouse/issues/48936). [#54544](https://github.com/ClickHouse/ClickHouse/pull/54544) ([Maksim Kita](https://github.com/kitaisreal)).
* Hash JOIN tries to shrink internal buffers consuming half of maximal available memory (set by `max_bytes_in_join`). [#54584](https://github.com/ClickHouse/ClickHouse/pull/54584) ([vdimir](https://github.com/vdimir)).
* Respect `max_block_size` for array join to avoid possible OOM. Close [#54290](https://github.com/ClickHouse/ClickHouse/issues/54290). [#54664](https://github.com/ClickHouse/ClickHouse/pull/54664) ([李扬](https://github.com/taiyang-li)).
* Reuse HTTP connections in the `s3` table function. [#54812](https://github.com/ClickHouse/ClickHouse/pull/54812) ([Michael Kolupaev](https://github.com/al13n321)).
* Replace the linear search in `MergeTreeRangeReader::Stream::ceilRowsToCompleteGranules` with a binary search. [#54869](https://github.com/ClickHouse/ClickHouse/pull/54869) ([usurai](https://github.com/usurai)).
#### Experimental Feature
* The creation of `Annoy` indexes can now be parallelized using setting `max_threads_for_annoy_index_creation`. [#54047](https://github.com/ClickHouse/ClickHouse/pull/54047) ([Robert Schulze](https://github.com/rschu1ze)).
* Parallel replicas over distributed don't read from all replicas [#54199](https://github.com/ClickHouse/ClickHouse/pull/54199) ([Igor Nikonov](https://github.com/devcrafter)).
#### Improvement
* Allow to replace long names of files of columns in `MergeTree` data parts to hashes of names. It helps to avoid `File name too long` error in some cases. [#50612](https://github.com/ClickHouse/ClickHouse/pull/50612) ([Anton Popov](https://github.com/CurtizJ)).
* Parse data in `JSON` format as `JSONEachRow` if failed to parse metadata. It will allow to read files with `.json` extension even if real format is JSONEachRow. Closes [#45740](https://github.com/ClickHouse/ClickHouse/issues/45740). [#54405](https://github.com/ClickHouse/ClickHouse/pull/54405) ([Kruglov Pavel](https://github.com/Avogar)).
* Output valid JSON/XML on excetpion during HTTP query execution. Add setting `http_write_exception_in_output_format` to enable/disable this behaviour (enabled by default). [#52853](https://github.com/ClickHouse/ClickHouse/pull/52853) ([Kruglov Pavel](https://github.com/Avogar)).
* View `information_schema.tables` now has a new field `data_length` which shows the approximate size of the data on disk. Required to run queries generated by Amazon QuickSight. [#55037](https://github.com/ClickHouse/ClickHouse/pull/55037) ([Robert Schulze](https://github.com/rschu1ze)).
* The MySQL interface gained a minimal implementation of prepared statements, just enough to allow a connection from Tableau Online to ClickHouse via the MySQL connector. [#54115](https://github.com/ClickHouse/ClickHouse/pull/54115) ([Serge Klochkov](https://github.com/slvrtrn)). Please note: the prepared statements implementation is pretty minimal, we do not support arguments binding yet, it is not required in this particular Tableau online use case. It will be implemented as a follow-up if necessary after extensive testing of Tableau Online in case we discover issues.
* Support case-insensitive and dot-all matching modes in `regexp_tree` dictionaries. [#50906](https://github.com/ClickHouse/ClickHouse/pull/50906) ([Johann Gan](https://github.com/johanngan)).
* Keeper improvement: Add a `createIfNotExists` Keeper command. [#48855](https://github.com/ClickHouse/ClickHouse/pull/48855) ([Konstantin Bogdanov](https://github.com/thevar1able)).
* More precise integer type inference, fix [#51236](https://github.com/ClickHouse/ClickHouse/issues/51236). [#53003](https://github.com/ClickHouse/ClickHouse/pull/53003) ([Chen768959](https://github.com/Chen768959)).
* Introduced resolving of charsets in the string literals for MaterializedMySQL. [#53220](https://github.com/ClickHouse/ClickHouse/pull/53220) ([Val Doroshchuk](https://github.com/valbok)).
* Fix a subtle issue with a rarely used `EmbeddedRocksDB` table engine in an extremely rare scenario: sometimes the `EmbeddedRocksDB` table engine does not close files correctly in NFS after running `DROP TABLE`. [#53502](https://github.com/ClickHouse/ClickHouse/pull/53502) ([Mingliang Pan](https://github.com/liangliangpan)).
* `RESTORE TABLE ON CLUSTER` must create replicated tables with a matching UUID on hosts. Otherwise the macro `{uuid}` in ZooKeeper path can't work correctly after RESTORE. This PR implements that. [#53765](https://github.com/ClickHouse/ClickHouse/pull/53765) ([Vitaly Baranov](https://github.com/vitlibar)).
* Added restore setting `restore_broken_parts_as_detached`: if it's true the RESTORE process won't stop on broken parts while restoring, instead all the broken parts will be copied to the `detached` folder with the prefix `broken-from-backup'. If it's false the RESTORE process will stop on the first broken part (if any). The default value is false. [#53877](https://github.com/ClickHouse/ClickHouse/pull/53877) ([Vitaly Baranov](https://github.com/vitlibar)).
* Add `elapsed_ns` field to HTTP headers X-ClickHouse-Progress and X-ClickHouse-Summary. [#54179](https://github.com/ClickHouse/ClickHouse/pull/54179) ([joelynch](https://github.com/joelynch)).
* Implementation of `reconfig` (https://github.com/ClickHouse/ClickHouse/pull/49450), `sync`, and `exists` commands for keeper-client. [#54201](https://github.com/ClickHouse/ClickHouse/pull/54201) ([pufit](https://github.com/pufit)).
* `clickhouse-local` and `clickhouse-client` now allow to specify the `--query` parameter multiple times, e.g. `./clickhouse-client --query "SELECT 1" --query "SELECT 2"`. This syntax is slightly more intuitive than `./clickhouse-client --multiquery "SELECT 1;S ELECT 2"`, a bit easier to script (e.g. `queries.push_back('--query "$q"')`) and more consistent with the behavior of existing parameter `--queries-file` (e.g. `./clickhouse client --queries-file queries1.sql --queries-file queries2.sql`). [#54249](https://github.com/ClickHouse/ClickHouse/pull/54249) ([Robert Schulze](https://github.com/rschu1ze)).
* Add sub-second precision to `formatReadableTimeDelta`. [#54250](https://github.com/ClickHouse/ClickHouse/pull/54250) ([Andrey Zvonov](https://github.com/zvonand)).
* Enable `allow_remove_stale_moving_parts` by default. [#54260](https://github.com/ClickHouse/ClickHouse/pull/54260) ([vdimir](https://github.com/vdimir)).
* Fix using count from cache and improve progress bar for reading from archives. [#54271](https://github.com/ClickHouse/ClickHouse/pull/54271) ([Kruglov Pavel](https://github.com/Avogar)).
* Add support for S3 credentials using SSO. To define a profile to be used with SSO, set `AWS_PROFILE` environment variable. [#54347](https://github.com/ClickHouse/ClickHouse/pull/54347) ([Antonio Andelic](https://github.com/antonio2368)).
* Support NULL as default for nested types Array/Tuple/Map for input formats. Closes [#51100](https://github.com/ClickHouse/ClickHouse/issues/51100). [#54351](https://github.com/ClickHouse/ClickHouse/pull/54351) ([Kruglov Pavel](https://github.com/Avogar)).
* Allow reading some unusual configuration of chunks from Arrow/Parquet formats. [#54370](https://github.com/ClickHouse/ClickHouse/pull/54370) ([Arthur Passos](https://github.com/arthurpassos)).
* Add `STD` alias to `stddevPop` function for MySQL compatibility. Closes [#54274](https://github.com/ClickHouse/ClickHouse/issues/54274). [#54382](https://github.com/ClickHouse/ClickHouse/pull/54382) ([Nikolay Degterinsky](https://github.com/evillique)).
* Add `addDate` function for compatibility with MySQL and `subDate` for consistency. Reference [#54275](https://github.com/ClickHouse/ClickHouse/issues/54275). [#54400](https://github.com/ClickHouse/ClickHouse/pull/54400) ([Nikolay Degterinsky](https://github.com/evillique)).
* Add `modification_time` into `system.detached_parts`. [#54506](https://github.com/ClickHouse/ClickHouse/pull/54506) ([Azat Khuzhin](https://github.com/azat)).
* Added a setting `splitby_max_substrings_includes_remaining_string` which controls if functions "splitBy*()" with argument "max_substring" > 0 include the remaining string (if any) in the result array (Python/Spark semantics) or not. The default behavior does not change. [#54518](https://github.com/ClickHouse/ClickHouse/pull/54518) ([Robert Schulze](https://github.com/rschu1ze)).
* Better integer types inference for `Int64`/`UInt64` fields. Continuation of [#53003](https://github.com/ClickHouse/ClickHouse/pull/53003). Now it works also for nested types like Arrays of Arrays and for functions like `map/tuple`. Issue: [#51236](https://github.com/ClickHouse/ClickHouse/issues/51236). [#54553](https://github.com/ClickHouse/ClickHouse/pull/54553) ([Kruglov Pavel](https://github.com/Avogar)).
* Added array operations for multiplying, dividing and modulo on scalar. Works in each way, for example `5 * [5, 5]` and `[5, 5] * 5` - both cases are possible. [#54608](https://github.com/ClickHouse/ClickHouse/pull/54608) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Add optional `version` argument to `rm` command in `keeper-client` to support safer deletes. [#54708](https://github.com/ClickHouse/ClickHouse/pull/54708) ([János Benjamin Antal](https://github.com/antaljanosbenjamin)).
* Disable killing the server by systemd (that may lead to data loss when using Buffer tables). [#54744](https://github.com/ClickHouse/ClickHouse/pull/54744) ([Azat Khuzhin](https://github.com/azat)).
* Added field `is_deterministic` to system table `system.functions` which indicates whether the result of a function is stable between two invocations (given exactly the same inputs) or not. [#54766](https://github.com/ClickHouse/ClickHouse/pull/54766) [#55035](https://github.com/ClickHouse/ClickHouse/pull/55035) ([Robert Schulze](https://github.com/rschu1ze)).
* Made the views in schema `information_schema` more compatible with the equivalent views in MySQL (i.e. modified and extended them) up to a point where Tableau Online is able to connect to ClickHouse. More specifically: 1. The type of field `information_schema.tables.table_type` changed from Enum8 to String. 2. Added fields `table_comment` and `table_collation` to view `information_schema.table`. 3. Added views `information_schema.key_column_usage` and `referential_constraints`. 4. Replaced uppercase aliases in `information_schema` views with concrete uppercase columns. [#54773](https://github.com/ClickHouse/ClickHouse/pull/54773) ([Serge Klochkov](https://github.com/slvrtrn)).
* The query cache now returns an error if the user tries to cache the result of a query with a non-deterministic function such as `now`, `randomString` and `dictGet`. Compared to the previous behavior (silently don't cache the result), this reduces confusion and surprise for users. [#54801](https://github.com/ClickHouse/ClickHouse/pull/54801) ([Robert Schulze](https://github.com/rschu1ze)).
* Forbid special columns like materialized/ephemeral/alias for `file`/`s3`/`url`/... storages, fix insert into ephemeral columns from files. Closes [#53477](https://github.com/ClickHouse/ClickHouse/issues/53477). [#54803](https://github.com/ClickHouse/ClickHouse/pull/54803) ([Kruglov Pavel](https://github.com/Avogar)).
* More configurable collecting metadata for backup. [#54804](https://github.com/ClickHouse/ClickHouse/pull/54804) ([Vitaly Baranov](https://github.com/vitlibar)).
* `clickhouse-local`'s log file (if enabled with --server_logs_file flag) will now prefix each line with timestamp, thread id, etc, just like `clickhouse-server`. [#54807](https://github.com/ClickHouse/ClickHouse/pull/54807) ([Michael Kolupaev](https://github.com/al13n321)).
* Field `is_obsolete` in the `system.merge_tree_settings` table - it is now 1 for obsolete merge tree settings. Previously, only the description indicated that the setting is obsolete. [#54837](https://github.com/ClickHouse/ClickHouse/pull/54837) ([Robert Schulze](https://github.com/rschu1ze)).
* Make it possible to use plural when using interval literals. `INTERVAL 2 HOURS` should be equivalent to `INTERVAL 2 HOUR`. [#54860](https://github.com/ClickHouse/ClickHouse/pull/54860) ([Jordi Villar](https://github.com/jrdi)).
* Always allow the creation of a projection with `Nullable` PK. This fixes [#54814](https://github.com/ClickHouse/ClickHouse/issues/54814). [#54895](https://github.com/ClickHouse/ClickHouse/pull/54895) ([Amos Bird](https://github.com/amosbird)).
* Retry backup's S3 operations after connection reset failure. [#54900](https://github.com/ClickHouse/ClickHouse/pull/54900) ([Vitaly Baranov](https://github.com/vitlibar)).
* Make the exception message exact in case of the maximum value of a settings is less than the minimum value. [#54925](https://github.com/ClickHouse/ClickHouse/pull/54925) ([János Benjamin Antal](https://github.com/antaljanosbenjamin)).
* `LIKE`, `match`, and other regular expressions matching functions now allow matching with patterns containing non-UTF-8 substrings by falling back to binary matching. Example: you can use `string LIKE '\xFE\xFF%'` to detect BOM. This closes [#54486](https://github.com/ClickHouse/ClickHouse/issues/54486). [#54942](https://github.com/ClickHouse/ClickHouse/pull/54942) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Added `ContextLockWaitMicroseconds` profile event. [#55029](https://github.com/ClickHouse/ClickHouse/pull/55029) ([Maksim Kita](https://github.com/kitaisreal)).
* The Keeper dynamically adjusts log levels. [#50372](https://github.com/ClickHouse/ClickHouse/pull/50372) ([helifu](https://github.com/helifu)).
* Added function `timestamp` for compatibility with MySQL. Closes [#54275](https://github.com/ClickHouse/ClickHouse/issues/54275). [#54639](https://github.com/ClickHouse/ClickHouse/pull/54639) ([Nikolay Degterinsky](https://github.com/evillique)).
#### Build/Testing/Packaging Improvement
* Bumped the compiler of official and continuous integration builds of ClickHouse from Clang 16 to 17. [#53831](https://github.com/ClickHouse/ClickHouse/pull/53831) ([Robert Schulze](https://github.com/rschu1ze)).
* Regenerated tld data for lookups (`tldLookup.generated.cpp`). [#54269](https://github.com/ClickHouse/ClickHouse/pull/54269) ([Bharat Nallan](https://github.com/bharatnc)).
* Remove the redundant `clickhouse-keeper-client` symlink. [#54587](https://github.com/ClickHouse/ClickHouse/pull/54587) ([Tomas Barton](https://github.com/deric)).
* Use `/usr/bin/env` to resolve bash - now it supports Nix OS. [#54603](https://github.com/ClickHouse/ClickHouse/pull/54603) ([Fionera](https://github.com/fionera)).
* CMake added `PROFILE_CPU` option needed to perform `perf record` without using a DWARF call graph. [#54917](https://github.com/ClickHouse/ClickHouse/pull/54917) ([Maksim Kita](https://github.com/kitaisreal)).
* If the linker is different than LLD, stop with a fatal error. [#55036](https://github.com/ClickHouse/ClickHouse/pull/55036) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Replaced the library to handle (encode/decode) base64 values from Turbo-Base64 to aklomp-base64. Both are SIMD-accelerated on x86 and ARM but 1. the license of the latter (BSD-2) is more favorable for ClickHouse, Turbo64 switched in the meantime to GPL-3, 2. with more GitHub stars, aklomp-base64 seems more future-proof, 3. aklomp-base64 has a slightly nicer API (which is arguably subjective), and 4. aklomp-base64 does not require us to hack around bugs (like non-threadsafe initialization). Note: aklomp-base64 rejects unpadded base64 values whereas Turbo-Base64 decodes them on a best-effort basis. RFC-4648 leaves it open whether padding is mandatory or not, but depending on the context this may be a behavioral change to be aware of. [#54119](https://github.com/ClickHouse/ClickHouse/pull/54119) ([Mikhail Koviazin](https://github.com/mkmkme)).
#### Bug Fix (user-visible misbehavior in an official stable release)
* Fix REPLACE/MOVE PARTITION with zero-copy replication (note: "zero-copy replication" is an experimental feature) [#54193](https://github.com/ClickHouse/ClickHouse/pull/54193) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Fix zero copy locks with hardlinks (note: "zero-copy replication" is an experimental feature) [#54859](https://github.com/ClickHouse/ClickHouse/pull/54859) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Fix zero copy garbage (note: "zero-copy replication" is an experimental feature) [#54550](https://github.com/ClickHouse/ClickHouse/pull/54550) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Pass HTTP retry timeout as milliseconds (it was incorrect before). [#54438](https://github.com/ClickHouse/ClickHouse/pull/54438) ([Duc Canh Le](https://github.com/canhld94)).
* Fix misleading error message in OUTFILE with `CapnProto`/`Protobuf` [#52870](https://github.com/ClickHouse/ClickHouse/pull/52870) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix summary reporting with parallel replicas with LIMIT [#53050](https://github.com/ClickHouse/ClickHouse/pull/53050) ([Raúl Marín](https://github.com/Algunenano)).
* Fix throttling of BACKUPs from/to S3 (in case native copy was not used) and in some other places as well [#53336](https://github.com/ClickHouse/ClickHouse/pull/53336) ([Azat Khuzhin](https://github.com/azat)).
* Fix IO throttling during copying whole directories [#53338](https://github.com/ClickHouse/ClickHouse/pull/53338) ([Azat Khuzhin](https://github.com/azat)).
* Fix: moved to prewhere condition actions can lose column [#53492](https://github.com/ClickHouse/ClickHouse/pull/53492) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Fixed internal error when replacing with byte-equal parts [#53735](https://github.com/ClickHouse/ClickHouse/pull/53735) ([Pedro Riera](https://github.com/priera)).
* Fix: require columns participating in interpolate expression [#53754](https://github.com/ClickHouse/ClickHouse/pull/53754) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Fix cluster discovery initialization + setting up fail points in config [#54113](https://github.com/ClickHouse/ClickHouse/pull/54113) ([vdimir](https://github.com/vdimir)).
* Fix issues in `accurateCastOrNull` [#54136](https://github.com/ClickHouse/ClickHouse/pull/54136) ([Salvatore Mesoraca](https://github.com/aiven-sal)).
* Fix nullable primary key with the FINAL modifier [#54164](https://github.com/ClickHouse/ClickHouse/pull/54164) ([Amos Bird](https://github.com/amosbird)).
* Fixed error that prevented insertion in replicated materialized view of new data in presence of duplicated data. [#54184](https://github.com/ClickHouse/ClickHouse/pull/54184) ([Pedro Riera](https://github.com/priera)).
* Fix: allow `IPv6` for bloom filter [#54200](https://github.com/ClickHouse/ClickHouse/pull/54200) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* fix possible type mismatch with `IPv4` [#54212](https://github.com/ClickHouse/ClickHouse/pull/54212) ([Bharat Nallan](https://github.com/bharatnc)).
* Fix `system.data_skipping_indices` for recreated indices [#54225](https://github.com/ClickHouse/ClickHouse/pull/54225) ([Artur Malchanau](https://github.com/Hexta)).
* fix name clash for multiple join rewriter v2 [#54240](https://github.com/ClickHouse/ClickHouse/pull/54240) ([Tao Wang](https://github.com/wangtZJU)).
* Fix unexpected errors in `system.errors` after join [#54306](https://github.com/ClickHouse/ClickHouse/pull/54306) ([vdimir](https://github.com/vdimir)).
* Fix `isZeroOrNull(NULL)` [#54316](https://github.com/ClickHouse/ClickHouse/pull/54316) ([flynn](https://github.com/ucasfl)).
* Fix: parallel replicas over distributed with `prefer_localhost_replica` = 1 [#54334](https://github.com/ClickHouse/ClickHouse/pull/54334) ([Igor Nikonov](https://github.com/devcrafter)).
* Fix logical error in vertical merge + replacing merge tree + optimize cleanup [#54368](https://github.com/ClickHouse/ClickHouse/pull/54368) ([alesapin](https://github.com/alesapin)).
* Fix possible error `URI contains invalid characters` in the `s3` table function [#54373](https://github.com/ClickHouse/ClickHouse/pull/54373) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix segfault in AST optimization of `arrayExists` function [#54379](https://github.com/ClickHouse/ClickHouse/pull/54379) ([Nikolay Degterinsky](https://github.com/evillique)).
* Check for overflow before addition in `analysisOfVariance` function [#54385](https://github.com/ClickHouse/ClickHouse/pull/54385) ([Antonio Andelic](https://github.com/antonio2368)).
* Reproduce and fix the bug in removeSharedRecursive [#54430](https://github.com/ClickHouse/ClickHouse/pull/54430) ([Sema Checherinda](https://github.com/CheSema)).
* Fix possible incorrect result with SimpleAggregateFunction in PREWHERE and FINAL [#54436](https://github.com/ClickHouse/ClickHouse/pull/54436) ([Azat Khuzhin](https://github.com/azat)).
* Fix filtering parts with indexHint for non analyzer [#54449](https://github.com/ClickHouse/ClickHouse/pull/54449) ([Azat Khuzhin](https://github.com/azat)).
* Fix aggregate projections with normalized states [#54480](https://github.com/ClickHouse/ClickHouse/pull/54480) ([Amos Bird](https://github.com/amosbird)).
* `clickhouse-local`: something for multiquery parameter [#54498](https://github.com/ClickHouse/ClickHouse/pull/54498) ([CuiShuoGuo](https://github.com/bakam412)).
* `clickhouse-local` supports `--database` command line argument [#54503](https://github.com/ClickHouse/ClickHouse/pull/54503) ([vdimir](https://github.com/vdimir)).
* Fix possible parsing error in `-WithNames` formats with disabled `input_format_with_names_use_header` [#54513](https://github.com/ClickHouse/ClickHouse/pull/54513) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix rare case of CHECKSUM_DOESNT_MATCH error [#54549](https://github.com/ClickHouse/ClickHouse/pull/54549) ([alesapin](https://github.com/alesapin)).
* Fix sorting of UNION ALL of already sorted results [#54564](https://github.com/ClickHouse/ClickHouse/pull/54564) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix snapshot install in Keeper [#54572](https://github.com/ClickHouse/ClickHouse/pull/54572) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix race in `ColumnUnique` [#54575](https://github.com/ClickHouse/ClickHouse/pull/54575) ([Nikita Taranov](https://github.com/nickitat)).
* Annoy/Usearch index: Fix LOGICAL_ERROR during build-up with default values [#54600](https://github.com/ClickHouse/ClickHouse/pull/54600) ([Robert Schulze](https://github.com/rschu1ze)).
* Fix serialization of `ColumnDecimal` [#54601](https://github.com/ClickHouse/ClickHouse/pull/54601) ([Nikita Taranov](https://github.com/nickitat)).
* Fix schema inference for *Cluster functions for column names with spaces [#54635](https://github.com/ClickHouse/ClickHouse/pull/54635) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix using structure from insertion tables in case of defaults and explicit insert columns [#54655](https://github.com/ClickHouse/ClickHouse/pull/54655) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix: avoid using regex match, possibly containing alternation, as a key condition. [#54696](https://github.com/ClickHouse/ClickHouse/pull/54696) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Fix ReplacingMergeTree with vertical merge and cleanup [#54706](https://github.com/ClickHouse/ClickHouse/pull/54706) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Fix virtual columns having incorrect values after ORDER BY [#54811](https://github.com/ClickHouse/ClickHouse/pull/54811) ([Michael Kolupaev](https://github.com/al13n321)).
* Fix filtering parts with indexHint for non analyzer [#54825](https://github.com/ClickHouse/ClickHouse/pull/54825) [#54449](https://github.com/ClickHouse/ClickHouse/pull/54449) ([Azat Khuzhin](https://github.com/azat)).
* Fix Keeper segfault during shutdown [#54841](https://github.com/ClickHouse/ClickHouse/pull/54841) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix `Invalid number of rows in Chunk` in MaterializedPostgreSQL [#54844](https://github.com/ClickHouse/ClickHouse/pull/54844) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Move obsolete format settings to separate section [#54855](https://github.com/ClickHouse/ClickHouse/pull/54855) ([Kruglov Pavel](https://github.com/Avogar)).
* Rebuild `minmax_count_projection` when partition key gets modified [#54943](https://github.com/ClickHouse/ClickHouse/pull/54943) ([Amos Bird](https://github.com/amosbird)).
* Fix bad cast to `ColumnVector<Int128>` in function `if` [#55019](https://github.com/ClickHouse/ClickHouse/pull/55019) ([Kruglov Pavel](https://github.com/Avogar)).
* Prevent attaching parts from tables with different projections or indices [#55062](https://github.com/ClickHouse/ClickHouse/pull/55062) ([János Benjamin Antal](https://github.com/antaljanosbenjamin)).
* Store NULL in scalar result map for empty subquery result [#52240](https://github.com/ClickHouse/ClickHouse/pull/52240) ([vdimir](https://github.com/vdimir)).
* Fix `FINAL` produces invalid read ranges in a rare case [#54934](https://github.com/ClickHouse/ClickHouse/pull/54934) ([Nikita Taranov](https://github.com/nickitat)).
* Fix: insert quorum w/o keeper retries [#55026](https://github.com/ClickHouse/ClickHouse/pull/55026) ([Igor Nikonov](https://github.com/devcrafter)).
* Fix simple state with nullable [#55030](https://github.com/ClickHouse/ClickHouse/pull/55030) ([Pedro Riera](https://github.com/priera)).
### <a id="238"></a> ClickHouse release 23.8 LTS, 2023-08-31
#### Backward Incompatible Change
* If a dynamic disk contains a name, it should be specified as `disk = disk(name = 'disk_name'`, ...) in disk function arguments. In previous version it could be specified as `disk = disk_<disk_name>(...)`, which is no longer supported. [#52820](https://github.com/ClickHouse/ClickHouse/pull/52820) ([Kseniia Sumarokova](https://github.com/kssenii)).
* `clickhouse-benchmark` will establish connections in parallel when invoked with `--concurrency` more than one. Previously it was unusable if you ran it with 1000 concurrent connections from Europe to the US. Correct calculation of QPS for connections with high latency. Backward incompatible change: the option for JSON output of `clickhouse-benchmark` is removed. If you've used this option, you can also extract data from the `system.query_log` in JSON format as a workaround. [#53293](https://github.com/ClickHouse/ClickHouse/pull/53293) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* The `microseconds` column is removed from the `system.text_log`, and the `milliseconds` column is removed from the `system.metric_log`, because they are redundant in the presence of the `event_time_microseconds` column. [#53601](https://github.com/ClickHouse/ClickHouse/pull/53601) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Deprecate the metadata cache feature. It is experimental and we have never used it. The feature is dangerous: [#51182](https://github.com/ClickHouse/ClickHouse/issues/51182). Remove the `system.merge_tree_metadata_cache` system table. The metadata cache is still available in this version but will be removed soon. This closes [#39197](https://github.com/ClickHouse/ClickHouse/issues/39197). [#51303](https://github.com/ClickHouse/ClickHouse/pull/51303) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Disable support for 3DES in TLS connections. [#52893](https://github.com/ClickHouse/ClickHouse/pull/52893) ([Kenji Noguchi](https://github.com/knoguchi)).
#### New Feature
* Direct import from zip/7z/tar archives. Example: `file('*.zip :: *.csv')`. [#50321](https://github.com/ClickHouse/ClickHouse/pull/50321) ([nikitakeba](https://github.com/nikitakeba)).
* Add column `ptr` to `system.trace_log` for `trace_type = 'MemorySample'`. This column contains an address of allocation. Added function `flameGraph` which can build flamegraph containing allocated and not released memory. Reworking of [#38391](https://github.com/ClickHouse/ClickHouse/issues/38391). [#45322](https://github.com/ClickHouse/ClickHouse/pull/45322) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Added table function `azureBlobStorageCluster`. The supported set of features is very similar to table function `s3Cluster`. [#50795](https://github.com/ClickHouse/ClickHouse/pull/50795) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Allow using `cluster`, `clusterAllReplicas`, `remote`, and `remoteSecure` without table name in issue [#50808](https://github.com/ClickHouse/ClickHouse/issues/50808). [#50848](https://github.com/ClickHouse/ClickHouse/pull/50848) ([Yangkuan Liu](https://github.com/LiuYangkuan)).
* A system table to monitor Kafka consumers. [#50999](https://github.com/ClickHouse/ClickHouse/pull/50999) ([Ilya Golshtein](https://github.com/ilejn)).
* Added `max_sessions_for_user` setting. [#51724](https://github.com/ClickHouse/ClickHouse/pull/51724) ([Alexey Gerasimchuck](https://github.com/Demilivor)).
* New functions `toUTCTimestamp/fromUTCTimestamp` to act same as spark's `to_utc_timestamp/from_utc_timestamp`. [#52117](https://github.com/ClickHouse/ClickHouse/pull/52117) ([KevinyhZou](https://github.com/KevinyhZou)).
* Add new functions `structureToCapnProtoSchema`/`structureToProtobufSchema` that convert ClickHouse table structure to CapnProto/Protobuf format schema. Allow to input/output data in CapnProto/Protobuf format without external format schema using autogenerated schema from table structure (controlled by settings `format_capn_proto_use_autogenerated_schema`/`format_protobuf_use_autogenerated_schema`). Allow to export autogenerated schema while input/output using setting `output_format_schema`. [#52278](https://github.com/ClickHouse/ClickHouse/pull/52278) ([Kruglov Pavel](https://github.com/Avogar)).
* A new field `query_cache_usage` in `system.query_log` now shows if and how the query cache was used. [#52384](https://github.com/ClickHouse/ClickHouse/pull/52384) ([Robert Schulze](https://github.com/rschu1ze)).
* Add new function `startsWithUTF8` and `endsWithUTF8`. [#52555](https://github.com/ClickHouse/ClickHouse/pull/52555) ([李扬](https://github.com/taiyang-li)).
* Allow variable number of columns in TSV/CustomSeparated/JSONCompactEachRow, make schema inference work with variable number of columns. Add settings `input_format_tsv_allow_variable_number_of_columns`, `input_format_custom_allow_variable_number_of_columns`, `input_format_json_compact_allow_variable_number_of_columns`. [#52692](https://github.com/ClickHouse/ClickHouse/pull/52692) ([Kruglov Pavel](https://github.com/Avogar)).
* Added `SYSTEM STOP/START PULLING REPLICATION LOG` queries (for testing `ReplicatedMergeTree`). [#52881](https://github.com/ClickHouse/ClickHouse/pull/52881) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Allow to execute constant non-deterministic functions in mutations on initiator. [#53129](https://github.com/ClickHouse/ClickHouse/pull/53129) ([Anton Popov](https://github.com/CurtizJ)).
* Add input format `One` that doesn't read any data and always returns single row with column `dummy` with type `UInt8` and value `0` like `system.one`. It can be used together with `_file/_path` virtual columns to list files in file/s3/url/hdfs/etc table functions without reading any data. [#53209](https://github.com/ClickHouse/ClickHouse/pull/53209) ([Kruglov Pavel](https://github.com/Avogar)).
* Add `tupleConcat` function. Closes [#52759](https://github.com/ClickHouse/ClickHouse/issues/52759). [#53239](https://github.com/ClickHouse/ClickHouse/pull/53239) ([Nikolay Degterinsky](https://github.com/evillique)).
* Support `TRUNCATE DATABASE` operation. [#53261](https://github.com/ClickHouse/ClickHouse/pull/53261) ([Bharat Nallan](https://github.com/bharatnc)).
* Add `max_threads_for_indexes` setting to limit number of threads used for primary key processing. [#53313](https://github.com/ClickHouse/ClickHouse/pull/53313) ([jorisgio](https://github.com/jorisgio)).
* Re-add SipHash keyed functions. [#53525](https://github.com/ClickHouse/ClickHouse/pull/53525) ([Salvatore Mesoraca](https://github.com/aiven-sal)).
* ([#52755](https://github.com/ClickHouse/ClickHouse/issues/52755) , [#52895](https://github.com/ClickHouse/ClickHouse/issues/52895)) Added functions `arrayRotateLeft`, `arrayRotateRight`, `arrayShiftLeft`, `arrayShiftRight`. [#53557](https://github.com/ClickHouse/ClickHouse/pull/53557) ([Mikhail Koviazin](https://github.com/mkmkme)).
* Add column `name` to `system.clusters` as an alias to cluster. [#53605](https://github.com/ClickHouse/ClickHouse/pull/53605) ([irenjj](https://github.com/irenjj)).
* The advanced dashboard now allows mass editing (save/load). [#53608](https://github.com/ClickHouse/ClickHouse/pull/53608) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* The advanced dashboard now has an option to maximize charts and move them around. [#53622](https://github.com/ClickHouse/ClickHouse/pull/53622) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Added support for adding and subtracting arrays: `[5,2] + [1,7]`. Division and multiplication were not implemented due to confusion between pointwise multiplication and the scalar product of arguments. Closes [#49939](https://github.com/ClickHouse/ClickHouse/issues/49939). [#52625](https://github.com/ClickHouse/ClickHouse/pull/52625) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Add support for string literals as table names. Closes [#52178](https://github.com/ClickHouse/ClickHouse/issues/52178). [#52635](https://github.com/ClickHouse/ClickHouse/pull/52635) ([hendrik-m](https://github.com/hendrik-m)).
#### Experimental Feature
* Add new table engine `S3Queue` for streaming data import from s3. Closes [#37012](https://github.com/ClickHouse/ClickHouse/issues/37012). [#49086](https://github.com/ClickHouse/ClickHouse/pull/49086) ([s-kat](https://github.com/s-kat)). It is not ready to use. Do not use it.
* Enable parallel reading from replicas over distributed table. Related to [#49708](https://github.com/ClickHouse/ClickHouse/issues/49708). [#53005](https://github.com/ClickHouse/ClickHouse/pull/53005) ([Igor Nikonov](https://github.com/devcrafter)).
* Add experimental support for HNSW as approximate neighbor search method. [#53447](https://github.com/ClickHouse/ClickHouse/pull/53447) ([Davit Vardanyan](https://github.com/davvard)). This is currently intended for those who continue working on the implementation. Do not use it.
#### Performance Improvement
* Parquet filter pushdown. I.e. when reading Parquet files, row groups (chunks of the file) are skipped based on the WHERE condition and the min/max values in each column. In particular, if the file is roughly sorted by some column, queries that filter by a short range of that column will be much faster. [#52951](https://github.com/ClickHouse/ClickHouse/pull/52951) ([Michael Kolupaev](https://github.com/al13n321)).
* Optimize reading small row groups by batching them together in Parquet. Closes [#53069](https://github.com/ClickHouse/ClickHouse/issues/53069). [#53281](https://github.com/ClickHouse/ClickHouse/pull/53281) ([Kruglov Pavel](https://github.com/Avogar)).
* Optimize count from files in most input formats. Closes [#44334](https://github.com/ClickHouse/ClickHouse/issues/44334). [#53637](https://github.com/ClickHouse/ClickHouse/pull/53637) ([Kruglov Pavel](https://github.com/Avogar)).
* Use filter by file/path before reading in `url`/`file`/`hdfs` table functions. [#53529](https://github.com/ClickHouse/ClickHouse/pull/53529) ([Kruglov Pavel](https://github.com/Avogar)).
* Enable JIT compilation for AArch64, PowerPC, SystemZ, RISC-V. [#38217](https://github.com/ClickHouse/ClickHouse/pull/38217) ([Maksim Kita](https://github.com/kitaisreal)).
* Add setting `rewrite_count_distinct_if_with_count_distinct_implementation` to rewrite `countDistinctIf` with `count_distinct_implementation`. Closes [#30642](https://github.com/ClickHouse/ClickHouse/issues/30642). [#46051](https://github.com/ClickHouse/ClickHouse/pull/46051) ([flynn](https://github.com/ucasfl)).
* Speed up merging of states of `uniq` and `uniqExact` aggregate functions by parallelizing conversion before merge. [#50748](https://github.com/ClickHouse/ClickHouse/pull/50748) ([Jiebin Sun](https://github.com/jiebinn)).
* Optimize aggregation performance of nullable string key when using a large number of variable length keys. [#51399](https://github.com/ClickHouse/ClickHouse/pull/51399) ([LiuNeng](https://github.com/liuneng1994)).
* Add a pass in Analyzer for time filter optimization with preimage. The performance experiments of SSB on the ICX device (Intel Xeon Platinum 8380 CPU, 80 cores, 160 threads) show that this change could bring an improvement of 8.5% to the geomean QPS when the experimental analyzer is enabled. [#52091](https://github.com/ClickHouse/ClickHouse/pull/52091) ([Zhiguo Zhou](https://github.com/ZhiguoZh)).
* Optimize the merge if all hash sets are single-level in the `uniqExact` (COUNT DISTINCT) function. [#52973](https://github.com/ClickHouse/ClickHouse/pull/52973) ([Jiebin Sun](https://github.com/jiebinn)).
* `Join` table engine: do not clone hash join data structure with all columns. [#53046](https://github.com/ClickHouse/ClickHouse/pull/53046) ([Duc Canh Le](https://github.com/canhld94)).
* Implement native `ORC` input format without the "apache arrow" library to improve performance. [#53324](https://github.com/ClickHouse/ClickHouse/pull/53324) ([李扬](https://github.com/taiyang-li)).
* The dashboard will tell the server to compress the data, which is useful for large time frames over slow internet connections. For example, one chart with 86400 points can be 1.5 MB uncompressed and 60 KB compressed with `br`. [#53569](https://github.com/ClickHouse/ClickHouse/pull/53569) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Better utilization of thread pool for BACKUPs and RESTOREs. [#53649](https://github.com/ClickHouse/ClickHouse/pull/53649) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Load filesystem cache metadata on startup in parallel. Configured by `load_metadata_threads` (default: 1) cache config setting. Related to [#52037](https://github.com/ClickHouse/ClickHouse/issues/52037). [#52943](https://github.com/ClickHouse/ClickHouse/pull/52943) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Improve `move_primary_key_columns_to_end_of_prewhere`. [#53337](https://github.com/ClickHouse/ClickHouse/pull/53337) ([Han Fei](https://github.com/hanfei1991)).
* This optimizes the interaction with ClickHouse Keeper. Previously the caller could register the same watch callback multiple times. In that case each entry was consuming memory and the same callback was called multiple times which didn't make much sense. In order to avoid this the caller could have some logic to not add the same watch multiple times. With this change this deduplication is done internally if the watch callback is passed via shared_ptr. [#53452](https://github.com/ClickHouse/ClickHouse/pull/53452) ([Alexander Gololobov](https://github.com/davenger)).
* Cache number of rows in files for count in file/s3/url/hdfs/azure functions. The cache can be enabled/disabled by setting `use_cache_for_count_from_files` (enabled by default). Continuation of https://github.com/ClickHouse/ClickHouse/pull/53637. [#53692](https://github.com/ClickHouse/ClickHouse/pull/53692) ([Kruglov Pavel](https://github.com/Avogar)).
* More careful thread management will improve the speed of the S3 table function over a large number of files by more than ~25%. [#53668](https://github.com/ClickHouse/ClickHouse/pull/53668) ([pufit](https://github.com/pufit)).
#### Improvement
* Add `stderr_reaction` configuration/setting to control the reaction (none, log or throw) when external command stderr has data. This helps make debugging external command easier. [#43210](https://github.com/ClickHouse/ClickHouse/pull/43210) ([Amos Bird](https://github.com/amosbird)).
* Add `partition` column to the `system part_log` and merge table. [#48990](https://github.com/ClickHouse/ClickHouse/pull/48990) ([Jianfei Hu](https://github.com/incfly)).
* The sizes of the (index) uncompressed/mark, mmap and query caches can now be configured dynamically at runtime (without server restart). [#51446](https://github.com/ClickHouse/ClickHouse/pull/51446) ([Robert Schulze](https://github.com/rschu1ze)).
* If a dictionary is created with a complex key, automatically choose the "complex key" layout variant. [#49587](https://github.com/ClickHouse/ClickHouse/pull/49587) ([xiebin](https://github.com/xbthink)).
* Add setting `use_concurrency_control` for better testing of the new concurrency control feature. [#49618](https://github.com/ClickHouse/ClickHouse/pull/49618) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Added suggestions for mistyped names for databases and tables. [#49801](https://github.com/ClickHouse/ClickHouse/pull/49801) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* While read small files from HDFS by Gluten, we found that it will cost more times when compare to directly query by Spark. And we did something with that. [#50063](https://github.com/ClickHouse/ClickHouse/pull/50063) ([KevinyhZou](https://github.com/KevinyhZou)).
* There were too many worthless error logs after session expiration, which we didn't like. [#50171](https://github.com/ClickHouse/ClickHouse/pull/50171) ([helifu](https://github.com/helifu)).
* Introduce fallback ZooKeeper sessions which are time-bound. Fixed `index` column in system.zookeeper_connection for DNS addresses. [#50424](https://github.com/ClickHouse/ClickHouse/pull/50424) ([Anton Kozlov](https://github.com/tonickkozlov)).
* Add ability to log when max_partitions_per_insert_block is reached. [#50948](https://github.com/ClickHouse/ClickHouse/pull/50948) ([Sean Haynes](https://github.com/seandhaynes)).
* Added a bunch of custom commands to clickhouse-keeper-client (mostly to make ClickHouse debugging easier). [#51117](https://github.com/ClickHouse/ClickHouse/pull/51117) ([pufit](https://github.com/pufit)).
* Updated check for connection string in `azureBlobStorage` table function as connection string with "sas" does not always begin with the default endpoint and updated connection URL to include "sas" token after adding Azure's container to URL. [#51141](https://github.com/ClickHouse/ClickHouse/pull/51141) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Fix description for filtering sets in the `full_sorting_merge` JOIN algorithm. [#51329](https://github.com/ClickHouse/ClickHouse/pull/51329) ([Tanay Tummalapalli](https://github.com/ttanay)).
* Fixed memory consumption in `Aggregator` when `max_block_size` is huge. [#51566](https://github.com/ClickHouse/ClickHouse/pull/51566) ([Nikita Taranov](https://github.com/nickitat)).
* Add `SYSTEM SYNC FILESYSTEM CACHE` command. It will compare in-memory state of filesystem cache with what it has on disk and fix in-memory state if needed. This is only needed if you are making manual interventions in on-disk data, which is highly discouraged. [#51622](https://github.com/ClickHouse/ClickHouse/pull/51622) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Attempt to create a generic proxy resolver for CH while keeping backwards compatibility with existing S3 storage conf proxy resolver. [#51749](https://github.com/ClickHouse/ClickHouse/pull/51749) ([Arthur Passos](https://github.com/arthurpassos)).
* Support reading tuple subcolumns from file/s3/hdfs/url/azureBlobStorage table functions. [#51806](https://github.com/ClickHouse/ClickHouse/pull/51806) ([Kruglov Pavel](https://github.com/Avogar)).
* Function `arrayIntersect` now returns the values in the order, corresponding to the first argument. Closes [#27622](https://github.com/ClickHouse/ClickHouse/issues/27622). [#51850](https://github.com/ClickHouse/ClickHouse/pull/51850) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Add new queries, which allow to create/drop of access entities in specified access storage or move access entities from one access storage to another. [#51912](https://github.com/ClickHouse/ClickHouse/pull/51912) ([pufit](https://github.com/pufit)).
* Make `ALTER TABLE FREEZE` queries not replicated in the Replicated database engine. [#52064](https://github.com/ClickHouse/ClickHouse/pull/52064) ([Mike Kot](https://github.com/myrrc)).
* Added possibility to flush system tables on unexpected shutdown. [#52174](https://github.com/ClickHouse/ClickHouse/pull/52174) ([Alexey Gerasimchuck](https://github.com/Demilivor)).
* Fix the case when `s3` table function refused to work with pre-signed URLs. close [#50846](https://github.com/ClickHouse/ClickHouse/issues/50846). [#52310](https://github.com/ClickHouse/ClickHouse/pull/52310) ([chen](https://github.com/xiedeyantu)).
* Add column `name` as an alias to `event` and `metric` in the `system.events` and `system.metrics` tables. Closes [#51257](https://github.com/ClickHouse/ClickHouse/issues/51257). [#52315](https://github.com/ClickHouse/ClickHouse/pull/52315) ([chen](https://github.com/xiedeyantu)).
* Added support of syntax `CREATE UNIQUE INDEX` in parser as a no-op for better SQL compatibility. `UNIQUE` index is not supported. Set `create_index_ignore_unique = 1` to ignore UNIQUE keyword in queries. [#52320](https://github.com/ClickHouse/ClickHouse/pull/52320) ([Ilya Yatsishin](https://github.com/qoega)).
* Add support of predefined macro (`{database}` and `{table}`) in some Kafka engine settings: topic, consumer, client_id, etc. [#52386](https://github.com/ClickHouse/ClickHouse/pull/52386) ([Yury Bogomolov](https://github.com/ybogo)).
* Disable updating the filesystem cache during backup/restore. Filesystem cache must not be updated during backup/restore, it seems it just slows down the process without any profit (because the BACKUP command can read a lot of data and it's no use to put all the data to the filesystem cache and immediately evict it). [#52402](https://github.com/ClickHouse/ClickHouse/pull/52402) ([Vitaly Baranov](https://github.com/vitlibar)).
* The configuration of S3 endpoint allow using it from the root, and append '/' automatically if needed. [#47809](https://github.com/ClickHouse/ClickHouse/issues/47809). [#52600](https://github.com/ClickHouse/ClickHouse/pull/52600) ([xiaolei565](https://github.com/xiaolei565)).
* For clickhouse-local allow positional options and populate global UDF settings (user_scripts_path and user_defined_executable_functions_config). [#52643](https://github.com/ClickHouse/ClickHouse/pull/52643) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* `system.asynchronous_metrics` now includes metrics "QueryCacheEntries" and "QueryCacheBytes" to inspect the query cache. [#52650](https://github.com/ClickHouse/ClickHouse/pull/52650) ([Robert Schulze](https://github.com/rschu1ze)).
* Added possibility to use `s3_storage_class` parameter in the `SETTINGS` clause of the `BACKUP` statement for backups to S3. [#52658](https://github.com/ClickHouse/ClickHouse/pull/52658) ([Roman Vasin](https://github.com/rvasin)).
* Add utility `print-backup-info.py` which parses a backup metadata file and prints information about the backup. [#52690](https://github.com/ClickHouse/ClickHouse/pull/52690) ([Vitaly Baranov](https://github.com/vitlibar)).
* Closes [#49510](https://github.com/ClickHouse/ClickHouse/issues/49510). Currently we have database and table names case-sensitive, but BI tools query `information_schema` sometimes in lowercase, sometimes in uppercase. For this reason we have `information_schema` database, containing lowercase tables, such as `information_schema.tables` and `INFORMATION_SCHEMA` database, containing uppercase tables, such as `INFORMATION_SCHEMA.TABLES`. But some tools are querying `INFORMATION_SCHEMA.tables` and `information_schema.TABLES`. The proposed solution is to duplicate both lowercase and uppercase tables in lowercase and uppercase `information_schema` database. [#52695](https://github.com/ClickHouse/ClickHouse/pull/52695) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Query`CHECK TABLE` has better performance and usability (sends progress updates, cancellable). [#52745](https://github.com/ClickHouse/ClickHouse/pull/52745) ([vdimir](https://github.com/vdimir)).
* Add support for `modulo`, `intDiv`, `intDivOrZero` for tuples by distributing them across tuple's elements. [#52758](https://github.com/ClickHouse/ClickHouse/pull/52758) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Search for default `yaml` and `yml` configs in clickhouse-client after `xml`. [#52767](https://github.com/ClickHouse/ClickHouse/pull/52767) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* When merging into non-'clickhouse' rooted configuration, configs with different root node name just bypassed without exception. [#52770](https://github.com/ClickHouse/ClickHouse/pull/52770) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Now it's possible to specify min (`memory_profiler_sample_min_allocation_size`) and max (`memory_profiler_sample_max_allocation_size`) size for allocations to be tracked with sampling memory profiler. [#52779](https://github.com/ClickHouse/ClickHouse/pull/52779) ([alesapin](https://github.com/alesapin)).
* Add `precise_float_parsing` setting to switch float parsing methods (fast/precise). [#52791](https://github.com/ClickHouse/ClickHouse/pull/52791) ([Andrey Zvonov](https://github.com/zvonand)).
* Use the same default paths for `clickhouse-keeper` (symlink) as for `clickhouse-keeper` (executable). [#52861](https://github.com/ClickHouse/ClickHouse/pull/52861) ([Vitaly Baranov](https://github.com/vitlibar)).
* Improve error message for table function `remote`. Closes [#40220](https://github.com/ClickHouse/ClickHouse/issues/40220). [#52959](https://github.com/ClickHouse/ClickHouse/pull/52959) ([jiyoungyoooo](https://github.com/jiyoungyoooo)).
* Added the possibility to specify custom storage policy in the `SETTINGS` clause of `RESTORE` queries. [#52970](https://github.com/ClickHouse/ClickHouse/pull/52970) ([Victor Krasnov](https://github.com/sirvickr)).
* Add the ability to throttle the S3 requests on backup operations (`BACKUP` and `RESTORE` commands now honor `s3_max_[get/put]_[rps/burst]`). [#52974](https://github.com/ClickHouse/ClickHouse/pull/52974) ([Daniel Pozo Escalona](https://github.com/danipozo)).
* Add settings to ignore ON CLUSTER clause in queries for management of replicated user-defined functions or access control entities with replicated storage. [#52975](https://github.com/ClickHouse/ClickHouse/pull/52975) ([Aleksei Filatov](https://github.com/aalexfvk)).
* EXPLAIN actions for JOIN step. [#53006](https://github.com/ClickHouse/ClickHouse/pull/53006) ([Maksim Kita](https://github.com/kitaisreal)).
* Make `hasTokenOrNull` and `hasTokenCaseInsensitiveOrNull` return null for empty needles. [#53059](https://github.com/ClickHouse/ClickHouse/pull/53059) ([ltrk2](https://github.com/ltrk2)).
* Allow to restrict allowed paths for filesystem caches. Mainly useful for dynamic disks. If in server config `filesystem_caches_path` is specified, all filesystem caches' paths will be restricted to this directory. E.g. if the `path` in cache config is relative - it will be put in `filesystem_caches_path`; if `path` in cache config is absolute, it will be required to lie inside `filesystem_caches_path`. If `filesystem_caches_path` is not specified in config, then behaviour will be the same as in earlier versions. [#53124](https://github.com/ClickHouse/ClickHouse/pull/53124) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Added a bunch of custom commands (mostly to make ClickHouse debugging easier). [#53127](https://github.com/ClickHouse/ClickHouse/pull/53127) ([pufit](https://github.com/pufit)).
* Add diagnostic info about file name during schema inference - it helps when you process multiple files with globs. [#53135](https://github.com/ClickHouse/ClickHouse/pull/53135) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Client will load suggestions using the main connection if the second connection is not allowed to create a session. [#53177](https://github.com/ClickHouse/ClickHouse/pull/53177) ([Alexey Gerasimchuck](https://github.com/Demilivor)).
* Add EXCEPT clause to `SYSTEM STOP/START LISTEN QUERIES [ALL/DEFAULT/CUSTOM]` query, for example `SYSTEM STOP LISTEN QUERIES ALL EXCEPT TCP, HTTP`. [#53280](https://github.com/ClickHouse/ClickHouse/pull/53280) ([Nikolay Degterinsky](https://github.com/evillique)).
* Change the default of `max_concurrent_queries` from 100 to 1000. It's ok to have many concurrent queries if they are not heavy, and mostly waiting for the network. Note: don't confuse concurrent queries and QPS: for example, ClickHouse server can do tens of thousands of QPS with less than 100 concurrent queries. [#53285](https://github.com/ClickHouse/ClickHouse/pull/53285) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Limit number of concurrent background partition optimize merges. [#53405](https://github.com/ClickHouse/ClickHouse/pull/53405) ([Duc Canh Le](https://github.com/canhld94)).
* Added a setting `allow_moving_table_directory_to_trash` that allows to ignore `Directory for table data already exists` error when replicating/recovering a `Replicated` database. [#53425](https://github.com/ClickHouse/ClickHouse/pull/53425) ([Alexander Tokmakov](https://github.com/tavplubix)).
* If server settings `asynchronous_metrics_update_period_s` and `asynchronous_heavy_metrics_update_period_s` are misconfigured to 0, it will now fail gracefully instead of terminating the application. [#53428](https://github.com/ClickHouse/ClickHouse/pull/53428) ([Robert Schulze](https://github.com/rschu1ze)).
* The ClickHouse server now respects memory limits changed via cgroups when reloading its configuration. [#53455](https://github.com/ClickHouse/ClickHouse/pull/53455) ([Robert Schulze](https://github.com/rschu1ze)).
* Add ability to turn off flush of Distributed tables on `DETACH`, `DROP`, or server shutdown. [#53501](https://github.com/ClickHouse/ClickHouse/pull/53501) ([Azat Khuzhin](https://github.com/azat)).
* The `domainRFC` function now supports IPv6 in square brackets. [#53506](https://github.com/ClickHouse/ClickHouse/pull/53506) ([Chen768959](https://github.com/Chen768959)).
* Use longer timeout for S3 CopyObject requests, which are used in backups. [#53533](https://github.com/ClickHouse/ClickHouse/pull/53533) ([Michael Kolupaev](https://github.com/al13n321)).
* Added server setting `aggregate_function_group_array_max_element_size`. This setting is used to limit array size for `groupArray` function at serialization. The default value is `16777215`. [#53550](https://github.com/ClickHouse/ClickHouse/pull/53550) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* `SCHEMA()` was added as alias for `DATABASE()` to improve MySQL compatibility. [#53587](https://github.com/ClickHouse/ClickHouse/pull/53587) ([Daniël van Eeden](https://github.com/dveeden)).
* Add asynchronous metrics about tables in the system database. For example, `TotalBytesOfMergeTreeTablesSystem`. This closes [#53603](https://github.com/ClickHouse/ClickHouse/issues/53603). [#53604](https://github.com/ClickHouse/ClickHouse/pull/53604) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* SQL editor in the Play UI and Dashboard will not use Grammarly. [#53614](https://github.com/ClickHouse/ClickHouse/pull/53614) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* As expert-level settings, it is now possible to (1) configure the size_ratio (i.e. the relative size of the protected queue) of the [index] mark/uncompressed caches, (2) configure the cache policy of the index mark and index uncompressed caches. [#53657](https://github.com/ClickHouse/ClickHouse/pull/53657) ([Robert Schulze](https://github.com/rschu1ze)).
* Added client info validation to the query packet in TCPHandler. [#53673](https://github.com/ClickHouse/ClickHouse/pull/53673) ([Alexey Gerasimchuck](https://github.com/Demilivor)).
* Retry loading parts in case of network errors while interaction with Microsoft Azure. [#53750](https://github.com/ClickHouse/ClickHouse/pull/53750) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Stacktrace for exceptions, Materailized view exceptions are propagated. [#53766](https://github.com/ClickHouse/ClickHouse/pull/53766) ([Ilya Golshtein](https://github.com/ilejn)).
* If no hostname or port were specified, keeper client will try to search for a connection string in the ClickHouse's config.xml. [#53769](https://github.com/ClickHouse/ClickHouse/pull/53769) ([pufit](https://github.com/pufit)).
* Add profile event `PartsLockMicroseconds` which shows the amount of microseconds we hold the data parts lock in MergeTree table engine family. [#53797](https://github.com/ClickHouse/ClickHouse/pull/53797) ([alesapin](https://github.com/alesapin)).
* Make reconnect limit in RAFT limits configurable for keeper. This configuration can help to make keeper to rebuild connection with peers quicker if the current connection is broken. [#53817](https://github.com/ClickHouse/ClickHouse/pull/53817) ([Pengyuan Bian](https://github.com/bianpengyuan)).
* Ignore foreign keys in tables definition to improve compatibility with MySQL, so a user wouldn't need to rewrite his SQL of the foreign key part, ref [#53380](https://github.com/ClickHouse/ClickHouse/issues/53380). [#53864](https://github.com/ClickHouse/ClickHouse/pull/53864) ([jsc0218](https://github.com/jsc0218)).
#### Build/Testing/Packaging Improvement
* Don't expose symbols from ClickHouse binary to dynamic linker. It might fix [#43933](https://github.com/ClickHouse/ClickHouse/issues/43933). [#47475](https://github.com/ClickHouse/ClickHouse/pull/47475) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Add `clickhouse-keeper-client` symlink to the clickhouse-server package. [#51882](https://github.com/ClickHouse/ClickHouse/pull/51882) ([Mikhail f. Shiryaev](https://github.com/Felixoid)).
* Add https://github.com/elliotchance/sqltest to CI to report the SQL 2016 conformance. [#52293](https://github.com/ClickHouse/ClickHouse/pull/52293) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Upgrade PRQL to 0.9.3. [#53060](https://github.com/ClickHouse/ClickHouse/pull/53060) ([Maximilian Roos](https://github.com/max-sixty)).
* System tables from CI checks are exported to ClickHouse Cloud. [#53086](https://github.com/ClickHouse/ClickHouse/pull/53086) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* The compiler's profile data (`-ftime-trace`) is uploaded to ClickHouse Cloud. [#53100](https://github.com/ClickHouse/ClickHouse/pull/53100) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Speed up Debug and Tidy builds. [#53178](https://github.com/ClickHouse/ClickHouse/pull/53178) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Speed up the build by removing tons and tonnes of garbage. One of the frequently included headers was poisoned by boost. [#53180](https://github.com/ClickHouse/ClickHouse/pull/53180) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Remove even more garbage. [#53182](https://github.com/ClickHouse/ClickHouse/pull/53182) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* The function `arrayAUC` was using heavy C++ templates - ditched them. [#53183](https://github.com/ClickHouse/ClickHouse/pull/53183) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Some translation units were always rebuilt regardless of ccache. The culprit is found and fixed. [#53184](https://github.com/ClickHouse/ClickHouse/pull/53184) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* The compiler's profile data (`-ftime-trace`) is uploaded to ClickHouse Cloud., the second attempt after [#53100](https://github.com/ClickHouse/ClickHouse/issues/53100). [#53213](https://github.com/ClickHouse/ClickHouse/pull/53213) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Export logs from CI in stateful tests to ClickHouse Cloud. [#53351](https://github.com/ClickHouse/ClickHouse/pull/53351) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Export logs from CI in stress tests. [#53353](https://github.com/ClickHouse/ClickHouse/pull/53353) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Export logs from CI in fuzzer. [#53354](https://github.com/ClickHouse/ClickHouse/pull/53354) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Preserve environment parameters in `clickhouse start` command. Fixes [#51962](https://github.com/ClickHouse/ClickHouse/issues/51962). [#53418](https://github.com/ClickHouse/ClickHouse/pull/53418) ([Mikhail f. Shiryaev](https://github.com/Felixoid)).
* Follow up for [#53418](https://github.com/ClickHouse/ClickHouse/issues/53418). Small improvements for install_check.py, adding tests for proper ENV parameters passing to the main process on `init.d start`. [#53457](https://github.com/ClickHouse/ClickHouse/pull/53457) ([Mikhail f. Shiryaev](https://github.com/Felixoid)).
* Reorganize file management in CMake to prevent potential duplications. For instance, `indexHint.cpp` is duplicated in both `dbms_sources` and `clickhouse_functions_sources`. [#53621](https://github.com/ClickHouse/ClickHouse/pull/53621) ([Amos Bird](https://github.com/amosbird)).
* Upgrade snappy to 1.1.10. [#53672](https://github.com/ClickHouse/ClickHouse/pull/53672) ([李扬](https://github.com/taiyang-li)).
* Slightly improve cmake build by sanitizing some dependencies and removing some duplicates. Each commit includes a short description of the changes made. [#53759](https://github.com/ClickHouse/ClickHouse/pull/53759) ([Amos Bird](https://github.com/amosbird)).
#### Bug Fix (user-visible misbehavior in an official stable release)
* Do not reset (experimental) Annoy index during build-up with more than one mark [#51325](https://github.com/ClickHouse/ClickHouse/pull/51325) ([Tian Xinhui](https://github.com/xinhuitian)).
* Fix usage of temporary directories during RESTORE [#51493](https://github.com/ClickHouse/ClickHouse/pull/51493) ([Azat Khuzhin](https://github.com/azat)).
* Fix binary arithmetic for Nullable(IPv4) [#51642](https://github.com/ClickHouse/ClickHouse/pull/51642) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Support IPv4 and IPv6 data types as dictionary attributes [#51756](https://github.com/ClickHouse/ClickHouse/pull/51756) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* A fix for checksum of compress marks [#51777](https://github.com/ClickHouse/ClickHouse/pull/51777) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Fix mistakenly comma parsing as part of datetime in CSV best effort parsing [#51950](https://github.com/ClickHouse/ClickHouse/pull/51950) ([Kruglov Pavel](https://github.com/Avogar)).
* Don't throw exception when executable UDF has parameters [#51961](https://github.com/ClickHouse/ClickHouse/pull/51961) ([Nikita Taranov](https://github.com/nickitat)).
* Fix recalculation of skip indexes and projections in `ALTER DELETE` queries [#52530](https://github.com/ClickHouse/ClickHouse/pull/52530) ([Anton Popov](https://github.com/CurtizJ)).
* MaterializedMySQL: Fix the infinite loop in ReadBuffer::read [#52621](https://github.com/ClickHouse/ClickHouse/pull/52621) ([Val Doroshchuk](https://github.com/valbok)).
* Load suggestion only with `clickhouse` dialect [#52628](https://github.com/ClickHouse/ClickHouse/pull/52628) ([János Benjamin Antal](https://github.com/antaljanosbenjamin)).
* Init and destroy ares channel on demand. [#52634](https://github.com/ClickHouse/ClickHouse/pull/52634) ([Arthur Passos](https://github.com/arthurpassos)).
* Fix filtering by virtual columns with OR expression [#52653](https://github.com/ClickHouse/ClickHouse/pull/52653) ([Azat Khuzhin](https://github.com/azat)).
* Fix crash in function `tuple` with one sparse column argument [#52659](https://github.com/ClickHouse/ClickHouse/pull/52659) ([Anton Popov](https://github.com/CurtizJ)).
* Fix named collections on cluster [#52687](https://github.com/ClickHouse/ClickHouse/pull/52687) ([Al Korgun](https://github.com/alkorgun)).
* Fix reading of unnecessary column in case of multistage `PREWHERE` [#52689](https://github.com/ClickHouse/ClickHouse/pull/52689) ([Anton Popov](https://github.com/CurtizJ)).
* Fix unexpected sort result on multi columns with nulls first direction [#52761](https://github.com/ClickHouse/ClickHouse/pull/52761) ([copperybean](https://github.com/copperybean)).
* Fix data race in Keeper reconfiguration [#52804](https://github.com/ClickHouse/ClickHouse/pull/52804) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix sorting of sparse columns with large limit [#52827](https://github.com/ClickHouse/ClickHouse/pull/52827) ([Anton Popov](https://github.com/CurtizJ)).
* clickhouse-keeper: fix implementation of server with poll. [#52833](https://github.com/ClickHouse/ClickHouse/pull/52833) ([Andy Fiddaman](https://github.com/citrus-it)).
* Make regexp analyzer recognize named capturing groups [#52840](https://github.com/ClickHouse/ClickHouse/pull/52840) ([Han Fei](https://github.com/hanfei1991)).
* Fix possible assert in `~PushingAsyncPipelineExecutor` in clickhouse-local [#52862](https://github.com/ClickHouse/ClickHouse/pull/52862) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix reading of empty `Nested(Array(LowCardinality(...)))` [#52949](https://github.com/ClickHouse/ClickHouse/pull/52949) ([Anton Popov](https://github.com/CurtizJ)).
* Added new tests for session_log and fixed the inconsistency between login and logout. [#52958](https://github.com/ClickHouse/ClickHouse/pull/52958) ([Alexey Gerasimchuck](https://github.com/Demilivor)).
* Fix password leak in show create mysql table [#52962](https://github.com/ClickHouse/ClickHouse/pull/52962) ([Duc Canh Le](https://github.com/canhld94)).
* Convert sparse column format to full in CreateSetAndFilterOnTheFlyStep [#53000](https://github.com/ClickHouse/ClickHouse/pull/53000) ([vdimir](https://github.com/vdimir)).
* Fix rare race condition with empty key prefix directory deletion in fs cache [#53055](https://github.com/ClickHouse/ClickHouse/pull/53055) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix ZstdDeflatingWriteBuffer truncating the output sometimes [#53064](https://github.com/ClickHouse/ClickHouse/pull/53064) ([Michael Kolupaev](https://github.com/al13n321)).
* Fix query_id in part_log with async flush queries [#53103](https://github.com/ClickHouse/ClickHouse/pull/53103) ([Raúl Marín](https://github.com/Algunenano)).
* Fix possible error from cache "Read unexpected size" [#53121](https://github.com/ClickHouse/ClickHouse/pull/53121) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Disable the new parquet encoder [#53130](https://github.com/ClickHouse/ClickHouse/pull/53130) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix "Not-ready Set" exception [#53162](https://github.com/ClickHouse/ClickHouse/pull/53162) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix character escaping in the PostgreSQL engine [#53250](https://github.com/ClickHouse/ClickHouse/pull/53250) ([Nikolay Degterinsky](https://github.com/evillique)).
* Experimental session_log table: Added new tests for session_log and fixed the inconsistency between login and logout. [#53255](https://github.com/ClickHouse/ClickHouse/pull/53255) ([Alexey Gerasimchuck](https://github.com/Demilivor)). Fixed inconsistency between login success and logout [#53302](https://github.com/ClickHouse/ClickHouse/pull/53302) ([Alexey Gerasimchuck](https://github.com/Demilivor)).
* Fix adding sub-second intervals to DateTime [#53309](https://github.com/ClickHouse/ClickHouse/pull/53309) ([Michael Kolupaev](https://github.com/al13n321)).
* Fix "Context has expired" error in dictionaries [#53342](https://github.com/ClickHouse/ClickHouse/pull/53342) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix incorrect normal projection AST format [#53347](https://github.com/ClickHouse/ClickHouse/pull/53347) ([Amos Bird](https://github.com/amosbird)).
* Forbid use_structure_from_insertion_table_in_table_functions when execute Scalar [#53348](https://github.com/ClickHouse/ClickHouse/pull/53348) ([flynn](https://github.com/ucasfl)).
* Fix loading lazy database during system.table select query [#53372](https://github.com/ClickHouse/ClickHouse/pull/53372) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Fixed system.data_skipping_indices for MaterializedMySQL [#53381](https://github.com/ClickHouse/ClickHouse/pull/53381) ([Filipp Ozinov](https://github.com/bakwc)).
* Fix processing single carriage return in TSV file segmentation engine [#53407](https://github.com/ClickHouse/ClickHouse/pull/53407) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix `Context has expired` error properly [#53433](https://github.com/ClickHouse/ClickHouse/pull/53433) ([Michael Kolupaev](https://github.com/al13n321)).
* Fix `timeout_overflow_mode` when having subquery in the rhs of IN [#53439](https://github.com/ClickHouse/ClickHouse/pull/53439) ([Duc Canh Le](https://github.com/canhld94)).
* Fix an unexpected behavior in [#53152](https://github.com/ClickHouse/ClickHouse/issues/53152) [#53440](https://github.com/ClickHouse/ClickHouse/pull/53440) ([Zhiguo Zhou](https://github.com/ZhiguoZh)).
* Fix JSON_QUERY Function parse error while path is all number [#53470](https://github.com/ClickHouse/ClickHouse/pull/53470) ([KevinyhZou](https://github.com/KevinyhZou)).
* Fix wrong columns order for queries with parallel FINAL. [#53489](https://github.com/ClickHouse/ClickHouse/pull/53489) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fixed SELECTing from ReplacingMergeTree with do_not_merge_across_partitions_select_final [#53511](https://github.com/ClickHouse/ClickHouse/pull/53511) ([Vasily Nemkov](https://github.com/Enmk)).
* Flush async insert queue first on shutdown [#53547](https://github.com/ClickHouse/ClickHouse/pull/53547) ([joelynch](https://github.com/joelynch)).
* Fix crash in join on sparse columna [#53548](https://github.com/ClickHouse/ClickHouse/pull/53548) ([vdimir](https://github.com/vdimir)).
* Fix possible UB in Set skipping index for functions with incorrect args [#53559](https://github.com/ClickHouse/ClickHouse/pull/53559) ([Azat Khuzhin](https://github.com/azat)).
* Fix possible UB in inverted indexes (experimental feature) [#53560](https://github.com/ClickHouse/ClickHouse/pull/53560) ([Azat Khuzhin](https://github.com/azat)).
* Fix: interpolate expression takes source column instead of same name aliased from select expression. [#53572](https://github.com/ClickHouse/ClickHouse/pull/53572) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Fix number of dropped granules in EXPLAIN PLAN index=1 [#53616](https://github.com/ClickHouse/ClickHouse/pull/53616) ([wangxiaobo](https://github.com/wzb5212)).
* Correctly handle totals and extremes with `DelayedSource` [#53644](https://github.com/ClickHouse/ClickHouse/pull/53644) ([Antonio Andelic](https://github.com/antonio2368)).
* Prepared set cache in mutation pipeline stuck [#53645](https://github.com/ClickHouse/ClickHouse/pull/53645) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix bug on mutations with subcolumns of type JSON in predicates of UPDATE and DELETE queries. [#53677](https://github.com/ClickHouse/ClickHouse/pull/53677) ([VanDarkholme7](https://github.com/VanDarkholme7)).
* Fix filter pushdown for full_sorting_merge join [#53699](https://github.com/ClickHouse/ClickHouse/pull/53699) ([vdimir](https://github.com/vdimir)).
* Try to fix bug with `NULL::LowCardinality(Nullable(...)) NOT IN` [#53706](https://github.com/ClickHouse/ClickHouse/pull/53706) ([Andrey Zvonov](https://github.com/zvonand)).
* Fix: sorted distinct with sparse columns [#53711](https://github.com/ClickHouse/ClickHouse/pull/53711) ([Igor Nikonov](https://github.com/devcrafter)).
* `transform`: correctly handle default column with multiple rows [#53742](https://github.com/ClickHouse/ClickHouse/pull/53742) ([Salvatore Mesoraca](https://github.com/aiven-sal)).
* Fix fuzzer crash in parseDateTime [#53764](https://github.com/ClickHouse/ClickHouse/pull/53764) ([Robert Schulze](https://github.com/rschu1ze)).
* MaterializedPostgreSQL: fix uncaught exception in getCreateTableQueryImpl [#53832](https://github.com/ClickHouse/ClickHouse/pull/53832) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix possible segfault while using PostgreSQL engine [#53847](https://github.com/ClickHouse/ClickHouse/pull/53847) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix named_collection_admin alias [#54066](https://github.com/ClickHouse/ClickHouse/pull/54066) ([Kseniia Sumarokova](https://github.com/kssenii)).
### <a id="237"></a> ClickHouse release 23.7, 2023-07-27
#### Backward Incompatible Change
* Add `NAMED COLLECTION` access type (aliases `USE NAMED COLLECTION`, `NAMED COLLECTION USAGE`). This PR is backward incompatible because this access type is disabled by default (because a parent access type `NAMED COLLECTION ADMIN` is disabled by default as well). Proposed in [#50277](https://github.com/ClickHouse/ClickHouse/issues/50277). To grant use `GRANT NAMED COLLECTION ON collection_name TO user` or `GRANT NAMED COLLECTION ON * TO user`, to be able to give these grants `named_collection_admin` is required in config (previously it was named `named_collection_control`, so will remain as an alias). [#50625](https://github.com/ClickHouse/ClickHouse/pull/50625) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fixing a typo in the `system.parts` column name `last_removal_attemp_time`. Now it is named `last_removal_attempt_time`. [#52104](https://github.com/ClickHouse/ClickHouse/pull/52104) ([filimonov](https://github.com/filimonov)).
* Bump version of the distributed_ddl_entry_format_version to 5 by default (enables opentelemetry and initial_query_idd pass through). This will not allow to process existing entries for distributed DDL after *downgrade* (but note, that usually there should be no such unprocessed entries). [#52128](https://github.com/ClickHouse/ClickHouse/pull/52128) ([Azat Khuzhin](https://github.com/azat)).
* Check projection metadata the same way we check ordinary metadata. This change may prevent the server from starting in case there was a table with an invalid projection. An example is a projection that created positional columns in PK (e.g. `projection p (select * order by 1, 4)` which is not allowed in table PK and can cause a crash during insert/merge). Drop such projections before the update. Fixes [#52353](https://github.com/ClickHouse/ClickHouse/issues/52353). [#52361](https://github.com/ClickHouse/ClickHouse/pull/52361) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* The experimental feature `hashid` is removed due to a bug. The quality of implementation was questionable at the start, and it didn't get through the experimental status. This closes [#52406](https://github.com/ClickHouse/ClickHouse/issues/52406). [#52449](https://github.com/ClickHouse/ClickHouse/pull/52449) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
#### New Feature
* Added `Overlay` database engine to combine multiple databases into one. Added `Filesystem` database engine to represent a directory in the filesystem as a set of implicitly available tables with auto-detected formats and structures. A new `S3` database engine allows to read-only interact with s3 storage by representing a prefix as a set of tables. A new `HDFS` database engine allows to interact with HDFS storage in the same way. [#48821](https://github.com/ClickHouse/ClickHouse/pull/48821) ([alekseygolub](https://github.com/alekseygolub)).
* Add support for external disks in Keeper for storing snapshots and logs. [#50098](https://github.com/ClickHouse/ClickHouse/pull/50098) ([Antonio Andelic](https://github.com/antonio2368)).
* Add support for multi-directory selection (`{}`) globs. [#50559](https://github.com/ClickHouse/ClickHouse/pull/50559) ([Andrey Zvonov](https://github.com/zvonand)).
* Kafka connector can fetch Avro schema from schema registry with basic authentication using url-encoded credentials. [#49664](https://github.com/ClickHouse/ClickHouse/pull/49664) ([Ilya Golshtein](https://github.com/ilejn)).
* Add function `arrayJaccardIndex` which computes the Jaccard similarity between two arrays. [#50076](https://github.com/ClickHouse/ClickHouse/pull/50076) ([FFFFFFFHHHHHHH](https://github.com/FFFFFFFHHHHHHH)).
* Add a column `is_obsolete` to `system.settings` and similar tables. Closes [#50819](https://github.com/ClickHouse/ClickHouse/issues/50819). [#50826](https://github.com/ClickHouse/ClickHouse/pull/50826) ([flynn](https://github.com/ucasfl)).
* Implement support of encrypted elements in configuration file. Added possibility to use encrypted text in leaf elements of configuration file. The text is encrypted using encryption codecs from `<encryption_codecs>` section. [#50986](https://github.com/ClickHouse/ClickHouse/pull/50986) ([Roman Vasin](https://github.com/rvasin)).
* Grace Hash Join algorithm is now applicable to FULL and RIGHT JOINs. [#49483](https://github.com/ClickHouse/ClickHouse/issues/49483). [#51013](https://github.com/ClickHouse/ClickHouse/pull/51013) ([lgbo](https://github.com/lgbo-ustc)).
* Add `SYSTEM STOP LISTEN` query for more graceful termination. Closes [#47972](https://github.com/ClickHouse/ClickHouse/issues/47972). [#51016](https://github.com/ClickHouse/ClickHouse/pull/51016) ([Nikolay Degterinsky](https://github.com/evillique)).
* Add `input_format_csv_allow_variable_number_of_columns` options. [#51273](https://github.com/ClickHouse/ClickHouse/pull/51273) ([Dmitry Kardymon](https://github.com/kardymonds)).
* Another boring feature: add function `substring_index`, as in Spark or MySQL. [#51472](https://github.com/ClickHouse/ClickHouse/pull/51472) ([李扬](https://github.com/taiyang-li)).
* A system table `jemalloc_bins` to show stats for jemalloc bins. Example `SELECT *, size * (nmalloc - ndalloc) AS allocated_bytes FROM system.jemalloc_bins WHERE allocated_bytes > 0 ORDER BY allocated_bytes DESC LIMIT 10`. Enjoy. [#51674](https://github.com/ClickHouse/ClickHouse/pull/51674) ([Alexander Gololobov](https://github.com/davenger)).
* Add `RowBinaryWithDefaults` format with extra byte before each column as a flag for using the column's default value. Closes [#50854](https://github.com/ClickHouse/ClickHouse/issues/50854). [#51695](https://github.com/ClickHouse/ClickHouse/pull/51695) ([Kruglov Pavel](https://github.com/Avogar)).
* Added `default_temporary_table_engine` setting. Same as `default_table_engine` but for temporary tables. [#51292](https://github.com/ClickHouse/ClickHouse/issues/51292). [#51708](https://github.com/ClickHouse/ClickHouse/pull/51708) ([velavokr](https://github.com/velavokr)).
* Added new `initcap` / `initcapUTF8` functions which convert the first letter of each word to upper case and the rest to lower case. [#51735](https://github.com/ClickHouse/ClickHouse/pull/51735) ([Dmitry Kardymon](https://github.com/kardymonds)).
* Create table now supports `PRIMARY KEY` syntax in column definition. Columns are added to primary index in the same order columns are defined. [#51881](https://github.com/ClickHouse/ClickHouse/pull/51881) ([Ilya Yatsishin](https://github.com/qoega)).
* Added the possibility to use date and time format specifiers in log and error log file names, either in config files (`log` and `errorlog` tags) or command line arguments (`--log-file` and `--errorlog-file`). [#51945](https://github.com/ClickHouse/ClickHouse/pull/51945) ([Victor Krasnov](https://github.com/sirvickr)).
* Added Peak Memory Usage statistic to HTTP headers. [#51946](https://github.com/ClickHouse/ClickHouse/pull/51946) ([Dmitry Kardymon](https://github.com/kardymonds)).
* Added new `hasSubsequence` (+`CaseInsensitive` and `UTF8` versions) functions to match subsequences in strings. [#52050](https://github.com/ClickHouse/ClickHouse/pull/52050) ([Dmitry Kardymon](https://github.com/kardymonds)).
* Add `array_agg` as alias of `groupArray` for PostgreSQL compatibility. Closes [#52100](https://github.com/ClickHouse/ClickHouse/issues/52100). ### Documentation entry for user-facing changes. [#52135](https://github.com/ClickHouse/ClickHouse/pull/52135) ([flynn](https://github.com/ucasfl)).
* Add `any_value` as a compatibility alias for `any` aggregate function. Closes [#52140](https://github.com/ClickHouse/ClickHouse/issues/52140). [#52147](https://github.com/ClickHouse/ClickHouse/pull/52147) ([flynn](https://github.com/ucasfl)).
* Add aggregate function `array_concat_agg` for compatibility with BigQuery, it's alias of `groupArrayArray`. Closes [#52139](https://github.com/ClickHouse/ClickHouse/issues/52139). [#52149](https://github.com/ClickHouse/ClickHouse/pull/52149) ([flynn](https://github.com/ucasfl)).
* Add `OCTET_LENGTH` as an alias to `length`. Closes [#52153](https://github.com/ClickHouse/ClickHouse/issues/52153). [#52176](https://github.com/ClickHouse/ClickHouse/pull/52176) ([FFFFFFFHHHHHHH](https://github.com/FFFFFFFHHHHHHH)).
* Added `firstLine` function to extract the first line from the multi-line string. This closes [#51172](https://github.com/ClickHouse/ClickHouse/issues/51172). [#52209](https://github.com/ClickHouse/ClickHouse/pull/52209) ([Mikhail Koviazin](https://github.com/mkmkme)).
* Implement KQL-style formatting for the `Interval` data type. This is only needed for compatibility with the `Kusto` query language. [#45671](https://github.com/ClickHouse/ClickHouse/pull/45671) ([ltrk2](https://github.com/ltrk2)).
* Added query `SYSTEM FLUSH ASYNC INSERT QUEUE` which flushes all pending asynchronous inserts to the destination tables. Added a server-side setting `async_insert_queue_flush_on_shutdown` (`true` by default) which determines whether to flush queue of asynchronous inserts on graceful shutdown. Setting `async_insert_threads` is now a server-side setting. [#49160](https://github.com/ClickHouse/ClickHouse/pull/49160) ([Anton Popov](https://github.com/CurtizJ)).
* Aliases `current_database` and a new function `current_schemas` for compatibility with PostgreSQL. [#51076](https://github.com/ClickHouse/ClickHouse/pull/51076) ([Pedro Riera](https://github.com/priera)).
* Add alias for functions `today` (now available under the `curdate`/`current_date` names) and `now` (`current_timestamp`). [#52106](https://github.com/ClickHouse/ClickHouse/pull/52106) ([Lloyd-Pottiger](https://github.com/Lloyd-Pottiger)).
* Support `async_deduplication_token` for async insert. [#52136](https://github.com/ClickHouse/ClickHouse/pull/52136) ([Han Fei](https://github.com/hanfei1991)).
* Add new setting `disable_url_encoding` that allows to disable decoding/encoding path in uri in URL engine. [#52337](https://github.com/ClickHouse/ClickHouse/pull/52337) ([Kruglov Pavel](https://github.com/Avogar)).
#### Performance Improvement
* Enable automatic selection of the sparse serialization format by default. It improves performance. The format is supported since version 22.1. After this change, downgrading to versions older than 22.1 might not be possible. A downgrade may require to set `ratio_of_defaults_for_sparse_serialization=0.9375` [55153](https://github.com/ClickHouse/ClickHouse/issues/55153). You can turn off the usage of the sparse serialization format by providing the `ratio_of_defaults_for_sparse_serialization = 1` setting for your MergeTree tables. [#49631](https://github.com/ClickHouse/ClickHouse/pull/49631) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Enable `move_all_conditions_to_prewhere` and `enable_multiple_prewhere_read_steps` settings by default. [#46365](https://github.com/ClickHouse/ClickHouse/pull/46365) ([Alexander Gololobov](https://github.com/davenger)).
* Improves performance of some queries by tuning allocator. [#46416](https://github.com/ClickHouse/ClickHouse/pull/46416) ([Azat Khuzhin](https://github.com/azat)).
* Now we use fixed-size tasks in `MergeTreePrefetchedReadPool` as in `MergeTreeReadPool`. Also from now we use connection pool for S3 requests. [#49732](https://github.com/ClickHouse/ClickHouse/pull/49732) ([Nikita Taranov](https://github.com/nickitat)).
* More pushdown to the right side of join. [#50532](https://github.com/ClickHouse/ClickHouse/pull/50532) ([Nikita Taranov](https://github.com/nickitat)).
* Improve grace_hash join by reserving hash table's size (resubmit). [#50875](https://github.com/ClickHouse/ClickHouse/pull/50875) ([lgbo](https://github.com/lgbo-ustc)).
* Waiting on lock in `OpenedFileCache` could be noticeable sometimes. We sharded it into multiple sub-maps (each with its own lock) to avoid contention. [#51341](https://github.com/ClickHouse/ClickHouse/pull/51341) ([Nikita Taranov](https://github.com/nickitat)).
* Move conditions with primary key columns to the end of PREWHERE chain. The idea is that conditions with PK columns are likely to be used in PK analysis and will not contribute much more to PREWHERE filtering. [#51958](https://github.com/ClickHouse/ClickHouse/pull/51958) ([Alexander Gololobov](https://github.com/davenger)).
* Speed up `COUNT(DISTINCT)` for String types by inlining SipHash. The performance experiments of *OnTime* on the ICX device (Intel Xeon Platinum 8380 CPU, 80 cores, 160 threads) show that this change could bring an improvement of *11.6%* to the QPS of the query *Q8* while having no impact on others. [#52036](https://github.com/ClickHouse/ClickHouse/pull/52036) ([Zhiguo Zhou](https://github.com/ZhiguoZh)).
* Enable `allow_vertical_merges_from_compact_to_wide_parts` by default. It will save memory usage during merges. [#52295](https://github.com/ClickHouse/ClickHouse/pull/52295) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix incorrect projection analysis which invalidates primary keys. This issue only exists when `query_plan_optimize_primary_key = 1, query_plan_optimize_projection = 1`. This fixes [#48823](https://github.com/ClickHouse/ClickHouse/issues/48823). This fixes [#51173](https://github.com/ClickHouse/ClickHouse/issues/51173). [#52308](https://github.com/ClickHouse/ClickHouse/pull/52308) ([Amos Bird](https://github.com/amosbird)).
* Reduce the number of syscalls in `FileCache::loadMetadata` - this speeds up server startup if the filesystem cache is configured. [#52435](https://github.com/ClickHouse/ClickHouse/pull/52435) ([Raúl Marín](https://github.com/Algunenano)).
* Allow to have strict lower boundary for file segment size by downloading remaining data in the background. Minimum size of file segment (if actual file size is bigger) is configured as cache configuration setting `boundary_alignment`, by default `4Mi`. Number of background threads are configured as cache configuration setting `background_download_threads`, by default `2`. Also `max_file_segment_size` was increased from `8Mi` to `32Mi` in this PR. [#51000](https://github.com/ClickHouse/ClickHouse/pull/51000) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Decreased default timeouts for S3 from 30 seconds to 3 seconds, and for other HTTP from 180 seconds to 30 seconds. [#51171](https://github.com/ClickHouse/ClickHouse/pull/51171) ([Michael Kolupaev](https://github.com/al13n321)).
* New setting `merge_tree_determine_task_size_by_prewhere_columns` added. If set to `true` only sizes of the columns from `PREWHERE` section will be considered to determine reading task size. Otherwise all the columns from query are considered. [#52606](https://github.com/ClickHouse/ClickHouse/pull/52606) ([Nikita Taranov](https://github.com/nickitat)).
#### Improvement
* Use read_bytes/total_bytes_to_read for progress bar in s3/file/url/... table functions for better progress indication. [#51286](https://github.com/ClickHouse/ClickHouse/pull/51286) ([Kruglov Pavel](https://github.com/Avogar)).
* Introduce a table setting `wait_for_unique_parts_send_before_shutdown_ms` which specify the amount of time replica will wait before closing interserver handler for replicated sends. Also fix inconsistency with shutdown of tables and interserver handlers: now server shutdown tables first and only after it shut down interserver handlers. [#51851](https://github.com/ClickHouse/ClickHouse/pull/51851) ([alesapin](https://github.com/alesapin)).
* Allow SQL standard `FETCH` without `OFFSET`. See https://antonz.org/sql-fetch/. [#51293](https://github.com/ClickHouse/ClickHouse/pull/51293) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Allow filtering HTTP headers for the URL/S3 table functions with the new `http_forbid_headers` section in config. Both exact matching and regexp filters are available. [#51038](https://github.com/ClickHouse/ClickHouse/pull/51038) ([Nikolay Degterinsky](https://github.com/evillique)).
* Don't show messages about `16 EiB` free space in logs, as they don't make sense. This closes [#49320](https://github.com/ClickHouse/ClickHouse/issues/49320). [#49342](https://github.com/ClickHouse/ClickHouse/pull/49342) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Properly check the limit for the `sleepEachRow` function. Add a setting `function_sleep_max_microseconds_per_block`. This is needed for generic query fuzzer. [#49343](https://github.com/ClickHouse/ClickHouse/pull/49343) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix two issues in `geoHash` functions. [#50066](https://github.com/ClickHouse/ClickHouse/pull/50066) ([李扬](https://github.com/taiyang-li)).
* Log async insert flush queries into `system.query_log`. [#51160](https://github.com/ClickHouse/ClickHouse/pull/51160) ([Raúl Marín](https://github.com/Algunenano)).
* Functions `date_diff` and `age` now support millisecond/microsecond unit and work with microsecond precision. [#51291](https://github.com/ClickHouse/ClickHouse/pull/51291) ([Dmitry Kardymon](https://github.com/kardymonds)).
* Improve parsing of path in clickhouse-keeper-client. [#51359](https://github.com/ClickHouse/ClickHouse/pull/51359) ([Azat Khuzhin](https://github.com/azat)).
* A third-party product depending on ClickHouse (Gluten: a Plugin to Double SparkSQL's Performance) had a bug. This fix avoids heap overflow in that third-party product while reading from HDFS. [#51386](https://github.com/ClickHouse/ClickHouse/pull/51386) ([李扬](https://github.com/taiyang-li)).
* Add ability to disable native copy for S3 (setting for BACKUP/RESTORE `allow_s3_native_copy`, and `s3_allow_native_copy` for `s3`/`s3_plain` disks). [#51448](https://github.com/ClickHouse/ClickHouse/pull/51448) ([Azat Khuzhin](https://github.com/azat)).
* Add column `primary_key_size` to `system.parts` table to show compressed primary key size on disk. Closes [#51400](https://github.com/ClickHouse/ClickHouse/issues/51400). [#51496](https://github.com/ClickHouse/ClickHouse/pull/51496) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Allow running `clickhouse-local` without procfs, without home directory existing, and without name resolution plugins from glibc. [#51518](https://github.com/ClickHouse/ClickHouse/pull/51518) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Add placeholder `%a` for rull filename in rename_files_after_processing setting. [#51603](https://github.com/ClickHouse/ClickHouse/pull/51603) ([Kruglov Pavel](https://github.com/Avogar)).
* Add column `modification_time` into `system.parts_columns`. [#51685](https://github.com/ClickHouse/ClickHouse/pull/51685) ([Azat Khuzhin](https://github.com/azat)).
* Add new setting `input_format_csv_use_default_on_bad_values` to CSV format that allows to insert default value when parsing of a single field failed. [#51716](https://github.com/ClickHouse/ClickHouse/pull/51716) ([KevinyhZou](https://github.com/KevinyhZou)).
* Added a crash log flush to the disk after the unexpected crash. [#51720](https://github.com/ClickHouse/ClickHouse/pull/51720) ([Alexey Gerasimchuck](https://github.com/Demilivor)).
* Fix behavior in dashboard page where errors unrelated to authentication are not shown. Also fix 'overlapping' chart behavior. [#51744](https://github.com/ClickHouse/ClickHouse/pull/51744) ([Zach Naimon](https://github.com/ArctypeZach)).
* Allow UUID to UInt128 conversion. [#51765](https://github.com/ClickHouse/ClickHouse/pull/51765) ([Dmitry Kardymon](https://github.com/kardymonds)).
* Added support for function `range` of Nullable arguments. [#51767](https://github.com/ClickHouse/ClickHouse/pull/51767) ([Dmitry Kardymon](https://github.com/kardymonds)).
* Convert condition like `toyear(x) = c` to `c1 <= x < c2`. [#51795](https://github.com/ClickHouse/ClickHouse/pull/51795) ([Han Fei](https://github.com/hanfei1991)).
* Improve MySQL compatibility of the statement `SHOW INDEX`. [#51796](https://github.com/ClickHouse/ClickHouse/pull/51796) ([Robert Schulze](https://github.com/rschu1ze)).
* Fix `use_structure_from_insertion_table_in_table_functions` does not work with `MATERIALIZED` and `ALIAS` columns. Closes [#51817](https://github.com/ClickHouse/ClickHouse/issues/51817). Closes [#51019](https://github.com/ClickHouse/ClickHouse/issues/51019). [#51825](https://github.com/ClickHouse/ClickHouse/pull/51825) ([flynn](https://github.com/ucasfl)).
* Cache dictionary now requests only unique keys from source. Closes [#51762](https://github.com/ClickHouse/ClickHouse/issues/51762). [#51853](https://github.com/ClickHouse/ClickHouse/pull/51853) ([Maksim Kita](https://github.com/kitaisreal)).
* Fixed the case when settings were not applied for EXPLAIN query when FORMAT was provided. [#51859](https://github.com/ClickHouse/ClickHouse/pull/51859) ([Nikita Taranov](https://github.com/nickitat)).
* Allow SETTINGS before FORMAT in DESCRIBE TABLE query for compatibility with SELECT query. Closes [#51544](https://github.com/ClickHouse/ClickHouse/issues/51544). [#51899](https://github.com/ClickHouse/ClickHouse/pull/51899) ([Nikolay Degterinsky](https://github.com/evillique)).
* Var-Int encoded integers (e.g. used by the native protocol) can now use the full 64-bit range. 3rd party clients are advised to update their var-int code accordingly. [#51905](https://github.com/ClickHouse/ClickHouse/pull/51905) ([Robert Schulze](https://github.com/rschu1ze)).
* Update certificates when they change without the need to manually SYSTEM RELOAD CONFIG. [#52030](https://github.com/ClickHouse/ClickHouse/pull/52030) ([Mike Kot](https://github.com/myrrc)).
* Added `allow_create_index_without_type` setting that allow to ignore `ADD INDEX` queries without specified `TYPE`. Standard SQL queries will just succeed without changing table schema. [#52056](https://github.com/ClickHouse/ClickHouse/pull/52056) ([Ilya Yatsishin](https://github.com/qoega)).
* Log messages are written to the `system.text_log` from the server startup. [#52113](https://github.com/ClickHouse/ClickHouse/pull/52113) ([Dmitry Kardymon](https://github.com/kardymonds)).
* In cases where the HTTP endpoint has multiple IP addresses and the first of them is unreachable, a timeout exception was thrown. Made session creation with handling all resolved endpoints. [#52116](https://github.com/ClickHouse/ClickHouse/pull/52116) ([Aleksei Filatov](https://github.com/aalexfvk)).
* Avro input format now supports Union even if it contains only a single type. Closes [#52131](https://github.com/ClickHouse/ClickHouse/issues/52131). [#52137](https://github.com/ClickHouse/ClickHouse/pull/52137) ([flynn](https://github.com/ucasfl)).
* Add setting `optimize_use_implicit_projections` to disable implicit projections (currently only `min_max_count` projection). [#52152](https://github.com/ClickHouse/ClickHouse/pull/52152) ([Amos Bird](https://github.com/amosbird)).
* It was possible to use the function `hasToken` for infinite loop. Now this possibility is removed. This closes [#52156](https://github.com/ClickHouse/ClickHouse/issues/52156). [#52160](https://github.com/ClickHouse/ClickHouse/pull/52160) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Create ZK ancestors optimistically. [#52195](https://github.com/ClickHouse/ClickHouse/pull/52195) ([Raúl Marín](https://github.com/Algunenano)).
* Fix [#50582](https://github.com/ClickHouse/ClickHouse/issues/50582). Avoid the `Not found column ... in block` error in some cases of reading in-order and constants. [#52259](https://github.com/ClickHouse/ClickHouse/pull/52259) ([Chen768959](https://github.com/Chen768959)).
* Check whether S2 geo primitives are invalid as early as possible on ClickHouse side. This closes: [#27090](https://github.com/ClickHouse/ClickHouse/issues/27090). [#52260](https://github.com/ClickHouse/ClickHouse/pull/52260) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Add back missing projection QueryAccessInfo when `query_plan_optimize_projection = 1`. This fixes [#50183](https://github.com/ClickHouse/ClickHouse/issues/50183) . This fixes [#50093](https://github.com/ClickHouse/ClickHouse/issues/50093). [#52327](https://github.com/ClickHouse/ClickHouse/pull/52327) ([Amos Bird](https://github.com/amosbird)).
* When `ZooKeeperRetriesControl` rethrows an error, it's more useful to see its original stack trace, not the one from `ZooKeeperRetriesControl` itself. [#52347](https://github.com/ClickHouse/ClickHouse/pull/52347) ([Vitaly Baranov](https://github.com/vitlibar)).
* Wait for zero copy replication lock even if some disks don't support it. [#52376](https://github.com/ClickHouse/ClickHouse/pull/52376) ([Raúl Marín](https://github.com/Algunenano)).
* Now interserver port will be closed only after tables are shut down. [#52498](https://github.com/ClickHouse/ClickHouse/pull/52498) ([alesapin](https://github.com/alesapin)).
#### Experimental Feature
* Writing parquet files is 10x faster, it's multi-threaded now. Almost the same speed as reading. [#49367](https://github.com/ClickHouse/ClickHouse/pull/49367) ([Michael Kolupaev](https://github.com/al13n321)). This is controlled by the setting `output_format_parquet_use_custom_encoder` which is disabled by default, because the feature is non-ideal.
* Added support for [PRQL](https://prql-lang.org/) as a query language. [#50686](https://github.com/ClickHouse/ClickHouse/pull/50686) ([János Benjamin Antal](https://github.com/antaljanosbenjamin)).
* Allow to add disk name for custom disks. Previously custom disks would use an internal generated disk name. Now it will be possible with `disk = disk_<name>(...)` (e.g. disk will have name `name`) . [#51552](https://github.com/ClickHouse/ClickHouse/pull/51552) ([Kseniia Sumarokova](https://github.com/kssenii)). This syntax can be changed in this release.
* (experimental MaterializedMySQL) Fixed crash when `mysqlxx::Pool::Entry` is used after it was disconnected. [#52063](https://github.com/ClickHouse/ClickHouse/pull/52063) ([Val Doroshchuk](https://github.com/valbok)).
* (experimental MaterializedMySQL) `CREATE TABLE ... AS SELECT` .. is now supported in MaterializedMySQL. [#52067](https://github.com/ClickHouse/ClickHouse/pull/52067) ([Val Doroshchuk](https://github.com/valbok)).
* (experimental MaterializedMySQL) Introduced automatic conversion of text types to utf8 for MaterializedMySQL. [#52084](https://github.com/ClickHouse/ClickHouse/pull/52084) ([Val Doroshchuk](https://github.com/valbok)).
* (experimental MaterializedMySQL) Now unquoted UTF-8 strings are supported in DDL for MaterializedMySQL. [#52318](https://github.com/ClickHouse/ClickHouse/pull/52318) ([Val Doroshchuk](https://github.com/valbok)).
* (experimental MaterializedMySQL) Now double quoted comments are supported in MaterializedMySQL. [#52355](https://github.com/ClickHouse/ClickHouse/pull/52355) ([Val Doroshchuk](https://github.com/valbok)).
* Upgrade Intel QPL from v1.1.0 to v1.2.0 2. Upgrade Intel accel-config from v3.5 to v4.0 3. Fixed issue that Device IOTLB miss has big perf. impact for IAA accelerators. [#52180](https://github.com/ClickHouse/ClickHouse/pull/52180) ([jasperzhu](https://github.com/jinjunzh)).
* The `session_timezone` setting (new in version 23.6) is demoted to experimental. [#52445](https://github.com/ClickHouse/ClickHouse/pull/52445) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Support ZooKeeper `reconfig` command for ClickHouse Keeper with incremental reconfiguration which can be enabled via `keeper_server.enable_reconfiguration` setting. Support adding servers, removing servers, and changing server priorities. [#49450](https://github.com/ClickHouse/ClickHouse/pull/49450) ([Mike Kot](https://github.com/myrrc)). It is suspected that this feature is incomplete.
#### Build/Testing/Packaging Improvement
* Add experimental ClickHouse builds for Linux RISC-V 64 to CI. [#31398](https://github.com/ClickHouse/ClickHouse/pull/31398) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Add integration test check with the enabled Analyzer. [#50926](https://github.com/ClickHouse/ClickHouse/pull/50926) [#52210](https://github.com/ClickHouse/ClickHouse/pull/52210) ([Dmitry Novik](https://github.com/novikd)).
* Reproducible builds for Rust. [#52395](https://github.com/ClickHouse/ClickHouse/pull/52395) ([Azat Khuzhin](https://github.com/azat)).
* Update Cargo dependencies. [#51721](https://github.com/ClickHouse/ClickHouse/pull/51721) ([Raúl Marín](https://github.com/Algunenano)).
* Make the function `CHColumnToArrowColumn::fillArrowArrayWithArrayColumnData` to work with nullable arrays, which are not possible in ClickHouse, but needed for Gluten. [#52112](https://github.com/ClickHouse/ClickHouse/pull/52112) ([李扬](https://github.com/taiyang-li)).
* We've updated the CCTZ library to master, but there are no user-visible changes. [#52124](https://github.com/ClickHouse/ClickHouse/pull/52124) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* The `system.licenses` table now includes the hard-forked library Poco. This closes [#52066](https://github.com/ClickHouse/ClickHouse/issues/52066). [#52127](https://github.com/ClickHouse/ClickHouse/pull/52127) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Check that there are no cases of bad punctuation: whitespace before a comma like `Hello ,world` instead of `Hello, world`. [#52549](https://github.com/ClickHouse/ClickHouse/pull/52549) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
#### Bug Fix (user-visible misbehavior in an official stable release)
* Fix MaterializedPostgreSQL syncTables [#49698](https://github.com/ClickHouse/ClickHouse/pull/49698) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix projection with optimize_aggregators_of_group_by_keys [#49709](https://github.com/ClickHouse/ClickHouse/pull/49709) ([Amos Bird](https://github.com/amosbird)).
* Fix optimize_skip_unused_shards with JOINs [#51037](https://github.com/ClickHouse/ClickHouse/pull/51037) ([Azat Khuzhin](https://github.com/azat)).
* Fix formatDateTime() with fractional negative datetime64 [#51290](https://github.com/ClickHouse/ClickHouse/pull/51290) ([Dmitry Kardymon](https://github.com/kardymonds)).
* Functions `hasToken*` were totally wrong. Add a test for [#43358](https://github.com/ClickHouse/ClickHouse/issues/43358) [#51378](https://github.com/ClickHouse/ClickHouse/pull/51378) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix optimization to move functions before sorting. [#51481](https://github.com/ClickHouse/ClickHouse/pull/51481) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix Block structure mismatch in Pipe::unitePipes for FINAL [#51492](https://github.com/ClickHouse/ClickHouse/pull/51492) ([Nikita Taranov](https://github.com/nickitat)).
* Fix SIGSEGV for clusters with zero weight across all shards (fixes INSERT INTO FUNCTION clusterAllReplicas()) [#51545](https://github.com/ClickHouse/ClickHouse/pull/51545) ([Azat Khuzhin](https://github.com/azat)).
* Fix timeout for hedged requests [#51582](https://github.com/ClickHouse/ClickHouse/pull/51582) ([Azat Khuzhin](https://github.com/azat)).
* Fix logical error in ANTI join with NULL [#51601](https://github.com/ClickHouse/ClickHouse/pull/51601) ([vdimir](https://github.com/vdimir)).
* Fix for moving 'IN' conditions to PREWHERE [#51610](https://github.com/ClickHouse/ClickHouse/pull/51610) ([Alexander Gololobov](https://github.com/davenger)).
* Do not apply PredicateExpressionsOptimizer for ASOF/ANTI join [#51633](https://github.com/ClickHouse/ClickHouse/pull/51633) ([vdimir](https://github.com/vdimir)).
* Fix async insert with deduplication for ReplicatedMergeTree using merging algorithms [#51676](https://github.com/ClickHouse/ClickHouse/pull/51676) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix reading from empty column in `parseSipHashKey` [#51804](https://github.com/ClickHouse/ClickHouse/pull/51804) ([Nikita Taranov](https://github.com/nickitat)).
* Fix segfault when create invalid EmbeddedRocksdb table [#51847](https://github.com/ClickHouse/ClickHouse/pull/51847) ([Duc Canh Le](https://github.com/canhld94)).
* Fix inserts into MongoDB tables [#51876](https://github.com/ClickHouse/ClickHouse/pull/51876) ([Nikolay Degterinsky](https://github.com/evillique)).
* Fix deadlock on DatabaseCatalog shutdown [#51908](https://github.com/ClickHouse/ClickHouse/pull/51908) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Fix error in subquery operators [#51922](https://github.com/ClickHouse/ClickHouse/pull/51922) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix async connect to hosts with multiple ips [#51934](https://github.com/ClickHouse/ClickHouse/pull/51934) ([Kruglov Pavel](https://github.com/Avogar)).
* Do not remove inputs after ActionsDAG::merge [#51947](https://github.com/ClickHouse/ClickHouse/pull/51947) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Check refcount in `RemoveManyObjectStorageOperation::finalize` instead of `execute` [#51954](https://github.com/ClickHouse/ClickHouse/pull/51954) ([vdimir](https://github.com/vdimir)).
* Allow parametric UDFs [#51964](https://github.com/ClickHouse/ClickHouse/pull/51964) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Small fix for toDateTime64() for dates after 2283-12-31 [#52130](https://github.com/ClickHouse/ClickHouse/pull/52130) ([Andrey Zvonov](https://github.com/zvonand)).
* Fix ORDER BY tuple of WINDOW functions [#52145](https://github.com/ClickHouse/ClickHouse/pull/52145) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix incorrect projection analysis when aggregation expression contains monotonic functions [#52151](https://github.com/ClickHouse/ClickHouse/pull/52151) ([Amos Bird](https://github.com/amosbird)).
* Fix error in `groupArrayMoving` functions [#52161](https://github.com/ClickHouse/ClickHouse/pull/52161) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Disable direct join for range dictionary [#52187](https://github.com/ClickHouse/ClickHouse/pull/52187) ([Duc Canh Le](https://github.com/canhld94)).
* Fix sticky mutations test (and extremely rare race condition) [#52197](https://github.com/ClickHouse/ClickHouse/pull/52197) ([alesapin](https://github.com/alesapin)).
* Fix race in Web disk [#52211](https://github.com/ClickHouse/ClickHouse/pull/52211) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix data race in Connection::setAsyncCallback on unknown packet from server [#52219](https://github.com/ClickHouse/ClickHouse/pull/52219) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix temp data deletion on startup, add test [#52275](https://github.com/ClickHouse/ClickHouse/pull/52275) ([vdimir](https://github.com/vdimir)).
* Don't use minmax_count projections when counting nullable columns [#52297](https://github.com/ClickHouse/ClickHouse/pull/52297) ([Amos Bird](https://github.com/amosbird)).
* MergeTree/ReplicatedMergeTree should use server timezone for log entries [#52325](https://github.com/ClickHouse/ClickHouse/pull/52325) ([Azat Khuzhin](https://github.com/azat)).
* Fix parameterized view with cte and multiple usage [#52328](https://github.com/ClickHouse/ClickHouse/pull/52328) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Disable expression templates for time intervals [#52335](https://github.com/ClickHouse/ClickHouse/pull/52335) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Fix `apply_snapshot` in Keeper [#52358](https://github.com/ClickHouse/ClickHouse/pull/52358) ([Antonio Andelic](https://github.com/antonio2368)).
* Update build-osx.md [#52377](https://github.com/ClickHouse/ClickHouse/pull/52377) ([AlexBykovski](https://github.com/AlexBykovski)).
* Fix `countSubstrings()` hang with empty needle and a column haystack [#52409](https://github.com/ClickHouse/ClickHouse/pull/52409) ([Sergei Trifonov](https://github.com/serxa)).
* Fix normal projection with merge table [#52432](https://github.com/ClickHouse/ClickHouse/pull/52432) ([Amos Bird](https://github.com/amosbird)).
* Fix possible double-free in Aggregator [#52439](https://github.com/ClickHouse/ClickHouse/pull/52439) ([Nikita Taranov](https://github.com/nickitat)).
* Fixed inserting into Buffer engine [#52440](https://github.com/ClickHouse/ClickHouse/pull/52440) ([Vasily Nemkov](https://github.com/Enmk)).
* The implementation of AnyHash was non-conformant. [#52448](https://github.com/ClickHouse/ClickHouse/pull/52448) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Check recursion depth in OptimizedRegularExpression [#52451](https://github.com/ClickHouse/ClickHouse/pull/52451) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix data-race DatabaseReplicated::startupTables()/canExecuteReplicatedMetadataAlter() [#52490](https://github.com/ClickHouse/ClickHouse/pull/52490) ([Azat Khuzhin](https://github.com/azat)).
* Fix abort in function `transform` [#52513](https://github.com/ClickHouse/ClickHouse/pull/52513) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix lightweight delete after drop of projection [#52517](https://github.com/ClickHouse/ClickHouse/pull/52517) ([Anton Popov](https://github.com/CurtizJ)).
* Fix possible error "Cannot drain connections: cancel first" [#52585](https://github.com/ClickHouse/ClickHouse/pull/52585) ([Kruglov Pavel](https://github.com/Avogar)).
### <a id="236"></a> ClickHouse release 23.6, 2023-06-29
#### Backward Incompatible Change
* Delete feature `do_not_evict_index_and_mark_files` in the fs cache. This feature was only making things worse. [#51253](https://github.com/ClickHouse/ClickHouse/pull/51253) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Remove ALTER support for experimental LIVE VIEW. [#51287](https://github.com/ClickHouse/ClickHouse/pull/51287) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Decrease the default values for `http_max_field_value_size` and `http_max_field_name_size` to 128 KiB. [#51163](https://github.com/ClickHouse/ClickHouse/pull/51163) ([Mikhail f. Shiryaev](https://github.com/Felixoid)).
* CGroups metrics related to CPU are replaced with one metric, `CGroupMaxCPU` for better usability. The `Normalized` CPU usage metrics will be normalized to CGroups limits instead of the total number of CPUs when they are set. This closes [#50836](https://github.com/ClickHouse/ClickHouse/issues/50836). [#50835](https://github.com/ClickHouse/ClickHouse/pull/50835) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
#### New Feature
* The function `transform` as well as `CASE` with value matching started to support all data types. This closes [#29730](https://github.com/ClickHouse/ClickHouse/issues/29730). This closes [#32387](https://github.com/ClickHouse/ClickHouse/issues/32387). This closes [#50827](https://github.com/ClickHouse/ClickHouse/issues/50827). This closes [#31336](https://github.com/ClickHouse/ClickHouse/issues/31336). This closes [#40493](https://github.com/ClickHouse/ClickHouse/issues/40493). [#51351](https://github.com/ClickHouse/ClickHouse/pull/51351) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Added option `--rename_files_after_processing <pattern>`. This closes [#34207](https://github.com/ClickHouse/ClickHouse/issues/34207). [#49626](https://github.com/ClickHouse/ClickHouse/pull/49626) ([alekseygolub](https://github.com/alekseygolub)).
* Add support for `TRUNCATE` modifier in `INTO OUTFILE` clause. Suggest using `APPEND` or `TRUNCATE` for `INTO OUTFILE` when file exists. [#50950](https://github.com/ClickHouse/ClickHouse/pull/50950) ([alekar](https://github.com/alekar)).
* Add table engine `Redis` and table function `redis`. It allows querying external Redis servers. [#50150](https://github.com/ClickHouse/ClickHouse/pull/50150) ([JackyWoo](https://github.com/JackyWoo)).
* Allow to skip empty files in file/s3/url/hdfs table functions using settings `s3_skip_empty_files`, `hdfs_skip_empty_files`, `engine_file_skip_empty_files`, `engine_url_skip_empty_files`. [#50364](https://github.com/ClickHouse/ClickHouse/pull/50364) ([Kruglov Pavel](https://github.com/Avogar)).
* Add a new setting named `use_mysql_types_in_show_columns` to alter the `SHOW COLUMNS` SQL statement to display MySQL equivalent types when a client is connected via the MySQL compatibility port. [#49577](https://github.com/ClickHouse/ClickHouse/pull/49577) ([Thomas Panetti](https://github.com/tpanetti)).
* Clickhouse-client can now be called with a connection string instead of "--host", "--port", "--user" etc. [#50689](https://github.com/ClickHouse/ClickHouse/pull/50689) ([Alexey Gerasimchuck](https://github.com/Demilivor)).
* Add setting `session_timezone`; it is used as the default timezone for a session when not explicitly specified. [#44149](https://github.com/ClickHouse/ClickHouse/pull/44149) ([Andrey Zvonov](https://github.com/zvonand)).
* Codec DEFLATE_QPL is now controlled via server setting "enable_deflate_qpl_codec" (default: false) instead of setting "allow_experimental_codecs". This marks DEFLATE_QPL non-experimental. [#50775](https://github.com/ClickHouse/ClickHouse/pull/50775) ([Robert Schulze](https://github.com/rschu1ze)).
#### Performance Improvement
* Improved scheduling of merge selecting and cleanup tasks in `ReplicatedMergeTree`. The tasks will not be executed too frequently when there's nothing to merge or cleanup. Added settings `max_merge_selecting_sleep_ms`, `merge_selecting_sleep_slowdown_factor`, `max_cleanup_delay_period` and `cleanup_thread_preferred_points_per_iteration`. It should close [#31919](https://github.com/ClickHouse/ClickHouse/issues/31919). [#50107](https://github.com/ClickHouse/ClickHouse/pull/50107) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Make filter push down through cross join. [#50605](https://github.com/ClickHouse/ClickHouse/pull/50605) ([Han Fei](https://github.com/hanfei1991)).
* Improve performance with enabled QueryProfiler using thread-local timer_id instead of global object. [#48778](https://github.com/ClickHouse/ClickHouse/pull/48778) ([Jiebin Sun](https://github.com/jiebinn)).
* Rewrite CapnProto input/output format to improve its performance. Map column names and CapnProto fields case insensitive, fix reading/writing of nested structure fields. [#49752](https://github.com/ClickHouse/ClickHouse/pull/49752) ([Kruglov Pavel](https://github.com/Avogar)).
* Optimize parquet write performance for parallel threads. [#50102](https://github.com/ClickHouse/ClickHouse/pull/50102) ([Hongbin Ma](https://github.com/binmahone)).
* Disable `parallelize_output_from_storages` for processing MATERIALIZED VIEWs and storages with one block only. [#50214](https://github.com/ClickHouse/ClickHouse/pull/50214) ([Azat Khuzhin](https://github.com/azat)).
* Merge PR [#46558](https://github.com/ClickHouse/ClickHouse/pull/46558). Avoid block permutation during sort if the block is already sorted. [#50697](https://github.com/ClickHouse/ClickHouse/pull/50697) ([Alexey Milovidov](https://github.com/alexey-milovidov), [Maksim Kita](https://github.com/kitaisreal)).
* Make multiple list requests to ZooKeeper in parallel to speed up reading from system.zookeeper table. [#51042](https://github.com/ClickHouse/ClickHouse/pull/51042) ([Alexander Gololobov](https://github.com/davenger)).
* Speedup initialization of DateTime lookup tables for time zones. This should reduce startup/connect time of clickhouse-client especially in debug build as it is rather heavy. [#51347](https://github.com/ClickHouse/ClickHouse/pull/51347) ([Alexander Gololobov](https://github.com/davenger)).
* Fix data lakes slowness because of synchronous head requests. (Related to Iceberg/Deltalake/Hudi being slow with a lot of files). [#50976](https://github.com/ClickHouse/ClickHouse/pull/50976) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Do not read all the columns from right GLOBAL JOIN table. [#50721](https://github.com/ClickHouse/ClickHouse/pull/50721) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
#### Experimental Feature
* Support parallel replicas with the analyzer. [#50441](https://github.com/ClickHouse/ClickHouse/pull/50441) ([Raúl Marín](https://github.com/Algunenano)).
* Add random sleep before large merges/mutations execution to split load more evenly between replicas in case of zero-copy replication. [#51282](https://github.com/ClickHouse/ClickHouse/pull/51282) ([alesapin](https://github.com/alesapin)).
* Do not replicate `ALTER PARTITION` queries and mutations through `Replicated` database if it has only one shard and the underlying table is `ReplicatedMergeTree`. [#51049](https://github.com/ClickHouse/ClickHouse/pull/51049) ([Alexander Tokmakov](https://github.com/tavplubix)).
#### Improvement
* Relax the thresholds for "too many parts" to be more modern. Return the backpressure during long-running insert queries. [#50856](https://github.com/ClickHouse/ClickHouse/pull/50856) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Allow to cast IPv6 to IPv4 address for CIDR ::ffff:0:0/96 (IPv4-mapped addresses). [#49759](https://github.com/ClickHouse/ClickHouse/pull/49759) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Update MongoDB protocol to support MongoDB 5.1 version and newer. Support for the versions with the old protocol (<3.6) is preserved. Closes [#45621](https://github.com/ClickHouse/ClickHouse/issues/45621), [#49879](https://github.com/ClickHouse/ClickHouse/issues/49879). [#50061](https://github.com/ClickHouse/ClickHouse/pull/50061) ([Nikolay Degterinsky](https://github.com/evillique)).
* Add setting `input_format_max_bytes_to_read_for_schema_inference` to limit the number of bytes to read in schema inference. Closes [#50577](https://github.com/ClickHouse/ClickHouse/issues/50577). [#50592](https://github.com/ClickHouse/ClickHouse/pull/50592) ([Kruglov Pavel](https://github.com/Avogar)).
* Respect setting `input_format_null_as_default` in schema inference. [#50602](https://github.com/ClickHouse/ClickHouse/pull/50602) ([Kruglov Pavel](https://github.com/Avogar)).
* Allow to skip trailing empty lines in CSV/TSV/CustomSeparated formats via settings `input_format_csv_skip_trailing_empty_lines`, `input_format_tsv_skip_trailing_empty_lines` and `input_format_custom_skip_trailing_empty_lines` (disabled by default). Closes [#49315](https://github.com/ClickHouse/ClickHouse/issues/49315). [#50635](https://github.com/ClickHouse/ClickHouse/pull/50635) ([Kruglov Pavel](https://github.com/Avogar)).
* Functions "toDateOrDefault|OrNull" and "accuateCast[OrDefault|OrNull]" now correctly parse numeric arguments. [#50709](https://github.com/ClickHouse/ClickHouse/pull/50709) ([Dmitry Kardymon](https://github.com/kardymonds)).
* Support CSV with whitespace or `\t` field delimiters, and these delimiters are supported in Spark. [#50712](https://github.com/ClickHouse/ClickHouse/pull/50712) ([KevinyhZou](https://github.com/KevinyhZou)).
* Settings `number_of_mutations_to_delay` and `number_of_mutations_to_throw` are enabled by default now with values 500 and 1000 respectively. [#50726](https://github.com/ClickHouse/ClickHouse/pull/50726) ([Anton Popov](https://github.com/CurtizJ)).
* The dashboard correctly shows missing values. This closes [#50831](https://github.com/ClickHouse/ClickHouse/issues/50831). [#50832](https://github.com/ClickHouse/ClickHouse/pull/50832) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Added the possibility to use date and time arguments in the syslog timestamp format in functions `parseDateTimeBestEffort*` and `parseDateTime64BestEffort*`. [#50925](https://github.com/ClickHouse/ClickHouse/pull/50925) ([Victor Krasnov](https://github.com/sirvickr)).
* Command line parameter "--password" in clickhouse-client can now be specified only once. [#50966](https://github.com/ClickHouse/ClickHouse/pull/50966) ([Alexey Gerasimchuck](https://github.com/Demilivor)).
* Use `hash_of_all_files` from `system.parts` to check identity of parts during on-cluster backups. [#50997](https://github.com/ClickHouse/ClickHouse/pull/50997) ([Vitaly Baranov](https://github.com/vitlibar)).
* The system table zookeeper_connection connected_time identifies the time when the connection is established (standard format), and session_uptime_elapsed_seconds is added, which labels the duration of the established connection session (in seconds). [#51026](https://github.com/ClickHouse/ClickHouse/pull/51026) ([郭小龙](https://github.com/guoxiaolongzte)).
* Improve the progress bar for file/s3/hdfs/url table functions by using chunk size from source data and using incremental total size counting in each thread. Fix the progress bar for *Cluster functions. This closes [#47250](https://github.com/ClickHouse/ClickHouse/issues/47250). [#51088](https://github.com/ClickHouse/ClickHouse/pull/51088) ([Kruglov Pavel](https://github.com/Avogar)).
* Add total_bytes_to_read to the Progress packet in TCP protocol for better Progress bar. [#51158](https://github.com/ClickHouse/ClickHouse/pull/51158) ([Kruglov Pavel](https://github.com/Avogar)).
* Better checking of data parts on disks with filesystem cache. [#51164](https://github.com/ClickHouse/ClickHouse/pull/51164) ([Anton Popov](https://github.com/CurtizJ)).
* Fix sometimes not correct current_elements_num in fs cache. [#51242](https://github.com/ClickHouse/ClickHouse/pull/51242) ([Kseniia Sumarokova](https://github.com/kssenii)).
#### Build/Testing/Packaging Improvement
* Add embedded keeper-client to standalone keeper binary. [#50964](https://github.com/ClickHouse/ClickHouse/pull/50964) ([pufit](https://github.com/pufit)).
* Actual LZ4 version is used now. [#50621](https://github.com/ClickHouse/ClickHouse/pull/50621) ([Nikita Taranov](https://github.com/nickitat)).
* ClickHouse server will print the list of changed settings on fatal errors. This closes [#51137](https://github.com/ClickHouse/ClickHouse/issues/51137). [#51138](https://github.com/ClickHouse/ClickHouse/pull/51138) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Allow building ClickHouse with clang-17. [#51300](https://github.com/ClickHouse/ClickHouse/pull/51300) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* [SQLancer](https://github.com/sqlancer/sqlancer) check is considered stable as bugs that were triggered by it are fixed. Now failures of SQLancer check will be reported as failed check status. [#51340](https://github.com/ClickHouse/ClickHouse/pull/51340) ([Ilya Yatsishin](https://github.com/qoega)).
* Split huge `RUN` in Dockerfile into smaller conditional. Install the necessary tools on demand in the same `RUN` layer, and remove them after that. Upgrade the OS only once at the beginning. Use a modern way to check the signed repository. Downgrade the base repo to ubuntu:20.04 to address the issues on older docker versions. Upgrade golang version to address golang vulnerabilities. [#51504](https://github.com/ClickHouse/ClickHouse/pull/51504) ([Mikhail f. Shiryaev](https://github.com/Felixoid)).
#### Bug Fix (user-visible misbehavior in an official stable release)
* Report loading status for executable dictionaries correctly [#48775](https://github.com/ClickHouse/ClickHouse/pull/48775) ([Anton Kozlov](https://github.com/tonickkozlov)).
* Proper mutation of skip indices and projections [#50104](https://github.com/ClickHouse/ClickHouse/pull/50104) ([Amos Bird](https://github.com/amosbird)).
* Cleanup moving parts [#50489](https://github.com/ClickHouse/ClickHouse/pull/50489) ([vdimir](https://github.com/vdimir)).
* Fix backward compatibility for IP types hashing in aggregate functions [#50551](https://github.com/ClickHouse/ClickHouse/pull/50551) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Fix Log family table return wrong rows count after truncate [#50585](https://github.com/ClickHouse/ClickHouse/pull/50585) ([flynn](https://github.com/ucasfl)).
* Fix bug in `uniqExact` parallel merging [#50590](https://github.com/ClickHouse/ClickHouse/pull/50590) ([Nikita Taranov](https://github.com/nickitat)).
* Revert recent grace hash join changes [#50699](https://github.com/ClickHouse/ClickHouse/pull/50699) ([vdimir](https://github.com/vdimir)).
* Query Cache: Try to fix bad cast from `ColumnConst` to `ColumnVector<char8_t>` [#50704](https://github.com/ClickHouse/ClickHouse/pull/50704) ([Robert Schulze](https://github.com/rschu1ze)).
* Avoid storing logs in Keeper containing unknown operation [#50751](https://github.com/ClickHouse/ClickHouse/pull/50751) ([Antonio Andelic](https://github.com/antonio2368)).
* SummingMergeTree support for DateTime64 [#50797](https://github.com/ClickHouse/ClickHouse/pull/50797) ([Jordi Villar](https://github.com/jrdi)).
* Add compatibility setting for non-const timezones [#50834](https://github.com/ClickHouse/ClickHouse/pull/50834) ([Robert Schulze](https://github.com/rschu1ze)).
* Fix hashing of LDAP params in the cache entries [#50865](https://github.com/ClickHouse/ClickHouse/pull/50865) ([Julian Maicher](https://github.com/jmaicher)).
* Fallback to parsing big integer from String instead of exception in Parquet format [#50873](https://github.com/ClickHouse/ClickHouse/pull/50873) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix checking the lock file too often while writing a backup [#50889](https://github.com/ClickHouse/ClickHouse/pull/50889) ([Vitaly Baranov](https://github.com/vitlibar)).
* Do not apply projection if read-in-order was enabled. [#50923](https://github.com/ClickHouse/ClickHouse/pull/50923) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix race in the Azure blob storage iterator [#50936](https://github.com/ClickHouse/ClickHouse/pull/50936) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Fix erroneous `sort_description` propagation in `CreatingSets` [#50955](https://github.com/ClickHouse/ClickHouse/pull/50955) ([Nikita Taranov](https://github.com/nickitat)).
* Fix Iceberg v2 optional metadata parsing [#50974](https://github.com/ClickHouse/ClickHouse/pull/50974) ([Kseniia Sumarokova](https://github.com/kssenii)).
* MaterializedMySQL: Keep parentheses for empty table overrides [#50977](https://github.com/ClickHouse/ClickHouse/pull/50977) ([Val Doroshchuk](https://github.com/valbok)).
* Fix crash in BackupCoordinationStageSync::setError() [#51012](https://github.com/ClickHouse/ClickHouse/pull/51012) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix subtly broken copy-on-write of ColumnLowCardinality dictionary [#51064](https://github.com/ClickHouse/ClickHouse/pull/51064) ([Michael Kolupaev](https://github.com/al13n321)).
* Generate safe IVs [#51086](https://github.com/ClickHouse/ClickHouse/pull/51086) ([Salvatore Mesoraca](https://github.com/aiven-sal)).
* Fix ineffective query cache for SELECTs with subqueries [#51132](https://github.com/ClickHouse/ClickHouse/pull/51132) ([Robert Schulze](https://github.com/rschu1ze)).
* Fix Set index with constant nullable comparison. [#51205](https://github.com/ClickHouse/ClickHouse/pull/51205) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix a crash in s3 and s3Cluster functions [#51209](https://github.com/ClickHouse/ClickHouse/pull/51209) ([Nikolay Degterinsky](https://github.com/evillique)).
* Fix a crash with compiled expressions [#51231](https://github.com/ClickHouse/ClickHouse/pull/51231) ([LiuNeng](https://github.com/liuneng1994)).
* Fix use-after-free in StorageURL when switching URLs [#51260](https://github.com/ClickHouse/ClickHouse/pull/51260) ([Michael Kolupaev](https://github.com/al13n321)).
* Updated check for parameterized view [#51272](https://github.com/ClickHouse/ClickHouse/pull/51272) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Fix multiple writing of same file to backup [#51299](https://github.com/ClickHouse/ClickHouse/pull/51299) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix fuzzer failure in ActionsDAG [#51301](https://github.com/ClickHouse/ClickHouse/pull/51301) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Remove garbage from function `transform` [#51350](https://github.com/ClickHouse/ClickHouse/pull/51350) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
### <a id="235"></a> ClickHouse release 23.5, 2023-06-08
#### Upgrade Notes
* Compress marks and primary key by default. It significantly reduces the cold query time. Upgrade notes: the support for compressed marks and primary key has been added in version 22.9. If you turned on compressed marks or primary key or installed version 23.5 or newer, which has compressed marks or primary key on by default, you will not be able to downgrade to version 22.8 or earlier. You can also explicitly disable compressed marks or primary keys by specifying the `compress_marks` and `compress_primary_key` settings in the `<merge_tree>` section of the server configuration file. **Upgrade notes:** If you upgrade from versions prior to 22.9, you should either upgrade all replicas at once or disable the compression before upgrade, or upgrade through an intermediate version, where the compressed marks are supported but not enabled by default, such as 23.3. [#42587](https://github.com/ClickHouse/ClickHouse/pull/42587) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Make local object storage work consistently with s3 object storage, fix problem with append (closes [#48465](https://github.com/ClickHouse/ClickHouse/issues/48465)), make it configurable as independent storage. The change is backward incompatible because the cache on top of local object storage is not compatible to previous versions. [#48791](https://github.com/ClickHouse/ClickHouse/pull/48791) ([Kseniia Sumarokova](https://github.com/kssenii)).
* The experimental feature "in-memory data parts" is removed. The data format is still supported, but the settings are no-op, and compact or wide parts will be used instead. This closes [#45409](https://github.com/ClickHouse/ClickHouse/issues/45409). [#49429](https://github.com/ClickHouse/ClickHouse/pull/49429) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Changed default values of settings `parallelize_output_from_storages` and `input_format_parquet_preserve_order`. This allows ClickHouse to reorder rows when reading from files (e.g. CSV or Parquet), greatly improving performance in many cases. To restore the old behavior of preserving order, use `parallelize_output_from_storages = 0`, `input_format_parquet_preserve_order = 1`. [#49479](https://github.com/ClickHouse/ClickHouse/pull/49479) ([Michael Kolupaev](https://github.com/al13n321)).
* Make projections production-ready. Add the `optimize_use_projections` setting to control whether the projections will be selected for SELECT queries. The setting `allow_experimental_projection_optimization` is obsolete and does nothing. [#49719](https://github.com/ClickHouse/ClickHouse/pull/49719) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Mark `joinGet` as non-deterministic (so as `dictGet`). It allows using them in mutations without an extra setting. [#49843](https://github.com/ClickHouse/ClickHouse/pull/49843) ([Azat Khuzhin](https://github.com/azat)).
* Revert the "`groupArray` returns cannot be nullable" change (due to binary compatibility breakage for `groupArray`/`groupArrayLast`/`groupArraySample` over `Nullable` types, which likely will lead to `TOO_LARGE_ARRAY_SIZE` or `CANNOT_READ_ALL_DATA`). [#49971](https://github.com/ClickHouse/ClickHouse/pull/49971) ([Azat Khuzhin](https://github.com/azat)).
* Setting `enable_memory_bound_merging_of_aggregation_results` is enabled by default. If you update from version prior to 22.12, we recommend to set this flag to `false` until update is finished. [#50319](https://github.com/ClickHouse/ClickHouse/pull/50319) ([Nikita Taranov](https://github.com/nickitat)).
#### New Feature
* Added storage engine AzureBlobStorage and azureBlobStorage table function. The supported set of features is very similar to storage/table function S3 [#50604] (https://github.com/ClickHouse/ClickHouse/pull/50604) ([alesapin](https://github.com/alesapin)) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni).
* Added native ClickHouse Keeper CLI Client, it is available as `clickhouse keeper-client` [#47414](https://github.com/ClickHouse/ClickHouse/pull/47414) ([pufit](https://github.com/pufit)).
* Add `urlCluster` table function. Refactor all *Cluster table functions to reduce code duplication. Make schema inference work for all possible *Cluster function signatures and for named collections. Closes [#38499](https://github.com/ClickHouse/ClickHouse/issues/38499). [#45427](https://github.com/ClickHouse/ClickHouse/pull/45427) ([attack204](https://github.com/attack204)), Pavel Kruglov.
* The query cache can now be used for production workloads. [#47977](https://github.com/ClickHouse/ClickHouse/pull/47977) ([Robert Schulze](https://github.com/rschu1ze)). The query cache can now support queries with totals and extremes modifier. [#48853](https://github.com/ClickHouse/ClickHouse/pull/48853) ([Robert Schulze](https://github.com/rschu1ze)). Make `allow_experimental_query_cache` setting as obsolete for backward-compatibility. It was removed in https://github.com/ClickHouse/ClickHouse/pull/47977. [#49934](https://github.com/ClickHouse/ClickHouse/pull/49934) ([Timur Solodovnikov](https://github.com/tsolodov)).
* Geographical data types (`Point`, `Ring`, `Polygon`, and `MultiPolygon`) are production-ready. [#50022](https://github.com/ClickHouse/ClickHouse/pull/50022) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Add schema inference to PostgreSQL, MySQL, MeiliSearch, and SQLite table engines. Closes [#49972](https://github.com/ClickHouse/ClickHouse/issues/49972). [#50000](https://github.com/ClickHouse/ClickHouse/pull/50000) ([Nikolay Degterinsky](https://github.com/evillique)).
* Password type in queries like `CREATE USER u IDENTIFIED BY 'p'` will be automatically set according to the setting `default_password_type` in the `config.xml` on the server. Closes [#42915](https://github.com/ClickHouse/ClickHouse/issues/42915). [#44674](https://github.com/ClickHouse/ClickHouse/pull/44674) ([Nikolay Degterinsky](https://github.com/evillique)).
* Add bcrypt password authentication type. Closes [#34599](https://github.com/ClickHouse/ClickHouse/issues/34599). [#44905](https://github.com/ClickHouse/ClickHouse/pull/44905) ([Nikolay Degterinsky](https://github.com/evillique)).
* Introduces new keyword `INTO OUTFILE 'file.txt' APPEND`. [#48880](https://github.com/ClickHouse/ClickHouse/pull/48880) ([alekar](https://github.com/alekar)).
* Added `system.zookeeper_connection` table that shows information about Keeper connections. [#45245](https://github.com/ClickHouse/ClickHouse/pull/45245) ([mateng915](https://github.com/mateng0915)).
* Add new function `generateRandomStructure` that generates random table structure. It can be used in combination with table function `generateRandom`. [#47409](https://github.com/ClickHouse/ClickHouse/pull/47409) ([Kruglov Pavel](https://github.com/Avogar)).
* Allow the use of `CASE` without an `ELSE` branch and extended `transform` to deal with more types. Also fix some issues that made transform() return incorrect results when decimal types were mixed with other numeric types. [#48300](https://github.com/ClickHouse/ClickHouse/pull/48300) ([Salvatore Mesoraca](https://github.com/aiven-sal)). This closes #2655. This closes #9596. This closes #38666.
* Added [server-side encryption using KMS keys](https://docs.aws.amazon.com/AmazonS3/latest/userguide/UsingKMSEncryption.html) with S3 tables, and the `header` setting with S3 disks. Closes [#48723](https://github.com/ClickHouse/ClickHouse/issues/48723). [#48724](https://github.com/ClickHouse/ClickHouse/pull/48724) ([Johann Gan](https://github.com/johanngan)).
* Add MemoryTracker for the background tasks (merges and mutation). Introduces `merges_mutations_memory_usage_soft_limit` and `merges_mutations_memory_usage_to_ram_ratio` settings that represent the soft memory limit for merges and mutations. If this limit is reached ClickHouse won't schedule new merge or mutation tasks. Also `MergesMutationsMemoryTracking` metric is introduced to allow observing current memory usage of background tasks. Resubmit [#46089](https://github.com/ClickHouse/ClickHouse/issues/46089). Closes [#48774](https://github.com/ClickHouse/ClickHouse/issues/48774). [#48787](https://github.com/ClickHouse/ClickHouse/pull/48787) ([Dmitry Novik](https://github.com/novikd)).
* Function `dotProduct` work for array. [#49050](https://github.com/ClickHouse/ClickHouse/pull/49050) ([FFFFFFFHHHHHHH](https://github.com/FFFFFFFHHHHHHH)).
* Support statement `SHOW INDEX` to improve compatibility with MySQL. [#49158](https://github.com/ClickHouse/ClickHouse/pull/49158) ([Robert Schulze](https://github.com/rschu1ze)).
* Add virtual column `_file` and `_path` support to table function `url`. - Improve error message for table function `url`. - resolves [#49231](https://github.com/ClickHouse/ClickHouse/issues/49231) - resolves [#49232](https://github.com/ClickHouse/ClickHouse/issues/49232). [#49356](https://github.com/ClickHouse/ClickHouse/pull/49356) ([Ziyi Tan](https://github.com/Ziy1-Tan)).
* Adding the `grants` field in the users.xml file, which allows specifying grants for users. [#49381](https://github.com/ClickHouse/ClickHouse/pull/49381) ([pufit](https://github.com/pufit)).
* Support full/right join by using grace hash join algorithm. [#49483](https://github.com/ClickHouse/ClickHouse/pull/49483) ([lgbo](https://github.com/lgbo-ustc)).
* `WITH FILL` modifier groups filling by sorting prefix. Controlled by `use_with_fill_by_sorting_prefix` setting (enabled by default). Related to [#33203](https://github.com/ClickHouse/ClickHouse/issues/33203)#issuecomment-1418736794. [#49503](https://github.com/ClickHouse/ClickHouse/pull/49503) ([Igor Nikonov](https://github.com/devcrafter)).
* Clickhouse-client now accepts queries after "--multiquery" when "--query" (or "-q") is absent. example: clickhouse-client --multiquery "select 1; select 2;". [#49870](https://github.com/ClickHouse/ClickHouse/pull/49870) ([Alexey Gerasimchuk](https://github.com/Demilivor)).
* Add separate `handshake_timeout` for receiving Hello packet from replica. Closes [#48854](https://github.com/ClickHouse/ClickHouse/issues/48854). [#49948](https://github.com/ClickHouse/ClickHouse/pull/49948) ([Kruglov Pavel](https://github.com/Avogar)).
* Added a function "space" which repeats a space as many times as specified. [#50103](https://github.com/ClickHouse/ClickHouse/pull/50103) ([Robert Schulze](https://github.com/rschu1ze)).
* Added --input_format_csv_trim_whitespaces option. [#50215](https://github.com/ClickHouse/ClickHouse/pull/50215) ([Alexey Gerasimchuk](https://github.com/Demilivor)).
* Allow the `dictGetAll` function for regexp tree dictionaries to return values from multiple matches as arrays. Closes [#50254](https://github.com/ClickHouse/ClickHouse/issues/50254). [#50255](https://github.com/ClickHouse/ClickHouse/pull/50255) ([Johann Gan](https://github.com/johanngan)).
* Added `toLastDayOfWeek` function to round a date or a date with time up to the nearest Saturday or Sunday. [#50315](https://github.com/ClickHouse/ClickHouse/pull/50315) ([Victor Krasnov](https://github.com/sirvickr)).
* Ability to ignore a skip index by specifying `ignore_data_skipping_indices`. [#50329](https://github.com/ClickHouse/ClickHouse/pull/50329) ([Boris Kuschel](https://github.com/bkuschel)).
* Add `system.user_processes` table and `SHOW USER PROCESSES` query to show memory info and ProfileEvents on user level. [#50492](https://github.com/ClickHouse/ClickHouse/pull/50492) ([János Benjamin Antal](https://github.com/antaljanosbenjamin)).
* Add server and format settings `display_secrets_in_show_and_select` for displaying secrets of tables, databases, table functions, and dictionaries. Add privilege `displaySecretsInShowAndSelect` controlling which users can view secrets. [#46528](https://github.com/ClickHouse/ClickHouse/pull/46528) ([Mike Kot](https://github.com/myrrc)).
* Allow to set up a ROW POLICY for all tables that belong to a DATABASE. [#47640](https://github.com/ClickHouse/ClickHouse/pull/47640) ([Ilya Golshtein](https://github.com/ilejn)).
#### Performance Improvement
* Compress marks and primary key by default. It significantly reduces the cold query time. Upgrade notes: the support for compressed marks and primary key has been added in version 22.9. If you turned on compressed marks or primary key or installed version 23.5 or newer, which has compressed marks or primary key on by default, you will not be able to downgrade to version 22.8 or earlier. You can also explicitly disable compressed marks or primary keys by specifying the `compress_marks` and `compress_primary_key` settings in the `<merge_tree>` section of the server configuration file. [#42587](https://github.com/ClickHouse/ClickHouse/pull/42587) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* New setting s3_max_inflight_parts_for_one_file sets the limit of concurrently loaded parts with multipart upload request in scope of one file. [#49961](https://github.com/ClickHouse/ClickHouse/pull/49961) ([Sema Checherinda](https://github.com/CheSema)).
* When reading from multiple files reduce parallel parsing threads for each file. Resolves [#42192](https://github.com/ClickHouse/ClickHouse/issues/42192). [#46661](https://github.com/ClickHouse/ClickHouse/pull/46661) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Use aggregate projection only if it reads fewer granules than normal reading. It should help in case if query hits the PK of the table, but not the projection. Fixes [#49150](https://github.com/ClickHouse/ClickHouse/issues/49150). [#49417](https://github.com/ClickHouse/ClickHouse/pull/49417) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Do not store blocks in `ANY` hash join if nothing is inserted. [#48633](https://github.com/ClickHouse/ClickHouse/pull/48633) ([vdimir](https://github.com/vdimir)).
* Fixes aggregate combinator `-If` when JIT compiled, and enable JIT compilation for aggregate functions. Closes [#48120](https://github.com/ClickHouse/ClickHouse/issues/48120). [#49083](https://github.com/ClickHouse/ClickHouse/pull/49083) ([Igor Nikonov](https://github.com/devcrafter)).
* For reading from remote tables we use smaller tasks (instead of reading the whole part) to make tasks stealing work * task size is determined by size of columns to read * always use 1mb buffers for reading from s3 * boundaries of cache segments aligned to 1mb so they have decent size even with small tasks. it also should prevent fragmentation. [#49287](https://github.com/ClickHouse/ClickHouse/pull/49287) ([Nikita Taranov](https://github.com/nickitat)).
* Introduced settings: - `merge_max_block_size_bytes` to limit the amount of memory used for background operations. - `vertical_merge_algorithm_min_bytes_to_activate` to add another condition to activate vertical merges. [#49313](https://github.com/ClickHouse/ClickHouse/pull/49313) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Default size of a read buffer for reading from local filesystem changed to a slightly better value. Also two new settings are introduced: `max_read_buffer_size_local_fs` and `max_read_buffer_size_remote_fs`. [#49321](https://github.com/ClickHouse/ClickHouse/pull/49321) ([Nikita Taranov](https://github.com/nickitat)).
* Improve memory usage and speed of `SPARSE_HASHED`/`HASHED` dictionaries (e.g. `SPARSE_HASHED` now eats 2.6x less memory, and is ~2x faster). [#49380](https://github.com/ClickHouse/ClickHouse/pull/49380) ([Azat Khuzhin](https://github.com/azat)).
* Optimize the `system.query_log` and `system.query_thread_log` tables by applying `LowCardinality` when appropriate. The queries over these tables will be faster. [#49530](https://github.com/ClickHouse/ClickHouse/pull/49530) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Better performance when reading local `Parquet` files (through parallel reading). [#49539](https://github.com/ClickHouse/ClickHouse/pull/49539) ([Michael Kolupaev](https://github.com/al13n321)).
* Improve the performance of `RIGHT/FULL JOIN` by up to 2 times in certain scenarios, especially when joining a small left table with a large right table. [#49585](https://github.com/ClickHouse/ClickHouse/pull/49585) ([lgbo](https://github.com/lgbo-ustc)).
* Improve performance of BLAKE3 by 11% by enabling LTO for Rust. [#49600](https://github.com/ClickHouse/ClickHouse/pull/49600) ([Azat Khuzhin](https://github.com/azat)). Now it is on par with C++.
* Optimize the structure of the `system.opentelemetry_span_log`. Use `LowCardinality` where appropriate. Although this table is generally stupid (it is using the Map data type even for common attributes), it will be slightly better. [#49647](https://github.com/ClickHouse/ClickHouse/pull/49647) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Try to reserve hash table's size in `grace_hash` join. [#49816](https://github.com/ClickHouse/ClickHouse/pull/49816) ([lgbo](https://github.com/lgbo-ustc)).
* Parallel merge of `uniqExactIf` states. Closes [#49885](https://github.com/ClickHouse/ClickHouse/issues/49885). [#50285](https://github.com/ClickHouse/ClickHouse/pull/50285) ([flynn](https://github.com/ucasfl)).
* Keeper improvement: add `CheckNotExists` request to Keeper, which allows to improve the performance of Replicated tables. [#48897](https://github.com/ClickHouse/ClickHouse/pull/48897) ([Antonio Andelic](https://github.com/antonio2368)).
* Keeper performance improvements: avoid serializing same request twice while processing. Cache deserialization results of large requests. Controlled by new coordination setting `min_request_size_for_cache`. [#49004](https://github.com/ClickHouse/ClickHouse/pull/49004) ([Antonio Andelic](https://github.com/antonio2368)).
* Reduced number of `List` ZooKeeper requests when selecting parts to merge and a lot of partitions do not have anything to merge. [#49637](https://github.com/ClickHouse/ClickHouse/pull/49637) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Rework locking in the FS cache [#44985](https://github.com/ClickHouse/ClickHouse/pull/44985) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Disable pure parallel replicas if trivial count optimization is possible. [#50594](https://github.com/ClickHouse/ClickHouse/pull/50594) ([Raúl Marín](https://github.com/Algunenano)).
* Don't send head request for all keys in Iceberg schema inference, only for keys that are used for reaing data. [#50203](https://github.com/ClickHouse/ClickHouse/pull/50203) ([Kruglov Pavel](https://github.com/Avogar)).
* Setting `enable_memory_bound_merging_of_aggregation_results` is enabled by default. [#50319](https://github.com/ClickHouse/ClickHouse/pull/50319) ([Nikita Taranov](https://github.com/nickitat)).
#### Experimental Feature
* `DEFLATE_QPL` codec lower the minimum simd version to SSE 4.2. [doc change in qpl](https://github.com/intel/qpl/commit/3f8f5cea27739f5261e8fd577dc233ffe88bf679) - Intel® QPL relies on a run-time kernels dispatcher and cpuid check to choose the best available implementation(sse/avx2/avx512) - restructured cmakefile for qpl build in clickhouse to align with latest upstream qpl. [#49811](https://github.com/ClickHouse/ClickHouse/pull/49811) ([jasperzhu](https://github.com/jinjunzh)).
* Add initial support to do JOINs with pure parallel replicas. [#49544](https://github.com/ClickHouse/ClickHouse/pull/49544) ([Raúl Marín](https://github.com/Algunenano)).
* More parallelism on `Outdated` parts removal with "zero-copy replication". [#49630](https://github.com/ClickHouse/ClickHouse/pull/49630) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Parallel Replicas: 1) Fixed an error `NOT_FOUND_COLUMN_IN_BLOCK` in case of using parallel replicas with non-replicated storage with disabled setting `parallel_replicas_for_non_replicated_merge_tree` 2) Now `allow_experimental_parallel_reading_from_replicas` have 3 possible values - 0, 1 and 2. 0 - disabled, 1 - enabled, silently disable them in case of failure (in case of FINAL or JOIN), 2 - enabled, throw an exception in case of failure. 3) If FINAL modifier is used in SELECT query and parallel replicas are enabled, ClickHouse will try to disable them if `allow_experimental_parallel_reading_from_replicas` is set to 1 and throw an exception otherwise. [#50195](https://github.com/ClickHouse/ClickHouse/pull/50195) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* When parallel replicas are enabled they will always skip unavailable servers (the behavior is controlled by the setting `skip_unavailable_shards`, enabled by default and can be only disabled). This closes: [#48565](https://github.com/ClickHouse/ClickHouse/issues/48565). [#50293](https://github.com/ClickHouse/ClickHouse/pull/50293) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
#### Improvement
* The `BACKUP` command will not decrypt data from encrypted disks while making a backup. Instead the data will be stored in a backup in encrypted form. Such backups can be restored only to an encrypted disk with the same (or extended) list of encryption keys. [#48896](https://github.com/ClickHouse/ClickHouse/pull/48896) ([Vitaly Baranov](https://github.com/vitlibar)).
* Added possibility to use temporary tables in FROM part of ATTACH PARTITION FROM and REPLACE PARTITION FROM. [#49436](https://github.com/ClickHouse/ClickHouse/pull/49436) ([Roman Vasin](https://github.com/rvasin)).
* Added setting `async_insert` for `MergeTree` tables. It has the same meaning as query-level setting `async_insert` and enables asynchronous inserts for specific table. Note: it doesn't take effect for insert queries from `clickhouse-client`, use query-level setting in that case. [#49122](https://github.com/ClickHouse/ClickHouse/pull/49122) ([Anton Popov](https://github.com/CurtizJ)).
* Add support for size suffixes in quota creation statement parameters. [#49087](https://github.com/ClickHouse/ClickHouse/pull/49087) ([Eridanus](https://github.com/Eridanus117)).
* Extend `first_value` and `last_value` to accept NULL. [#46467](https://github.com/ClickHouse/ClickHouse/pull/46467) ([lgbo](https://github.com/lgbo-ustc)).
* Add alias `str_to_map` and `mapFromString` for `extractKeyValuePairs`. closes https://github.com/clickhouse/clickhouse/issues/47185. [#49466](https://github.com/ClickHouse/ClickHouse/pull/49466) ([flynn](https://github.com/ucasfl)).
* Add support for CGroup version 2 for asynchronous metrics about the memory usage and availability. This closes [#37983](https://github.com/ClickHouse/ClickHouse/issues/37983). [#45999](https://github.com/ClickHouse/ClickHouse/pull/45999) ([sichenzhao](https://github.com/sichenzhao)).
* Cluster table functions should always skip unavailable shards. close [#46314](https://github.com/ClickHouse/ClickHouse/issues/46314). [#46765](https://github.com/ClickHouse/ClickHouse/pull/46765) ([zk_kiger](https://github.com/zk-kiger)).
* Allow CSV file to contain empty columns in its header. [#47496](https://github.com/ClickHouse/ClickHouse/pull/47496) ([你不要过来啊](https://github.com/iiiuwioajdks)).
* Add Google Cloud Storage S3 compatible table function `gcs`. Like the `oss` and `cosn` functions, it is just an alias over the `s3` table function, and it does not bring any new features. [#47815](https://github.com/ClickHouse/ClickHouse/pull/47815) ([Kuba Kaflik](https://github.com/jkaflik)).
* Add ability to use strict parts size for S3 (compatibility with CloudFlare R2 S3 Storage). [#48492](https://github.com/ClickHouse/ClickHouse/pull/48492) ([Azat Khuzhin](https://github.com/azat)).
* Added new columns with info about `Replicated` database replicas to `system.clusters`: `database_shard_name`, `database_replica_name`, `is_active`. Added an optional `FROM SHARD` clause to `SYSTEM DROP DATABASE REPLICA` query. [#48548](https://github.com/ClickHouse/ClickHouse/pull/48548) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Add a new column `zookeeper_name` in system.replicas, to indicate on which (auxiliary) zookeeper cluster the replicated table's metadata is stored. [#48549](https://github.com/ClickHouse/ClickHouse/pull/48549) ([cangyin](https://github.com/cangyin)).
* `IN` operator support the comparison of `Date` and `Date32`. Closes [#48736](https://github.com/ClickHouse/ClickHouse/issues/48736). [#48806](https://github.com/ClickHouse/ClickHouse/pull/48806) ([flynn](https://github.com/ucasfl)).
* Support for erasure codes in `HDFS`, author: @M1eyu2018, @tomscut. [#48833](https://github.com/ClickHouse/ClickHouse/pull/48833) ([M1eyu](https://github.com/M1eyu2018)).
* Implement SYSTEM DROP REPLICA from auxiliary ZooKeeper clusters, may be close [#48931](https://github.com/ClickHouse/ClickHouse/issues/48931). [#48932](https://github.com/ClickHouse/ClickHouse/pull/48932) ([wangxiaobo](https://github.com/wzb5212)).
* Add Array data type to MongoDB. Closes [#48598](https://github.com/ClickHouse/ClickHouse/issues/48598). [#48983](https://github.com/ClickHouse/ClickHouse/pull/48983) ([Nikolay Degterinsky](https://github.com/evillique)).
* Support storing `Interval` data types in tables. [#49085](https://github.com/ClickHouse/ClickHouse/pull/49085) ([larryluogit](https://github.com/larryluogit)).
* Allow using `ntile` window function without explicit window frame definition: `ntile(3) OVER (ORDER BY a)`, close [#46763](https://github.com/ClickHouse/ClickHouse/issues/46763). [#49093](https://github.com/ClickHouse/ClickHouse/pull/49093) ([vdimir](https://github.com/vdimir)).
* Added settings (`number_of_mutations_to_delay`, `number_of_mutations_to_throw`) to delay or throw `ALTER` queries that create mutations (`ALTER UPDATE`, `ALTER DELETE`, `ALTER MODIFY COLUMN`, ...) in case when table already has a lot of unfinished mutations. [#49117](https://github.com/ClickHouse/ClickHouse/pull/49117) ([Anton Popov](https://github.com/CurtizJ)).
* Catch exception from `create_directories` in filesystem cache. [#49203](https://github.com/ClickHouse/ClickHouse/pull/49203) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Copies embedded examples to a new field `example` in `system.functions` to supplement the field `description`. [#49222](https://github.com/ClickHouse/ClickHouse/pull/49222) ([Dan Roscigno](https://github.com/DanRoscigno)).
* Enable connection options for the MongoDB dictionary. Example: ``` xml <source> <mongodb> <host>localhost</host> <port>27017</port> <user></user> <password></password> <db>test</db> <collection>dictionary_source</collection> <options>ssl=true</options> </mongodb> </source> ``` ### Documentation entry for user-facing changes. [#49225](https://github.com/ClickHouse/ClickHouse/pull/49225) ([MikhailBurdukov](https://github.com/MikhailBurdukov)).
* Added an alias `asymptotic` for `asymp` computational method for `kolmogorovSmirnovTest`. Improved documentation. [#49286](https://github.com/ClickHouse/ClickHouse/pull/49286) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Aggregation function groupBitAnd/Or/Xor now work on signed integer data. This makes them consistent with the behavior of scalar functions bitAnd/Or/Xor. [#49292](https://github.com/ClickHouse/ClickHouse/pull/49292) ([exmy](https://github.com/exmy)).
* Split function-documentation into more fine-granular fields. [#49300](https://github.com/ClickHouse/ClickHouse/pull/49300) ([Robert Schulze](https://github.com/rschu1ze)).
* Use multiple threads shared between all tables within a server to load outdated data parts. The the size of the pool and its queue is controlled by `max_outdated_parts_loading_thread_pool_size` and `outdated_part_loading_thread_pool_queue_size` settings. [#49317](https://github.com/ClickHouse/ClickHouse/pull/49317) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Don't overestimate the size of processed data for `LowCardinality` columns when they share dictionaries between blocks. This closes [#49322](https://github.com/ClickHouse/ClickHouse/issues/49322). See also [#48745](https://github.com/ClickHouse/ClickHouse/issues/48745). [#49323](https://github.com/ClickHouse/ClickHouse/pull/49323) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Parquet writer now uses reasonable row group size when invoked through `OUTFILE`. [#49325](https://github.com/ClickHouse/ClickHouse/pull/49325) ([Michael Kolupaev](https://github.com/al13n321)).
* Allow restricted keywords like `ARRAY` as an alias if the alias is quoted. Closes [#49324](https://github.com/ClickHouse/ClickHouse/issues/49324). [#49360](https://github.com/ClickHouse/ClickHouse/pull/49360) ([Nikolay Degterinsky](https://github.com/evillique)).
* Data parts loading and deletion jobs were moved to shared server-wide pools instead of per-table pools. Pools sizes are controlled via settings `max_active_parts_loading_thread_pool_size`, `max_outdated_parts_loading_thread_pool_size` and `max_parts_cleaning_thread_pool_size` in top-level config. Table-level settings `max_part_loading_threads` and `max_part_removal_threads` became obsolete. [#49474](https://github.com/ClickHouse/ClickHouse/pull/49474) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Allow `?password=pass` in URL of the Play UI. Password is replaced in browser history. [#49505](https://github.com/ClickHouse/ClickHouse/pull/49505) ([Mike Kot](https://github.com/myrrc)).
* Allow reading zero-size objects from remote filesystems. (because empty files are not backup'd, so we might end up with zero blobs in metadata file). Closes [#49480](https://github.com/ClickHouse/ClickHouse/issues/49480). [#49519](https://github.com/ClickHouse/ClickHouse/pull/49519) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Attach thread MemoryTracker to `total_memory_tracker` after `ThreadGroup` detached. [#49527](https://github.com/ClickHouse/ClickHouse/pull/49527) ([Dmitry Novik](https://github.com/novikd)).
* Fix parameterized views when a query parameter is used multiple times in the query. [#49556](https://github.com/ClickHouse/ClickHouse/pull/49556) ([Azat Khuzhin](https://github.com/azat)).
* Release memory allocated for the last sent ProfileEvents snapshot in the context of a query. Followup [#47564](https://github.com/ClickHouse/ClickHouse/issues/47564). [#49561](https://github.com/ClickHouse/ClickHouse/pull/49561) ([Dmitry Novik](https://github.com/novikd)).
* Function "makeDate" now provides a MySQL-compatible overload (year & day of the year argument). [#49603](https://github.com/ClickHouse/ClickHouse/pull/49603) ([Robert Schulze](https://github.com/rschu1ze)).
* Support `dictionary` table function for `RegExpTreeDictionary`. [#49666](https://github.com/ClickHouse/ClickHouse/pull/49666) ([Han Fei](https://github.com/hanfei1991)).
* Added weighted fair IO scheduling policy. Added dynamic resource manager, which allows IO scheduling hierarchy to be updated in runtime w/o server restarts. [#49671](https://github.com/ClickHouse/ClickHouse/pull/49671) ([Sergei Trifonov](https://github.com/serxa)).
* Add compose request after multipart upload to GCS. This enables the usage of copy operation on objects uploaded with the multipart upload. It's recommended to set `s3_strict_upload_part_size` to some value because compose request can fail on objects created with parts of different sizes. [#49693](https://github.com/ClickHouse/ClickHouse/pull/49693) ([Antonio Andelic](https://github.com/antonio2368)).
* For the `extractKeyValuePairs` function: improve the "best-effort" parsing logic to accept `key_value_delimiter` as a valid part of the value. This also simplifies branching and might even speed up things a bit. [#49760](https://github.com/ClickHouse/ClickHouse/pull/49760) ([Arthur Passos](https://github.com/arthurpassos)).
* Add `initial_query_id` field for system.processors_profile_log [#49777](https://github.com/ClickHouse/ClickHouse/pull/49777) ([helifu](https://github.com/helifu)).
* System log tables can now have custom sorting keys. [#49778](https://github.com/ClickHouse/ClickHouse/pull/49778) ([helifu](https://github.com/helifu)).
* A new field `partitions` to `system.query_log` is used to indicate which partitions are participating in the calculation. [#49779](https://github.com/ClickHouse/ClickHouse/pull/49779) ([helifu](https://github.com/helifu)).
* Added `enable_the_endpoint_id_with_zookeeper_name_prefix` setting for `ReplicatedMergeTree` (disabled by default). When enabled, it adds ZooKeeper cluster name to table's interserver communication endpoint. It avoids `Duplicate interserver IO endpoint` errors when having replicated tables with the same path, but different auxiliary ZooKeepers. [#49780](https://github.com/ClickHouse/ClickHouse/pull/49780) ([helifu](https://github.com/helifu)).
* Add query parameters to `clickhouse-local`. Closes [#46561](https://github.com/ClickHouse/ClickHouse/issues/46561). [#49785](https://github.com/ClickHouse/ClickHouse/pull/49785) ([Nikolay Degterinsky](https://github.com/evillique)).
* Allow loading dictionaries and functions from YAML by default. In previous versions, it required editing the `dictionaries_config` or `user_defined_executable_functions_config` in the configuration file, as they expected `*.xml` files. [#49812](https://github.com/ClickHouse/ClickHouse/pull/49812) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* The Kafka table engine now allows to use alias columns. [#49824](https://github.com/ClickHouse/ClickHouse/pull/49824) ([Aleksandr Musorin](https://github.com/AVMusorin)).
* Add setting to limit the max number of pairs produced by `extractKeyValuePairs`, a safeguard to avoid using way too much memory. [#49836](https://github.com/ClickHouse/ClickHouse/pull/49836) ([Arthur Passos](https://github.com/arthurpassos)).
* Add support for (an unusual) case where the arguments in the `IN` operator are single-element tuples. [#49844](https://github.com/ClickHouse/ClickHouse/pull/49844) ([MikhailBurdukov](https://github.com/MikhailBurdukov)).
* `bitHammingDistance` function support `String` and `FixedString` data type. Closes [#48827](https://github.com/ClickHouse/ClickHouse/issues/48827). [#49858](https://github.com/ClickHouse/ClickHouse/pull/49858) ([flynn](https://github.com/ucasfl)).
* Fix timeout resetting errors in the client on OS X. [#49863](https://github.com/ClickHouse/ClickHouse/pull/49863) ([alekar](https://github.com/alekar)).
* Add support for big integers, such as UInt128, Int128, UInt256, and Int256 in the function `bitCount`. This enables Hamming distance over large bit masks for AI applications. [#49867](https://github.com/ClickHouse/ClickHouse/pull/49867) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fingerprints to be used instead of key IDs in encrypted disks. This simplifies the configuration of encrypted disks. [#49882](https://github.com/ClickHouse/ClickHouse/pull/49882) ([Vitaly Baranov](https://github.com/vitlibar)).
* Add UUID data type to PostgreSQL. Closes [#49739](https://github.com/ClickHouse/ClickHouse/issues/49739). [#49894](https://github.com/ClickHouse/ClickHouse/pull/49894) ([Nikolay Degterinsky](https://github.com/evillique)).
* Function `toUnixTimestamp` now accepts `Date` and `Date32` arguments. [#49989](https://github.com/ClickHouse/ClickHouse/pull/49989) ([Victor Krasnov](https://github.com/sirvickr)).
* Charge only server memory for dictionaries. [#49995](https://github.com/ClickHouse/ClickHouse/pull/49995) ([Azat Khuzhin](https://github.com/azat)).
* The server will allow using the `SQL_*` settings such as `SQL_AUTO_IS_NULL` as no-ops for MySQL compatibility. This closes [#49927](https://github.com/ClickHouse/ClickHouse/issues/49927). [#50013](https://github.com/ClickHouse/ClickHouse/pull/50013) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Preserve initial_query_id for ON CLUSTER queries, which is useful for introspection (under `distributed_ddl_entry_format_version=5`). [#50015](https://github.com/ClickHouse/ClickHouse/pull/50015) ([Azat Khuzhin](https://github.com/azat)).
* Preserve backward incompatibility for renamed settings by using aliases (`allow_experimental_projection_optimization` for `optimize_use_projections`, `allow_experimental_lightweight_delete` for `enable_lightweight_delete`). [#50044](https://github.com/ClickHouse/ClickHouse/pull/50044) ([Azat Khuzhin](https://github.com/azat)).
* Support passing FQDN through setting my_hostname to register cluster node in keeper. Add setting of invisible to support multi compute groups. A compute group as a cluster, is invisible to other compute groups. [#50186](https://github.com/ClickHouse/ClickHouse/pull/50186) ([Yangkuan Liu](https://github.com/LiuYangkuan)).
* Fix PostgreSQL reading all the data even though `LIMIT n` could be specified. [#50187](https://github.com/ClickHouse/ClickHouse/pull/50187) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Add new profile events for queries with subqueries (`QueriesWithSubqueries`/`SelectQueriesWithSubqueries`/`InsertQueriesWithSubqueries`). [#50204](https://github.com/ClickHouse/ClickHouse/pull/50204) ([Azat Khuzhin](https://github.com/azat)).
* Adding the roles field in the users.xml file, which allows specifying roles with grants via a config file. [#50278](https://github.com/ClickHouse/ClickHouse/pull/50278) ([pufit](https://github.com/pufit)).
* Report `CGroupCpuCfsPeriod` and `CGroupCpuCfsQuota` in AsynchronousMetrics. - Respect cgroup v2 memory limits during server startup. [#50379](https://github.com/ClickHouse/ClickHouse/pull/50379) ([alekar](https://github.com/alekar)).
* Add a signal handler for SIGQUIT to work the same way as SIGINT. Closes [#50298](https://github.com/ClickHouse/ClickHouse/issues/50298). [#50435](https://github.com/ClickHouse/ClickHouse/pull/50435) ([Nikolay Degterinsky](https://github.com/evillique)).
* In case JSON parse fails due to the large size of the object output the last position to allow debugging. [#50474](https://github.com/ClickHouse/ClickHouse/pull/50474) ([Valentin Alexeev](https://github.com/valentinalexeev)).
* Support decimals with not fixed size. Closes [#49130](https://github.com/ClickHouse/ClickHouse/issues/49130). [#50586](https://github.com/ClickHouse/ClickHouse/pull/50586) ([Kruglov Pavel](https://github.com/Avogar)).
#### Build/Testing/Packaging Improvement
* New and improved `keeper-bench`. Everything can be customized from YAML/XML file: - request generator - each type of request generator can have a specific set of fields - multi requests can be generated just by doing the same under `multi` key - for each request or subrequest in multi a `weight` field can be defined to control distribution - define trees that need to be setup for a test run - hosts can be defined with all timeouts customizable and it's possible to control how many sessions to generate for each host - integers defined with `min_value` and `max_value` fields are random number generators. [#48547](https://github.com/ClickHouse/ClickHouse/pull/48547) ([Antonio Andelic](https://github.com/antonio2368)).
* Io_uring is not supported on macos, don't choose it when running tests on local to avoid occasional failures. [#49250](https://github.com/ClickHouse/ClickHouse/pull/49250) ([Frank Chen](https://github.com/FrankChen021)).
* Support named fault injection for testing. [#49361](https://github.com/ClickHouse/ClickHouse/pull/49361) ([Han Fei](https://github.com/hanfei1991)).
* Allow running ClickHouse in the OS where the `prctl` (process control) syscall is not available, such as AWS Lambda. [#49538](https://github.com/ClickHouse/ClickHouse/pull/49538) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fixed the issue of build conflict between contrib/isa-l and isa-l in qpl [49296](https://github.com/ClickHouse/ClickHouse/issues/49296). [#49584](https://github.com/ClickHouse/ClickHouse/pull/49584) ([jasperzhu](https://github.com/jinjunzh)).
* Utilities are now only build if explicitly requested ("-DENABLE_UTILS=1") instead of by default, this reduces link times in typical development builds. [#49620](https://github.com/ClickHouse/ClickHouse/pull/49620) ([Robert Schulze](https://github.com/rschu1ze)).
* Pull build description of idxd-config into a separate CMake file to avoid accidental removal in future. [#49651](https://github.com/ClickHouse/ClickHouse/pull/49651) ([jasperzhu](https://github.com/jinjunzh)).
* Add CI check with an enabled analyzer in the master. Follow-up [#49562](https://github.com/ClickHouse/ClickHouse/issues/49562). [#49668](https://github.com/ClickHouse/ClickHouse/pull/49668) ([Dmitry Novik](https://github.com/novikd)).
* Switch to LLVM/clang 16. [#49678](https://github.com/ClickHouse/ClickHouse/pull/49678) ([Azat Khuzhin](https://github.com/azat)).
* Allow building ClickHouse with clang-17. [#49851](https://github.com/ClickHouse/ClickHouse/pull/49851) ([Alexey Milovidov](https://github.com/alexey-milovidov)). [#50410](https://github.com/ClickHouse/ClickHouse/pull/50410) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* ClickHouse is now easier to be integrated into other cmake projects. [#49991](https://github.com/ClickHouse/ClickHouse/pull/49991) ([Amos Bird](https://github.com/amosbird)). (Which is strongly discouraged - Alexey Milovidov).
* Fix strange additional QEMU logging after [#47151](https://github.com/ClickHouse/ClickHouse/issues/47151), see https://s3.amazonaws.com/clickhouse-test-reports/50078/a4743996ee4f3583884d07bcd6501df0cfdaa346/stateless_tests__release__databasereplicated__[3_4].html. [#50442](https://github.com/ClickHouse/ClickHouse/pull/50442) ([Mikhail f. Shiryaev](https://github.com/Felixoid)).
* ClickHouse can work on Linux RISC-V 6.1.22. This closes [#50456](https://github.com/ClickHouse/ClickHouse/issues/50456). [#50457](https://github.com/ClickHouse/ClickHouse/pull/50457) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Bump internal protobuf to v3.18 (fixes bogus CVE-2022-1941). [#50400](https://github.com/ClickHouse/ClickHouse/pull/50400) ([Robert Schulze](https://github.com/rschu1ze)).
* Bump internal libxml2 to v2.10.4 (fixes bogus CVE-2023-28484 and bogus CVE-2023-29469). [#50402](https://github.com/ClickHouse/ClickHouse/pull/50402) ([Robert Schulze](https://github.com/rschu1ze)).
* Bump c-ares to v1.19.1 (bogus CVE-2023-32067, bogus CVE-2023-31130, bogus CVE-2023-31147). [#50403](https://github.com/ClickHouse/ClickHouse/pull/50403) ([Robert Schulze](https://github.com/rschu1ze)).
* Fix bogus CVE-2022-2469 in libgsasl. [#50404](https://github.com/ClickHouse/ClickHouse/pull/50404) ([Robert Schulze](https://github.com/rschu1ze)).
#### Bug Fix (user-visible misbehavior in an official stable release)
* ActionsDAG: fix wrong optimization [#47584](https://github.com/ClickHouse/ClickHouse/pull/47584) ([Salvatore Mesoraca](https://github.com/aiven-sal)).
* Correctly handle concurrent snapshots in Keeper [#48466](https://github.com/ClickHouse/ClickHouse/pull/48466) ([Antonio Andelic](https://github.com/antonio2368)).
* MergeTreeMarksLoader holds DataPart instead of DataPartStorage [#48515](https://github.com/ClickHouse/ClickHouse/pull/48515) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Sequence state fix [#48603](https://github.com/ClickHouse/ClickHouse/pull/48603) ([Ilya Golshtein](https://github.com/ilejn)).
* Back/Restore concurrency check on previous fails [#48726](https://github.com/ClickHouse/ClickHouse/pull/48726) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Fix Attaching a table with non-existent ZK path does not increase the ReadonlyReplica metric [#48954](https://github.com/ClickHouse/ClickHouse/pull/48954) ([wangxiaobo](https://github.com/wzb5212)).
* Fix possible terminate called for uncaught exception in some places [#49112](https://github.com/ClickHouse/ClickHouse/pull/49112) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix key not found error for queries with multiple StorageJoin [#49137](https://github.com/ClickHouse/ClickHouse/pull/49137) ([vdimir](https://github.com/vdimir)).
* Fix wrong query result when using nullable primary key [#49172](https://github.com/ClickHouse/ClickHouse/pull/49172) ([Duc Canh Le](https://github.com/canhld94)).
* Fix reinterpretAs*() on big endian machines [#49198](https://github.com/ClickHouse/ClickHouse/pull/49198) ([Suzy Wang](https://github.com/SuzyWangIBMer)).
* (Experimental zero-copy replication) Lock zero copy parts more atomically [#49211](https://github.com/ClickHouse/ClickHouse/pull/49211) ([alesapin](https://github.com/alesapin)).
* Fix race on Outdated parts loading [#49223](https://github.com/ClickHouse/ClickHouse/pull/49223) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Fix all key value is null and group use rollup return wrong answer [#49282](https://github.com/ClickHouse/ClickHouse/pull/49282) ([Shuai li](https://github.com/loneylee)).
* Fix calculating load_factor for HASHED dictionaries with SHARDS [#49319](https://github.com/ClickHouse/ClickHouse/pull/49319) ([Azat Khuzhin](https://github.com/azat)).
* Disallow configuring compression CODECs for alias columns [#49363](https://github.com/ClickHouse/ClickHouse/pull/49363) ([Timur Solodovnikov](https://github.com/tsolodov)).
* Fix bug in removal of existing part directory [#49365](https://github.com/ClickHouse/ClickHouse/pull/49365) ([alesapin](https://github.com/alesapin)).
* Properly fix GCS when HMAC is used [#49390](https://github.com/ClickHouse/ClickHouse/pull/49390) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix fuzz bug when subquery set is not built when reading from remote() [#49425](https://github.com/ClickHouse/ClickHouse/pull/49425) ([Alexander Gololobov](https://github.com/davenger)).
* Invert `shutdown_wait_unfinished_queries` [#49427](https://github.com/ClickHouse/ClickHouse/pull/49427) ([Konstantin Bogdanov](https://github.com/thevar1able)).
* (Experimental zero-copy replication) Fix another zero copy bug [#49473](https://github.com/ClickHouse/ClickHouse/pull/49473) ([alesapin](https://github.com/alesapin)).
* Fix postgres database setting [#49481](https://github.com/ClickHouse/ClickHouse/pull/49481) ([Mal Curtis](https://github.com/snikch)).
* Correctly handle `s3Cluster` arguments [#49490](https://github.com/ClickHouse/ClickHouse/pull/49490) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix bug in TraceCollector destructor. [#49508](https://github.com/ClickHouse/ClickHouse/pull/49508) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Fix AsynchronousReadIndirectBufferFromRemoteFS breaking on short seeks [#49525](https://github.com/ClickHouse/ClickHouse/pull/49525) ([Michael Kolupaev](https://github.com/al13n321)).
* Fix dictionaries loading order [#49560](https://github.com/ClickHouse/ClickHouse/pull/49560) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Forbid the change of data type of Object('json') column [#49563](https://github.com/ClickHouse/ClickHouse/pull/49563) ([Nikolay Degterinsky](https://github.com/evillique)).
* Fix stress test (Logical error: Expected 7134 >= 11030) [#49623](https://github.com/ClickHouse/ClickHouse/pull/49623) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix bug in DISTINCT [#49628](https://github.com/ClickHouse/ClickHouse/pull/49628) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix: DISTINCT in order with zero values in non-sorted columns [#49636](https://github.com/ClickHouse/ClickHouse/pull/49636) ([Igor Nikonov](https://github.com/devcrafter)).
* Fix one-off error in big integers found by UBSan with fuzzer [#49645](https://github.com/ClickHouse/ClickHouse/pull/49645) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix reading from sparse columns after restart [#49660](https://github.com/ClickHouse/ClickHouse/pull/49660) ([Anton Popov](https://github.com/CurtizJ)).
* Fix assert in SpanHolder::finish() with fibers [#49673](https://github.com/ClickHouse/ClickHouse/pull/49673) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix short circuit functions and mutations with sparse arguments [#49716](https://github.com/ClickHouse/ClickHouse/pull/49716) ([Anton Popov](https://github.com/CurtizJ)).
* Fix writing appended files to incremental backups [#49725](https://github.com/ClickHouse/ClickHouse/pull/49725) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix "There is no physical column _row_exists in table" error occurring during lightweight delete mutation on a table with Object column. [#49737](https://github.com/ClickHouse/ClickHouse/pull/49737) ([Alexander Gololobov](https://github.com/davenger)).
* Fix msan issue in randomStringUTF8(uneven number) [#49750](https://github.com/ClickHouse/ClickHouse/pull/49750) ([Robert Schulze](https://github.com/rschu1ze)).
* Fix aggregate function kolmogorovSmirnovTest [#49768](https://github.com/ClickHouse/ClickHouse/pull/49768) ([FFFFFFFHHHHHHH](https://github.com/FFFFFFFHHHHHHH)).
* Fix settings aliases in native protocol [#49776](https://github.com/ClickHouse/ClickHouse/pull/49776) ([Azat Khuzhin](https://github.com/azat)).
* Fix `arrayMap` with array of tuples with single argument [#49789](https://github.com/ClickHouse/ClickHouse/pull/49789) ([Anton Popov](https://github.com/CurtizJ)).
* Fix per-query IO/BACKUPs throttling settings [#49797](https://github.com/ClickHouse/ClickHouse/pull/49797) ([Azat Khuzhin](https://github.com/azat)).
* Fix setting NULL in profile definition [#49831](https://github.com/ClickHouse/ClickHouse/pull/49831) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix a bug with projections and the aggregate_functions_null_for_empty setting (for query_plan_optimize_projection) [#49873](https://github.com/ClickHouse/ClickHouse/pull/49873) ([Amos Bird](https://github.com/amosbird)).
* Fix processing pending batch for Distributed async INSERT after restart [#49884](https://github.com/ClickHouse/ClickHouse/pull/49884) ([Azat Khuzhin](https://github.com/azat)).
* Fix assertion in CacheMetadata::doCleanup [#49914](https://github.com/ClickHouse/ClickHouse/pull/49914) ([Kseniia Sumarokova](https://github.com/kssenii)).
* fix `is_prefix` in OptimizeRegularExpression [#49919](https://github.com/ClickHouse/ClickHouse/pull/49919) ([Han Fei](https://github.com/hanfei1991)).
* Fix metrics `WriteBufferFromS3Bytes`, `WriteBufferFromS3Microseconds` and `WriteBufferFromS3RequestsErrors` [#49930](https://github.com/ClickHouse/ClickHouse/pull/49930) ([Aleksandr Musorin](https://github.com/AVMusorin)).
* Fix IPv6 encoding in protobuf [#49933](https://github.com/ClickHouse/ClickHouse/pull/49933) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Fix possible Logical error on bad Nullable parsing for text formats [#49960](https://github.com/ClickHouse/ClickHouse/pull/49960) ([Kruglov Pavel](https://github.com/Avogar)).
* Add setting output_format_parquet_compliant_nested_types to produce more compatible Parquet files [#50001](https://github.com/ClickHouse/ClickHouse/pull/50001) ([Michael Kolupaev](https://github.com/al13n321)).
* Fix logical error in stress test "Not enough space to add ..." [#50021](https://github.com/ClickHouse/ClickHouse/pull/50021) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Avoid deadlock when starting table in attach thread of `ReplicatedMergeTree` [#50026](https://github.com/ClickHouse/ClickHouse/pull/50026) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix assert in SpanHolder::finish() with fibers attempt 2 [#50034](https://github.com/ClickHouse/ClickHouse/pull/50034) ([Kruglov Pavel](https://github.com/Avogar)).
* Add proper escaping for DDL OpenTelemetry context serialization [#50045](https://github.com/ClickHouse/ClickHouse/pull/50045) ([Azat Khuzhin](https://github.com/azat)).
* Fix reporting broken projection parts [#50052](https://github.com/ClickHouse/ClickHouse/pull/50052) ([Amos Bird](https://github.com/amosbird)).
* JIT compilation not equals NaN fix [#50056](https://github.com/ClickHouse/ClickHouse/pull/50056) ([Maksim Kita](https://github.com/kitaisreal)).
* Fix crashing in case of Replicated database without arguments [#50058](https://github.com/ClickHouse/ClickHouse/pull/50058) ([Azat Khuzhin](https://github.com/azat)).
* Fix crash with `multiIf` and constant condition and nullable arguments [#50123](https://github.com/ClickHouse/ClickHouse/pull/50123) ([Anton Popov](https://github.com/CurtizJ)).
* Fix invalid index analysis for date related keys [#50153](https://github.com/ClickHouse/ClickHouse/pull/50153) ([Amos Bird](https://github.com/amosbird)).
* do not allow modify order by when there are no order by cols [#50154](https://github.com/ClickHouse/ClickHouse/pull/50154) ([Han Fei](https://github.com/hanfei1991)).
* Fix broken index analysis when binary operator contains a null constant argument [#50177](https://github.com/ClickHouse/ClickHouse/pull/50177) ([Amos Bird](https://github.com/amosbird)).
* clickhouse-client: disallow usage of `--query` and `--queries-file` at the same time [#50210](https://github.com/ClickHouse/ClickHouse/pull/50210) ([Alexey Gerasimchuk](https://github.com/Demilivor)).
* Fix UB for INTO OUTFILE extensions (APPEND / AND STDOUT) and WATCH EVENTS [#50216](https://github.com/ClickHouse/ClickHouse/pull/50216) ([Azat Khuzhin](https://github.com/azat)).
* Fix skipping spaces at end of row in CustomSeparatedIgnoreSpaces format [#50224](https://github.com/ClickHouse/ClickHouse/pull/50224) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix iceberg metadata parsing [#50232](https://github.com/ClickHouse/ClickHouse/pull/50232) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix nested distributed SELECT in WITH clause [#50234](https://github.com/ClickHouse/ClickHouse/pull/50234) ([Azat Khuzhin](https://github.com/azat)).
* Fix msan issue in keyed siphash [#50245](https://github.com/ClickHouse/ClickHouse/pull/50245) ([Robert Schulze](https://github.com/rschu1ze)).
* Fix bugs in Poco sockets in non-blocking mode, use true non-blocking sockets [#50252](https://github.com/ClickHouse/ClickHouse/pull/50252) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix checksum calculation for backup entries [#50264](https://github.com/ClickHouse/ClickHouse/pull/50264) ([Vitaly Baranov](https://github.com/vitlibar)).
* Comparison functions NaN fix [#50287](https://github.com/ClickHouse/ClickHouse/pull/50287) ([Maksim Kita](https://github.com/kitaisreal)).
* JIT aggregation nullable key fix [#50291](https://github.com/ClickHouse/ClickHouse/pull/50291) ([Maksim Kita](https://github.com/kitaisreal)).
* Fix clickhouse-local crashing when writing empty Arrow or Parquet output [#50328](https://github.com/ClickHouse/ClickHouse/pull/50328) ([Michael Kolupaev](https://github.com/al13n321)).
* Fix crash when Pool::Entry::disconnect() is called [#50334](https://github.com/ClickHouse/ClickHouse/pull/50334) ([Val Doroshchuk](https://github.com/valbok)).
* Improved fetch part by holding directory lock longer [#50339](https://github.com/ClickHouse/ClickHouse/pull/50339) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Fix bitShift* functions with both constant arguments [#50343](https://github.com/ClickHouse/ClickHouse/pull/50343) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix Keeper deadlock on exception when preprocessing requests. [#50387](https://github.com/ClickHouse/ClickHouse/pull/50387) ([frinkr](https://github.com/frinkr)).
* Fix hashing of const integer values [#50421](https://github.com/ClickHouse/ClickHouse/pull/50421) ([Robert Schulze](https://github.com/rschu1ze)).
* Fix merge_tree_min_rows_for_seek/merge_tree_min_bytes_for_seek for data skipping indexes [#50432](https://github.com/ClickHouse/ClickHouse/pull/50432) ([Azat Khuzhin](https://github.com/azat)).
* Limit the number of in-flight tasks for loading outdated parts [#50450](https://github.com/ClickHouse/ClickHouse/pull/50450) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Keeper fix: apply uncommitted state after snapshot install [#50483](https://github.com/ClickHouse/ClickHouse/pull/50483) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix incorrect constant folding [#50536](https://github.com/ClickHouse/ClickHouse/pull/50536) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix logical error in stress test (Not enough space to add ...) [#50583](https://github.com/ClickHouse/ClickHouse/pull/50583) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix converting Null to LowCardinality(Nullable) in values table function [#50637](https://github.com/ClickHouse/ClickHouse/pull/50637) ([Kruglov Pavel](https://github.com/Avogar)).
* Revert invalid RegExpTreeDictionary optimization [#50642](https://github.com/ClickHouse/ClickHouse/pull/50642) ([Johann Gan](https://github.com/johanngan)).
### <a id="234"></a> ClickHouse release 23.4, 2023-04-26
#### Backward Incompatible Change
* Formatter '%M' in function formatDateTime() now prints the month name instead of the minutes. This makes the behavior consistent with MySQL. The previous behavior can be restored using setting "formatdatetime_parsedatetime_m_is_month_name = 0". [#47246](https://github.com/ClickHouse/ClickHouse/pull/47246) ([Robert Schulze](https://github.com/rschu1ze)).
* This change makes sense only if you are using the virtual filesystem cache. If `path` in the virtual filesystem cache configuration is not empty and is not an absolute path, then it will be put in `<clickhouse server data directory>/caches/<path_from_cache_config>`. [#48784](https://github.com/ClickHouse/ClickHouse/pull/48784) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Primary/secondary indices and sorting keys with identical expressions are now rejected. This behavior can be disabled using setting `allow_suspicious_indices`. [#48536](https://github.com/ClickHouse/ClickHouse/pull/48536) ([凌涛](https://github.com/lingtaolf)).
#### New Feature
* Support new aggregate function `quantileGK`/`quantilesGK`, like [approx_percentile](https://spark.apache.org/docs/latest/api/sql/index.html#approx_percentile) in spark. Greenwald-Khanna algorithm refer to http://infolab.stanford.edu/~datar/courses/cs361a/papers/quantiles.pdf. [#46428](https://github.com/ClickHouse/ClickHouse/pull/46428) ([李扬](https://github.com/taiyang-li)).
* Add a statement `SHOW COLUMNS` which shows distilled information from system.columns. [#48017](https://github.com/ClickHouse/ClickHouse/pull/48017) ([Robert Schulze](https://github.com/rschu1ze)).
* Added `LIGHTWEIGHT` and `PULL` modifiers for `SYSTEM SYNC REPLICA` query. `LIGHTWEIGHT` version waits for fetches and drop-ranges only (merges and mutations are ignored). `PULL` version pulls new entries from ZooKeeper and does not wait for them. Fixes [#47794](https://github.com/ClickHouse/ClickHouse/issues/47794). [#48085](https://github.com/ClickHouse/ClickHouse/pull/48085) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Add `kafkaMurmurHash` function for compatibility with Kafka DefaultPartitioner. Closes [#47834](https://github.com/ClickHouse/ClickHouse/issues/47834). [#48185](https://github.com/ClickHouse/ClickHouse/pull/48185) ([Nikolay Degterinsky](https://github.com/evillique)).
* Allow to easily create a user with the same grants as the current user by using `GRANT CURRENT GRANTS`. [#48262](https://github.com/ClickHouse/ClickHouse/pull/48262) ([pufit](https://github.com/pufit)).
* Add statistical aggregate function `kolmogorovSmirnovTest`. Close [#48228](https://github.com/ClickHouse/ClickHouse/issues/48228). [#48325](https://github.com/ClickHouse/ClickHouse/pull/48325) ([FFFFFFFHHHHHHH](https://github.com/FFFFFFFHHHHHHH)).
* Added a `lost_part_count` column to the `system.replicas` table. The column value shows the total number of lost parts in the corresponding table. Value is stored in zookeeper and can be used instead of not persistent `ReplicatedDataLoss` profile event for monitoring. [#48526](https://github.com/ClickHouse/ClickHouse/pull/48526) ([Sergei Trifonov](https://github.com/serxa)).
* Add `soundex` function for compatibility. Closes [#39880](https://github.com/ClickHouse/ClickHouse/issues/39880). [#48567](https://github.com/ClickHouse/ClickHouse/pull/48567) ([FriendLey](https://github.com/FriendLey)).
* Support `Map` type for JSONExtract. [#48629](https://github.com/ClickHouse/ClickHouse/pull/48629) ([李扬](https://github.com/taiyang-li)).
* Add `PrettyJSONEachRow` format to output pretty JSON with new line delimiters and 4 space indents. [#48898](https://github.com/ClickHouse/ClickHouse/pull/48898) ([Kruglov Pavel](https://github.com/Avogar)).
* Add `ParquetMetadata` input format to read Parquet file metadata. [#48911](https://github.com/ClickHouse/ClickHouse/pull/48911) ([Kruglov Pavel](https://github.com/Avogar)).
* Add `extractKeyValuePairs` function to extract key value pairs from strings. Input strings might contain noise (i.e. log files / do not need to be 100% formatted in key-value-pair format), the algorithm will look for key value pairs matching the arguments passed to the function. As of now, function accepts the following arguments: `data_column` (mandatory), `key_value_pair_delimiter` (defaults to `:`), `pair_delimiters` (defaults to `\space \, \;`) and `quoting_character` (defaults to double quotes). [#43606](https://github.com/ClickHouse/ClickHouse/pull/43606) ([Arthur Passos](https://github.com/arthurpassos)).
* Functions replaceOne(), replaceAll(), replaceRegexpOne() and replaceRegexpAll() can now be called with non-const pattern and replacement arguments. [#46589](https://github.com/ClickHouse/ClickHouse/pull/46589) ([Robert Schulze](https://github.com/rschu1ze)).
* Added functions to work with columns of type `Map`: `mapConcat`, `mapSort`, `mapExists`. [#48071](https://github.com/ClickHouse/ClickHouse/pull/48071) ([Anton Popov](https://github.com/CurtizJ)).
#### Performance Improvement
* Reading files in `Parquet` format is now much faster. IO and decoding are parallelized (controlled by `max_threads` setting), and only required data ranges are read. [#47964](https://github.com/ClickHouse/ClickHouse/pull/47964) ([Michael Kolupaev](https://github.com/al13n321)).
* If we run a mutation with IN (subquery) like this: `ALTER TABLE t UPDATE col='new value' WHERE id IN (SELECT id FROM huge_table)` and the table `t` has multiple parts than for each part a set for subquery `SELECT id FROM huge_table` is built in memory. And if there are many parts then this might consume a lot of memory (and lead to an OOM) and CPU. The solution is to introduce a short-lived cache of sets that are currently being built by mutation tasks. If another task of the same mutation is executed concurrently it can look up the set in the cache, wait for it to be built and reuse it. [#46835](https://github.com/ClickHouse/ClickHouse/pull/46835) ([Alexander Gololobov](https://github.com/davenger)).
* Only check dependencies if necessary when applying `ALTER TABLE` queries. [#48062](https://github.com/ClickHouse/ClickHouse/pull/48062) ([Raúl Marín](https://github.com/Algunenano)).
* Optimize function `mapUpdate`. [#48118](https://github.com/ClickHouse/ClickHouse/pull/48118) ([Anton Popov](https://github.com/CurtizJ)).
* Now an internal query to local replica is sent explicitly and data from it received through loopback interface. Setting `prefer_localhost_replica` is not respected for parallel replicas. This is needed for better scheduling and makes the code cleaner: the initiator is only responsible for coordinating of the reading process and merging results, continuously answering for requests while all the secondary queries read the data. Note: Using loopback interface is not so performant, otherwise some replicas could starve for tasks which could lead to even slower query execution and not utilizing all possible resources. The initialization of the coordinator is now even more lazy. All incoming requests contain the information about the reading algorithm we initialize the coordinator with it when first request comes. If any replica decides to read with a different algorithm–an exception will be thrown and a query will be aborted. [#48246](https://github.com/ClickHouse/ClickHouse/pull/48246) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Do not build set for the right side of `IN` clause with subquery when it is used only for analysis of skip indexes, and they are disabled by setting (`use_skip_indexes=0`). Previously it might affect the performance of queries. [#48299](https://github.com/ClickHouse/ClickHouse/pull/48299) ([Anton Popov](https://github.com/CurtizJ)).
* Query processing is parallelized right after reading `FROM file(...)`. Related to [#38755](https://github.com/ClickHouse/ClickHouse/issues/38755). [#48525](https://github.com/ClickHouse/ClickHouse/pull/48525) ([Igor Nikonov](https://github.com/devcrafter)). Query processing is parallelized right after reading from any data source. Affected data sources are mostly simple or external storages like table functions `url`, `file`. [#48727](https://github.com/ClickHouse/ClickHouse/pull/48727) ([Igor Nikonov](https://github.com/devcrafter)). This is controlled by the setting `parallelize_output_from_storages` which is not enabled by default.
* Lowered contention of ThreadPool mutex (may increase performance for a huge amount of small jobs). [#48750](https://github.com/ClickHouse/ClickHouse/pull/48750) ([Sergei Trifonov](https://github.com/serxa)).
* Reduce memory usage for multiple `ALTER DELETE` mutations. [#48522](https://github.com/ClickHouse/ClickHouse/pull/48522) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Remove the excessive connection attempts if the `skip_unavailable_shards` setting is enabled. [#48771](https://github.com/ClickHouse/ClickHouse/pull/48771) ([Azat Khuzhin](https://github.com/azat)).
#### Experimental Feature
* Entries in the query cache are now squashed to max_block_size and compressed. [#45912](https://github.com/ClickHouse/ClickHouse/pull/45912) ([Robert Schulze](https://github.com/rschu1ze)).
* It is now possible to define per-user quotas in the query cache. [#48284](https://github.com/ClickHouse/ClickHouse/pull/48284) ([Robert Schulze](https://github.com/rschu1ze)).
* Some fixes for parallel replicas [#48433](https://github.com/ClickHouse/ClickHouse/pull/48433) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Implement zero-copy-replication (an experimental feature) on encrypted disks. [#48741](https://github.com/ClickHouse/ClickHouse/pull/48741) ([Vitaly Baranov](https://github.com/vitlibar)).
#### Improvement
* Increase default value for `connect_timeout_with_failover_ms` to 1000 ms (because of adding async connections in https://github.com/ClickHouse/ClickHouse/pull/47229) . Closes [#5188](https://github.com/ClickHouse/ClickHouse/issues/5188). [#49009](https://github.com/ClickHouse/ClickHouse/pull/49009) ([Kruglov Pavel](https://github.com/Avogar)).
* Several improvements around data lakes: - Make `Iceberg` work with non-partitioned data. - Support `Iceberg` format version v2 (previously only v1 was supported) - Support reading partitioned data for `DeltaLake`/`Hudi` - Faster reading of `DeltaLake` metadata by using Delta's checkpoint files - Fixed incorrect `Hudi` reads: previously it incorrectly chose which data to read and therefore was able to read correctly only small size tables - Made these engines to pickup updates of changed data (previously the state was set on table creation) - Make proper testing for `Iceberg`/`DeltaLake`/`Hudi` using spark. [#47307](https://github.com/ClickHouse/ClickHouse/pull/47307) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Add async connection to socket and async writing to socket. Make creating connections and sending query/external tables async across shards. Refactor code with fibers. Closes [#46931](https://github.com/ClickHouse/ClickHouse/issues/46931). We will be able to increase `connect_timeout_with_failover_ms` by default after this PR (https://github.com/ClickHouse/ClickHouse/issues/5188). [#47229](https://github.com/ClickHouse/ClickHouse/pull/47229) ([Kruglov Pavel](https://github.com/Avogar)).
* Support config sections `keeper`/`keeper_server` as an alternative to `zookeeper`. Close [#34766](https://github.com/ClickHouse/ClickHouse/issues/34766) , [#34767](https://github.com/ClickHouse/ClickHouse/issues/34767). [#35113](https://github.com/ClickHouse/ClickHouse/pull/35113) ([李扬](https://github.com/taiyang-li)).
* It is possible to set _secure_ flag in named_collections for a dictionary with a ClickHouse table source. Addresses [#38450](https://github.com/ClickHouse/ClickHouse/issues/38450) . [#46323](https://github.com/ClickHouse/ClickHouse/pull/46323) ([Ilya Golshtein](https://github.com/ilejn)).
* `bitCount` function support `FixedString` and `String` data type. [#49044](https://github.com/ClickHouse/ClickHouse/pull/49044) ([flynn](https://github.com/ucasfl)).
* Added configurable retries for all operations with [Zoo]Keeper for Backup queries. [#47224](https://github.com/ClickHouse/ClickHouse/pull/47224) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Enable `use_environment_credentials` for S3 by default, so the entire provider chain is constructed by default. [#47397](https://github.com/ClickHouse/ClickHouse/pull/47397) ([Antonio Andelic](https://github.com/antonio2368)).
* Currently, the JSON_VALUE function is similar as spark's get_json_object function, which support to get value from JSON string by a path like '$.key'. But still has something different - 1. in spark's get_json_object will return null while the path is not exist, but in JSON_VALUE will return empty string; - 2. in spark's get_json_object will return a complex type value, such as a JSON object/array value, but in JSON_VALUE will return empty string. [#47494](https://github.com/ClickHouse/ClickHouse/pull/47494) ([KevinyhZou](https://github.com/KevinyhZou)).
* For `use_structure_from_insertion_table_in_table_functions` more flexible insert table structure propagation to table function. Fixed an issue with name mapping and using virtual columns. No more need for 'auto' setting. [#47962](https://github.com/ClickHouse/ClickHouse/pull/47962) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Do not continue retrying to connect to Keeper if the query is killed or over limits. [#47985](https://github.com/ClickHouse/ClickHouse/pull/47985) ([Raúl Marín](https://github.com/Algunenano)).
* Support Enum output/input in `BSONEachRow`, allow all map key types and avoid extra calculations on output. [#48122](https://github.com/ClickHouse/ClickHouse/pull/48122) ([Kruglov Pavel](https://github.com/Avogar)).
* Support more ClickHouse types in `ORC`/`Arrow`/`Parquet` formats: Enum(8|16), (U)Int(128|256), Decimal256 (for ORC), allow reading IPv4 from Int32 values (ORC outputs IPv4 as Int32, and we couldn't read it back), fix reading Nullable(IPv6) from binary data for `ORC`. [#48126](https://github.com/ClickHouse/ClickHouse/pull/48126) ([Kruglov Pavel](https://github.com/Avogar)).
* Add columns `perform_ttl_move_on_insert`, `load_balancing` for table `system.storage_policies`, modify column `volume_type` type to `Enum8`. [#48167](https://github.com/ClickHouse/ClickHouse/pull/48167) ([lizhuoyu5](https://github.com/lzydmxy)).
* Added support for `BACKUP ALL` command which backups all tables and databases, including temporary and system ones. [#48189](https://github.com/ClickHouse/ClickHouse/pull/48189) ([Vitaly Baranov](https://github.com/vitlibar)).
* Function mapFromArrays supports `Map` type as an input. [#48207](https://github.com/ClickHouse/ClickHouse/pull/48207) ([李扬](https://github.com/taiyang-li)).
* The output of some SHOW PROCESSLIST is now sorted. [#48241](https://github.com/ClickHouse/ClickHouse/pull/48241) ([Robert Schulze](https://github.com/rschu1ze)).
* Per-query/per-server throttling for remote IO/local IO/BACKUPs (server settings: `max_remote_read_network_bandwidth_for_server`, `max_remote_write_network_bandwidth_for_server`, `max_local_read_bandwidth_for_server`, `max_local_write_bandwidth_for_server`, `max_backup_bandwidth_for_server`, settings: `max_remote_read_network_bandwidth`, `max_remote_write_network_bandwidth`, `max_local_read_bandwidth`, `max_local_write_bandwidth`, `max_backup_bandwidth`). [#48242](https://github.com/ClickHouse/ClickHouse/pull/48242) ([Azat Khuzhin](https://github.com/azat)).
* Support more types in `CapnProto` format: Map, (U)Int(128|256), Decimal(128|256). Allow integer conversions during input/output. [#48257](https://github.com/ClickHouse/ClickHouse/pull/48257) ([Kruglov Pavel](https://github.com/Avogar)).
* Don't throw CURRENT_WRITE_BUFFER_IS_EXHAUSTED for normal behaviour. [#48288](https://github.com/ClickHouse/ClickHouse/pull/48288) ([Raúl Marín](https://github.com/Algunenano)).
* Add new setting `keeper_map_strict_mode` which enforces extra guarantees on operations made on top of `KeeperMap` tables. [#48293](https://github.com/ClickHouse/ClickHouse/pull/48293) ([Antonio Andelic](https://github.com/antonio2368)).
* Check primary key type for simple dictionary is native unsigned integer type Add setting `check_dictionary_primary_key ` for compatibility(set `check_dictionary_primary_key =false` to disable checking). [#48335](https://github.com/ClickHouse/ClickHouse/pull/48335) ([lizhuoyu5](https://github.com/lzydmxy)).
* Don't replicate mutations for `KeeperMap` because it's unnecessary. [#48354](https://github.com/ClickHouse/ClickHouse/pull/48354) ([Antonio Andelic](https://github.com/antonio2368)).
* Allow to write/read unnamed tuple as nested Message in Protobuf format. Tuple elements and Message fields are matched by position. [#48390](https://github.com/ClickHouse/ClickHouse/pull/48390) ([Kruglov Pavel](https://github.com/Avogar)).
* Support `additional_table_filters` and `additional_result_filter` settings in the new planner. Also, add a documentation entry for `additional_result_filter`. [#48405](https://github.com/ClickHouse/ClickHouse/pull/48405) ([Dmitry Novik](https://github.com/novikd)).
* `parseDateTime` now understands format string '%f' (fractional seconds). [#48420](https://github.com/ClickHouse/ClickHouse/pull/48420) ([Robert Schulze](https://github.com/rschu1ze)).
* Format string "%f" in formatDateTime() now prints "000000" if the formatted value has no fractional seconds, the previous behavior (single zero) can be restored using setting "formatdatetime_f_prints_single_zero = 1". [#48422](https://github.com/ClickHouse/ClickHouse/pull/48422) ([Robert Schulze](https://github.com/rschu1ze)).
* Don't replicate DELETE and TRUNCATE for KeeperMap. [#48434](https://github.com/ClickHouse/ClickHouse/pull/48434) ([Antonio Andelic](https://github.com/antonio2368)).
* Generate valid Decimals and Bools in generateRandom function. [#48436](https://github.com/ClickHouse/ClickHouse/pull/48436) ([Kruglov Pavel](https://github.com/Avogar)).
* Allow trailing commas in expression list of SELECT query, for example `SELECT a, b, c, FROM table`. Closes [#37802](https://github.com/ClickHouse/ClickHouse/issues/37802). [#48438](https://github.com/ClickHouse/ClickHouse/pull/48438) ([Nikolay Degterinsky](https://github.com/evillique)).
* Override `CLICKHOUSE_USER` and `CLICKHOUSE_PASSWORD` environment variables with `--user` and `--password` client parameters. Closes [#38909](https://github.com/ClickHouse/ClickHouse/issues/38909). [#48440](https://github.com/ClickHouse/ClickHouse/pull/48440) ([Nikolay Degterinsky](https://github.com/evillique)).
* Added retries to loading of data parts in `MergeTree` tables in case of retryable errors. [#48442](https://github.com/ClickHouse/ClickHouse/pull/48442) ([Anton Popov](https://github.com/CurtizJ)).
* Add support for `Date`, `Date32`, `DateTime`, `DateTime64` data types to `arrayMin`, `arrayMax`, `arrayDifference` functions. Closes [#21645](https://github.com/ClickHouse/ClickHouse/issues/21645). [#48445](https://github.com/ClickHouse/ClickHouse/pull/48445) ([Nikolay Degterinsky](https://github.com/evillique)).
* Add support for `{server_uuid}` macro. It is useful for identifying replicas in autoscaled clusters when new replicas are constantly added and removed in runtime. This closes [#48554](https://github.com/ClickHouse/ClickHouse/issues/48554). [#48563](https://github.com/ClickHouse/ClickHouse/pull/48563) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* The installation script will create a hard link instead of copying if it is possible. [#48578](https://github.com/ClickHouse/ClickHouse/pull/48578) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Support `SHOW TABLE` syntax meaning the same as `SHOW CREATE TABLE`. Closes [#48580](https://github.com/ClickHouse/ClickHouse/issues/48580). [#48591](https://github.com/ClickHouse/ClickHouse/pull/48591) ([flynn](https://github.com/ucasfl)).
* HTTP temporary buffers now support working by evicting data from the virtual filesystem cache. [#48664](https://github.com/ClickHouse/ClickHouse/pull/48664) ([Vladimir C](https://github.com/vdimir)).
* Make Schema inference works for `CREATE AS SELECT`. Closes [#47599](https://github.com/ClickHouse/ClickHouse/issues/47599). [#48679](https://github.com/ClickHouse/ClickHouse/pull/48679) ([flynn](https://github.com/ucasfl)).
* Added a `replicated_max_mutations_in_one_entry` setting for `ReplicatedMergeTree` that allows limiting the number of mutation commands per one `MUTATE_PART` entry (default is 10000). [#48731](https://github.com/ClickHouse/ClickHouse/pull/48731) ([Alexander Tokmakov](https://github.com/tavplubix)).
* In AggregateFunction types, don't count unused arena bytes as `read_bytes`. [#48745](https://github.com/ClickHouse/ClickHouse/pull/48745) ([Raúl Marín](https://github.com/Algunenano)).
* Fix some MySQL-related settings not being handled with the MySQL dictionary source + named collection. Closes [#48402](https://github.com/ClickHouse/ClickHouse/issues/48402). [#48759](https://github.com/ClickHouse/ClickHouse/pull/48759) ([Kseniia Sumarokova](https://github.com/kssenii)).
* If a user set `max_single_part_upload_size` to a very large value, it can lead to a crash due to a bug in the AWS S3 SDK. This fixes [#47679](https://github.com/ClickHouse/ClickHouse/issues/47679). [#48816](https://github.com/ClickHouse/ClickHouse/pull/48816) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix data race in `RabbitMQ` ([report](https://pastila.nl/?004f7100/de1505289ab5bb355e67ebe6c7cc8707)), refactor the code. [#48845](https://github.com/ClickHouse/ClickHouse/pull/48845) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Add aliases `name` and `part_name` form `system.parts` and `system.part_log`. Closes [#48718](https://github.com/ClickHouse/ClickHouse/issues/48718). [#48850](https://github.com/ClickHouse/ClickHouse/pull/48850) ([sichenzhao](https://github.com/sichenzhao)).
* Functions "arrayDifferenceSupport()", "arrayCumSum()" and "arrayCumSumNonNegative()" now support input arrays of wide integer types (U)Int128/256. [#48866](https://github.com/ClickHouse/ClickHouse/pull/48866) ([cluster](https://github.com/infdahai)).
* Multi-line history in clickhouse-client is now no longer padded. This makes pasting more natural. [#48870](https://github.com/ClickHouse/ClickHouse/pull/48870) ([Joanna Hulboj](https://github.com/jh0x)).
* Implement a slight improvement for the rare case when ClickHouse is run inside LXC and LXCFS is used. The LXCFS has an issue: sometimes it returns an error "Transport endpoint is not connected" on reading from the file inside `/proc`. This error was correctly logged into ClickHouse's server log. We have additionally workaround this issue by reopening a file. This is a minuscule change. [#48922](https://github.com/ClickHouse/ClickHouse/pull/48922) ([Real](https://github.com/RunningXie)).
* Improve memory accounting for prefetches. Randomise prefetch settings In CI. [#48973](https://github.com/ClickHouse/ClickHouse/pull/48973) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Correctly set headers for native copy operations on GCS. [#48981](https://github.com/ClickHouse/ClickHouse/pull/48981) ([Antonio Andelic](https://github.com/antonio2368)).
* Add support for specifying setting names in the command line with dashes instead of underscores, for example, `--max-threads` instead of `--max_threads`. Additionally, support Unicode dash characters like `—` instead of `--` - this is useful when you communicate with a team in another company, and a manager from that team copy-pasted code from MS Word. [#48985](https://github.com/ClickHouse/ClickHouse/pull/48985) ([alekseygolub](https://github.com/alekseygolub)).
* Add fallback to password authentication when authentication with SSL user certificate has failed. Closes [#48974](https://github.com/ClickHouse/ClickHouse/issues/48974). [#48989](https://github.com/ClickHouse/ClickHouse/pull/48989) ([Nikolay Degterinsky](https://github.com/evillique)).
* Improve the embedded dashboard. Close [#46671](https://github.com/ClickHouse/ClickHouse/issues/46671). [#49036](https://github.com/ClickHouse/ClickHouse/pull/49036) ([Kevin Zhang](https://github.com/Kinzeng)).
* Add profile events for log messages, so you can easily see the count of log messages by severity. [#49042](https://github.com/ClickHouse/ClickHouse/pull/49042) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* In previous versions, the `LineAsString` format worked inconsistently when the parallel parsing was enabled or not, in presence of DOS or macOS Classic line breaks. This closes [#49039](https://github.com/ClickHouse/ClickHouse/issues/49039). [#49052](https://github.com/ClickHouse/ClickHouse/pull/49052) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* The exception message about the unparsed query parameter will also tell about the name of the parameter. Reimplement [#48878](https://github.com/ClickHouse/ClickHouse/issues/48878). Close [#48772](https://github.com/ClickHouse/ClickHouse/issues/48772). [#49061](https://github.com/ClickHouse/ClickHouse/pull/49061) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
#### Build/Testing/Packaging Improvement
* Update time zones. The following were updated: Africa/Cairo, Africa/Casablanca, Africa/El_Aaiun, America/Bogota, America/Cambridge_Bay, America/Ciudad_Juarez, America/Godthab, America/Inuvik, America/Iqaluit, America/Nuuk, America/Ojinaga, America/Pangnirtung, America/Rankin_Inlet, America/Resolute, America/Whitehorse, America/Yellowknife, Asia/Gaza, Asia/Hebron, Asia/Kuala_Lumpur, Asia/Singapore, Canada/Yukon, Egypt, Europe/Kirov, Europe/Volgograd, Singapore. [#48572](https://github.com/ClickHouse/ClickHouse/pull/48572) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Reduce the number of dependencies in the header files to speed up the build. [#47984](https://github.com/ClickHouse/ClickHouse/pull/47984) ([Dmitry Novik](https://github.com/novikd)).
* Randomize compression of marks and indices in tests. [#48286](https://github.com/ClickHouse/ClickHouse/pull/48286) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Bump internal ZSTD from 1.5.4 to 1.5.5. [#46797](https://github.com/ClickHouse/ClickHouse/pull/46797) ([Robert Schulze](https://github.com/rschu1ze)).
* Randomize vertical merges from compact to wide parts in tests. [#48287](https://github.com/ClickHouse/ClickHouse/pull/48287) ([Raúl Marín](https://github.com/Algunenano)).
* Support for CRC32 checksum in HDFS. Fix performance issues. [#48614](https://github.com/ClickHouse/ClickHouse/pull/48614) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Remove remainders of GCC support. [#48671](https://github.com/ClickHouse/ClickHouse/pull/48671) ([Robert Schulze](https://github.com/rschu1ze)).
* Add CI run with new analyzer infrastructure enabled. [#48719](https://github.com/ClickHouse/ClickHouse/pull/48719) ([Dmitry Novik](https://github.com/novikd)).
#### Bug Fix (user-visible misbehavior in an official stable release)
* Fix system.query_views_log for MVs that are pushed from background threads [#46668](https://github.com/ClickHouse/ClickHouse/pull/46668) ([Azat Khuzhin](https://github.com/azat)).
* Fix several `RENAME COLUMN` bugs [#46946](https://github.com/ClickHouse/ClickHouse/pull/46946) ([alesapin](https://github.com/alesapin)).
* Fix minor hiliting issues in clickhouse-format [#47610](https://github.com/ClickHouse/ClickHouse/pull/47610) ([Natasha Murashkina](https://github.com/murfel)).
* Fix a bug in LLVM's libc++ leading to a crash for uploading parts to S3 which size is greater than INT_MAX [#47693](https://github.com/ClickHouse/ClickHouse/pull/47693) ([Azat Khuzhin](https://github.com/azat)).
* Fix overflow in the `sparkbar` function [#48121](https://github.com/ClickHouse/ClickHouse/pull/48121) ([Vladimir C](https://github.com/vdimir)).
* Fix race in S3 [#48190](https://github.com/ClickHouse/ClickHouse/pull/48190) ([Anton Popov](https://github.com/CurtizJ)).
* Disable JIT for aggregate functions due to inconsistent behavior [#48195](https://github.com/ClickHouse/ClickHouse/pull/48195) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix alter formatting (minor) [#48289](https://github.com/ClickHouse/ClickHouse/pull/48289) ([Natasha Murashkina](https://github.com/murfel)).
* Fix CPU usage in RabbitMQ (was worsened in 23.2 after [#44404](https://github.com/ClickHouse/ClickHouse/issues/44404)) [#48311](https://github.com/ClickHouse/ClickHouse/pull/48311) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix crash in EXPLAIN PIPELINE for Merge over Distributed [#48320](https://github.com/ClickHouse/ClickHouse/pull/48320) ([Azat Khuzhin](https://github.com/azat)).
* Fix serializing LowCardinality as Arrow dictionary [#48361](https://github.com/ClickHouse/ClickHouse/pull/48361) ([Kruglov Pavel](https://github.com/Avogar)).
* Reset downloader for cache file segment in TemporaryFileStream [#48386](https://github.com/ClickHouse/ClickHouse/pull/48386) ([Vladimir C](https://github.com/vdimir)).
* Fix possible SYSTEM SYNC REPLICA stuck in case of DROP/REPLACE PARTITION [#48391](https://github.com/ClickHouse/ClickHouse/pull/48391) ([Azat Khuzhin](https://github.com/azat)).
* Fix a startup error when loading a distributed table that depends on a dictionary [#48419](https://github.com/ClickHouse/ClickHouse/pull/48419) ([MikhailBurdukov](https://github.com/MikhailBurdukov)).
* Don't check dependencies when renaming system tables automatically [#48431](https://github.com/ClickHouse/ClickHouse/pull/48431) ([Raúl Marín](https://github.com/Algunenano)).
* Update only affected rows in KeeperMap storage [#48435](https://github.com/ClickHouse/ClickHouse/pull/48435) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix possible segfault in the VFS cache [#48469](https://github.com/ClickHouse/ClickHouse/pull/48469) ([Kseniia Sumarokova](https://github.com/kssenii)).
* `toTimeZone` function throws an error when no constant string is provided [#48471](https://github.com/ClickHouse/ClickHouse/pull/48471) ([Jordi Villar](https://github.com/jrdi)).
* Fix logical error with IPv4 in Protobuf, add support for Date32 [#48486](https://github.com/ClickHouse/ClickHouse/pull/48486) ([Kruglov Pavel](https://github.com/Avogar)).
* "changed" flag in system.settings was calculated incorrectly for settings with multiple values [#48516](https://github.com/ClickHouse/ClickHouse/pull/48516) ([MikhailBurdukov](https://github.com/MikhailBurdukov)).
* Fix storage `Memory` with enabled compression [#48517](https://github.com/ClickHouse/ClickHouse/pull/48517) ([Anton Popov](https://github.com/CurtizJ)).
* Fix bracketed-paste mode messing up password input in the event of client reconnection [#48528](https://github.com/ClickHouse/ClickHouse/pull/48528) ([Michael Kolupaev](https://github.com/al13n321)).
* Fix nested map for keys of IP and UUID types [#48556](https://github.com/ClickHouse/ClickHouse/pull/48556) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Fix an uncaught exception in case of parallel loader for hashed dictionaries [#48571](https://github.com/ClickHouse/ClickHouse/pull/48571) ([Azat Khuzhin](https://github.com/azat)).
* The `groupArray` aggregate function correctly works for empty result over nullable types [#48593](https://github.com/ClickHouse/ClickHouse/pull/48593) ([lgbo](https://github.com/lgbo-ustc)).
* Fix bug in Keeper when a node is not created with scheme `auth` in ACL sometimes. [#48595](https://github.com/ClickHouse/ClickHouse/pull/48595) ([Aleksei Filatov](https://github.com/aalexfvk)).
* Allow IPv4 comparison operators with UInt [#48611](https://github.com/ClickHouse/ClickHouse/pull/48611) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Fix possible error from cache [#48636](https://github.com/ClickHouse/ClickHouse/pull/48636) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Async inserts with empty data will no longer throw exception. [#48663](https://github.com/ClickHouse/ClickHouse/pull/48663) ([Anton Popov](https://github.com/CurtizJ)).
* Fix table dependencies in case of failed RENAME TABLE [#48683](https://github.com/ClickHouse/ClickHouse/pull/48683) ([Azat Khuzhin](https://github.com/azat)).
* If the primary key has duplicate columns (which is only possible for projections), in previous versions it might lead to a bug [#48838](https://github.com/ClickHouse/ClickHouse/pull/48838) ([Amos Bird](https://github.com/amosbird)).
* Fix for a race condition in ZooKeeper when joining send_thread/receive_thread [#48849](https://github.com/ClickHouse/ClickHouse/pull/48849) ([Alexander Gololobov](https://github.com/davenger)).
* Fix unexpected part name error when trying to drop a ignored detached part with zero copy replication [#48862](https://github.com/ClickHouse/ClickHouse/pull/48862) ([Michael Lex](https://github.com/mlex)).
* Fix reading `Date32` Parquet/Arrow column into not a `Date32` column [#48864](https://github.com/ClickHouse/ClickHouse/pull/48864) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix `UNKNOWN_IDENTIFIER` error while selecting from table with row policy and column with dots [#48976](https://github.com/ClickHouse/ClickHouse/pull/48976) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix aggregation by empty nullable strings [#48999](https://github.com/ClickHouse/ClickHouse/pull/48999) ([LiuNeng](https://github.com/liuneng1994)).
### <a id="233"></a> ClickHouse release 23.3 LTS, 2023-03-30
#### Upgrade Notes
* Lightweight DELETEs are production ready and enabled by default. The `DELETE` query for MergeTree tables is now available by default.
* The behavior of `*domain*RFC` and `netloc` functions is slightly changed: relaxed the set of symbols that are allowed in the URL authority for better conformance. [#46841](https://github.com/ClickHouse/ClickHouse/pull/46841) ([Azat Khuzhin](https://github.com/azat)).
* Prohibited creating tables based on KafkaEngine with DEFAULT/EPHEMERAL/ALIAS/MATERIALIZED statements for columns. [#47138](https://github.com/ClickHouse/ClickHouse/pull/47138) ([Aleksandr Musorin](https://github.com/AVMusorin)).
* An "asynchronous connection drain" feature is removed. Related settings and metrics are removed as well. It was an internal feature, so the removal should not affect users who had never heard about that feature. [#47486](https://github.com/ClickHouse/ClickHouse/pull/47486) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Support 256-bit Decimal data type (more than 38 digits) in `arraySum`/`Min`/`Max`/`Avg`/`Product`, `arrayCumSum`/`CumSumNonNegative`, `arrayDifference`, array construction, IN operator, query parameters, `groupArrayMovingSum`, statistical functions, `min`/`max`/`any`/`argMin`/`argMax`, PostgreSQL wire protocol, MySQL table engine and function, `sumMap`, `mapAdd`, `mapSubtract`, `arrayIntersect`. Add support for big integers in `arrayIntersect`. Statistical aggregate functions involving moments (such as `corr` or various `TTest`s) will use `Float64` as their internal representation (they were using `Decimal128` before this change, but it was pointless), and these functions can return `nan` instead of `inf` in case of infinite variance. Some functions were allowed on `Decimal256` data types but returned `Decimal128` in previous versions - now it is fixed. This closes [#47569](https://github.com/ClickHouse/ClickHouse/issues/47569). This closes [#44864](https://github.com/ClickHouse/ClickHouse/issues/44864). This closes [#28335](https://github.com/ClickHouse/ClickHouse/issues/28335). [#47594](https://github.com/ClickHouse/ClickHouse/pull/47594) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Make backup_threads/restore_threads server settings (instead of user settings). [#47881](https://github.com/ClickHouse/ClickHouse/pull/47881) ([Azat Khuzhin](https://github.com/azat)).
* Do not allow const and non-deterministic secondary indices [#46839](https://github.com/ClickHouse/ClickHouse/pull/46839) ([Anton Popov](https://github.com/CurtizJ)).
#### New Feature
* Add a new mode for splitting the work on replicas using settings `parallel_replicas_custom_key` and `parallel_replicas_custom_key_filter_type`. If the cluster consists of a single shard with multiple replicas, up to `max_parallel_replicas` will be randomly picked and turned into shards. For each shard, a corresponding filter is added to the query on the initiator before being sent to the shard. If the cluster consists of multiple shards, it will behave the same as `sample_key` but with the possibility to define an arbitrary key. [#45108](https://github.com/ClickHouse/ClickHouse/pull/45108) ([Antonio Andelic](https://github.com/antonio2368)).
* An option to display partial result on cancel: Added query setting `partial_result_on_first_cancel` allowing the canceled query (e.g. due to Ctrl-C) to return a partial result. [#45689](https://github.com/ClickHouse/ClickHouse/pull/45689) ([Alexey Perevyshin](https://github.com/alexX512)).
* Added support of arbitrary tables engines for temporary tables (except for Replicated and KeeperMap engines). Close [#31497](https://github.com/ClickHouse/ClickHouse/issues/31497). [#46071](https://github.com/ClickHouse/ClickHouse/pull/46071) ([Roman Vasin](https://github.com/rvasin)).
* Add support for replication of user-defined SQL functions using centralized storage in Keeper. [#46085](https://github.com/ClickHouse/ClickHouse/pull/46085) ([Aleksei Filatov](https://github.com/aalexfvk)).
* Implement `system.server_settings` (similar to `system.settings`), which will contain server configurations. [#46550](https://github.com/ClickHouse/ClickHouse/pull/46550) ([pufit](https://github.com/pufit)).
* Support for `UNDROP TABLE` query. Closes [#46811](https://github.com/ClickHouse/ClickHouse/issues/46811). [#47241](https://github.com/ClickHouse/ClickHouse/pull/47241) ([chen](https://github.com/xiedeyantu)).
* Allow separate grants for named collections (e.g. to be able to give `SHOW/CREATE/ALTER/DROP named collection` access only to certain collections, instead of all at once). Closes [#40894](https://github.com/ClickHouse/ClickHouse/issues/40894). Add new access type `NAMED_COLLECTION_CONTROL` which is not given to user default unless explicitly added to the user config (is required to be able to do `GRANT ALL`), also `show_named_collections` is no longer obligatory to be manually specified for user default to be able to have full access rights as was in 23.2. [#46241](https://github.com/ClickHouse/ClickHouse/pull/46241) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Allow nested custom disks. Previously custom disks supported only flat disk structure. [#47106](https://github.com/ClickHouse/ClickHouse/pull/47106) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Introduce a function `widthBucket` (with a `WIDTH_BUCKET` alias for compatibility). [#42974](https://github.com/ClickHouse/ClickHouse/issues/42974). [#46790](https://github.com/ClickHouse/ClickHouse/pull/46790) ([avoiderboi](https://github.com/avoiderboi)).
* Add new function `parseDateTime`/`parseDateTimeInJodaSyntax` according to the specified format string. parseDateTime parses String to DateTime in MySQL syntax, parseDateTimeInJodaSyntax parses in Joda syntax. [#46815](https://github.com/ClickHouse/ClickHouse/pull/46815) ([李扬](https://github.com/taiyang-li)).
* Use `dummy UInt8` for the default structure of table function `null`. Closes [#46930](https://github.com/ClickHouse/ClickHouse/issues/46930). [#47006](https://github.com/ClickHouse/ClickHouse/pull/47006) ([flynn](https://github.com/ucasfl)).
* Support for date format with a comma, like `Dec 15, 2021` in the `parseDateTimeBestEffort` function. Closes [#46816](https://github.com/ClickHouse/ClickHouse/issues/46816). [#47071](https://github.com/ClickHouse/ClickHouse/pull/47071) ([chen](https://github.com/xiedeyantu)).
* Add settings `http_wait_end_of_query` and `http_response_buffer_size` that corresponds to URL params `wait_end_of_query` and `buffer_size` for the HTTP interface. This allows changing these settings in the profiles. [#47108](https://github.com/ClickHouse/ClickHouse/pull/47108) ([Vladimir C](https://github.com/vdimir)).
* Add `system.dropped_tables` table that shows tables that were dropped from `Atomic` databases but were not completely removed yet. [#47364](https://github.com/ClickHouse/ClickHouse/pull/47364) ([chen](https://github.com/xiedeyantu)).
* Add `INSTR` as alias of `positionCaseInsensitive` for MySQL compatibility. Closes [#47529](https://github.com/ClickHouse/ClickHouse/issues/47529). [#47535](https://github.com/ClickHouse/ClickHouse/pull/47535) ([flynn](https://github.com/ucasfl)).
* Added `toDecimalString` function allowing to convert numbers to string with fixed precision. [#47838](https://github.com/ClickHouse/ClickHouse/pull/47838) ([Andrey Zvonov](https://github.com/zvonand)).
* Add a merge tree setting `max_number_of_mutations_for_replica`. It limits the number of part mutations per replica to the specified amount. Zero means no limit on the number of mutations per replica (the execution can still be constrained by other settings). [#48047](https://github.com/ClickHouse/ClickHouse/pull/48047) ([Vladimir C](https://github.com/vdimir)).
* Add the Map-related function `mapFromArrays`, which allows the creation of a map from a pair of arrays. [#31125](https://github.com/ClickHouse/ClickHouse/pull/31125) ([李扬](https://github.com/taiyang-li)).
* Allow control of compression in Parquet/ORC/Arrow output formats, adds support for more compression input formats. This closes [#13541](https://github.com/ClickHouse/ClickHouse/issues/13541). [#47114](https://github.com/ClickHouse/ClickHouse/pull/47114) ([Kruglov Pavel](https://github.com/Avogar)).
* Add SSL User Certificate authentication to the native protocol. Closes [#47077](https://github.com/ClickHouse/ClickHouse/issues/47077). [#47596](https://github.com/ClickHouse/ClickHouse/pull/47596) ([Nikolay Degterinsky](https://github.com/evillique)).
* Add *OrNull() and *OrZero() variants for `parseDateTime`, add alias `str_to_date` for MySQL parity. [#48000](https://github.com/ClickHouse/ClickHouse/pull/48000) ([Robert Schulze](https://github.com/rschu1ze)).
* Added operator `REGEXP` (similar to operators "LIKE", "IN", "MOD" etc.) for better compatibility with MySQL [#47869](https://github.com/ClickHouse/ClickHouse/pull/47869) ([Robert Schulze](https://github.com/rschu1ze)).
#### Performance Improvement
* Marks in memory are now compressed, using 3-6x less memory. [#47290](https://github.com/ClickHouse/ClickHouse/pull/47290) ([Michael Kolupaev](https://github.com/al13n321)).
* Backups for large numbers of files were unbelievably slow in previous versions. Not anymore. Now they are unbelievably fast. [#47251](https://github.com/ClickHouse/ClickHouse/pull/47251) ([Alexey Milovidov](https://github.com/alexey-milovidov)). Introduced a separate thread pool for backup's IO operations. This will allow scaling it independently of other pools and increase performance. [#47174](https://github.com/ClickHouse/ClickHouse/pull/47174) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)). Use MultiRead request and retries for collecting metadata at the final stage of backup processing. [#47243](https://github.com/ClickHouse/ClickHouse/pull/47243) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)). If a backup and restoring data are both in S3 then server-side copy should be used from now on. [#47546](https://github.com/ClickHouse/ClickHouse/pull/47546) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fixed excessive reading in queries with `FINAL`. [#47801](https://github.com/ClickHouse/ClickHouse/pull/47801) ([Nikita Taranov](https://github.com/nickitat)).
* Setting `max_final_threads` would be set to the number of cores at server startup (by the same algorithm as used for `max_threads`). This improves the concurrency of `final` execution on servers with high number of CPUs. [#47915](https://github.com/ClickHouse/ClickHouse/pull/47915) ([Nikita Taranov](https://github.com/nickitat)).
* Allow executing reading pipeline for DIRECT dictionary with CLICKHOUSE source in multiple threads. To enable set `dictionary_use_async_executor=1` in `SETTINGS` section for source in `CREATE DICTIONARY` statement. [#47986](https://github.com/ClickHouse/ClickHouse/pull/47986) ([Vladimir C](https://github.com/vdimir)).
* Optimize one nullable key aggregate performance. [#45772](https://github.com/ClickHouse/ClickHouse/pull/45772) ([LiuNeng](https://github.com/liuneng1994)).
* Implemented lowercase `tokenbf_v1` index utilization for `hasTokenOrNull`, `hasTokenCaseInsensitive` and `hasTokenCaseInsensitiveOrNull`. [#46252](https://github.com/ClickHouse/ClickHouse/pull/46252) ([ltrk2](https://github.com/ltrk2)).
* Optimize functions `position` and `LIKE` by searching the first two chars using SIMD. [#46289](https://github.com/ClickHouse/ClickHouse/pull/46289) ([Jiebin Sun](https://github.com/jiebinn)).
* Optimize queries from the `system.detached_parts`, which could be significantly large. Added several sources with respect to the block size limitation; in each block, an IO thread pool is used to calculate the part size, i.e. to make syscalls in parallel. [#46624](https://github.com/ClickHouse/ClickHouse/pull/46624) ([Sema Checherinda](https://github.com/CheSema)).
* Increase the default value of `max_replicated_merges_in_queue` for ReplicatedMergeTree tables from 16 to 1000. It allows faster background merge operation on clusters with a very large number of replicas, such as clusters with shared storage in ClickHouse Cloud. [#47050](https://github.com/ClickHouse/ClickHouse/pull/47050) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Updated `clickhouse-copier` to use `GROUP BY` instead of `DISTINCT` to get the list of partitions. For large tables, this reduced the select time from over 500s to under 1s. [#47386](https://github.com/ClickHouse/ClickHouse/pull/47386) ([Clayton McClure](https://github.com/cmcclure-twilio)).
* Fix performance degradation in `ASOF JOIN`. [#47544](https://github.com/ClickHouse/ClickHouse/pull/47544) ([Ongkong](https://github.com/ongkong)).
* Even more batching in Keeper. Improve performance by avoiding breaking batches on read requests. [#47978](https://github.com/ClickHouse/ClickHouse/pull/47978) ([Antonio Andelic](https://github.com/antonio2368)).
* Allow PREWHERE for Merge with different DEFAULT expressions for columns. [#46831](https://github.com/ClickHouse/ClickHouse/pull/46831) ([Azat Khuzhin](https://github.com/azat)).
#### Experimental Feature
* Parallel replicas: Improved the overall performance by better utilizing the local replica, and forbid the reading with parallel replicas from non-replicated MergeTree by default. [#47858](https://github.com/ClickHouse/ClickHouse/pull/47858) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Support filter push down to left table for JOIN with `Join`, `Dictionary` and `EmbeddedRocksDB` tables if the experimental Analyzer is enabled. [#47280](https://github.com/ClickHouse/ClickHouse/pull/47280) ([Maksim Kita](https://github.com/kitaisreal)).
* Now ReplicatedMergeTree with zero copy replication has less load to Keeper. [#47676](https://github.com/ClickHouse/ClickHouse/pull/47676) ([alesapin](https://github.com/alesapin)).
* Fix create materialized view with MaterializedPostgreSQL [#40807](https://github.com/ClickHouse/ClickHouse/pull/40807) ([Maksim Buren](https://github.com/maks-buren630501)).
#### Improvement
* Enable `input_format_json_ignore_unknown_keys_in_named_tuple` by default. [#46742](https://github.com/ClickHouse/ClickHouse/pull/46742) ([Kruglov Pavel](https://github.com/Avogar)).
* Allow errors to be ignored while pushing to MATERIALIZED VIEW (add new setting `materialized_views_ignore_errors`, by default to `false`, but it is set to `true` for flushing logs to `system.*_log` tables unconditionally). [#46658](https://github.com/ClickHouse/ClickHouse/pull/46658) ([Azat Khuzhin](https://github.com/azat)).
* Track the file queue of distributed sends in memory. [#45491](https://github.com/ClickHouse/ClickHouse/pull/45491) ([Azat Khuzhin](https://github.com/azat)).
* Now `X-ClickHouse-Query-Id` and `X-ClickHouse-Timezone` headers are added to responses in all queries via HTTP protocol. Previously it was done only for `SELECT` queries. [#46364](https://github.com/ClickHouse/ClickHouse/pull/46364) ([Anton Popov](https://github.com/CurtizJ)).
* External tables from `MongoDB`: support for connection to a replica set via a URI with a host:port enum and support for the readPreference option in MongoDB dictionaries. Example URI: mongodb://db0.example.com:27017,db1.example.com:27017,db2.example.com:27017/?replicaSet=myRepl&readPreference=primary. [#46524](https://github.com/ClickHouse/ClickHouse/pull/46524) ([artem-yadr](https://github.com/artem-yadr)).
* This improvement should be invisible for users. Re-implement projection analysis on top of query plan. Added setting `query_plan_optimize_projection=1` to switch between old and new version. Fixes [#44963](https://github.com/ClickHouse/ClickHouse/issues/44963). [#46537](https://github.com/ClickHouse/ClickHouse/pull/46537) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Use Parquet format v2 instead of v1 in output format by default. Add setting `output_format_parquet_version` to control parquet version, possible values `1.0`, `2.4`, `2.6`, `2.latest` (default). [#46617](https://github.com/ClickHouse/ClickHouse/pull/46617) ([Kruglov Pavel](https://github.com/Avogar)).
* It is now possible to use the new configuration syntax to configure Kafka topics with periods (`.`) in their name. [#46752](https://github.com/ClickHouse/ClickHouse/pull/46752) ([Robert Schulze](https://github.com/rschu1ze)).
* Fix heuristics that check hyperscan patterns for problematic repeats. [#46819](https://github.com/ClickHouse/ClickHouse/pull/46819) ([Robert Schulze](https://github.com/rschu1ze)).
* Don't report ZK node exists to system.errors when a block was created concurrently by a different replica. [#46820](https://github.com/ClickHouse/ClickHouse/pull/46820) ([Raúl Marín](https://github.com/Algunenano)).
* Increase the limit for opened files in `clickhouse-local`. It will be able to read from `web` tables on servers with a huge number of CPU cores. Do not back off reading from the URL table engine in case of too many opened files. This closes [#46852](https://github.com/ClickHouse/ClickHouse/issues/46852). [#46853](https://github.com/ClickHouse/ClickHouse/pull/46853) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Exceptions thrown when numbers cannot be parsed now have an easier-to-read exception message. [#46917](https://github.com/ClickHouse/ClickHouse/pull/46917) ([Robert Schulze](https://github.com/rschu1ze)).
* Added update `system.backups` after every processed task to track the progress of backups. [#46989](https://github.com/ClickHouse/ClickHouse/pull/46989) ([Aleksandr Musorin](https://github.com/AVMusorin)).
* Allow types conversion in Native input format. Add settings `input_format_native_allow_types_conversion` that controls it (enabled by default). [#46990](https://github.com/ClickHouse/ClickHouse/pull/46990) ([Kruglov Pavel](https://github.com/Avogar)).
* Allow IPv4 in the `range` function to generate IP ranges. [#46995](https://github.com/ClickHouse/ClickHouse/pull/46995) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Improve exception message when it's impossible to move a part from one volume/disk to another. [#47032](https://github.com/ClickHouse/ClickHouse/pull/47032) ([alesapin](https://github.com/alesapin)).
* Support `Bool` type in `JSONType` function. Previously `Null` type was mistakenly returned for bool values. [#47046](https://github.com/ClickHouse/ClickHouse/pull/47046) ([Anton Popov](https://github.com/CurtizJ)).
* Use `_request_body` parameter to configure predefined HTTP queries. [#47086](https://github.com/ClickHouse/ClickHouse/pull/47086) ([Constantine Peresypkin](https://github.com/pkit)).
* Automatic indentation in the built-in UI SQL editor when Enter is pressed. [#47113](https://github.com/ClickHouse/ClickHouse/pull/47113) ([Alexey Korepanov](https://github.com/alexkorep)).
* Self-extraction with 'sudo' will attempt to set uid and gid of extracted files to running user. [#47116](https://github.com/ClickHouse/ClickHouse/pull/47116) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Previously, the `repeat` function's second argument only accepted an unsigned integer type, which meant it could not accept values such as -1. This behavior differed from that of the Spark function. In this update, the repeat function has been modified to match the behavior of the Spark function. It now accepts the same types of inputs, including negative integers. Extensive testing has been performed to verify the correctness of the updated implementation. [#47134](https://github.com/ClickHouse/ClickHouse/pull/47134) ([KevinyhZou](https://github.com/KevinyhZou)). Note: the changelog entry was rewritten by ChatGPT.
* Remove `::__1` part from stacktraces. Display `std::basic_string<char, ...` as `String` in stacktraces. [#47171](https://github.com/ClickHouse/ClickHouse/pull/47171) ([Mike Kot](https://github.com/myrrc)).
* Reimplement interserver mode to avoid replay attacks (note, that change is backward compatible with older servers). [#47213](https://github.com/ClickHouse/ClickHouse/pull/47213) ([Azat Khuzhin](https://github.com/azat)).
* Improve recognition of regular expression groups and refine the regexp_tree dictionary. [#47218](https://github.com/ClickHouse/ClickHouse/pull/47218) ([Han Fei](https://github.com/hanfei1991)).
* Keeper improvement: Add new 4LW `clrs` to clean resources used by Keeper (e.g. release unused memory). [#47256](https://github.com/ClickHouse/ClickHouse/pull/47256) ([Antonio Andelic](https://github.com/antonio2368)).
* Add optional arguments to codecs `DoubleDelta(bytes_size)`, `Gorilla(bytes_size)`, `FPC(level, float_size)`, this allows using these codecs without column type in `clickhouse-compressor`. Fix possible aborts and arithmetic errors in `clickhouse-compressor` with these codecs. Fixes: https://github.com/ClickHouse/ClickHouse/discussions/47262. [#47271](https://github.com/ClickHouse/ClickHouse/pull/47271) ([Kruglov Pavel](https://github.com/Avogar)).
* Add support for big int types to the `runningDifference` function. Closes [#47194](https://github.com/ClickHouse/ClickHouse/issues/47194). [#47322](https://github.com/ClickHouse/ClickHouse/pull/47322) ([Nikolay Degterinsky](https://github.com/evillique)).
* Add an expiration window for S3 credentials that have an expiration time to avoid `ExpiredToken` errors in some edge cases. It can be controlled with `expiration_window_seconds` config, the default is 120 seconds. [#47423](https://github.com/ClickHouse/ClickHouse/pull/47423) ([Antonio Andelic](https://github.com/antonio2368)).
* Support Decimals and Date32 in `Avro` format. [#47434](https://github.com/ClickHouse/ClickHouse/pull/47434) ([Kruglov Pavel](https://github.com/Avogar)).
* Do not start the server if an interrupted conversion from `Ordinary` to `Atomic` was detected, print a better error message with troubleshooting instructions. [#47487](https://github.com/ClickHouse/ClickHouse/pull/47487) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Add a new column `kind` to the `system.opentelemetry_span_log`. This column holds the value of [SpanKind](https://opentelemetry.io/docs/reference/specification/trace/api/#spankind) defined in OpenTelemtry. [#47499](https://github.com/ClickHouse/ClickHouse/pull/47499) ([Frank Chen](https://github.com/FrankChen021)).
* Allow reading/writing nested arrays in `Protobuf` format with only the root field name as column name. Previously column name should've contained all nested field names (like `a.b.c Array(Array(Array(UInt32)))`, now you can use just `a Array(Array(Array(UInt32)))`. [#47650](https://github.com/ClickHouse/ClickHouse/pull/47650) ([Kruglov Pavel](https://github.com/Avogar)).
* Added an optional `STRICT` modifier for `SYSTEM SYNC REPLICA` which makes the query wait for the replication queue to become empty (just like it worked before https://github.com/ClickHouse/ClickHouse/pull/45648). [#47659](https://github.com/ClickHouse/ClickHouse/pull/47659) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Improve the naming of some OpenTelemetry span logs. [#47667](https://github.com/ClickHouse/ClickHouse/pull/47667) ([Frank Chen](https://github.com/FrankChen021)).
* Prevent using too long chains of aggregate function combinators (they can lead to slow queries in the analysis stage). This closes [#47715](https://github.com/ClickHouse/ClickHouse/issues/47715). [#47716](https://github.com/ClickHouse/ClickHouse/pull/47716) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Support for subquery in parameterized views; resolves [#46741](https://github.com/ClickHouse/ClickHouse/issues/46741) [#47725](https://github.com/ClickHouse/ClickHouse/pull/47725) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Fix memory leak in MySQL integration (reproduces with `connection_auto_close=1`). [#47732](https://github.com/ClickHouse/ClickHouse/pull/47732) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Improved error handling in the code related to Decimal parameters, resulting in more informative error messages. Previously, when incorrect Decimal parameters were supplied, the error message generated was unclear or unhelpful. With this update, the error message printed has been fixed to provide more detailed and useful information, making it easier to identify and correct issues related to Decimal parameters. [#47812](https://github.com/ClickHouse/ClickHouse/pull/47812) ([Yu Feng](https://github.com/Vigor-jpg)). Note: this changelog entry is rewritten by ChatGPT.
* The parameter `exact_rows_before_limit` is used to make `rows_before_limit_at_least` is designed to accurately reflect the number of rows returned before the limit is reached. This pull request addresses issues encountered when the query involves distributed processing across multiple shards or sorting operations. Prior to this update, these scenarios were not functioning as intended. [#47874](https://github.com/ClickHouse/ClickHouse/pull/47874) ([Amos Bird](https://github.com/amosbird)).
* ThreadPools metrics introspection. [#47880](https://github.com/ClickHouse/ClickHouse/pull/47880) ([Azat Khuzhin](https://github.com/azat)).
* Add `WriteBufferFromS3Microseconds` and `WriteBufferFromS3RequestsErrors` profile events. [#47885](https://github.com/ClickHouse/ClickHouse/pull/47885) ([Antonio Andelic](https://github.com/antonio2368)).
* Add `--link` and `--noninteractive` (`-y`) options to ClickHouse install. Closes [#47750](https://github.com/ClickHouse/ClickHouse/issues/47750). [#47887](https://github.com/ClickHouse/ClickHouse/pull/47887) ([Nikolay Degterinsky](https://github.com/evillique)).
* Fixed `UNKNOWN_TABLE` exception when attaching to a materialized view that has dependent tables that are not available. This might be useful when trying to restore state from a backup. [#47975](https://github.com/ClickHouse/ClickHouse/pull/47975) ([MikhailBurdukov](https://github.com/MikhailBurdukov)).
* Fix case when the (optional) path is not added to an encrypted disk configuration. [#47981](https://github.com/ClickHouse/ClickHouse/pull/47981) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Support for CTE in parameterized views Implementation: Updated to allow query parameters while evaluating scalar subqueries. [#48065](https://github.com/ClickHouse/ClickHouse/pull/48065) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Support big integers `(U)Int128/(U)Int256`, `Map` with any key type and `DateTime64` with any precision (not only 3 and 6). [#48119](https://github.com/ClickHouse/ClickHouse/pull/48119) ([Kruglov Pavel](https://github.com/Avogar)).
* Allow skipping errors related to unknown enum values in row input formats. [#48133](https://github.com/ClickHouse/ClickHouse/pull/48133) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
#### Build/Testing/Packaging Improvement
* ClickHouse now builds with `C++23`. [#47424](https://github.com/ClickHouse/ClickHouse/pull/47424) ([Robert Schulze](https://github.com/rschu1ze)).
* Fuzz `EXPLAIN` queries in the AST Fuzzer. [#47803](https://github.com/ClickHouse/ClickHouse/pull/47803) [#47852](https://github.com/ClickHouse/ClickHouse/pull/47852) ([flynn](https://github.com/ucasfl)).
* Split stress test and the automated backward compatibility check (now Upgrade check). [#44879](https://github.com/ClickHouse/ClickHouse/pull/44879) ([Kruglov Pavel](https://github.com/Avogar)).
* Updated the Ubuntu Image for Docker to calm down some bogus security reports. [#46784](https://github.com/ClickHouse/ClickHouse/pull/46784) ([Julio Jimenez](https://github.com/juliojimenez)). Please note that ClickHouse has no dependencies and does not require Docker.
* Adds a prompt to allow the removal of an existing `clickhouse` download when using "curl | sh" download of ClickHouse. Prompt is "ClickHouse binary clickhouse already exists. Overwrite? \[y/N\]". [#46859](https://github.com/ClickHouse/ClickHouse/pull/46859) ([Dan Roscigno](https://github.com/DanRoscigno)).
* Fix error during server startup on old distros (e.g. Amazon Linux 2) and on ARM that glibc 2.28 symbols are not found. [#47008](https://github.com/ClickHouse/ClickHouse/pull/47008) ([Robert Schulze](https://github.com/rschu1ze)).
* Prepare for clang 16. [#47027](https://github.com/ClickHouse/ClickHouse/pull/47027) ([Amos Bird](https://github.com/amosbird)).
* Added a CI check which ensures ClickHouse can run with an old glibc on ARM. [#47063](https://github.com/ClickHouse/ClickHouse/pull/47063) ([Robert Schulze](https://github.com/rschu1ze)).
* Add a style check to prevent incorrect usage of the `NDEBUG` macro. [#47699](https://github.com/ClickHouse/ClickHouse/pull/47699) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Speed up the build a little. [#47714](https://github.com/ClickHouse/ClickHouse/pull/47714) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Bump `vectorscan` to 5.4.9. [#47955](https://github.com/ClickHouse/ClickHouse/pull/47955) ([Robert Schulze](https://github.com/rschu1ze)).
* Add a unit test to assert Apache Arrow's fatal logging does not abort. It covers the changes in [ClickHouse/arrow#16](https://github.com/ClickHouse/arrow/pull/16). [#47958](https://github.com/ClickHouse/ClickHouse/pull/47958) ([Arthur Passos](https://github.com/arthurpassos)).
* Restore the ability of native macOS debug server build to start. [#48050](https://github.com/ClickHouse/ClickHouse/pull/48050) ([Robert Schulze](https://github.com/rschu1ze)). Note: this change is only relevant for development, as the ClickHouse official builds are done with cross-compilation.
#### Bug Fix (user-visible misbehavior in an official stable release)
* Fix formats parser resetting, test processing bad messages in `Kafka` [#45693](https://github.com/ClickHouse/ClickHouse/pull/45693) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix data size calculation in Keeper [#46086](https://github.com/ClickHouse/ClickHouse/pull/46086) ([Antonio Andelic](https://github.com/antonio2368)).
* Fixed a bug in automatic retries of `DROP TABLE` query with `ReplicatedMergeTree` tables and `Atomic` databases. In rare cases it could lead to `Can't get data for node /zk_path/log_pointer` and `The specified key does not exist` errors if the ZooKeeper session expired during DROP and a new replicated table with the same path in ZooKeeper was created in parallel. [#46384](https://github.com/ClickHouse/ClickHouse/pull/46384) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Fix incorrect alias recursion while normalizing queries that prevented some queries to run. [#46609](https://github.com/ClickHouse/ClickHouse/pull/46609) ([Raúl Marín](https://github.com/Algunenano)).
* Fix IPv4/IPv6 serialization/deserialization in binary formats [#46616](https://github.com/ClickHouse/ClickHouse/pull/46616) ([Kruglov Pavel](https://github.com/Avogar)).
* ActionsDAG: do not change result of `and` during optimization [#46653](https://github.com/ClickHouse/ClickHouse/pull/46653) ([Salvatore Mesoraca](https://github.com/aiven-sal)).
* Improve query cancellation when a client dies [#46681](https://github.com/ClickHouse/ClickHouse/pull/46681) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Fix arithmetic operations in aggregate optimization [#46705](https://github.com/ClickHouse/ClickHouse/pull/46705) ([Duc Canh Le](https://github.com/canhld94)).
* Fix possible `clickhouse-local`'s abort on JSONEachRow schema inference [#46731](https://github.com/ClickHouse/ClickHouse/pull/46731) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix changing an expired role [#46772](https://github.com/ClickHouse/ClickHouse/pull/46772) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix combined PREWHERE column accumulation from multiple steps [#46785](https://github.com/ClickHouse/ClickHouse/pull/46785) ([Alexander Gololobov](https://github.com/davenger)).
* Use initial range for fetching file size in HTTP read buffer. Without this change, some remote files couldn't be processed. [#46824](https://github.com/ClickHouse/ClickHouse/pull/46824) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix the incorrect progress bar while using the URL tables [#46830](https://github.com/ClickHouse/ClickHouse/pull/46830) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix MSan report in `maxIntersections` function [#46847](https://github.com/ClickHouse/ClickHouse/pull/46847) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix a bug in `Map` data type [#46856](https://github.com/ClickHouse/ClickHouse/pull/46856) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix wrong results of some LIKE searches when the LIKE pattern contains quoted non-quotable characters [#46875](https://github.com/ClickHouse/ClickHouse/pull/46875) ([Robert Schulze](https://github.com/rschu1ze)).
* Fix - WITH FILL would produce abort when the Filling Transform processing an empty block [#46897](https://github.com/ClickHouse/ClickHouse/pull/46897) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Fix date and int inference from string in JSON [#46972](https://github.com/ClickHouse/ClickHouse/pull/46972) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix bug in zero-copy replication disk choice during fetch [#47010](https://github.com/ClickHouse/ClickHouse/pull/47010) ([alesapin](https://github.com/alesapin)).
* Fix a typo in systemd service definition [#47051](https://github.com/ClickHouse/ClickHouse/pull/47051) ([Palash Goel](https://github.com/palash-goel)).
* Fix the NOT_IMPLEMENTED error with CROSS JOIN and algorithm = auto [#47068](https://github.com/ClickHouse/ClickHouse/pull/47068) ([Vladimir C](https://github.com/vdimir)).
* Fix the problem that the 'ReplicatedMergeTree' table failed to insert two similar data when the 'part_type' is configured as 'InMemory' mode (experimental feature). [#47121](https://github.com/ClickHouse/ClickHouse/pull/47121) ([liding1992](https://github.com/liding1992)).
* External dictionaries / library-bridge: Fix error "unknown library method 'extDict_libClone'" [#47136](https://github.com/ClickHouse/ClickHouse/pull/47136) ([alex filatov](https://github.com/phil-88)).
* Fix race condition in a grace hash join with limit [#47153](https://github.com/ClickHouse/ClickHouse/pull/47153) ([Vladimir C](https://github.com/vdimir)).
* Fix concrete columns PREWHERE support [#47154](https://github.com/ClickHouse/ClickHouse/pull/47154) ([Azat Khuzhin](https://github.com/azat)).
* Fix possible deadlock in Query Status [#47161](https://github.com/ClickHouse/ClickHouse/pull/47161) ([Kruglov Pavel](https://github.com/Avogar)).
* Forbid insert select for the same `Join` table, as it leads to a deadlock [#47260](https://github.com/ClickHouse/ClickHouse/pull/47260) ([Vladimir C](https://github.com/vdimir)).
* Skip merged partitions for `min_age_to_force_merge_seconds` merges [#47303](https://github.com/ClickHouse/ClickHouse/pull/47303) ([Antonio Andelic](https://github.com/antonio2368)).
* Modify find_first_symbols, so it works as expected for find_first_not_symbols [#47304](https://github.com/ClickHouse/ClickHouse/pull/47304) ([Arthur Passos](https://github.com/arthurpassos)).
* Fix big numbers inference in CSV [#47410](https://github.com/ClickHouse/ClickHouse/pull/47410) ([Kruglov Pavel](https://github.com/Avogar)).
* Disable logical expression optimizer for expression with aliases. [#47451](https://github.com/ClickHouse/ClickHouse/pull/47451) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix error in `decodeURLComponent` [#47457](https://github.com/ClickHouse/ClickHouse/pull/47457) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix explain graph with projection [#47473](https://github.com/ClickHouse/ClickHouse/pull/47473) ([flynn](https://github.com/ucasfl)).
* Fix query parameters [#47488](https://github.com/ClickHouse/ClickHouse/pull/47488) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Parameterized view: a bug fix. [#47495](https://github.com/ClickHouse/ClickHouse/pull/47495) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Fuzzer of data formats, and the corresponding fixes. [#47519](https://github.com/ClickHouse/ClickHouse/pull/47519) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix monotonicity check for `DateTime64` [#47526](https://github.com/ClickHouse/ClickHouse/pull/47526) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix "block structure mismatch" for a Nullable LowCardinality column [#47537](https://github.com/ClickHouse/ClickHouse/pull/47537) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Proper fix for a bug in Apache Parquet [#45878](https://github.com/ClickHouse/ClickHouse/issues/45878) [#47538](https://github.com/ClickHouse/ClickHouse/pull/47538) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix `BSONEachRow` parallel parsing when document size is invalid [#47540](https://github.com/ClickHouse/ClickHouse/pull/47540) ([Kruglov Pavel](https://github.com/Avogar)).
* Preserve error in `system.distribution_queue` on `SYSTEM FLUSH DISTRIBUTED` [#47541](https://github.com/ClickHouse/ClickHouse/pull/47541) ([Azat Khuzhin](https://github.com/azat)).
* Check for duplicate column in `BSONEachRow` format [#47609](https://github.com/ClickHouse/ClickHouse/pull/47609) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix wait for zero copy lock during move [#47631](https://github.com/ClickHouse/ClickHouse/pull/47631) ([alesapin](https://github.com/alesapin)).
* Fix aggregation by partitions [#47634](https://github.com/ClickHouse/ClickHouse/pull/47634) ([Nikita Taranov](https://github.com/nickitat)).
* Fix bug in tuple as array serialization in `BSONEachRow` format [#47690](https://github.com/ClickHouse/ClickHouse/pull/47690) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix crash in `polygonsSymDifferenceCartesian` [#47702](https://github.com/ClickHouse/ClickHouse/pull/47702) ([pufit](https://github.com/pufit)).
* Fix reading from storage `File` compressed files with `zlib` and `gzip` compression [#47796](https://github.com/ClickHouse/ClickHouse/pull/47796) ([Anton Popov](https://github.com/CurtizJ)).
* Improve empty query detection for PostgreSQL (for pgx golang driver) [#47854](https://github.com/ClickHouse/ClickHouse/pull/47854) ([Azat Khuzhin](https://github.com/azat)).
* Fix DateTime monotonicity check for LowCardinality types [#47860](https://github.com/ClickHouse/ClickHouse/pull/47860) ([Antonio Andelic](https://github.com/antonio2368)).
* Use restore_threads (not backup_threads) for RESTORE ASYNC [#47861](https://github.com/ClickHouse/ClickHouse/pull/47861) ([Azat Khuzhin](https://github.com/azat)).
* Fix DROP COLUMN with ReplicatedMergeTree containing projections [#47883](https://github.com/ClickHouse/ClickHouse/pull/47883) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix for Replicated database recovery [#47901](https://github.com/ClickHouse/ClickHouse/pull/47901) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Hotfix for too verbose warnings in HTTP [#47903](https://github.com/ClickHouse/ClickHouse/pull/47903) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Fix "Field value too long" in `catboostEvaluate` [#47970](https://github.com/ClickHouse/ClickHouse/pull/47970) ([Robert Schulze](https://github.com/rschu1ze)).
* Fix [#36971](https://github.com/ClickHouse/ClickHouse/issues/36971): Watchdog: exit with non-zero code if child process exits [#47973](https://github.com/ClickHouse/ClickHouse/pull/47973) ([Коренберг Марк](https://github.com/socketpair)).
* Fix for "index file `cidx` is unexpectedly long" [#48010](https://github.com/ClickHouse/ClickHouse/pull/48010) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Fix MaterializedPostgreSQL query to get attributes (replica-identity) [#48015](https://github.com/ClickHouse/ClickHouse/pull/48015) ([Solomatov Sergei](https://github.com/solomatovs)).
* parseDateTime(): Fix UB (signed integer overflow) [#48019](https://github.com/ClickHouse/ClickHouse/pull/48019) ([Robert Schulze](https://github.com/rschu1ze)).
* Use unique names for Records in Avro to avoid reusing its schema [#48057](https://github.com/ClickHouse/ClickHouse/pull/48057) ([Kruglov Pavel](https://github.com/Avogar)).
* Correctly set TCP/HTTP socket timeouts in Keeper [#48108](https://github.com/ClickHouse/ClickHouse/pull/48108) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix possible member call on null pointer in `Avro` format [#48184](https://github.com/ClickHouse/ClickHouse/pull/48184) ([Kruglov Pavel](https://github.com/Avogar)).
### <a id="232"></a> ClickHouse release 23.2, 2023-02-23
#### Backward Incompatible Change
* Extend function "toDayOfWeek()" (alias: "DAYOFWEEK") with a mode argument that encodes whether the week starts on Monday or Sunday and whether counting starts at 0 or 1. For consistency with other date time functions, the mode argument was inserted between the time and the time zone arguments. This breaks existing usage of the (previously undocumented) 2-argument syntax "toDayOfWeek(time, time_zone)". A fix is to rewrite the function into "toDayOfWeek(time, 0, time_zone)". [#45233](https://github.com/ClickHouse/ClickHouse/pull/45233) ([Robert Schulze](https://github.com/rschu1ze)).
* Rename setting `max_query_cache_size` to `filesystem_cache_max_download_size`. [#45614](https://github.com/ClickHouse/ClickHouse/pull/45614) ([Kseniia Sumarokova](https://github.com/kssenii)).
* The `default` user will not have permissions for access type `SHOW NAMED COLLECTION` by default (e.g. `default` user will no longer be able to grant ALL to other users as it was before, therefore this PR is backward incompatible). [#46010](https://github.com/ClickHouse/ClickHouse/pull/46010) ([Kseniia Sumarokova](https://github.com/kssenii)).
* If the SETTINGS clause is specified before the FORMAT clause, the settings will be applied to formatting as well. [#46003](https://github.com/ClickHouse/ClickHouse/pull/46003) ([Azat Khuzhin](https://github.com/azat)).
* Remove support for setting `materialized_postgresql_allow_automatic_update` (which was by default turned off). [#46106](https://github.com/ClickHouse/ClickHouse/pull/46106) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Slightly improve performance of `countDigits` on realistic datasets. This closed [#44518](https://github.com/ClickHouse/ClickHouse/issues/44518). In previous versions, `countDigits(0)` returned `0`; now it returns `1`, which is more correct, and follows the existing documentation. [#46187](https://github.com/ClickHouse/ClickHouse/pull/46187) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Disallow creation of new columns compressed by a combination of codecs "Delta" or "DoubleDelta" followed by codecs "Gorilla" or "FPC". This can be bypassed using setting "allow_suspicious_codecs = true". [#45652](https://github.com/ClickHouse/ClickHouse/pull/45652) ([Robert Schulze](https://github.com/rschu1ze)).
#### New Feature
* Add `StorageIceberg` and table function `iceberg` to access iceberg table store on S3. [#45384](https://github.com/ClickHouse/ClickHouse/pull/45384) ([flynn](https://github.com/ucasfl)).
* Allow configuring storage as `SETTINGS disk = '<disk_name>'` (instead of `storage_policy`) and with explicit disk creation `SETTINGS disk = disk(type=s3, ...)`. [#41976](https://github.com/ClickHouse/ClickHouse/pull/41976) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Expose `ProfileEvents` counters in `system.part_log`. [#38614](https://github.com/ClickHouse/ClickHouse/pull/38614) ([Bharat Nallan](https://github.com/bharatnc)).
* Enrichment of the existing `ReplacingMergeTree` engine to allow duplicate the insertion. It leverages the power of both `ReplacingMergeTree` and `CollapsingMergeTree` in one MergeTree engine. Deleted data are not returned when queried, but not removed from disk neither. [#41005](https://github.com/ClickHouse/ClickHouse/pull/41005) ([youennL-cs](https://github.com/youennL-cs)).
* Add `generateULID` function. Closes [#36536](https://github.com/ClickHouse/ClickHouse/issues/36536). [#44662](https://github.com/ClickHouse/ClickHouse/pull/44662) ([Nikolay Degterinsky](https://github.com/evillique)).
* Add `corrMatrix` aggregate function, calculating each two columns. In addition, since Aggregatefunctions `covarSamp` and `covarPop` are similar to `corr`, I add `covarSampMatrix`, `covarPopMatrix` by the way. @alexey-milovidov closes [#44587](https://github.com/ClickHouse/ClickHouse/issues/44587). [#44680](https://github.com/ClickHouse/ClickHouse/pull/44680) ([FFFFFFFHHHHHHH](https://github.com/FFFFFFFHHHHHHH)).
* Introduce arrayShuffle function for random array permutations. [#45271](https://github.com/ClickHouse/ClickHouse/pull/45271) ([Joanna Hulboj](https://github.com/jh0x)).
* Support types `FIXED_SIZE_BINARY` type in Arrow, `FIXED_LENGTH_BYTE_ARRAY` in `Parquet` and match them to `FixedString`. Add settings `output_format_parquet_fixed_string_as_fixed_byte_array/output_format_arrow_fixed_string_as_fixed_byte_array` to control default output type for FixedString. Closes [#45326](https://github.com/ClickHouse/ClickHouse/issues/45326). [#45340](https://github.com/ClickHouse/ClickHouse/pull/45340) ([Kruglov Pavel](https://github.com/Avogar)).
* Add a new column `last_exception_time` to system.replication_queue. [#45457](https://github.com/ClickHouse/ClickHouse/pull/45457) ([Frank Chen](https://github.com/FrankChen021)).
* Add two new functions which allow for user-defined keys/seeds with SipHash{64,128}. [#45513](https://github.com/ClickHouse/ClickHouse/pull/45513) ([Salvatore Mesoraca](https://github.com/aiven-sal)).
* Allow a three-argument version for table function `format`. close [#45808](https://github.com/ClickHouse/ClickHouse/issues/45808). [#45873](https://github.com/ClickHouse/ClickHouse/pull/45873) ([FFFFFFFHHHHHHH](https://github.com/FFFFFFFHHHHHHH)).
* Add `JodaTime` format support for 'x','w','S'. Refer to https://joda-time.sourceforge.net/apidocs/org/joda/time/format/DateTimeFormat.html. [#46073](https://github.com/ClickHouse/ClickHouse/pull/46073) ([zk_kiger](https://github.com/zk-kiger)).
* Support window function `ntile`. ([lgbo](https://github.com/lgbo-ustc)).
* Add setting `final` to implicitly apply the `FINAL` modifier to every table. [#40945](https://github.com/ClickHouse/ClickHouse/pull/40945) ([Arthur Passos](https://github.com/arthurpassos)).
* Added `arrayPartialSort` and `arrayPartialReverseSort` functions. [#46296](https://github.com/ClickHouse/ClickHouse/pull/46296) ([Joanna Hulboj](https://github.com/jh0x)).
* The new http parameter `client_protocol_version` allows setting a client protocol version for HTTP responses using the Native format. [#40397](https://github.com/ClickHouse/ClickHouse/issues/40397). [#46360](https://github.com/ClickHouse/ClickHouse/pull/46360) ([Geoff Genz](https://github.com/genzgd)).
* Add new function `regexpExtract`, like spark function `REGEXP_EXTRACT` for compatibility. It is similar to the existing function `extract`. [#46469](https://github.com/ClickHouse/ClickHouse/pull/46469) ([李扬](https://github.com/taiyang-li)).
* Add new function `JSONArrayLength`, which returns the number of elements in the outermost JSON array. The function returns NULL if the input JSON string is invalid. [#46631](https://github.com/ClickHouse/ClickHouse/pull/46631) ([李扬](https://github.com/taiyang-li)).
#### Performance Improvement
* The introduced logic works if PREWHERE condition is a conjunction of multiple conditions (cond1 AND cond2 AND ... ). It groups those conditions that require reading the same columns into steps. After each step the corresponding part of the full condition is computed and the result rows might be filtered. This allows to read fewer rows in the next steps thus saving IO bandwidth and doing less computation. This logic is disabled by default for now. It will be enabled by default in one of the future releases once it is known to not have any regressions, so it is highly encouraged to be used for testing. It can be controlled by 2 settings: "enable_multiple_prewhere_read_steps" and "move_all_conditions_to_prewhere". [#46140](https://github.com/ClickHouse/ClickHouse/pull/46140) ([Alexander Gololobov](https://github.com/davenger)).
* An option added to aggregate partitions independently if table partition key and group by key are compatible. Controlled by the setting `allow_aggregate_partitions_independently`. Disabled by default because of limited applicability (please refer to the docs). [#45364](https://github.com/ClickHouse/ClickHouse/pull/45364) ([Nikita Taranov](https://github.com/nickitat)).
* Allow using Vertical merge algorithm with parts in Compact format. This will allow ClickHouse server to use much less memory for background operations. This closes [#46084](https://github.com/ClickHouse/ClickHouse/issues/46084). [#45681](https://github.com/ClickHouse/ClickHouse/pull/45681) [#46282](https://github.com/ClickHouse/ClickHouse/pull/46282) ([Anton Popov](https://github.com/CurtizJ)).
* Optimize `Parquet` reader by using batch reader. [#45878](https://github.com/ClickHouse/ClickHouse/pull/45878) ([LiuNeng](https://github.com/liuneng1994)).
* Add new `local_filesystem_read_method` method `io_uring` based on the asynchronous Linux [io_uring](https://kernel.dk/io_uring.pdf) subsystem, improving read performance almost universally compared to the default `pread` method. [#38456](https://github.com/ClickHouse/ClickHouse/pull/38456) ([Saulius Valatka](https://github.com/sauliusvl)).
* Rewrite aggregate functions with `if` expression as argument when logically equivalent. For example, `avg(if(cond, col, null))` can be rewritten to avgIf(cond, col). It is helpful in performance. [#44730](https://github.com/ClickHouse/ClickHouse/pull/44730) ([李扬](https://github.com/taiyang-li)).
* Improve lower/upper function performance with avx512 instructions. [#37894](https://github.com/ClickHouse/ClickHouse/pull/37894) ([yaqi-zhao](https://github.com/yaqi-zhao)).
* Remove the limitation that on systems with >=32 cores and SMT disabled ClickHouse uses only half of the cores (the case when you disable Hyper Threading in BIOS). [#44973](https://github.com/ClickHouse/ClickHouse/pull/44973) ([Robert Schulze](https://github.com/rschu1ze)).
* Improve performance of function `multiIf` by columnar executing, speed up by 2.3x. [#45296](https://github.com/ClickHouse/ClickHouse/pull/45296) ([李扬](https://github.com/taiyang-li)).
* Add fast path for function `position` when the needle is empty. [#45382](https://github.com/ClickHouse/ClickHouse/pull/45382) ([李扬](https://github.com/taiyang-li)).
* Enable `query_plan_remove_redundant_sorting` optimization by default. Optimization implemented in [#45420](https://github.com/ClickHouse/ClickHouse/issues/45420). [#45567](https://github.com/ClickHouse/ClickHouse/pull/45567) ([Igor Nikonov](https://github.com/devcrafter)).
* Increased HTTP Transfer Encoding chunk size to improve performance of large queries using the HTTP interface. [#45593](https://github.com/ClickHouse/ClickHouse/pull/45593) ([Geoff Genz](https://github.com/genzgd)).
* Fixed performance of short `SELECT` queries that read from tables with large number of `Array`/`Map`/`Nested` columns. [#45630](https://github.com/ClickHouse/ClickHouse/pull/45630) ([Anton Popov](https://github.com/CurtizJ)).
* Improve performance of filtering for big integers and decimal types. [#45949](https://github.com/ClickHouse/ClickHouse/pull/45949) ([李扬](https://github.com/taiyang-li)).
* This change could effectively reduce the overhead of obtaining the filter from ColumnNullable(UInt8) and improve the overall query performance. To evaluate the impact of this change, we adopted TPC-H benchmark but revised the column types from non-nullable to nullable, and we measured the QPS of its queries as the performance indicator. [#45962](https://github.com/ClickHouse/ClickHouse/pull/45962) ([Zhiguo Zhou](https://github.com/ZhiguoZh)).
* Make the `_part` and `_partition_id` virtual column be `LowCardinality(String)` type. Closes [#45964](https://github.com/ClickHouse/ClickHouse/issues/45964). [#45975](https://github.com/ClickHouse/ClickHouse/pull/45975) ([flynn](https://github.com/ucasfl)).
* Improve the performance of Decimal conversion when the scale does not change. [#46095](https://github.com/ClickHouse/ClickHouse/pull/46095) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Allow to increase prefetching for read data. [#46168](https://github.com/ClickHouse/ClickHouse/pull/46168) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Rewrite `arrayExists(x -> x = 1, arr)` -> `has(arr, 1)`, which improve performance by 1.34x. [#46188](https://github.com/ClickHouse/ClickHouse/pull/46188) ([李扬](https://github.com/taiyang-li)).
* Fix too big memory usage for vertical merges on non-remote disk. Respect `max_insert_delayed_streams_for_parallel_write` for the remote disk. [#46275](https://github.com/ClickHouse/ClickHouse/pull/46275) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Update zstd to v1.5.4. It has some minor improvements in performance and compression ratio. If you run replicas with different versions of ClickHouse you may see reasonable error messages `Data after merge/mutation is not byte-identical to data on another replicas.` with explanation. These messages are Ok and you should not worry. [#46280](https://github.com/ClickHouse/ClickHouse/pull/46280) ([Raúl Marín](https://github.com/Algunenano)).
* Fix performance degradation caused by [#39737](https://github.com/ClickHouse/ClickHouse/issues/39737). [#46309](https://github.com/ClickHouse/ClickHouse/pull/46309) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* The `replicas_status` handle will answer quickly even in case of a large replication queue. [#46310](https://github.com/ClickHouse/ClickHouse/pull/46310) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Add avx512 support for aggregate function `sum`, function unary arithmetic, function comparison. [#37870](https://github.com/ClickHouse/ClickHouse/pull/37870) ([zhao zhou](https://github.com/zzachimed)).
* Rewrote the code around marks distribution and the overall coordination of the reading in order to achieve the maximum performance improvement. This closes [#34527](https://github.com/ClickHouse/ClickHouse/issues/34527). [#43772](https://github.com/ClickHouse/ClickHouse/pull/43772) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Remove redundant DISTINCT clauses in query (subqueries). Implemented on top of query plan. It does similar optimization as `optimize_duplicate_order_by_and_distinct` regarding DISTINCT clauses. Can be enabled via `query_plan_remove_redundant_distinct` setting. Related to [#42648](https://github.com/ClickHouse/ClickHouse/issues/42648). [#44176](https://github.com/ClickHouse/ClickHouse/pull/44176) ([Igor Nikonov](https://github.com/devcrafter)).
* A few query rewrite optimizations: `sumIf(123, cond) -> 123 * countIf(1, cond)`, `sum(if(cond, 123, 0)) -> 123 * countIf(cond)`, `sum(if(cond, 0, 123)) -> 123 * countIf(not(cond))` [#44728](https://github.com/ClickHouse/ClickHouse/pull/44728) ([李扬](https://github.com/taiyang-li)).
* Improved how memory bound merging and aggregation in order on top query plan interact. Previously we fell back to explicit sorting for AIO in some cases when it wasn't actually needed. [#45892](https://github.com/ClickHouse/ClickHouse/pull/45892) ([Nikita Taranov](https://github.com/nickitat)).
* Concurrent merges are scheduled using round-robin by default to ensure fair and starvation-free operation. Previously in heavily overloaded shards, big merges could possibly be starved by smaller merges due to the use of strict priority scheduling. Added `background_merges_mutations_scheduling_policy` server config option to select scheduling algorithm (`round_robin` or `shortest_task_first`). [#46247](https://github.com/ClickHouse/ClickHouse/pull/46247) ([Sergei Trifonov](https://github.com/serxa)).
#### Improvement
* Enable retries for INSERT by default in case of ZooKeeper session loss. We already use it in production. [#46308](https://github.com/ClickHouse/ClickHouse/pull/46308) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Add ability to ignore unknown keys in JSON object for named tuples (`input_format_json_ignore_unknown_keys_in_named_tuple`). [#45678](https://github.com/ClickHouse/ClickHouse/pull/45678) ([Azat Khuzhin](https://github.com/azat)).
* Support optimizing the `where` clause with sorting key expression move to `prewhere` for query with `final`. [#38893](https://github.com/ClickHouse/ClickHouse/issues/38893). [#38950](https://github.com/ClickHouse/ClickHouse/pull/38950) ([hexiaoting](https://github.com/hexiaoting)).
* Add new metrics for backups: num_processed_files and processed_files_size described actual number of processed files. [#42244](https://github.com/ClickHouse/ClickHouse/pull/42244) ([Aleksandr](https://github.com/AVMusorin)).
* Added retries on interserver DNS errors. [#43179](https://github.com/ClickHouse/ClickHouse/pull/43179) ([Anton Kozlov](https://github.com/tonickkozlov)).
* Keeper improvement: try preallocating space on the disk to avoid undefined out-of-space issues. Introduce setting `max_log_file_size` for the maximum size of Keeper's Raft log files. [#44370](https://github.com/ClickHouse/ClickHouse/pull/44370) ([Antonio Andelic](https://github.com/antonio2368)).
* Optimize behavior for a replica delay api logic in case the replica is read-only. [#45148](https://github.com/ClickHouse/ClickHouse/pull/45148) ([mateng915](https://github.com/mateng0915)).
* Ask for the password in clickhouse-client interactively in a case when the empty password is wrong. Closes [#46702](https://github.com/ClickHouse/ClickHouse/issues/46702). [#46730](https://github.com/ClickHouse/ClickHouse/pull/46730) ([Nikolay Degterinsky](https://github.com/evillique)).
* Mark `Gorilla` compression on columns of non-Float* type as suspicious. [#45376](https://github.com/ClickHouse/ClickHouse/pull/45376) ([Robert Schulze](https://github.com/rschu1ze)).
* Show replica name that is executing a merge in the `postpone_reason` column. [#45458](https://github.com/ClickHouse/ClickHouse/pull/45458) ([Frank Chen](https://github.com/FrankChen021)).
* Save exception stack trace in part_log. [#45459](https://github.com/ClickHouse/ClickHouse/pull/45459) ([Frank Chen](https://github.com/FrankChen021)).
* The `regexp_tree` dictionary is polished and now it is compatible with https://github.com/ua-parser/uap-core. [#45631](https://github.com/ClickHouse/ClickHouse/pull/45631) ([Han Fei](https://github.com/hanfei1991)).
* Updated checking of `SYSTEM SYNC REPLICA`, resolves [#45508](https://github.com/ClickHouse/ClickHouse/issues/45508) [#45648](https://github.com/ClickHouse/ClickHouse/pull/45648) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Rename setting `replication_alter_partitions_sync` to `alter_sync`. [#45659](https://github.com/ClickHouse/ClickHouse/pull/45659) ([Antonio Andelic](https://github.com/antonio2368)).
* The `generateRandom` table function and the engine now support `LowCardinality` data types. This is useful for testing, for example you can write `INSERT INTO table SELECT * FROM generateRandom() LIMIT 1000`. This is needed to debug [#45590](https://github.com/ClickHouse/ClickHouse/issues/45590). [#45661](https://github.com/ClickHouse/ClickHouse/pull/45661) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* The experimental query result cache now provides more modular configuration settings. [#45679](https://github.com/ClickHouse/ClickHouse/pull/45679) ([Robert Schulze](https://github.com/rschu1ze)).
* Renamed "query result cache" to "query cache". [#45682](https://github.com/ClickHouse/ClickHouse/pull/45682) ([Robert Schulze](https://github.com/rschu1ze)).
* add `SYSTEM SYNC FILE CACHE` command. It will do the `sync` syscall. [#8921](https://github.com/ClickHouse/ClickHouse/issues/8921). [#45685](https://github.com/ClickHouse/ClickHouse/pull/45685) ([DR](https://github.com/freedomDR)).
* Add a new S3 setting `allow_head_object_request`. This PR makes usage of `GetObjectAttributes` request instead of `HeadObject` introduced in https://github.com/ClickHouse/ClickHouse/pull/45288 optional (and disabled by default). [#45701](https://github.com/ClickHouse/ClickHouse/pull/45701) ([Vitaly Baranov](https://github.com/vitlibar)).
* Add ability to override connection settings based on connection names (that said that now you can forget about storing password for each connection, you can simply put everything into `~/.clickhouse-client/config.xml` and even use different history files for them, which can be also useful). [#45715](https://github.com/ClickHouse/ClickHouse/pull/45715) ([Azat Khuzhin](https://github.com/azat)).
* Arrow format: support the duration type. Closes [#45669](https://github.com/ClickHouse/ClickHouse/issues/45669). [#45750](https://github.com/ClickHouse/ClickHouse/pull/45750) ([flynn](https://github.com/ucasfl)).
* Extend the logging in the Query Cache to improve investigations of the caching behavior. [#45751](https://github.com/ClickHouse/ClickHouse/pull/45751) ([Robert Schulze](https://github.com/rschu1ze)).
* The query cache's server-level settings are now reconfigurable at runtime. [#45758](https://github.com/ClickHouse/ClickHouse/pull/45758) ([Robert Schulze](https://github.com/rschu1ze)).
* Hide password in logs when a table function's arguments are specified with a named collection. [#45774](https://github.com/ClickHouse/ClickHouse/pull/45774) ([Vitaly Baranov](https://github.com/vitlibar)).
* Improve internal S3 client to correctly deduce regions and redirections for different types of URLs. [#45783](https://github.com/ClickHouse/ClickHouse/pull/45783) ([Antonio Andelic](https://github.com/antonio2368)).
* Add support for Map, IPv4 and IPv6 types in generateRandom. Mostly useful for testing. [#45785](https://github.com/ClickHouse/ClickHouse/pull/45785) ([Raúl Marín](https://github.com/Algunenano)).
* Support empty/notEmpty for IP types. [#45799](https://github.com/ClickHouse/ClickHouse/pull/45799) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* The column `num_processed_files` was split into two columns: `num_files` (for BACKUP) and `files_read` (for RESTORE). The column `processed_files_size` was split into two columns: `total_size` (for BACKUP) and `bytes_read` (for RESTORE). [#45800](https://github.com/ClickHouse/ClickHouse/pull/45800) ([Vitaly Baranov](https://github.com/vitlibar)).
* Add support for `SHOW ENGINES` query for MySQL compatibility. [#45859](https://github.com/ClickHouse/ClickHouse/pull/45859) ([Filatenkov Artur](https://github.com/FArthur-cmd)).
* Improved how the obfuscator deals with queries. [#45867](https://github.com/ClickHouse/ClickHouse/pull/45867) ([Raúl Marín](https://github.com/Algunenano)).
* Improve behaviour of conversion into Date for boundary value 65535 (2149-06-06). [#46042](https://github.com/ClickHouse/ClickHouse/pull/46042) [#45914](https://github.com/ClickHouse/ClickHouse/pull/45914) ([Joanna Hulboj](https://github.com/jh0x)).
* Add setting `check_referential_table_dependencies` to check referential dependencies on `DROP TABLE`. This PR solves [#38326](https://github.com/ClickHouse/ClickHouse/issues/38326). [#45936](https://github.com/ClickHouse/ClickHouse/pull/45936) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix `tupleElement` to return `Null` when having `Null` argument. Closes [#45894](https://github.com/ClickHouse/ClickHouse/issues/45894). [#45952](https://github.com/ClickHouse/ClickHouse/pull/45952) ([flynn](https://github.com/ucasfl)).
* Throw an error on no files satisfying the S3 wildcard. Closes [#45587](https://github.com/ClickHouse/ClickHouse/issues/45587). [#45957](https://github.com/ClickHouse/ClickHouse/pull/45957) ([chen](https://github.com/xiedeyantu)).
* Use cluster state data to check concurrent backup/restore. [#45982](https://github.com/ClickHouse/ClickHouse/pull/45982) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* ClickHouse Client: Use "exact" matching for fuzzy search, which has correct case ignorance and more appropriate algorithm for matching SQL queries. [#46000](https://github.com/ClickHouse/ClickHouse/pull/46000) ([Azat Khuzhin](https://github.com/azat)).
* Forbid wrong create View syntax `CREATE View X TO Y AS SELECT`. Closes [#4331](https://github.com/ClickHouse/ClickHouse/issues/4331). [#46043](https://github.com/ClickHouse/ClickHouse/pull/46043) ([flynn](https://github.com/ucasfl)).
* Storage `Log` family support setting the `storage_policy`. Closes [#43421](https://github.com/ClickHouse/ClickHouse/issues/43421). [#46044](https://github.com/ClickHouse/ClickHouse/pull/46044) ([flynn](https://github.com/ucasfl)).
* Improve `JSONColumns` format when the result is empty. Closes [#46024](https://github.com/ClickHouse/ClickHouse/issues/46024). [#46053](https://github.com/ClickHouse/ClickHouse/pull/46053) ([flynn](https://github.com/ucasfl)).
* Add reference implementation for SipHash128. [#46065](https://github.com/ClickHouse/ClickHouse/pull/46065) ([Salvatore Mesoraca](https://github.com/aiven-sal)).
* Add a new metric to record allocations times and bytes using mmap. [#46068](https://github.com/ClickHouse/ClickHouse/pull/46068) ([李扬](https://github.com/taiyang-li)).
* Currently for functions like `leftPad`, `rightPad`, `leftPadUTF8`, `rightPadUTF8`, the second argument `length` must be UInt8|16|32|64|128|256. Which is too strict for clickhouse users, besides, it is not consistent with other similar functions like `arrayResize`, `substring` and so on. [#46103](https://github.com/ClickHouse/ClickHouse/pull/46103) ([李扬](https://github.com/taiyang-li)).
* Fix assertion in the `welchTTest` function in debug build when the resulting statistics is NaN. Unified the behavior with other similar functions. Change the behavior of `studentTTest` to return NaN instead of throwing an exception because the previous behavior was inconvenient. This closes [#41176](https://github.com/ClickHouse/ClickHouse/issues/41176) This closes [#42162](https://github.com/ClickHouse/ClickHouse/issues/42162). [#46141](https://github.com/ClickHouse/ClickHouse/pull/46141) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* More convenient usage of big integers and ORDER BY WITH FILL. Allow using plain integers for start and end points in WITH FILL when ORDER BY big (128-bit and 256-bit) integers. Fix the wrong result for big integers with negative start or end points. This closes [#16733](https://github.com/ClickHouse/ClickHouse/issues/16733). [#46152](https://github.com/ClickHouse/ClickHouse/pull/46152) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Add `parts`, `active_parts` and `total_marks` columns to `system.tables` on [issue](https://github.com/ClickHouse/ClickHouse/issues/44336). [#46161](https://github.com/ClickHouse/ClickHouse/pull/46161) ([attack204](https://github.com/attack204)).
* Functions "multi[Fuzzy]Match(Any|AnyIndex|AllIndices}" now reject regexes which will likely evaluate very slowly in vectorscan. [#46167](https://github.com/ClickHouse/ClickHouse/pull/46167) ([Robert Schulze](https://github.com/rschu1ze)).
* When `insert_null_as_default` is enabled and column doesn't have defined default value, the default of column type will be used. Also this PR fixes using default values on nulls in case of LowCardinality columns. [#46171](https://github.com/ClickHouse/ClickHouse/pull/46171) ([Kruglov Pavel](https://github.com/Avogar)).
* Prefer explicitly defined access keys for S3 clients. If `use_environment_credentials` is set to `true`, and the user has provided the access key through query or config, they will be used instead of the ones from the environment variable. [#46191](https://github.com/ClickHouse/ClickHouse/pull/46191) ([Antonio Andelic](https://github.com/antonio2368)).
* Add an alias "DATE_FORMAT()" for function "formatDateTime()" to improve compatibility with MySQL's SQL dialect, extend function `formatDateTime` with substitutions "a", "b", "c", "h", "i", "k", "l" "r", "s", "W". ### Documentation entry for user-facing changes User-readable short description: `DATE_FORMAT` is an alias of `formatDateTime`. Formats a Time according to the given Format string. Format is a constant expression, so you cannot have multiple formats for a single result column. (Provide link to [formatDateTime](https://clickhouse.com/docs/en/sql-reference/functions/date-time-functions/#formatdatetime)). [#46302](https://github.com/ClickHouse/ClickHouse/pull/46302) ([Jake Bamrah](https://github.com/JakeBamrah)).
* Add `ProfileEvents` and `CurrentMetrics` about the callback tasks for parallel replicas (`s3Cluster` and `MergeTree` tables). [#46313](https://github.com/ClickHouse/ClickHouse/pull/46313) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Add support for `DELETE` and `UPDATE` for tables using `KeeperMap` storage engine. [#46330](https://github.com/ClickHouse/ClickHouse/pull/46330) ([Antonio Andelic](https://github.com/antonio2368)).
* Allow writing RENAME queries with query parameters. Resolves [#45778](https://github.com/ClickHouse/ClickHouse/issues/45778). [#46407](https://github.com/ClickHouse/ClickHouse/pull/46407) ([Nikolay Degterinsky](https://github.com/evillique)).
* Fix parameterized SELECT queries with REPLACE transformer. Resolves [#33002](https://github.com/ClickHouse/ClickHouse/issues/33002). [#46420](https://github.com/ClickHouse/ClickHouse/pull/46420) ([Nikolay Degterinsky](https://github.com/evillique)).
* Exclude the internal database used for temporary/external tables from the calculation of asynchronous metric "NumberOfDatabases". This makes the behavior consistent with system table "system.databases". [#46435](https://github.com/ClickHouse/ClickHouse/pull/46435) ([Robert Schulze](https://github.com/rschu1ze)).
* Added `last_exception_time` column into distribution_queue table. [#46564](https://github.com/ClickHouse/ClickHouse/pull/46564) ([Aleksandr](https://github.com/AVMusorin)).
* Support for IN clause with parameter in parameterized views. [#46583](https://github.com/ClickHouse/ClickHouse/pull/46583) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Do not load named collections on server startup (load them on first access instead). [#46607](https://github.com/ClickHouse/ClickHouse/pull/46607) ([Kseniia Sumarokova](https://github.com/kssenii)).
#### Build/Testing/Packaging Improvement
* Introduce GWP-ASan implemented by the LLVM runtime. This closes [#27039](https://github.com/ClickHouse/ClickHouse/issues/27039). [#45226](https://github.com/ClickHouse/ClickHouse/pull/45226) ([Han Fei](https://github.com/hanfei1991)).
* We want to make our tests less stable and more flaky: add randomization for merge tree settings in tests. [#38983](https://github.com/ClickHouse/ClickHouse/pull/38983) ([Anton Popov](https://github.com/CurtizJ)).
* Enable the HDFS support in PowerPC and which helps to fixes the following functional tests 02113_hdfs_assert.sh, 02244_hdfs_cluster.sql and 02368_cancel_write_into_hdfs.sh. [#44949](https://github.com/ClickHouse/ClickHouse/pull/44949) ([MeenaRenganathan22](https://github.com/MeenaRenganathan22)).
* Add systemd.service file for clickhouse-keeper. Fixes [#44293](https://github.com/ClickHouse/ClickHouse/issues/44293). [#45568](https://github.com/ClickHouse/ClickHouse/pull/45568) ([Mikhail f. Shiryaev](https://github.com/Felixoid)).
* ClickHouse's fork of poco was moved from "contrib/" to "base/poco/". [#46075](https://github.com/ClickHouse/ClickHouse/pull/46075) ([Robert Schulze](https://github.com/rschu1ze)).
* Add an option for `clickhouse-watchdog` to restart the child process. This does not make a lot of use. [#46312](https://github.com/ClickHouse/ClickHouse/pull/46312) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* If the environment variable `CLICKHOUSE_DOCKER_RESTART_ON_EXIT` is set to 1, the Docker container will run `clickhouse-server` as a child instead of the first process, and restart it when it exited. [#46391](https://github.com/ClickHouse/ClickHouse/pull/46391) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix Systemd service file. [#46461](https://github.com/ClickHouse/ClickHouse/pull/46461) ([SuperDJY](https://github.com/cmsxbc)).
* Raised the minimum Clang version needed to build ClickHouse from 12 to 15. [#46710](https://github.com/ClickHouse/ClickHouse/pull/46710) ([Robert Schulze](https://github.com/rschu1ze)).
* Upgrade Intel QPL from v0.3.0 to v1.0.0 2. Build libaccel-config and link it statically to QPL library instead of dynamically. [#45809](https://github.com/ClickHouse/ClickHouse/pull/45809) ([jasperzhu](https://github.com/jinjunzh)).
#### Bug Fix (user-visible misbehavior in official stable release)
* Flush data exactly by `rabbitmq_flush_interval_ms` or by `rabbitmq_max_block_size` in `StorageRabbitMQ`. Closes [#42389](https://github.com/ClickHouse/ClickHouse/issues/42389). Closes [#45160](https://github.com/ClickHouse/ClickHouse/issues/45160). [#44404](https://github.com/ClickHouse/ClickHouse/pull/44404) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Use PODArray to render in sparkBar function, so we can control the memory usage. Close [#44467](https://github.com/ClickHouse/ClickHouse/issues/44467). [#44489](https://github.com/ClickHouse/ClickHouse/pull/44489) ([Duc Canh Le](https://github.com/canhld94)).
* Fix functions (quantilesExactExclusive, quantilesExactInclusive) return unsorted array element. [#45379](https://github.com/ClickHouse/ClickHouse/pull/45379) ([wujunfu](https://github.com/wujunfu)).
* Fix uncaught exception in HTTPHandler when open telemetry is enabled. [#45456](https://github.com/ClickHouse/ClickHouse/pull/45456) ([Frank Chen](https://github.com/FrankChen021)).
* Don't infer Dates from 8 digit numbers. It could lead to wrong data to be read. [#45581](https://github.com/ClickHouse/ClickHouse/pull/45581) ([Kruglov Pavel](https://github.com/Avogar)).
* Fixes to correctly use `odbc_bridge_use_connection_pooling` setting. [#45591](https://github.com/ClickHouse/ClickHouse/pull/45591) ([Bharat Nallan](https://github.com/bharatnc)).
* When the callback in the cache is called, it is possible that this cache is destructed. To keep it safe, we capture members by value. It's also safe for task schedule because it will be deactivated before storage is destroyed. Resolve [#45548](https://github.com/ClickHouse/ClickHouse/issues/45548). [#45601](https://github.com/ClickHouse/ClickHouse/pull/45601) ([Han Fei](https://github.com/hanfei1991)).
* Fix data corruption when codecs Delta or DoubleDelta are combined with codec Gorilla. [#45615](https://github.com/ClickHouse/ClickHouse/pull/45615) ([Robert Schulze](https://github.com/rschu1ze)).
* Correctly check types when using N-gram bloom filter index to avoid invalid reads. [#45617](https://github.com/ClickHouse/ClickHouse/pull/45617) ([Antonio Andelic](https://github.com/antonio2368)).
* A couple of segfaults have been reported around `c-ares`. They were introduced in my previous pull requests. I have fixed them with the help of Alexander Tokmakov. [#45629](https://github.com/ClickHouse/ClickHouse/pull/45629) ([Arthur Passos](https://github.com/arthurpassos)).
* Fix key description when encountering duplicate primary keys. This can happen in projections. See [#45590](https://github.com/ClickHouse/ClickHouse/issues/45590) for details. [#45686](https://github.com/ClickHouse/ClickHouse/pull/45686) ([Amos Bird](https://github.com/amosbird)).
* Set compression method and level for backup Closes [#45690](https://github.com/ClickHouse/ClickHouse/issues/45690). [#45737](https://github.com/ClickHouse/ClickHouse/pull/45737) ([Pradeep Chhetri](https://github.com/chhetripradeep)).
* Should use `select_query_typed.limitByOffset()` instead of `select_query_typed.limitOffset()`. [#45817](https://github.com/ClickHouse/ClickHouse/pull/45817) ([刘陶峰](https://github.com/taofengliu)).
* When use experimental analyzer, queries like `SELECT number FROM numbers(100) LIMIT 10 OFFSET 10;` get wrong results (empty result for this sql). That is caused by an unnecessary offset step added by planner. [#45822](https://github.com/ClickHouse/ClickHouse/pull/45822) ([刘陶峰](https://github.com/taofengliu)).
* Backward compatibility - allow implicit narrowing conversion from UInt64 to IPv4 - required for "INSERT ... VALUES ..." expression. [#45865](https://github.com/ClickHouse/ClickHouse/pull/45865) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Bugfix IPv6 parser for mixed ip4 address with missed first octet (like `::.1.2.3`). [#45871](https://github.com/ClickHouse/ClickHouse/pull/45871) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Add the `query_kind` column to the `system.processes` table and the `SHOW PROCESSLIST` query. Remove duplicate code. It fixes a bug: the global configuration parameter `max_concurrent_select_queries` was not respected to queries with `INTERSECT` or `EXCEPT` chains. [#45872](https://github.com/ClickHouse/ClickHouse/pull/45872) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix crash in a function `stochasticLinearRegression`. Found by WingFuzz. [#45985](https://github.com/ClickHouse/ClickHouse/pull/45985) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix crash in `SELECT` queries with `INTERSECT` and `EXCEPT` modifiers that read data from tables with enabled sparse columns (controlled by setting `ratio_of_defaults_for_sparse_serialization`). [#45987](https://github.com/ClickHouse/ClickHouse/pull/45987) ([Anton Popov](https://github.com/CurtizJ)).
* Fix read in order optimization for DESC sorting with FINAL, close [#45815](https://github.com/ClickHouse/ClickHouse/issues/45815). [#46009](https://github.com/ClickHouse/ClickHouse/pull/46009) ([Vladimir C](https://github.com/vdimir)).
* Fix reading of non existing nested columns with multiple level in compact parts. [#46045](https://github.com/ClickHouse/ClickHouse/pull/46045) ([Azat Khuzhin](https://github.com/azat)).
* Fix elapsed column in system.processes (10x error). [#46047](https://github.com/ClickHouse/ClickHouse/pull/46047) ([Azat Khuzhin](https://github.com/azat)).
* Follow-up fix for Replace domain IP types (IPv4, IPv6) with native https://github.com/ClickHouse/ClickHouse/pull/43221. [#46087](https://github.com/ClickHouse/ClickHouse/pull/46087) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Fix environment variable substitution in the configuration when a parameter already has a value. This closes [#46131](https://github.com/ClickHouse/ClickHouse/issues/46131). This closes [#9547](https://github.com/ClickHouse/ClickHouse/issues/9547). [#46144](https://github.com/ClickHouse/ClickHouse/pull/46144) ([pufit](https://github.com/pufit)).
* Fix incorrect predicate push down with grouping sets. Closes [#45947](https://github.com/ClickHouse/ClickHouse/issues/45947). [#46151](https://github.com/ClickHouse/ClickHouse/pull/46151) ([flynn](https://github.com/ucasfl)).
* Fix possible pipeline stuck error on `fulls_sorting_join` with constant keys. [#46175](https://github.com/ClickHouse/ClickHouse/pull/46175) ([Vladimir C](https://github.com/vdimir)).
* Never rewrite tuple functions as literals during formatting to avoid incorrect results. [#46232](https://github.com/ClickHouse/ClickHouse/pull/46232) ([Salvatore Mesoraca](https://github.com/aiven-sal)).
* Fix possible out of bounds error while reading LowCardinality(Nullable) in Arrow format. [#46270](https://github.com/ClickHouse/ClickHouse/pull/46270) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix `SYSTEM UNFREEZE` queries failing with the exception `CANNOT_PARSE_INPUT_ASSERTION_FAILED`. [#46325](https://github.com/ClickHouse/ClickHouse/pull/46325) ([Aleksei Filatov](https://github.com/aalexfvk)).
* Fix possible crash which can be caused by an integer overflow while deserializing aggregating state of a function that stores HashTable. [#46349](https://github.com/ClickHouse/ClickHouse/pull/46349) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix possible `LOGICAL_ERROR` in asynchronous inserts with invalid data sent in format `VALUES`. [#46350](https://github.com/ClickHouse/ClickHouse/pull/46350) ([Anton Popov](https://github.com/CurtizJ)).
* Fixed a LOGICAL_ERROR on an attempt to execute `ALTER ... MOVE PART ... TO TABLE`. This type of query was never actually supported. [#46359](https://github.com/ClickHouse/ClickHouse/pull/46359) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Fix s3Cluster schema inference in parallel distributed insert select when `parallel_distributed_insert_select` is enabled. [#46381](https://github.com/ClickHouse/ClickHouse/pull/46381) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix queries like `ALTER TABLE ... UPDATE nested.arr1 = nested.arr2 ...`, where `arr1` and `arr2` are fields of the same `Nested` column. [#46387](https://github.com/ClickHouse/ClickHouse/pull/46387) ([Anton Popov](https://github.com/CurtizJ)).
* Scheduler may fail to schedule a task. If it happens, the whole MulityPartUpload should be aborted and `UploadHelper` must wait for already scheduled tasks. [#46451](https://github.com/ClickHouse/ClickHouse/pull/46451) ([Dmitry Novik](https://github.com/novikd)).
* Fix PREWHERE for Merge with different default types (fixes some `NOT_FOUND_COLUMN_IN_BLOCK` when the default type for the column differs, also allow `PREWHERE` when the type of column is the same across tables, and prohibit it, only if it differs). [#46454](https://github.com/ClickHouse/ClickHouse/pull/46454) ([Azat Khuzhin](https://github.com/azat)).
* Fix a crash that could happen when constant values are used in `ORDER BY`. Fixes [#46466](https://github.com/ClickHouse/ClickHouse/issues/46466). [#46493](https://github.com/ClickHouse/ClickHouse/pull/46493) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Do not throw exception if `disk` setting was specified on query level, but `storage_policy` was specified in config merge tree settings section. `disk` will override setting from config. [#46533](https://github.com/ClickHouse/ClickHouse/pull/46533) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix an invalid processing of constant `LowCardinality` argument in function `arrayMap`. This bug could lead to a segfault in release, and logical error `Bad cast` in debug build. [#46569](https://github.com/ClickHouse/ClickHouse/pull/46569) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* fixes [#46557](https://github.com/ClickHouse/ClickHouse/issues/46557). [#46611](https://github.com/ClickHouse/ClickHouse/pull/46611) ([Alexander Gololobov](https://github.com/davenger)).
* Fix endless restarts of clickhouse-server systemd unit if server cannot start within 1m30sec (Disable timeout logic for starting clickhouse-server from systemd service). [#46613](https://github.com/ClickHouse/ClickHouse/pull/46613) ([Azat Khuzhin](https://github.com/azat)).
* Allocated during asynchronous inserts memory buffers were deallocated in the global context and MemoryTracker counters for corresponding user and query were not updated correctly. That led to false positive OOM exceptions. [#46622](https://github.com/ClickHouse/ClickHouse/pull/46622) ([Dmitry Novik](https://github.com/novikd)).
* Updated to not clear on_expression from table_join as its used by future analyze runs resolves [#45185](https://github.com/ClickHouse/ClickHouse/issues/45185). [#46487](https://github.com/ClickHouse/ClickHouse/pull/46487) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
### <a id="231"></a> ClickHouse release 23.1, 2023-01-26
### ClickHouse release 23.1
#### Upgrade Notes
* The `SYSTEM RESTART DISK` query becomes a no-op. [#44647](https://github.com/ClickHouse/ClickHouse/pull/44647) ([alesapin](https://github.com/alesapin)).
* The `PREALLOCATE` option for `HASHED`/`SPARSE_HASHED` dictionaries becomes a no-op. [#45388](https://github.com/ClickHouse/ClickHouse/pull/45388) ([Azat Khuzhin](https://github.com/azat)). It does not give significant advantages anymore.
* Disallow `Gorilla` codec on columns of non-Float32 or non-Float64 type. [#45252](https://github.com/ClickHouse/ClickHouse/pull/45252) ([Robert Schulze](https://github.com/rschu1ze)). It was pointless and led to inconsistencies.
* Parallel quorum inserts might work incorrectly with `*MergeTree` tables created with the deprecated syntax. Therefore, parallel quorum inserts support is completely disabled for such tables. It does not affect tables created with a new syntax. [#45430](https://github.com/ClickHouse/ClickHouse/pull/45430) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Use the `GetObjectAttributes` request instead of the `HeadObject` request to get the size of an object in AWS S3. This change fixes handling endpoints without explicit regions after updating the AWS SDK, for example. [#45288](https://github.com/ClickHouse/ClickHouse/pull/45288) ([Vitaly Baranov](https://github.com/vitlibar)). AWS S3 and Minio are tested, but keep in mind that various S3-compatible services (GCS, R2, B2) may have subtle incompatibilities. This change also may require you to adjust the ACL to allow the `GetObjectAttributes` request.
* Forbid paths in timezone names. For example, a timezone name like `/usr/share/zoneinfo/Asia/Aden` is not allowed; the IANA timezone database name like `Asia/Aden` should be used. [#44225](https://github.com/ClickHouse/ClickHouse/pull/44225) ([Kruglov Pavel](https://github.com/Avogar)).
* Queries combining equijoin and constant expressions (e.g., `JOIN ON t1.x = t2.x AND 1 = 1`) are forbidden due to incorrect results. [#44016](https://github.com/ClickHouse/ClickHouse/pull/44016) ([Vladimir C](https://github.com/vdimir)).
#### New Feature
* Dictionary source for extracting keys by traversing regular expressions tree. It can be used for User-Agent parsing. [#40878](https://github.com/ClickHouse/ClickHouse/pull/40878) ([Vage Ogannisian](https://github.com/nooblose)). [#43858](https://github.com/ClickHouse/ClickHouse/pull/43858) ([Han Fei](https://github.com/hanfei1991)).
* Added parametrized view functionality, now it's possible to specify query parameters for the View table engine. resolves [#40907](https://github.com/ClickHouse/ClickHouse/issues/40907). [#41687](https://github.com/ClickHouse/ClickHouse/pull/41687) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Add `quantileInterpolatedWeighted`/`quantilesInterpolatedWeighted` functions. [#38252](https://github.com/ClickHouse/ClickHouse/pull/38252) ([Bharat Nallan](https://github.com/bharatnc)).
* Array join support for the `Map` type, like the function "explode" in Spark. [#43239](https://github.com/ClickHouse/ClickHouse/pull/43239) ([李扬](https://github.com/taiyang-li)).
* Support SQL standard binary and hex string literals. [#43785](https://github.com/ClickHouse/ClickHouse/pull/43785) ([Mo Xuan](https://github.com/mo-avatar)).
* Allow formatting `DateTime` in Joda-Time style. Refer to [the Joda-Time docs](https://joda-time.sourceforge.net/apidocs/org/joda/time/format/DateTimeFormat.html). [#43818](https://github.com/ClickHouse/ClickHouse/pull/43818) ([李扬](https://github.com/taiyang-li)).
* Implemented a fractional second formatter (`%f`) for `formatDateTime`. [#44060](https://github.com/ClickHouse/ClickHouse/pull/44060) ([ltrk2](https://github.com/ltrk2)). [#44497](https://github.com/ClickHouse/ClickHouse/pull/44497) ([Alexander Gololobov](https://github.com/davenger)).
* Added `age` function to calculate the difference between two dates or dates with time values expressed as the number of full units. Closes [#41115](https://github.com/ClickHouse/ClickHouse/issues/41115). [#44421](https://github.com/ClickHouse/ClickHouse/pull/44421) ([Robert Schulze](https://github.com/rschu1ze)).
* Add `Null` source for dictionaries. Closes [#44240](https://github.com/ClickHouse/ClickHouse/issues/44240). [#44502](https://github.com/ClickHouse/ClickHouse/pull/44502) ([mayamika](https://github.com/mayamika)).
* Allow configuring the S3 storage class with the `s3_storage_class` configuration option. Such as `<s3_storage_class>STANDARD/INTELLIGENT_TIERING</s3_storage_class>` Closes [#44443](https://github.com/ClickHouse/ClickHouse/issues/44443). [#44707](https://github.com/ClickHouse/ClickHouse/pull/44707) ([chen](https://github.com/xiedeyantu)).
* Insert default values in case of missing elements in JSON object while parsing named tuple. Add setting `input_format_json_defaults_for_missing_elements_in_named_tuple` that controls this behaviour. Closes [#45142](https://github.com/ClickHouse/ClickHouse/issues/45142)#issuecomment-1380153217. [#45231](https://github.com/ClickHouse/ClickHouse/pull/45231) ([Kruglov Pavel](https://github.com/Avogar)).
* Record server startup time in ProfileEvents (`ServerStartupMilliseconds`). Resolves [#43188](https://github.com/ClickHouse/ClickHouse/issues/43188). [#45250](https://github.com/ClickHouse/ClickHouse/pull/45250) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Refactor and Improve streaming engines Kafka/RabbitMQ/NATS and add support for all formats, also refactor formats a bit: - Fix producing messages in row-based formats with suffixes/prefixes. Now every message is formatted completely with all delimiters and can be parsed back using input format. - Support block-based formats like Native, Parquet, ORC, etc. Every block is formatted as a separate message. The number of rows in one message depends on the block size, so you can control it via the setting `max_block_size`. - Add new engine settings `kafka_max_rows_per_message/rabbitmq_max_rows_per_message/nats_max_rows_per_message`. They control the number of rows formatted in one message in row-based formats. Default value: 1. - Fix high memory consumption in the NATS table engine. - Support arbitrary binary data in NATS producer (previously it worked only with strings contained \0 at the end) - Add missing Kafka/RabbitMQ/NATS engine settings in the documentation. - Refactor producing and consuming in Kafka/RabbitMQ/NATS, separate it from WriteBuffers/ReadBuffers semantic. - Refactor output formats: remove callbacks on each row used in Kafka/RabbitMQ/NATS (now we don't use callbacks there), allow to use IRowOutputFormat directly, clarify row end and row between delimiters, make it possible to reset output format to start formatting again - Add proper implementation in formatRow function (bonus after formats refactoring). [#42777](https://github.com/ClickHouse/ClickHouse/pull/42777) ([Kruglov Pavel](https://github.com/Avogar)).
* Support reading/writing `Nested` tables as `List` of `Struct` in `CapnProto` format. Read/write `Decimal32/64` as `Int32/64`. Closes [#43319](https://github.com/ClickHouse/ClickHouse/issues/43319). [#43379](https://github.com/ClickHouse/ClickHouse/pull/43379) ([Kruglov Pavel](https://github.com/Avogar)).
* Added a `message_format_string` column to `system.text_log`. The column contains a pattern that was used to format the message. [#44543](https://github.com/ClickHouse/ClickHouse/pull/44543) ([Alexander Tokmakov](https://github.com/tavplubix)). This allows various analytics over the ClickHouse logs.
* Try to autodetect headers with column names (and maybe types) for CSV/TSV/CustomSeparated input formats.
Add settings input_format_tsv/csv/custom_detect_header that enable this behaviour (enabled by default). Closes [#44640](https://github.com/ClickHouse/ClickHouse/issues/44640). [#44953](https://github.com/ClickHouse/ClickHouse/pull/44953) ([Kruglov Pavel](https://github.com/Avogar)).
#### Experimental Feature
* Add an experimental inverted index as a new secondary index type for efficient text search. [#38667](https://github.com/ClickHouse/ClickHouse/pull/38667) ([larryluogit](https://github.com/larryluogit)).
* Add experimental query result cache. [#43797](https://github.com/ClickHouse/ClickHouse/pull/43797) ([Robert Schulze](https://github.com/rschu1ze)).
* Added extendable and configurable scheduling subsystem for IO requests (not yet integrated with IO code itself). [#41840](https://github.com/ClickHouse/ClickHouse/pull/41840) ([Sergei Trifonov](https://github.com/serxa)). This feature does nothing at all, enjoy.
* Added `SYSTEM DROP DATABASE REPLICA` that removes metadata of a dead replica of a `Replicated` database. Resolves [#41794](https://github.com/ClickHouse/ClickHouse/issues/41794). [#42807](https://github.com/ClickHouse/ClickHouse/pull/42807) ([Alexander Tokmakov](https://github.com/tavplubix)).
#### Performance Improvement
* Do not load inactive parts at startup of `MergeTree` tables. [#42181](https://github.com/ClickHouse/ClickHouse/pull/42181) ([Anton Popov](https://github.com/CurtizJ)).
* Improved latency of reading from storage `S3` and table function `s3` with large numbers of small files. Now settings `remote_filesystem_read_method` and `remote_filesystem_read_prefetch` take effect while reading from storage `S3`. [#43726](https://github.com/ClickHouse/ClickHouse/pull/43726) ([Anton Popov](https://github.com/CurtizJ)).
* Optimization for reading struct fields in Parquet/ORC files. Only the required fields are loaded. [#44484](https://github.com/ClickHouse/ClickHouse/pull/44484) ([lgbo](https://github.com/lgbo-ustc)).
* Two-level aggregation algorithm was mistakenly disabled for queries over the HTTP interface. It was enabled back, and it leads to a major performance improvement. [#45450](https://github.com/ClickHouse/ClickHouse/pull/45450) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Added mmap support for StorageFile, which should improve the performance of clickhouse-local. [#43927](https://github.com/ClickHouse/ClickHouse/pull/43927) ([pufit](https://github.com/pufit)).
* Added sharding support in HashedDictionary to allow parallel load (almost linear scaling based on number of shards). [#40003](https://github.com/ClickHouse/ClickHouse/pull/40003) ([Azat Khuzhin](https://github.com/azat)).
* Speed up query parsing. [#42284](https://github.com/ClickHouse/ClickHouse/pull/42284) ([Raúl Marín](https://github.com/Algunenano)).
* Always replace OR chain `expr = x1 OR ... OR expr = xN` to `expr IN (x1, ..., xN)` in the case where `expr` is a `LowCardinality` column. Setting `optimize_min_equality_disjunction_chain_length` is ignored in this case. [#42889](https://github.com/ClickHouse/ClickHouse/pull/42889) ([Guo Wangyang](https://github.com/guowangy)).
* Slightly improve performance by optimizing the code around ThreadStatus. [#43586](https://github.com/ClickHouse/ClickHouse/pull/43586) ([Zhiguo Zhou](https://github.com/ZhiguoZh)).
* Optimize the column-wise ternary logic evaluation by achieving auto-vectorization. In the performance test of this [microbenchmark](https://github.com/ZhiguoZh/ClickHouse/blob/20221123-ternary-logic-opt-example/src/Functions/examples/associative_applier_perf.cpp), we've observed a peak **performance gain** of **21x** on the ICX device (Intel Xeon Platinum 8380 CPU). [#43669](https://github.com/ClickHouse/ClickHouse/pull/43669) ([Zhiguo Zhou](https://github.com/ZhiguoZh)).
* Avoid acquiring read locks in the `system.tables` table if possible. [#43840](https://github.com/ClickHouse/ClickHouse/pull/43840) ([Raúl Marín](https://github.com/Algunenano)).
* Optimize ThreadPool. The performance experiments of SSB (Star Schema Benchmark) on the ICX device (Intel Xeon Platinum 8380 CPU, 80 cores, 160 threads) shows that this change could effectively decrease the lock contention for ThreadPoolImpl::mutex by **75%**, increasing the CPU utilization and improving the overall performance by **2.4%**. [#44308](https://github.com/ClickHouse/ClickHouse/pull/44308) ([Zhiguo Zhou](https://github.com/ZhiguoZh)).
* Now the optimisation for predicting the hash table size is applied only if the cached hash table size is sufficiently large (thresholds were determined empirically and hardcoded). [#44455](https://github.com/ClickHouse/ClickHouse/pull/44455) ([Nikita Taranov](https://github.com/nickitat)).
* Small performance improvement for asynchronous reading from remote filesystems. [#44868](https://github.com/ClickHouse/ClickHouse/pull/44868) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Add fast path for: - `col like '%%'`; - `col like '%'`; - `col not like '%'`; - `col not like '%'`; - `match(col, '.*')`. [#45244](https://github.com/ClickHouse/ClickHouse/pull/45244) ([李扬](https://github.com/taiyang-li)).
* Slightly improve happy path optimisation in filtering (WHERE clause). [#45289](https://github.com/ClickHouse/ClickHouse/pull/45289) ([Nikita Taranov](https://github.com/nickitat)).
* Provide monotonicity info for `toUnixTimestamp64*` to enable more algebraic optimizations for index analysis. [#44116](https://github.com/ClickHouse/ClickHouse/pull/44116) ([Nikita Taranov](https://github.com/nickitat)).
* Allow the configuration of temporary data for query processing (spilling to disk) to cooperate with the filesystem cache (taking up the space from the cache disk) [#43972](https://github.com/ClickHouse/ClickHouse/pull/43972) ([Vladimir C](https://github.com/vdimir)). This mainly improves [ClickHouse Cloud](https://clickhouse.cloud/), but can be used for self-managed setups as well, if you know what to do.
* Make `system.replicas` table do parallel fetches of replicas statuses. Closes [#43918](https://github.com/ClickHouse/ClickHouse/issues/43918). [#43998](https://github.com/ClickHouse/ClickHouse/pull/43998) ([Nikolay Degterinsky](https://github.com/evillique)).
* Optimize memory consumption during backup to S3: files to S3 now will be copied directly without using `WriteBufferFromS3` (which could use a lot of memory). [#45188](https://github.com/ClickHouse/ClickHouse/pull/45188) ([Vitaly Baranov](https://github.com/vitlibar)).
* Add a cache for async block ids. This will reduce the number of requests of ZooKeeper when we enable async inserts deduplication. [#45106](https://github.com/ClickHouse/ClickHouse/pull/45106) ([Han Fei](https://github.com/hanfei1991)).
#### Improvement
* Use structure from insertion table in generateRandom without arguments. [#45239](https://github.com/ClickHouse/ClickHouse/pull/45239) ([Kruglov Pavel](https://github.com/Avogar)).
* Allow to implicitly convert floats stored in string fields of JSON to integers in `JSONExtract` functions. E.g. `JSONExtract('{"a": "1000.111"}', 'a', 'UInt64')` -> `1000`, previously it returned 0. [#45432](https://github.com/ClickHouse/ClickHouse/pull/45432) ([Anton Popov](https://github.com/CurtizJ)).
* Added fields `supports_parallel_parsing` and `supports_parallel_formatting` to table `system.formats` for better introspection. [#45499](https://github.com/ClickHouse/ClickHouse/pull/45499) ([Anton Popov](https://github.com/CurtizJ)).
* Improve reading CSV field in CustomSeparated/Template format. Closes [#42352](https://github.com/ClickHouse/ClickHouse/issues/42352) Closes [#39620](https://github.com/ClickHouse/ClickHouse/issues/39620). [#43332](https://github.com/ClickHouse/ClickHouse/pull/43332) ([Kruglov Pavel](https://github.com/Avogar)).
* Unify query elapsed time measurements. [#43455](https://github.com/ClickHouse/ClickHouse/pull/43455) ([Raúl Marín](https://github.com/Algunenano)).
* Improve automatic usage of structure from insertion table in table functions file/hdfs/s3 when virtual columns are present in a select query, it fixes the possible error `Block structure mismatch` or `number of columns mismatch`. [#43695](https://github.com/ClickHouse/ClickHouse/pull/43695) ([Kruglov Pavel](https://github.com/Avogar)).
* Add support for signed arguments in the function `range`. Fixes [#43333](https://github.com/ClickHouse/ClickHouse/issues/43333). [#43733](https://github.com/ClickHouse/ClickHouse/pull/43733) ([sanyu](https://github.com/wineternity)).
* Remove redundant sorting, for example, sorting related ORDER BY clauses in subqueries. Implemented on top of query plan. It does similar optimization as `optimize_duplicate_order_by_and_distinct` regarding `ORDER BY` clauses, but more generic, since it's applied to any redundant sorting steps (not only caused by ORDER BY clause) and applied to subqueries of any depth. Related to [#42648](https://github.com/ClickHouse/ClickHouse/issues/42648). [#43905](https://github.com/ClickHouse/ClickHouse/pull/43905) ([Igor Nikonov](https://github.com/devcrafter)).
* Add the ability to disable deduplication of files for BACKUP (for backups without deduplication ATTACH can be used instead of full RESTORE). For example `BACKUP foo TO S3(...) SETTINGS deduplicate_files=0` (default `deduplicate_files=1`). [#43947](https://github.com/ClickHouse/ClickHouse/pull/43947) ([Azat Khuzhin](https://github.com/azat)).
* Refactor and improve schema inference for text formats. Add new setting `schema_inference_make_columns_nullable` that controls making result types `Nullable` (enabled by default);. [#44019](https://github.com/ClickHouse/ClickHouse/pull/44019) ([Kruglov Pavel](https://github.com/Avogar)).
* Better support for `PROXYv1` protocol. [#44135](https://github.com/ClickHouse/ClickHouse/pull/44135) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Add information about the latest part check by cleanup threads into `system.parts` table. [#44244](https://github.com/ClickHouse/ClickHouse/pull/44244) ([Dmitry Novik](https://github.com/novikd)).
* Disable table functions in readonly mode for inserts. [#44290](https://github.com/ClickHouse/ClickHouse/pull/44290) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Add a setting `simultaneous_parts_removal_limit` to allow limiting the number of parts being processed by one iteration of CleanupThread. [#44461](https://github.com/ClickHouse/ClickHouse/pull/44461) ([Dmitry Novik](https://github.com/novikd)).
* Do not initialize ReadBufferFromS3 when only virtual columns are needed in a query. This may be helpful to [#44246](https://github.com/ClickHouse/ClickHouse/issues/44246). [#44493](https://github.com/ClickHouse/ClickHouse/pull/44493) ([chen](https://github.com/xiedeyantu)).
* Prevent duplicate column names hints. Closes [#44130](https://github.com/ClickHouse/ClickHouse/issues/44130). [#44519](https://github.com/ClickHouse/ClickHouse/pull/44519) ([Joanna Hulboj](https://github.com/jh0x)).
* Allow macro substitution in endpoint of disks. Resolve [#40951](https://github.com/ClickHouse/ClickHouse/issues/40951). [#44533](https://github.com/ClickHouse/ClickHouse/pull/44533) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Improve schema inference when `input_format_json_read_object_as_string` is enabled. [#44546](https://github.com/ClickHouse/ClickHouse/pull/44546) ([Kruglov Pavel](https://github.com/Avogar)).
* Add a user-level setting `database_replicated_allow_replicated_engine_arguments` which allows banning the creation of `ReplicatedMergeTree` tables with arguments in `DatabaseReplicated`. [#44566](https://github.com/ClickHouse/ClickHouse/pull/44566) ([alesapin](https://github.com/alesapin)).
* Prevent users from mistakenly specifying zero (invalid) value for `index_granularity`. This closes [#44536](https://github.com/ClickHouse/ClickHouse/issues/44536). [#44578](https://github.com/ClickHouse/ClickHouse/pull/44578) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Added possibility to set path to service keytab file in `keytab` parameter in `kerberos` section of config.xml. [#44594](https://github.com/ClickHouse/ClickHouse/pull/44594) ([Roman Vasin](https://github.com/rvasin)).
* Use already written part of the query for fuzzy search (pass to the `skim` library, which is written in Rust and linked statically to ClickHouse). [#44600](https://github.com/ClickHouse/ClickHouse/pull/44600) ([Azat Khuzhin](https://github.com/azat)).
* Enable `input_format_json_read_objects_as_strings` by default to be able to read nested JSON objects while JSON Object type is experimental. [#44657](https://github.com/ClickHouse/ClickHouse/pull/44657) ([Kruglov Pavel](https://github.com/Avogar)).
* Improvement for deduplication of async inserts: when users do duplicate async inserts, we should deduplicate inside the memory before we query Keeper. [#44682](https://github.com/ClickHouse/ClickHouse/pull/44682) ([Han Fei](https://github.com/hanfei1991)).
* Input/output `Avro` format will parse bool type as ClickHouse bool type. [#44684](https://github.com/ClickHouse/ClickHouse/pull/44684) ([Kruglov Pavel](https://github.com/Avogar)).
* Support Bool type in Arrow/Parquet/ORC. Closes [#43970](https://github.com/ClickHouse/ClickHouse/issues/43970). [#44698](https://github.com/ClickHouse/ClickHouse/pull/44698) ([Kruglov Pavel](https://github.com/Avogar)).
* Don't greedily parse beyond the quotes when reading UUIDs - it may lead to mistakenly successful parsing of incorrect data. [#44686](https://github.com/ClickHouse/ClickHouse/pull/44686) ([Raúl Marín](https://github.com/Algunenano)).
* Infer UInt64 in case of Int64 overflow and fix some transforms in schema inference. [#44696](https://github.com/ClickHouse/ClickHouse/pull/44696) ([Kruglov Pavel](https://github.com/Avogar)).
* Previously dependency resolving inside `Replicated` database was done in a hacky way, and now it's done right using an explicit graph. [#44697](https://github.com/ClickHouse/ClickHouse/pull/44697) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Fix `output_format_pretty_row_numbers` does not preserve the counter across the blocks. Closes [#44815](https://github.com/ClickHouse/ClickHouse/issues/44815). [#44832](https://github.com/ClickHouse/ClickHouse/pull/44832) ([flynn](https://github.com/ucasfl)).
* Don't report errors in `system.errors` due to parts being merged concurrently with the background cleanup process. [#44874](https://github.com/ClickHouse/ClickHouse/pull/44874) ([Raúl Marín](https://github.com/Algunenano)).
* Optimize and fix metrics for Distributed async INSERT. [#44922](https://github.com/ClickHouse/ClickHouse/pull/44922) ([Azat Khuzhin](https://github.com/azat)).
* Added settings to disallow concurrent backups and restores resolves [#43891](https://github.com/ClickHouse/ClickHouse/issues/43891) Implementation: * Added server-level settings to disallow concurrent backups and restores, which are read and set when BackupWorker is created in Context. * Settings are set to true by default. * Before starting backup or restores, added a check to see if any other backups/restores are running. For internal requests, it checks if it is from the self node using backup_uuid. [#45072](https://github.com/ClickHouse/ClickHouse/pull/45072) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Add `<storage_policy>` config parameter for system logs. [#45320](https://github.com/ClickHouse/ClickHouse/pull/45320) ([Stig Bakken](https://github.com/stigsb)).
#### Build/Testing/Packaging Improvement
* Statically link with the `skim` library (it is written in Rust) for fuzzy search in clickhouse client/local history. [#44239](https://github.com/ClickHouse/ClickHouse/pull/44239) ([Azat Khuzhin](https://github.com/azat)).
* We removed support for shared linking because of Rust. Actually, Rust is only an excuse for this removal, and we wanted to remove it nevertheless. [#44828](https://github.com/ClickHouse/ClickHouse/pull/44828) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Remove the dependency on the `adduser` tool from the packages, because we don't use it. This fixes [#44934](https://github.com/ClickHouse/ClickHouse/issues/44934). [#45011](https://github.com/ClickHouse/ClickHouse/pull/45011) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* The `SQLite` library is updated to the latest. It is used for the SQLite database and table integration engines. Also, fixed a false-positive TSan report. This closes [#45027](https://github.com/ClickHouse/ClickHouse/issues/45027). [#45031](https://github.com/ClickHouse/ClickHouse/pull/45031) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* CRC-32 changes to address the WeakHash collision issue in PowerPC. [#45144](https://github.com/ClickHouse/ClickHouse/pull/45144) ([MeenaRenganathan22](https://github.com/MeenaRenganathan22)).
* Update aws-c* submodules [#43020](https://github.com/ClickHouse/ClickHouse/pull/43020) ([Vitaly Baranov](https://github.com/vitlibar)).
* Automatically merge green backport PRs and green approved PRs [#41110](https://github.com/ClickHouse/ClickHouse/pull/41110) ([Mikhail f. Shiryaev](https://github.com/Felixoid)).
* Introduce a [website](https://aretestsgreenyet.com/) for the status of ClickHouse CI. [Source](https://github.com/ClickHouse/aretestsgreenyet).
#### Bug Fix
* Replace domain IP types (IPv4, IPv6) with native. [#43221](https://github.com/ClickHouse/ClickHouse/pull/43221) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)). It automatically fixes some missing implementations in the code.
* Fix the backup process if mutations get killed during the backup process. [#45351](https://github.com/ClickHouse/ClickHouse/pull/45351) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix the `Invalid number of rows in Chunk` exception message. [#41404](https://github.com/ClickHouse/ClickHouse/issues/41404). [#42126](https://github.com/ClickHouse/ClickHouse/pull/42126) ([Alexander Gololobov](https://github.com/davenger)).
* Fix possible use of an uninitialized value after executing expressions after sorting. Closes [#43386](https://github.com/ClickHouse/ClickHouse/issues/43386) [#43635](https://github.com/ClickHouse/ClickHouse/pull/43635) ([Kruglov Pavel](https://github.com/Avogar)).
* Better handling of NULL in aggregate combinators, fix possible segfault/logical error while using an obscure optimization `optimize_rewrite_sum_if_to_count_if`. Closes [#43758](https://github.com/ClickHouse/ClickHouse/issues/43758). [#43813](https://github.com/ClickHouse/ClickHouse/pull/43813) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix CREATE USER/ROLE query settings constraints. [#43993](https://github.com/ClickHouse/ClickHouse/pull/43993) ([Nikolay Degterinsky](https://github.com/evillique)).
* Fixed bug with non-parsable default value for `EPHEMERAL` column in table metadata. [#44026](https://github.com/ClickHouse/ClickHouse/pull/44026) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Fix parsing of bad version from compatibility setting. [#44224](https://github.com/ClickHouse/ClickHouse/pull/44224) ([Kruglov Pavel](https://github.com/Avogar)).
* Bring interval subtraction from datetime in line with addition. [#44241](https://github.com/ClickHouse/ClickHouse/pull/44241) ([ltrk2](https://github.com/ltrk2)).
* Remove limits on the maximum size of the result for view. [#44261](https://github.com/ClickHouse/ClickHouse/pull/44261) ([lizhuoyu5](https://github.com/lzydmxy)).
* Fix possible logical error in cache if `do_not_evict_index_and_mrk_files=1`. Closes [#42142](https://github.com/ClickHouse/ClickHouse/issues/42142). [#44268](https://github.com/ClickHouse/ClickHouse/pull/44268) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix possible too early cache write interruption in write-through cache (caching could be stopped due to false assumption when it shouldn't have). [#44289](https://github.com/ClickHouse/ClickHouse/pull/44289) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix possible crash in the case function `IN` with constant arguments was used as a constant argument together with `LowCardinality`. Fixes [#44221](https://github.com/ClickHouse/ClickHouse/issues/44221). [#44346](https://github.com/ClickHouse/ClickHouse/pull/44346) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix support for complex parameters (like arrays) of parametric aggregate functions. This closes [#30975](https://github.com/ClickHouse/ClickHouse/issues/30975). The aggregate function `sumMapFiltered` was unusable in distributed queries before this change. [#44358](https://github.com/ClickHouse/ClickHouse/pull/44358) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix reading ObjectId in BSON schema inference. [#44382](https://github.com/ClickHouse/ClickHouse/pull/44382) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix race which can lead to premature temp parts removal before merge finishes in ReplicatedMergeTree. This issue could lead to errors like `No such file or directory: xxx`. Fixes [#43983](https://github.com/ClickHouse/ClickHouse/issues/43983). [#44383](https://github.com/ClickHouse/ClickHouse/pull/44383) ([alesapin](https://github.com/alesapin)).
* Some invalid `SYSTEM ... ON CLUSTER` queries worked in an unexpected way if a cluster name was not specified. It's fixed, now invalid queries throw `SYNTAX_ERROR` as they should. Fixes [#44264](https://github.com/ClickHouse/ClickHouse/issues/44264). [#44387](https://github.com/ClickHouse/ClickHouse/pull/44387) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Fix reading Map type in ORC format. [#44400](https://github.com/ClickHouse/ClickHouse/pull/44400) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix reading columns that are not presented in input data in Parquet/ORC formats. Previously it could lead to error `INCORRECT_NUMBER_OF_COLUMNS`. Closes [#44333](https://github.com/ClickHouse/ClickHouse/issues/44333). [#44405](https://github.com/ClickHouse/ClickHouse/pull/44405) ([Kruglov Pavel](https://github.com/Avogar)).
* Previously the `bar` function used the same '▋' (U+258B "Left five eighths block") character to display both 5/8 and 6/8 bars. This change corrects this behavior by using '▊' (U+258A "Left three quarters block") for displaying 6/8 bar. [#44410](https://github.com/ClickHouse/ClickHouse/pull/44410) ([Alexander Gololobov](https://github.com/davenger)).
* Placing profile settings after profile settings constraints in the configuration file made constraints ineffective. [#44411](https://github.com/ClickHouse/ClickHouse/pull/44411) ([Konstantin Bogdanov](https://github.com/thevar1able)).
* Fix `SYNTAX_ERROR` while running `EXPLAIN AST INSERT` queries with data. Closes [#44207](https://github.com/ClickHouse/ClickHouse/issues/44207). [#44413](https://github.com/ClickHouse/ClickHouse/pull/44413) ([save-my-heart](https://github.com/save-my-heart)).
* Fix reading bool value with CRLF in CSV format. Closes [#44401](https://github.com/ClickHouse/ClickHouse/issues/44401). [#44442](https://github.com/ClickHouse/ClickHouse/pull/44442) ([Kruglov Pavel](https://github.com/Avogar)).
* Don't execute and/or/if/multiIf on a LowCardinality dictionary, so the result type cannot be LowCardinality. It could lead to the error `Illegal column ColumnLowCardinality` in some cases. Fixes [#43603](https://github.com/ClickHouse/ClickHouse/issues/43603). [#44469](https://github.com/ClickHouse/ClickHouse/pull/44469) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix mutations with the setting `max_streams_for_merge_tree_reading`. [#44472](https://github.com/ClickHouse/ClickHouse/pull/44472) ([Anton Popov](https://github.com/CurtizJ)).
* Fix potential null pointer dereference with GROUPING SETS in ASTSelectQuery::formatImpl ([#43049](https://github.com/ClickHouse/ClickHouse/issues/43049)). [#44479](https://github.com/ClickHouse/ClickHouse/pull/44479) ([Robert Schulze](https://github.com/rschu1ze)).
* Validate types in table function arguments, CAST function arguments, JSONAsObject schema inference according to settings. [#44501](https://github.com/ClickHouse/ClickHouse/pull/44501) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix IN function with LowCardinality and const column, close [#44503](https://github.com/ClickHouse/ClickHouse/issues/44503). [#44506](https://github.com/ClickHouse/ClickHouse/pull/44506) ([Duc Canh Le](https://github.com/canhld94)).
* Fixed a bug in the normalization of a `DEFAULT` expression in `CREATE TABLE` statement. The second argument of the function `in` (or the right argument of operator `IN`) might be replaced with the result of its evaluation during CREATE query execution. Fixes [#44496](https://github.com/ClickHouse/ClickHouse/issues/44496). [#44547](https://github.com/ClickHouse/ClickHouse/pull/44547) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Projections do not work in presence of WITH ROLLUP, WITH CUBE and WITH TOTALS. In previous versions, a query produced an exception instead of skipping the usage of projections. This closes [#44614](https://github.com/ClickHouse/ClickHouse/issues/44614). This closes [#42772](https://github.com/ClickHouse/ClickHouse/issues/42772). [#44615](https://github.com/ClickHouse/ClickHouse/pull/44615) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Async blocks were not cleaned because the function `get all blocks sorted by time` didn't get async blocks. [#44651](https://github.com/ClickHouse/ClickHouse/pull/44651) ([Han Fei](https://github.com/hanfei1991)).
* Fix `LOGICAL_ERROR` `The top step of the right pipeline should be ExpressionStep` for JOIN with subquery, UNION, and TOTALS. Fixes [#43687](https://github.com/ClickHouse/ClickHouse/issues/43687). [#44673](https://github.com/ClickHouse/ClickHouse/pull/44673) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Avoid `std::out_of_range` exception in the Executable table engine. [#44681](https://github.com/ClickHouse/ClickHouse/pull/44681) ([Kruglov Pavel](https://github.com/Avogar)).
* Do not apply `optimize_syntax_fuse_functions` to quantiles on AST, close [#44712](https://github.com/ClickHouse/ClickHouse/issues/44712). [#44713](https://github.com/ClickHouse/ClickHouse/pull/44713) ([Vladimir C](https://github.com/vdimir)).
* Fix bug with wrong type in Merge table and PREWHERE, close [#43324](https://github.com/ClickHouse/ClickHouse/issues/43324). [#44716](https://github.com/ClickHouse/ClickHouse/pull/44716) ([Vladimir C](https://github.com/vdimir)).
* Fix a possible crash during shutdown (while destroying TraceCollector). Fixes [#44757](https://github.com/ClickHouse/ClickHouse/issues/44757). [#44758](https://github.com/ClickHouse/ClickHouse/pull/44758) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix a possible crash in distributed query processing. The crash could happen if a query with totals or extremes returned an empty result and there are mismatched types in the Distributed and the local tables. Fixes [#44738](https://github.com/ClickHouse/ClickHouse/issues/44738). [#44760](https://github.com/ClickHouse/ClickHouse/pull/44760) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix fsync for fetches (`min_compressed_bytes_to_fsync_after_fetch`)/small files (ttl.txt, columns.txt) in mutations (`min_rows_to_fsync_after_merge`/`min_compressed_bytes_to_fsync_after_merge`). [#44781](https://github.com/ClickHouse/ClickHouse/pull/44781) ([Azat Khuzhin](https://github.com/azat)).
* A rare race condition was possible when querying the `system.parts` or `system.parts_columns` tables in the presence of parts being moved between disks. Introduced in [#41145](https://github.com/ClickHouse/ClickHouse/issues/41145). [#44809](https://github.com/ClickHouse/ClickHouse/pull/44809) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix the error `Context has expired` which could appear with enabled projections optimization. Can be reproduced for queries with specific functions, like `dictHas/dictGet` which use context in runtime. Fixes [#44844](https://github.com/ClickHouse/ClickHouse/issues/44844). [#44850](https://github.com/ClickHouse/ClickHouse/pull/44850) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* A fix for `Cannot read all data` error which could happen while reading `LowCardinality` dictionary from remote fs. Fixes [#44709](https://github.com/ClickHouse/ClickHouse/issues/44709). [#44875](https://github.com/ClickHouse/ClickHouse/pull/44875) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Ignore cases when hardware monitor sensors cannot be read instead of showing a full exception message in logs. [#44895](https://github.com/ClickHouse/ClickHouse/pull/44895) ([Raúl Marín](https://github.com/Algunenano)).
* Use `max_delay_to_insert` value in case the calculated time to delay INSERT exceeds the setting value. Related to [#44902](https://github.com/ClickHouse/ClickHouse/issues/44902). [#44916](https://github.com/ClickHouse/ClickHouse/pull/44916) ([Igor Nikonov](https://github.com/devcrafter)).
* Fix error `Different order of columns in UNION subquery` for queries with `UNION`. Fixes [#44866](https://github.com/ClickHouse/ClickHouse/issues/44866). [#44920](https://github.com/ClickHouse/ClickHouse/pull/44920) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Delay for INSERT can be calculated incorrectly, which can lead to always using `max_delay_to_insert` setting as delay instead of a correct value. Using simple formula `max_delay_to_insert * (parts_over_threshold/max_allowed_parts_over_threshold)` i.e. delay grows proportionally to parts over threshold. Closes [#44902](https://github.com/ClickHouse/ClickHouse/issues/44902). [#44954](https://github.com/ClickHouse/ClickHouse/pull/44954) ([Igor Nikonov](https://github.com/devcrafter)).
* Fix alter table TTL error when a wide part has the lightweight delete mask. [#44959](https://github.com/ClickHouse/ClickHouse/pull/44959) ([Mingliang Pan](https://github.com/liangliangpan)).
* Follow-up fix for Replace domain IP types (IPv4, IPv6) with native [#43221](https://github.com/ClickHouse/ClickHouse/issues/43221). [#45024](https://github.com/ClickHouse/ClickHouse/pull/45024) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Follow-up fix for Replace domain IP types (IPv4, IPv6) with native https://github.com/ClickHouse/ClickHouse/pull/43221. [#45043](https://github.com/ClickHouse/ClickHouse/pull/45043) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* A buffer overflow was possible in the parser. Found by fuzzer. [#45047](https://github.com/ClickHouse/ClickHouse/pull/45047) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix possible cannot-read-all-data error in storage FileLog. Closes [#45051](https://github.com/ClickHouse/ClickHouse/issues/45051), [#38257](https://github.com/ClickHouse/ClickHouse/issues/38257). [#45057](https://github.com/ClickHouse/ClickHouse/pull/45057) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Memory efficient aggregation (setting `distributed_aggregation_memory_efficient`) is disabled when grouping sets are present in the query. [#45058](https://github.com/ClickHouse/ClickHouse/pull/45058) ([Nikita Taranov](https://github.com/nickitat)).
* Fix `RANGE_HASHED` dictionary to count range columns as part of the primary key during updates when `update_field` is specified. Closes [#44588](https://github.com/ClickHouse/ClickHouse/issues/44588). [#45061](https://github.com/ClickHouse/ClickHouse/pull/45061) ([Maksim Kita](https://github.com/kitaisreal)).
* Fix error `Cannot capture column` for `LowCardinality` captured argument of nested lambda. Fixes [#45028](https://github.com/ClickHouse/ClickHouse/issues/45028). [#45065](https://github.com/ClickHouse/ClickHouse/pull/45065) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix the wrong query result of `additional_table_filters` (additional filter was not applied) in case the minmax/count projection is used. [#45133](https://github.com/ClickHouse/ClickHouse/pull/45133) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fixed bug in `histogram` function accepting negative values. [#45147](https://github.com/ClickHouse/ClickHouse/pull/45147) ([simpleton](https://github.com/rgzntrade)).
* Fix wrong column nullability in StoreageJoin, close [#44940](https://github.com/ClickHouse/ClickHouse/issues/44940). [#45184](https://github.com/ClickHouse/ClickHouse/pull/45184) ([Vladimir C](https://github.com/vdimir)).
* Fix `background_fetches_pool_size` settings reload (increase at runtime). [#45189](https://github.com/ClickHouse/ClickHouse/pull/45189) ([Raúl Marín](https://github.com/Algunenano)).
* Correctly process `SELECT` queries on KV engines (e.g. KeeperMap, EmbeddedRocksDB) using `IN` on the key with subquery producing different type. [#45215](https://github.com/ClickHouse/ClickHouse/pull/45215) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix logical error in SEMI JOIN & join_use_nulls in some cases, close [#45163](https://github.com/ClickHouse/ClickHouse/issues/45163), close [#45209](https://github.com/ClickHouse/ClickHouse/issues/45209). [#45230](https://github.com/ClickHouse/ClickHouse/pull/45230) ([Vladimir C](https://github.com/vdimir)).
* Fix heap-use-after-free in reading from s3. [#45253](https://github.com/ClickHouse/ClickHouse/pull/45253) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix bug when the Avro Union type is ['null', Nested type], closes [#45275](https://github.com/ClickHouse/ClickHouse/issues/45275). Fix bug that incorrectly infers `bytes` type to `Float`. [#45276](https://github.com/ClickHouse/ClickHouse/pull/45276) ([flynn](https://github.com/ucasfl)).
* Throw a correct exception when explicit PREWHERE cannot be used with a table using the storage engine `Merge`. [#45319](https://github.com/ClickHouse/ClickHouse/pull/45319) ([Antonio Andelic](https://github.com/antonio2368)).
* Under WSL1 Ubuntu self-extracting ClickHouse fails to decompress due to inconsistency - /proc/self/maps reporting 32bit file's inode, while stat reporting 64bit inode. [#45339](https://github.com/ClickHouse/ClickHouse/pull/45339) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Fix race in Distributed table startup (that could lead to processing file of async INSERT multiple times). [#45360](https://github.com/ClickHouse/ClickHouse/pull/45360) ([Azat Khuzhin](https://github.com/azat)).
* Fix a possible crash while reading from storage `S3` and table function `s3` in the case when `ListObject` request has failed. [#45371](https://github.com/ClickHouse/ClickHouse/pull/45371) ([Anton Popov](https://github.com/CurtizJ)).
* Fix `SELECT ... FROM system.dictionaries` exception when there is a dictionary with a bad structure (e.g. incorrect type in XML config). [#45399](https://github.com/ClickHouse/ClickHouse/pull/45399) ([Aleksei Filatov](https://github.com/aalexfvk)).
* Fix s3Cluster schema inference when structure from insertion table is used in `INSERT INTO ... SELECT * FROM s3Cluster` queries. [#45422](https://github.com/ClickHouse/ClickHouse/pull/45422) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix bug in JSON/BSONEachRow parsing with HTTP that could lead to using default values for some columns instead of values from data. [#45424](https://github.com/ClickHouse/ClickHouse/pull/45424) ([Kruglov Pavel](https://github.com/Avogar)).
* Fixed bug (Code: 632. DB::Exception: Unexpected data ... after parsed IPv6 value ...) with typed parsing of IP types from text source. [#45425](https://github.com/ClickHouse/ClickHouse/pull/45425) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* close [#45297](https://github.com/ClickHouse/ClickHouse/issues/45297) Add check for empty regular expressions. [#45428](https://github.com/ClickHouse/ClickHouse/pull/45428) ([Han Fei](https://github.com/hanfei1991)).
* Fix possible (likely distributed) query hung. [#45448](https://github.com/ClickHouse/ClickHouse/pull/45448) ([Azat Khuzhin](https://github.com/azat)).
* Fix possible deadlock with `allow_asynchronous_read_from_io_pool_for_merge_tree` enabled in case of exception from `ThreadPool::schedule`. [#45481](https://github.com/ClickHouse/ClickHouse/pull/45481) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix possible in-use table after DETACH. [#45493](https://github.com/ClickHouse/ClickHouse/pull/45493) ([Azat Khuzhin](https://github.com/azat)).
* Fix rare abort in the case when a query is canceled and parallel parsing was used during its execution. [#45498](https://github.com/ClickHouse/ClickHouse/pull/45498) ([Anton Popov](https://github.com/CurtizJ)).
* Fix a race between Distributed table creation and INSERT into it (could lead to CANNOT_LINK during INSERT into the table). [#45502](https://github.com/ClickHouse/ClickHouse/pull/45502) ([Azat Khuzhin](https://github.com/azat)).
* Add proper default (SLRU) to cache policy getter. Closes [#45514](https://github.com/ClickHouse/ClickHouse/issues/45514). [#45524](https://github.com/ClickHouse/ClickHouse/pull/45524) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Disallow array join in mutations closes [#42637](https://github.com/ClickHouse/ClickHouse/issues/42637) [#44447](https://github.com/ClickHouse/ClickHouse/pull/44447) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Fix for qualified asterisks with alias table name and column transformer. Resolves [#44736](https://github.com/ClickHouse/ClickHouse/issues/44736). [#44755](https://github.com/ClickHouse/ClickHouse/pull/44755) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
## [Changelog for 2022](https://clickhouse.com/docs/en/whats-new/changelog/2022)
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