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ClickHouse release v24.1, 2024-01-30
Changelog for 2023

2024 Changelog

ClickHouse release 24.1, 2024-01-30

Backward Incompatible Change

  • The setting print_pretty_type_names is turned on by default. You can turn it off to keep the old behavior or SET compatibility = '23.12'. #57726 (Alexey Milovidov).
  • The MergeTree setting clean_deleted_rows is deprecated, it has no effect anymore. The CLEANUP keyword for OPTIMIZE is not allowed by default (unless allow_experimental_replacing_merge_with_cleanup is enabled). #58316 (Alexander Tokmakov).
  • The function reverseDNSQuery is no longer available. This closes #58368. #58369 (Alexey Milovidov).
  • Enable various changes to improve the access control in the configuration file. These changes affect the behavior, and you check the config.xml in the access_control_improvements section. In case you are not confident, keep the values in the configuration file as they were in the previous version. #58584 (Alexey Milovidov).
  • Improve the operation of sumMapFiltered with NaN values. NaN values are now placed at the end (instead of randomly) and considered different from any values. -0 is now also treated as equal to 0; since 0 values are discarded, -0 values are discarded too. #58959 (Raúl Marín).
  • The function visibleWidth will behave according to the docs. In previous versions, it simply counted code points after string serialization, like the lengthUTF8 function, but didn't consider zero-width and combining characters, full-width characters, tabs, and deletes. Now the behavior is changed accordingly. If you want to keep the old behavior, set function_visible_width_behavior to 0, or set compatibility to 23.12 or lower. #59022 (Alexey Milovidov).
  • Kusto dialect is disabled until these two bugs will be fixed: #59037 and #59036. #59305 (Alexey Milovidov). Any attempt to use Kusto will result in exception.
  • More efficient implementation of the FINAL modifier no longer guarantees preserving the order even if max_threads = 1. If you counted on the previous behavior, set enable_vertical_final to 0 or compatibility to 23.12.

New Feature

  • Implement Variant data type that represents a union of other data types. Type Variant(T1, T2, ..., TN) means that each row of this type has a value of either type T1 or T2 or ... or TN or none of them (NULL value). Variant type is available under a setting allow_experimental_variant_type. Reference: #54864. #58047 (Kruglov Pavel).
  • Certain settings (currently min_compress_block_size and max_compress_block_size) can now be specified at column-level where they take precedence over the corresponding table-level setting. Example: CREATE TABLE tab (col String SETTINGS (min_compress_block_size = 81920, max_compress_block_size = 163840)) ENGINE = MergeTree ORDER BY tuple();. #55201 (Duc Canh Le).
  • Add quantileDD aggregate function as well as the corresponding quantilesDD and medianDD. It is based on the DDSketch https://www.vldb.org/pvldb/vol12/p2195-masson.pdf. ### Documentation entry for user-facing changes. #56342 (Srikanth Chekuri).
  • Allow to configure any kind of object storage with any kind of metadata type. #58357 (Kseniia Sumarokova).
  • Added null_status_on_timeout_only_active and throw_only_active modes for distributed_ddl_output_mode that allow to avoid waiting for inactive replicas. #58350 (Alexander Tokmakov).
  • Add function arrayShingles to compute subarrays, e.g. arrayShingles([1, 2, 3, 4, 5], 3) returns [[1,2,3],[2,3,4],[3,4,5]]. #58396 (Zheng Miao).
  • Added functions punycodeEncode, punycodeDecode, idnaEncode and idnaDecode which are useful for translating international domain names to an ASCII representation according to the IDNA standard. #58454 (Robert Schulze).
  • Added string similarity functions dramerauLevenshteinDistance, jaroSimilarity and jaroWinklerSimilarity. #58531 (Robert Schulze).
  • Add two settings output_format_compression_level to change output compression level and output_format_compression_zstd_window_log to explicitly set compression window size and enable long-range mode for zstd compression if output compression method is zstd. Applied for INTO OUTFILE and when writing to table functions file, url, hdfs, s3, and azureBlobStorage. #58539 (Duc Canh Le).
  • Automatically disable ANSI escape sequences in Pretty formats if the output is not a terminal. Add new auto mode to setting output_format_pretty_color. #58614 (Shaun Struwig).
  • Added function sqidDecode which decodes Sqids. #58544 (Robert Schulze).
  • Allow to read Bool values into String in JSON input formats. It's done under a setting input_format_json_read_bools_as_strings that is enabled by default. #58561 (Kruglov Pavel).
  • Added function seriesDecomposeSTL which decomposes a time series into a season, a trend and a residual component. #57078 (Bhavna Jindal).
  • Introduced MySQL Binlog Client for MaterializedMySQL: One binlog connection for many databases. #57323 (Val Doroshchuk).
  • Intel QuickAssist Technology (QAT) provides hardware-accelerated compression and cryptograpy. ClickHouse got a new compression codec ZSTD_QAT which utilizes QAT for zstd compression. The codec uses Intel's QATlib and Inte's QAT ZSTD Plugin. Right now, only compression can be accelerated in hardware (a software fallback kicks in in case QAT could not be initialized), decompression always runs in software. #57509 (jasperzhu).
  • Implementing the new way how object storage keys are generated for s3 disks. Now the format could be defined in terms of re2 regex syntax with key_template option in disc description. #57663 (Sema Checherinda).
  • Table system.dropped_tables_parts contains parts of system.dropped_tables tables (dropped but not yet removed tables). #58038 (Yakov Olkhovskiy).
  • Add settings max_materialized_views_size_for_table to limit the number of materialized views attached to a table. #58068 (zhongyuankai).
  • clickhouse-format improvements: support INSERT queries with VALUES; support comments (use --comments to output them); support --max_line_length option to format only long queries in multiline. #58246 (vdimir).
  • Attach all system tables in clickhouse-local, including system.parts. This closes #58312. #58359 (Alexey Milovidov).
  • Support for Enum data types in function transform. This closes #58241. #58360 (Alexey Milovidov).
  • Add table system.database_engines. #58390 (Bharat Nallan). Allow registering database engines independently in the codebase. #58365 (Bharat Nallan). Allow registering interpreters independently. #58443 (Bharat Nallan).
  • Added FROM <Replicas> modifier for SYSTEM SYNC REPLICA LIGHTWEIGHT query. With the FROM modifier ensures we wait for fetches and drop-ranges only for the specified source replicas, as well as any replica not in zookeeper or with an empty source_replica. #58393 (Jayme Bird).
  • Added setting update_insert_deduplication_token_in_dependent_materialized_views. This setting allows to update insert deduplication token with table identifier during insert in dependent materialized views. Closes #59165. #59238 (Maksim Kita).
  • Added statement SYSTEM RELOAD ASYNCHRONOUS METRICS which updates the asynchronous metrics. Mostly useful for testing and development. #53710 (Robert Schulze).
  • Attach parts from a different disk ALTER TABLE destination ATTACH PARTITION tuple() FROM source where source is an instant table. #60112(Unalian).

Performance Improvement

  • Coordination for parallel replicas is rewritten for better parallelism and cache locality. It has been tested for linear scalability on hundreds of replicas. It also got support for reading in order. #57968 (Nikita Taranov).
  • Replace HTTP outgoing buffering based with the native ClickHouse buffers. Add bytes counting metrics for interfaces. #56064 (Yakov Olkhovskiy).
  • Large aggregation states of uniqExact will be merged in parallel in distrubuted queries. #59009 (Nikita Taranov).
  • Lower memory usage after reading from MergeTree tables. #59290 (Anton Popov).
  • Lower memory usage in vertical merges. #59340 (Anton Popov).
  • Avoid huge memory consumption during Keeper startup for more cases. #58455 (Antonio Andelic).
  • Keeper improvement: reduce Keeper's memory usage for stored nodes. #59002 (Antonio Andelic).
  • More cache-friendly final implementation. Note on the behaviour change: previously queries with FINAL modifier that read with a single stream (e.g. max_threads = 1) produced sorted output without explicitly provided ORDER BY clause. This is no longer guaranteed when enable_vertical_final = true (and it is so by default). #54366 (Duc Canh Le).
  • Bypass extra copying in ReadBufferFromIStream which is used, e.g., for reading from S3. #56961 (Nikita Taranov).
  • Optimize array element function when input is Array(Map)/Array(Array(Num)/Array(Array(String))/Array(BigInt)/Array(Decimal). The previous implementations did more allocations than needed. The optimization speed up is up to ~6x especially when input type is Array(Map). #56403 (李扬).
  • Read column once while reading more than one subcolumn from it in compact parts. #57631 (Kruglov Pavel).
  • Rewrite the AST of sum(column + constant) function. This is available as an optimization pass for Analyzer #57853 (Jiebin Sun).
  • The evaluation of function match now utilizes skipping indices ngrambf_v1 and tokenbf_v1. #57882 (凌涛).
  • The evaluation of function match now utilizes inverted indices. #58284 (凌涛).
  • MergeTree FINAL does not compare rows from same non-L0 part. #58142 (Duc Canh Le).
  • Speed up iota calls (filling array with consecutive numbers). #58271 (Raúl Marín).
  • Speedup MIN/MAX for non-numeric types. #58334 (Raúl Marín).
  • Optimize the combination of filters (like in multi-stage PREWHERE) with BMI2/SSE intrinsics #58800 (Zhiguo Zhou).
  • Use one thread less in clickhouse-local. #58968 (Alexey Milovidov).
  • Improve the multiIf function performance when the type is Nullable. #57745 (KevinyhZou).
  • Add SYSTEM JEMALLOC PURGE for purging unused jemalloc pages, SYSTEM JEMALLOC [ ENABLE | DISABLE | FLUSH ] PROFILE for controlling jemalloc profile if the profiler is enabled. Add jemalloc-related 4LW command in Keeper: jmst for dumping jemalloc stats, jmfp, jmep, jmdp for controlling jemalloc profile if the profiler is enabled. #58665 (Antonio Andelic).
  • Lower memory consumption in backups to S3. #58962 (Vitaly Baranov).

Improvement

  • Added comments (brief descriptions) to all columns of system tables. There are several reasons for this: - We use system tables a lot, and sometimes it could be very difficult for developer to understand the purpose and the meaning of a particular column. - We change (add new ones or modify existing) system tables a lot and the documentation for them is always outdated. For example take a look at the documentation page for system.parts. It misses a lot of columns - We would like to eventually generate documentation directly from ClickHouse. #58356 (Nikita Mikhaylov).
  • Allow queries without aliases for subqueries for PASTE JOIN. #58654 (Yarik Briukhovetskyi).
  • Enable MySQL/MariaDB integration on macOS. This closes #21191. #46316 (Alexey Milovidov) (Robert Schulze).
  • Disable max_rows_in_set_to_optimize_join by default. #56396 (vdimir).
  • Add <host_name> config parameter that allows avoiding resolving hostnames in ON CLUSTER DDL queries and Replicated database engines. This mitigates the possibility of the queue being stuck in case of a change in cluster definition. Closes #57573. #57603 (Nikolay Degterinsky).
  • Increase load_metadata_threads to 16 for the filesystem cache. It will make the server start up faster. #57732 (Alexey Milovidov).
  • Add ability to throttle merges/mutations (max_mutations_bandwidth_for_server/max_merges_bandwidth_for_server). #57877 (Azat Khuzhin).
  • Replaced undocumented (boolean) column is_hot_reloadable in system table system.server_settings by (Enum8) column changeable_without_restart with possible values No, Yes, IncreaseOnly and DecreaseOnly. Also documented the column. #58029 (skyoct).
  • Cluster discovery supports setting username and password, close #58063. #58123 (vdimir).
  • Support query parameters in ALTER TABLE ... PART. #58297 (Azat Khuzhin).
  • Create consumers for Kafka tables on the fly (but keep them for some period - kafka_consumers_pool_ttl_ms, since last used), this should fix problem with statistics for system.kafka_consumers (that does not consumed when nobody reads from Kafka table, which leads to live memory leak and slow table detach) and also this PR enables stats for system.kafka_consumers by default again. #58310 (Azat Khuzhin).
  • sparkBar as an alias to sparkbar. #58335 (凌涛).
  • Avoid sending ComposeObject requests after upload to GCS. #58343 (Azat Khuzhin).
  • Correctly handle keys with dot in the name in configurations XMLs. #58354 (Azat Khuzhin).
  • Make function format return constant on constant arguments. This closes #58355. #58358 (Alexey Milovidov).
  • Adding a setting max_estimated_execution_time to separate max_execution_time and max_estimated_execution_time. #58402 (Zhang Yifan).
  • Provide a hint when an invalid database engine name is used. #58444 (Bharat Nallan).
  • Add settings for better control of indexes type in Arrow dictionary. Use signed integer type for indexes by default as Arrow recommends. Closes #57401. #58519 (Kruglov Pavel).
  • Implement #58575 Support CLICKHOUSE_PASSWORD_FILE environment variable when running the docker image. #58583 (Eyal Halpern Shalev).
  • When executing some queries, which require a lot of streams for reading data, the error "Paste JOIN requires sorted tables only" was previously thrown. Now the numbers of streams resize to 1 in that case. #58608 (Yarik Briukhovetskyi).
  • Better message for INVALID_IDENTIFIER error. #58703 (Yakov Olkhovskiy).
  • Improved handling of signed numeric literals in normalizeQuery. #58710 (Salvatore Mesoraca).
  • Support Point data type for MySQL. #58721 (Kseniia Sumarokova).
  • When comparing a Float32 column and a const string, read the string as Float32 (instead of Float64). #58724 (Raúl Marín).
  • Improve S3 compatibility, add ECloud EOS storage support. #58786 (xleoken).
  • Allow KILL QUERY to cancel backups / restores. This PR also makes running backups and restores visible in system.processes. Also, there is a new setting in the server configuration now - shutdown_wait_backups_and_restores (default=true) which makes the server either wait on shutdown for all running backups and restores to finish or just cancel them. #58804 (Vitaly Baranov).
  • Avro format to support ZSTD codec. Closes #58735. #58805 (flynn).
  • MySQL interface gained support for net_write_timeout and net_read_timeout settings. net_write_timeout is translated into the native send_timeout ClickHouse setting and, similarly, net_read_timeout into receive_timeout. Fixed an issue where it was possible to set MySQL sql_select_limit setting only if the entire statement was in upper case. #58835 (Serge Klochkov).
  • A better exception message while conflict of creating dictionary and table with the same name. #58841 (Yarik Briukhovetskyi).
  • Make sure that for custom (created from SQL) disks ether filesystem_caches_path (a common directory prefix for all filesystem caches) or custom_cached_disks_base_directory (a common directory prefix for only filesystem caches created from custom disks) is specified in server config. custom_cached_disks_base_directory has higher priority for custom disks over filesystem_caches_path, which is used if the former one is absent. Filesystem cache setting path must lie inside that directory, otherwise exception will be thrown preventing disk to be created. This will not affect disks created on an older version and server was upgraded - then the exception will not be thrown to allow the server to successfully start). custom_cached_disks_base_directory is added to default server config as /var/lib/clickhouse/caches/. Closes #57825. #58869 (Kseniia Sumarokova).
  • MySQL interface gained compatibility with SHOW WARNINGS/SHOW COUNT(*) WARNINGS queries, though the returned result is always an empty set. #58929 (Serge Klochkov).
  • Skip unavailable replicas when executing parallel distributed INSERT SELECT. #58931 (Alexander Tokmakov).
  • Display word-descriptive log level while enabling structured log formatting in json. #58936 (Tim Liou).
  • MySQL interface gained support for CAST(x AS SIGNED) and CAST(x AS UNSIGNED) statements via data type aliases: SIGNED for Int64, and UNSIGNED for UInt64. This improves compatibility with BI tools such as Looker Studio. #58954 (Serge Klochkov).
  • Change working directory to the data path in docker container. #58975 (cangyin).
  • Added setting for Azure Blob Storage azure_max_unexpected_write_error_retries , can also be set from config under azure section. #59001 (SmitaRKulkarni).
  • Allow server to start with broken data lake table. Closes #58625. #59080 (Kseniia Sumarokova).
  • Allow to ignore schema evolution in the Iceberg table engine and read all data using schema specified by the user on table creation or latest schema parsed from metadata on table creation. This is done under a setting iceberg_engine_ignore_schema_evolution that is disabled by default. Note that enabling this setting can lead to incorrect result as in case of evolved schema all data files will be read using the same schema. #59133 (Kruglov Pavel).
  • Prohibit mutable operations (INSERT/ALTER/OPTIMIZE/...) on read-only/write-once storages with a proper TABLE_IS_READ_ONLY error (to avoid leftovers). Avoid leaving left-overs on write-once disks (format_version.txt) on CREATE/ATTACH. Ignore DROP for ReplicatedMergeTree (so as for MergeTree). Fix iterating over s3_plain (MetadataStorageFromPlainObjectStorage::iterateDirectory). Note read-only is web disk, and write-once is s3_plain. #59170 (Azat Khuzhin).
  • Fix bug in the experimental _block_number column which could lead to logical error during complex combination of ALTERs and merges. Fixes #56202. Replaces #58601. #59295 (alesapin).
  • Play UI understands when an exception is returned inside JSON. Adjustment for #52853. #59303 (Alexey Milovidov).
  • /binary HTTP handler allows to specify user, host, and optionally, password in the query string. #59311 (Alexey Milovidov).
  • Support backups for compressed in-memory tables. This closes #57893. #59315 (Alexey Milovidov).
  • Support the FORMAT clause in BACKUP and RESTORE queries. #59338 (Vitaly Baranov).
  • Function concatWithSeparator now supports arbitrary argument types (instead of only String and FixedString arguments). For example, SELECT concatWithSeparator('.', 'number', 1) now returns number.1. #59341 (Robert Schulze).

Build/Testing/Packaging Improvement

  • Improve aliases for clickhouse binary (now ch/clickhouse is clickhouse-local or clickhouse depends on the arguments) and add bash completion for new aliases. #58344 (Azat Khuzhin).
  • Add settings changes check to CI to check that all settings changes are reflected in settings changes history. #58555 (Kruglov Pavel).
  • Use tables directly attached from S3 in stateful tests. #58791 (Alexey Milovidov).
  • Save the whole fuzzer.log as an archive instead of the last 100k lines. tail -n 100000 often removes lines with table definitions. Example:. #58821 (Dmitry Novik).
  • Enable Rust on macOS with Aarch64 (this will add fuzzy search in client with skim and the PRQL language, though I don't think that are people who host ClickHouse on darwin, so it is mostly for fuzzy search in client I would say). #59272 (Azat Khuzhin).
  • Fix aggregation issue in mixed x86_64 and ARM clusters #59132 (Harry Lee).

Bug Fix (user-visible misbehavior in an official stable release)

Changelog for 2023