ClickHouse/CHANGELOG.md

ClickHouse release v21.11.1.8636-prestable FIXME as compared to v21.10.2.15-stable

Backward Incompatible Change

• Remove setting odbc_max_field_size because it is not used anymore. Closes #30413. #30778 (Kseniia Sumarokova).
• Change order of json_path and json in sql json function (to be correct). Closes #30449. #30474 (Kseniia Sumarokova).
• Remove MergeTree table setting write_final_mark. It will be always true. #30455 (Kseniia Sumarokova).
• Function bayesAB is removed. This closes #26233. #29934 (alexey-milovidov).
• Now ClickHouse Keeper snapshots compressed with ZSTD codec by default instead of custom ClickHouse LZ4 block compression. This behavior can be turned off with compress_snapshots_with_zstd_format coordination setting (must be equal on all quorum replicas). Backward incompatibility is quite rare and may happen only when new node will send snapshot (happens in case of recovery) to the old node which is unable to read snapshots in ZSTD format. #29417 (alesapin).

New Feature

• Support ALTER TABLE for tables in Memory databases. #30866 (tavplubix).
• New function mapExtractKeyLike to get the map only kept elements matched specified pattern. #30793 (凌涛).
• CompiledExpressionCache limit elements size using compiled_expression_cache_elements_size setting. #30667 (Maksim Kita).
• Add ability to change nodes configuration (in .xml file) for ClickHouse Keeper. #30372 (alesapin).
• Added HashedArray dictionary type. Closes #30236. #30242 (Maksim Kita).
• Added new JSONExtractKeys function ... #30056 (Vitaly).
• Added function tokens. That allow to split string into tokens using non-alpha numeric ASCII characters as separators. #29981 (Maksim Kita).
• Add support for FreeBSD aarch64. #29952 (MikaelUrankar).
• User can now create dictionaries with comments: CREATE DICTIONARY ... COMMENT 'vaue' ... #29899 (Vasily Nemkov).
• Added columns data_compressed_bytes, data_uncompressed_bytes, marks_bytes into system.data_skipping_indices. Added columns secondary_indices_compressed_bytes, secondary_indices_uncompressed_bytes, secondary_indices_marks_bytes into system.parts. Closes #29697. #29896 (Maksim Kita).
• Add table alias to system.tables and database alias to system.databases #29677. #29882 (kevin wan).
• Predefined configuration for table function remote. Closes #29756. #29774 (Kseniia Sumarokova).
• Returns String with OS Kernel version. #29755 (Memo).
• Added function ngram. Closes #29699. #29738 (Maksim Kita).
• Support EXISTS(subquery). Closes #6852. #29731 (Kseniia Sumarokova).
• • Added MD4 and SHA384 functions. #29602 (Nikita Tikhomirov).
• Clickhouse HTTP Server can enable HSTS by set hsts_max_age in config.xml with a positive number. #29516 (凌涛).
• Huawei OBS Storage support. Closes #24294. #29511 (kevin wan).
• New function mapContainsKeyLike to get the map that key matches a simple regular expression. #29471 (凌涛).
• Users now can set comments to database in CREATE DATABASE statement ... #29429 (Vasily Nemkov).
• clickhouse-format support option --query. #29325 (凌涛).
• Add CapnProto output format, refactor CapnProto input format. #29291 (Kruglov Pavel).
• Implemented ALTER TABLE x MODIFY COMMENT. #29264 (Vasily Nemkov).
• Adds H3 inspection functions that are missing from ClickHouse but are available via the H3 api: https://h3geo.org/docs/api/inspection. #29209 (Bharat Nallan).
• Allow non-replicated ALTER TABLE FETCH and ATTACH in Replicated databases. #29202 (Kevin Michel).
• Added a setting output_format_csv_null_representation: This is the same as output_format_tsv_null_representation but is for CSV output. #29123 (PHO).
• Added function zookeeperSessionUptime() which returns uptime of current ZooKeeper session in seconds. #28983 (tavplubix).
• Implements the h3ToGeoBoundary function. #28952 (Ivan Veselov).
• Add aggregate function exponentialMovingAverage that can be used as window function. This closes #27511. #28914 (alexey-milovidov).
• Allow to include subcolumns of table columns into DESCRIBE query result (can be enabled by setting describe_include_subcolumns). #28905 (Anton Popov).
• Executable, ExecutablePool added option send_chunk_header. If this option is true then chunk rows_count with line break will be sent to client before chunk. #28833 (Maksim Kita).
• Added executable user defined functions. #28803 (Maksim Kita).
• Added INFORMATION_SCHEMA database with SCHEMATA, TABLES, VIEWS and COLUMNS views to the corresponding tables in system database. Closes #9770. #28691 (tavplubix).
• Add normalizeUTF8NFC, normalizeUTF8NFD, normalizeUTF8NFKC, normalizeUTF8NFKD functions. #28633 (darkkeks).
• Allow predefined connections to external data sources. Closes #28367. #28577 (Kseniia Sumarokova).
• tokenbf_v1 and ngram support Map with key of String of FixedSring type. It enhance data skipping in query with map key filter. sql CREATE TABLE map_tokenbf ( row_id UInt32, map Map(String, String), INDEX map_tokenbf map TYPE ngrambf_v1(4,256,2,0) GRANULARITY 1 ) Engine=MergeTree() Order by id With table above, the query select * from map_tokebf where map['K']='V' will skip the granule that doesn't contain key A . Of course, how many rows will skipped is depended on the granularity and index_granularity you set. #28511 (凌涛).
• Send profile events from server to client. New packet type ProfileEvents was introduced. Closes #26177. #28364 (Dmitry Novik).
• This closes #27763. #28325 (小路).
• Support adding / deleting tables to replication from PostgreSQL dynamically in database engine MaterializedPostgreSQL. Support alter for database settings. Closes #27573. #28301 (Kseniia Sumarokova).
• This fully closes #4509 and even more. #27933 (Alexey Boykov).
• Add sparkbar aggregate function. This closes #26175. #27481 (小路).
• Add interactive mode for clickhouse-local. Also merge code of clickhouse-client and clickhouse-local together. Closes #7203. Closes #25516. Closes #22401. #26231 (Kseniia Sumarokova).
• Implementation of a table engine to consume application log files in ClickHouse. closes #6953. #25969 (flynn).
• Added an ability to suspend and resume a process of a merge. This is needed for a better scheduling and controlling of merges execution. #22381. #25165 (Nikita Mikhaylov).
• Added function accurateCastOrDefault(x, T). Closes #21330. Authors @taiyang-li. #23028 (Maksim Kita).
• Logging all successful and failed login, and logout events to a new system.session_log table. ... #22415 (Vasily Nemkov).
• • Add Function toUUIDOrDefault, toUInt8/16/32/64/256OrDefault, toInt8/16/32/64/128/256OrDefault, which enables user defining default value(not null) when string parsing is failed. #21330 (taiyang-li).
• Queries with JOIN ON support OR. #21320 (Ilya Golshtein).
• New asynchronous insert mode allows to accumulate inserted data and store it in a single batch in background. On server-side it controlled by settings async_insert_threads, async_insert_max_data_size and async_insert_busy_timeout_ms. For client it can be enabled by setting async_insert for INSERT queries with data inlined in query or in separate buffer (e.g. for INSERT queries via HTTP protocol). If wait_for_async_insert is true (by default) the client will wait until data will be flushed to table. Implements #18282. #20557 (Ivan).

Performance Improvement

• Queries with INTO OUTFILE in clickhouse-client will use multiple threads. Fix the issue with flickering progress-bar when using INTO OUTFILE. This closes #30873. This closes #30872. #30886 (alexey-milovidov).
• • Improve filter bitmask generator function all in one with sse/avx2/avx512 instructions. #30670 (jasperzhu).
• Dictionaries support read from multiple threads. #30500 (Maksim Kita).
• ColumnDecimal improve performance for filter operation. #30431 (Jun Jin).
• Improve performance of aggregation in order of primary key (with enabled setting optimize_aggregation_in_order). #30266 (Anton Popov).
• • To take advantage of X86_64 feature, Use AVX2/AVX512 instructions to accelerate filter operation. #30014 (jasperzhu).
• • Remove branchy code in filter operation with a better implementation with popcnt/ctz which have better performance. #29881 (Jun Jin).
• Improve the performance of SUM of nullable floating point numbers. #28906 (Raúl Marín).
• Attempt to improve performance of string comparison. #28767 (alexey-milovidov).
• Reduce default settings for S3 multipart upload part size. #28679 (ianton-ru).
• Speed up bitmapAnd function. #28332 (dddounaiking).
• Removed sub-optimal mutation notifications in StorageMergeTree when merges are still going. #27552 (Vladimir Chebotarev).
• If query has multiple quantile aggregate functions with the same arguments but different level parameter:. #26657 (hexiaoting).

Improvement

• Rename the columns of SessionLog: session_id -> auth_id, session_name -> session_id, changed_settings -> settings. #30882 (Vitaly Baranov).
• Allow to parse values of Date data type in text formats as YYYYMMDD in addition to YYYY-MM-DD. This closes #30870. #30871 (alexey-milovidov).
• Arrays of all serializable types are now supported by arrayStringConcat. #30840 (Nickita Taranov).
• SQLUserDefinedFunctions support ON CLUSTER. Example CREATE FUNCTION test_function ON CLUSTER 'cluster' AS x -> x + 1;. Closes #30666. #30734 (Maksim Kita).
• Get memory amount with Docker/cgroups limitations. See #25662. #30574 (Pavel Medvedev).
• Make query, which fetched table structure for PostgreSQL database because, more reliable. #30477 (Kseniia Sumarokova).
• SQLUserDefinedFunctions support CREATE OR REPLACE, CREATE IF NOT EXISTS syntaxes. #30454 (Maksim Kita).
• SQLUserDefinedFunctions added DROP IF EXISTS support. Example DROP FUNCTION IF EXISTS test_function. #30437 (Maksim Kita).
• SQLUserDefinedFunctions support lambdas. Example CREATE FUNCTION lambda_function AS x -> arrayMap(element -> element * 2, x);. #30435 (Maksim Kita).
• More full support of positional arguments. #30433 (Kseniia Sumarokova).
• Allow extract non-string element as string using JSONExtractString. This is for https://github.com/ClickHouse/ClickHouse/pull/25452#issuecomment-927123287. #30426 (Amos Bird).
• Added an ability to use FINAL clause in SELECT queries from GraphiteMergeTree. #30360 (Nikita Mikhaylov).
• Minor improvements in replica cloning and enqueuing fetch for broken parts, that should avoid extremely rare hanging of GET_PART entries in replication queue. #30346 (tavplubix).
• Allow symlinks to files in user_files directory for file table function. #30309 (Kseniia Sumarokova).
• Fixed comparison of Date32 with Date, DateTime, DateTime64, String. #30219 (liang.huang).
• Allow to remove SAMPLE BY expression from MergeTree tables (ALTER TABLE <table> REMOVE SAMPLE BY). #30180 (Anton Popov).
• Support SQL user defined functions for clickhouse-local. #30179 (Maksim Kita).
• Now Keeper (as part of clickhouse-server) will start asynchronously if it can connect to some other node. #30170 (alesapin).
• Now clickhouse-client supports native multi-line editing. #30143 (Amos Bird).
• PolygonDictionary added support for read method if setting store_polygon_key_column = true. Closes #30090. #30142 (Maksim Kita).
• Reduce amount of redundant compressed data read from disk for some types SELECT queries (only for MergeTree engines family). #30111 (alesapin).
• Improve solution https://github.com/ClickHouse/ClickHouse/pull/28853 See also https://github.com/ClickHouse/ClickHouse/pull/29928. #30084 (Vitaly Baranov).
• Add ability to print raw profile events to clickhouse-client (This can be useful for debugging and for testing). #30064 (Azat Khuzhin).
• ProfileEvents::Counters snapshot doesn't store data in std::atomic anymore. #30000 (Dmitry Novik).
• Now clickhouse use DNS cache while communicating with external S3. #29999 (alesapin).
• Fix data-race between flush() and startup() in StorageBuffer. #29930 (Azat Khuzhin).
• Fix lock-order-inversion between DROP TABLE for DatabaseMemory and LiveView. #29929 (Azat Khuzhin).
• Fix lock-order-inversion between periodic dictionary reload and config reload. #29928 (Azat Khuzhin).
• Better exception message while reading column from Arrow-supported formats like Arrow, ArrowStream, Parquet and ORC. This closes #29926. #29927 (alexey-milovidov).
• Update zoneinfo files to 2021c. #29925 (alexey-milovidov).
• Add ability to configure retries and delays between them for clickhouse-copier. #29921 (Azat Khuzhin).
• Now min-max aggregation over the first expression of primary key is optimized by projection. This is for https://github.com/ClickHouse/ClickHouse/issues/329. #29918 (Amos Bird).
• Add shutdown_wait_unfinished_queries server setting to allowing waiting for running queries up to shutdown_wait_unfinished time. This is for #24451 . #29914 (Amos Bird).
• Remove unused variable in s3cluster. #29912 (taiyang-li).
• Add ability to trace peak memory usage (with new trace_type - MemoryPeak). #29858 (Azat Khuzhin).
• Added partitioned table prefix 'p' for the query for fetching replica identity index. #29828 (Shoh Jahon).
• Web UI: render bars in table cells. #29792 (alexey-milovidov).
• Remove some redundant seek calls while reading compressed blocks in MergeTree table engines family. #29766 (alesapin).
• Apply max_untracked_memory/memory_profiler_step/memory_profiler_sample_probability during mutate/merge. #29681 (Azat Khuzhin).
• Add ClickHouse logo to Play UI. #29674 (alexey-milovidov).
• Make url table function to process multiple URLs in parallel. This closes #29670 and closes #29671. #29673 (alexey-milovidov).
• Query obfuscator clickhouse-format --obfuscate now works with more types of queries. #29672 (alexey-milovidov).
• Fixed the issue: clickhouse-format --obfuscate cannot process queries with embedded dictionaries (functions regionTo...). #29667 (alexey-milovidov).
• Fix incorrect nullable processing of JSONFunctions. This fixes #29615 . Mark as improvement because https://github.com/ClickHouse/ClickHouse/pull/28012 is not released. #29659 (Amos Bird).
• Increase listen_backlog by default (to match default in newer linux kernel). #29643 (Azat Khuzhin).
• Allow user to change log levels without restart. #29586 (Nikolay Degterinsky).
• Reload dictionaries, models, user defined executable functions if servers config dictionaries_config, models_config, user_defined_executable_functions_config changes. Closes #28142. #29529 (Maksim Kita).
• Get rid of pointless restriction on projection name. Now projection name can start with tmp_. #29520 (Amos Bird).
• Fixed There is no query or query context has expired error in mutations with nested subqueries. Do not allow subqueries in mutation if table is replicated and allow_nondeterministic_mutations setting is disabled. #29495 (tavplubix).
• Add support for IS NULL/IS NOT NULL for external dbs (i.e. MySQL). #29463 (Azat Khuzhin).
• Enable per-query memory profiler (set to memory_profiler_step=4MiB) globally. #29455 (Azat Khuzhin).
• Transform isNull/isNotNull to IS NULL/IS NOT NULL (for external dbs, i.e. MySQL). #29446 (Azat Khuzhin).
• Apply config changes to max_concurrent_queries during runtime (no need to restart). #29414 (Raúl Marín).
• Added setting use_skip_indexes. #29405 (Maksim Kita).
• fix lost in memory part when freeze. #29376 (Mo Xuan).
• Pass through initial query_id for clickhouse-benchmark (previously if you run remote query via clickhouse-benchmark, queries on shards will not be linked to the initial query via initial_query_id). #29364 (Azat Khuzhin).
• Allow to write number in query as binary literal. Example SELECT 0b001;. #29304 (Maksim Kita).
• Primary key index and partition filter can work in tuple. #29281 (凌涛).
• Skip indexes tokenbf_v1 and ngrambf_v1 added support for Array data type with key of String of FixedString type. #29280 (Maksim Kita).
• Function has added support for map data type. #29267 (Maksim Kita).
• Add compress_logs settings for clickhouse-keeper which allow to compress clickhouse-keeper logs in ZSTD . Implements: #26977. #29223 (alesapin).
• Skip indexes tokenbf_v1 and ngrambf_v1 added support for Map data type with key of String of FixedString type. Author @lingtaolf. #29220 (Maksim Kita).
• Add ability to disable converting expressions to local filter for external queries (external_table_strict_query=true). #29206 (Azat Khuzhin).
• Allow to asynchronous reads for remote fs disks. #29205 (Kseniia Sumarokova).
• Add CORS support. Add headers for preflight options request. Closes #18693. #29155 (Filatenkov Artur).
• Added an ability to execute more merges and mutations than the number of threads in background pool. Merges and mutations will be executed step by step according to their sizes (lower is more prioritized). The ratio of the number of tasks to threads to execute is controlled by a setting background_merges_mutations_concurrency_ratio, 2 by default. #29140 (Nikita Mikhaylov).
• Disable projections when ARRAY JOIN is used. Currently projection analysis will break array join aliases. #29139 (Amos Bird).
• Fix possible LogicalError, support more types in MsgPack input/output format. #29077 (Kruglov Pavel).
• Allow to input and output LowCardinality columns in ORC input/output format. #29062 (Kruglov Pavel).
• Select from system.distributed_ddl_queue might show incorrect values, it's fixed. #29061 (tavplubix).
• Correct behaviour with unknown methods for http connection. Solves #29050. #29057 (Filatenkov Artur).
• Fix bug in clickhouse-keeper-converter which can lead to some data loss while restoring from ZooKeeper logs (not snapshot). #29030 (小路).
• Apply settings from CREATE AS SELECT queries (fixes: #28810). #28962 (Azat Khuzhin).
• add default database setting for alter table ... on cluster ... replace/move partition from/to ... #28955 (anneji-dev).
• gRPC: Allow change server-side compression from client. #28953 (Vitaly Baranov).
• Add time dependency for clickhouse-server unit (systemd and sysvinit init). #28891 (Azat Khuzhin).
• Skip "no data" exception when reading thermal sensors for asynchronous metrics. This closes #28852. #28882 (alexey-milovidov).
• Fixed race condition that might cause Dictionary not found error for existing dictionary in rare cases. #28853 (tavplubix).
• Relax nested function for If-combinator check (but forbid nested identical combinators). #28828 (Azat Khuzhin).
• Fix uncaught exception during server termination. #28761 (Azat Khuzhin).
• Forbid cleaning of tmp directories that can be used by an active mutation/merge. #28760 (Azat Khuzhin).
• Allow optimization : optimize_arithmetic_operations_in_aggregate_functions = 1 when alias is used. I cannot figure out why it was disabled. We set aliases in all other TreeOptimizers, except this one. Maybe I'm missing something important) @4ertus2 could you give a bad example?. #28746 (Amos Bird).
• Implement detach_not_byte_identical_parts setting for ReplicatedMergeTree, that will detach instead of remove not byte-identical parts (after mege/mutate). #28708 (Azat Khuzhin).
• Implement max_suspicious_broken_parts_bytes setting for MergeTree (to limit total size of all broken parts, default is 1GiB). #28707 (Azat Khuzhin).
• This PR enables expanding macros in RabbitMQ settings, for example:. #28683 (Vitaly Baranov).
• Resolve table dependencies on metadata loading. Closes #8004, closes #15170. #28373 (tavplubix).
• Speed up part loading process with multiple disks are in use. The idea is similar to https://github.com/ClickHouse/ClickHouse/pull/16423 . Prod env shows improvement: 24 min -> 16 min . #28363 (Amos Bird).
• Avoid error "Division by zero" when denominator is Nullable in functions divide, intDiv and modulo. Closes #22621. #28352 (Kruglov Pavel).
• Reload stacktrace cache when symbol is reloaded. #28137 (Amos Bird).
• This PR allows reading data of a table using the Log engine in multiple threads. #28125 (Vitaly Baranov).
• Fix misbehavior of NULL column handling in json functions. This fixes #27930. #28012 (Amos Bird).
• Add dedicated Mark/Uncompressed cache for skip indices. Not sure how to test it properly. #27961 (Amos Bird).
• Correct Codec(AES_128_GCM_SIV). #27476 (Filatenkov Artur).
• Add compression for INTO OUTPUT and FROM INFILE with additional optional parameter. #27135 (Filatenkov Artur).
• • Allow to mix using join with other join types. #23881 (darkkeks).

Bug Fix

• Fix reading from empty file on encrypted disk. #30494 (Vitaly Baranov).
• Fix releasing query ID and session ID at the end of query processing while handing gRPC call. This PR fixes flaky test test_grpc_protocol/test.py::test_session. #29954 (Vitaly Baranov).
• Fix shutdown of AccessControlManager. Now there can't be reloading of the configuration after AccessControlManager has been destroyed. This PR fixes the flaky test test_user_directories/test.py::test_relative_path. #29951 (Vitaly Baranov).
• Fix bug in clickhouse-keeper-converter which can lead to incorrect ZooKeeper log deserialization. #29071 (小路).
• Fix transformation of disjunctions chain to IN (controlled by settings optimize_min_equality_disjunction_chain_length) in distributed queries with settings legacy_column_name_of_tuple_literal = 0. #28658 (Anton Popov).
• Allow using a materialized column as the sharding key in a distributed table even if insert_allow_materialized_columns=0:. #28637 (Vitaly Baranov).

Build/Testing/Packaging Improvement

• Recursive submodules are no longer needed for ClickHouse. #30315 (alexey-milovidov).
• ClickHouse can be statically built with Musl. This is added as experiment, it does not support building odbc-bridge, library-bridge, integration with CatBoost and some libraries. #30248 (alexey-milovidov).
• Add tests for encrypted disk & encryption codec and ReplicatedMergeTree. #30172 (Vitaly Baranov).
• Enable Protobuf, Arrow, ORC, Parquet for AArch64 and Darwin builds. This closes #29248. This closes #28018. #30015 (alexey-milovidov).
• Add cross-build for PowerPC (powerpc64le). This closes #9589. Enable support for interaction with MySQL for AArch64 and PowerPC. This closes #26301. #30010 (alexey-milovidov).
• Leave only required files in cross-compile toolchains. Include them as submodules (earlier they were downloaded as tarballs). #29974 (alexey-milovidov).
• Fix an build error because of Rename "common" to "base". #29688 (Sergei Semin).
• Turning on experimental constexpr expressions evaluator for clang to speed up template code compilation. #29668 (myrrc).
• Add ability to compile using newer version fo glibc w/o using new symbols. #29594 (Azat Khuzhin).
• N/A Detailed description / Documentation draft:. #29367 (kevin wan).
• Add a test for https://github.com/ClickHouse/ClickHouse/pull/28683. #28934 (Vitaly Baranov).
• Convert skip_list .json into first line comments. #28909 (Vitaly Baranov).
• Reduce Debug build binary size by clang optimization. #28736 (flynn).
• Now all images for CI will be placed in the separate dockerhub repo. #28656 (alesapin).
• Improve support for build with clang-13. #28046 (Sergei Semin).
• Switch clang builds to 12 version. #20495 (Ilya Yatsishin).

Bug Fix (user-visible misbehaviour in official stable or prestable release

• Fix ORDER BY ... WITH FILL with set TO and FROM and no rows in result set. #30888 (Anton Popov).

Bug Fix (user-visible misbehaviour in official stable or prestable release)

• Fix set index not used in AND/OR expressions when there are more than two operands. This fixes #30416 . #30887 (Amos Bird).
• Fix crash when projection with hashing function is materialized. This fixes #30861 . The issue is similar to https://github.com/ClickHouse/ClickHouse/pull/28560 which is a lack of proper understanding of the invariant of header's emptyness. #30877 (Amos Bird).
• Fixed ambiguity when extracting auxiliary ZooKeeper name from ZooKeeper path in ReplicatedMergeTree. Previously server might fail to start with Unknown auxiliary ZooKeeper name if ZooKeeper path contains a colon. Fixes #29052. Also it was allowed to specify ZooKeeper path that does not start with slash, but now it's deprecated and creation of new tables with such path is not allowed. Slashes and colons in auxiliary ZooKeeper names are not allowed too. #30822 (tavplubix).
• Clean temporary directory when localBackup failed by some reason. #30797 (ianton-ru).
• Fixed a race condition between REPLACE/MOVE PARTITION and background merge in non-replicated MergeTree that might cause a part of moved/replaced data to remain in partition. Fixes #29327. #30717 (tavplubix).
• Fix PREWHERE with WHERE in case of always true PREWHERE. #30668 (Azat Khuzhin).
• Functions for case-insensitive search in UTF8 strings like positionCaseInsensitiveUTF8 and countSubstringsCaseInsensitiveUTF8 might find substrings that actually does not match, it's fixed. #30663 (tavplubix).
• Update aws-sdk submodule for throttling in Yandex.S3. #30646 (ianton-ru).
• Limit push down optimization could cause a error Cannot find column. Fixes #30438. #30562 (Nikolai Kochetov).
• Add missing parenthesis for isNotNull/isNull rewrites to IS [NOT] NULL (fixes queries that has something like isNotNull(1)+isNotNull(2)). #30520 (Azat Khuzhin).
• • Fix deadlock on ALTER with scalar subquery to the same table, close #30461. #30492 (Vladimir C).
• Fixed segfault which might happen if session expired during execution of REPLACE PARTITION. #30432 (tavplubix).
• Makes #30162 less possible ... #30370 (Vasily Nemkov).
• Queries with condition like IN (subquery) could return incorrect result in case if aggregate projection applied. Fixed creation of sets for projections. #30310 (Amos Bird).
• Fix column alias resolution of JOIN queries when projection is enabled. This fixes #30146. #30293 (Amos Bird).
• fix replaceRegexpAll bug. #30292 (Memo).
• Fix ComplexKeyHashedDictionary, ComplexKeySparseHashedDictionary parsing preallocate option from layout config. #30246 (Maksim Kita).
• Fix [I]LIKE function. Closes #28661. #30244 (Nikolay Degterinsky).
• Fix crash with shortcircuit and lowcardinality in multiIf. #30243 (Raúl Marín).
• FlatDictionary, HashedDictionary fix bytes_allocated calculation for nullable attributes. #30238 (Maksim Kita).
• • Allow identifiers staring with numbers in multiple joins. #30230 (Vladimir C).
• Fix reading from MergeTree with max_read_buffer_size=0 (can lead to Can't adjust last granule LOGICAL_ERROR, or even data loss). #30192 (Azat Khuzhin).
• Fix pread_fake_async/pread_threadpool with min_bytes_to_use_direct_io. #30191 (Azat Khuzhin).
• Fix INSERT SELECT incorrectly fills MATERIALIZED column based of Nullable column. #30189 (Azat Khuzhin).
• Support nullable arguments in function initializeAggregation. #30177 (Anton Popov).
• Fix error Port is already connected for queries with GLOBAL IN and WITH TOTALS. Only for 21.9 and 21.10. #30086 (Nikolai Kochetov).
• Fix race between MOVE PARTITION and merges/mutations for MergeTree. #30074 (Azat Khuzhin).
• Dropped Memory database might reappear after server restart, it's fixed (#29795). Also added force_remove_data_recursively_on_drop setting as a workaround for Directory not empty error when dropping Ordinary database (because it's not possible to remove data leftovers manually in cloud environment). #30054 (tavplubix).
• Fix crash of sample by tuple(), closes #30004. #30016 (flynn).
• try to close issue: #29965. #29976 (hexiaoting).
• Fix possible data-race between FileChecker and StorageLog/StorageStripeLog. #29959 (Azat Khuzhin).
• Fix data-race between LogSink::writeMarks() and LogSource in StorageLog. #29946 (Azat Khuzhin).
• Fix potential resource leak of the concurrent query limit of merge tree tables introduced in https://github.com/ClickHouse/ClickHouse/pull/19544 . #29879 (Amos Bird).
• Fix system tables recreation check (fails to detect changes in enum values). #29857 (Azat Khuzhin).
• MaterializedMySQL: Fix an issue where if the connection to MySQL was lost, only parts of a transaction could be processed. #29837 (Håvard Kvålen).
• Avoid Timeout exceeded: elapsed 18446744073.709553 seconds error that might happen in extremely rare cases, presumably due to some bug in kernel. Fixes #29154. #29811 (tavplubix).
• Fix bad cast in ATTACH TABLE ... FROM 'path' query when non-string literal is used instead of path. It may lead to reading of uninitialized memory. #29790 (alexey-milovidov).
• Fix concurrent access to LowCardinality during GROUP BY (leads to SIGSEGV). #29782 (Azat Khuzhin).
• Fix incorrect GROUP BY (multiple rows with the same keys in result) in case of distributed query when shards had mixed versions <= 21.3 and >= 21.4, GROUP BY key had several columns all with fixed size, and two-level aggregation was activated (see group_by_two_level_threshold and group_by_two_level_threshold_bytes). Fixes #29580. #29735 (Nikolai Kochetov).
• Fixed incorrect behaviour of setting materialized_postgresql_tables_list at server restart. Found in #28529. #29686 (Kseniia Sumarokova).
• Condition in filter predicate could be lost after push-down optimisation. #29625 (Nikolai Kochetov).
• Fix JIT expression compilation with aliases and short-circuit expression evaluation. Closes #29403. #29574 (Maksim Kita).
• Fix rare segfault in ALTER MODIFY query when using incorrect table identifier in DEFAULT expression like x.y.z... Fixes #29184. #29573 (alesapin).
• Fix null deference for GROUP BY WITH TOTALS HAVING (when the column from HAVING wasn't selected). #29553 (Azat Khuzhin).
• Avoid deadlocks when reading and writting on JOIN Engine tables at the same time. #29544 (Raúl Marín).
• Fix bug in check pathStartsWith becuase there was bug with the usage of std::mismatch: The behavior is undefined if the second range is shorter than the first range.. #29531 (Kseniia Sumarokova).
• In ODBC bridge add retries for error Invalid cursor state. It is a retriable error. Closes #29473. #29518 (Kseniia Sumarokova).
• Fixed incorrect table name parsing on loading of Lazy database. Fixes #29456. #29476 (tavplubix).
• Fix possible Block structure mismatch for subqueries with pushed-down HAVING predicate. Fixes #29010. #29475 (Nikolai Kochetov).
• Fix Logical error Cannot capture columns in functions greatest/least. Closes #29334. #29454 (Kruglov Pavel).
• rocksdb: fix race condition during multiple DB opening (and get back some tests that triggers the problem on CI). #29393 (Azat Khuzhin).
• Fix replicated access storage not shutting down cleanly when misconfigured. #29388 (Kevin Michel).
• Remove window function nth_value as it is not memory-safe. This closes #29347. #29348 (alexey-milovidov).
• Fix vertical merges of projection parts. This fixes #29253 . This PR also fixes several projection merge/mutation issues introduced in https://github.com/ClickHouse/ClickHouse/pull/25165. #29337 (Amos Bird).
• Fix hanging DDL queries on Replicated database while adding a new replica. #29328 (Kevin Michel).
• Fix connection timeouts (send_timeout/receive_timeout). #29282 (Azat Khuzhin).
• Fix failed assertion in ReadBufferFromHDFS. Update libhdfs3 library to be able to run in tests in debug. Closes #29251. Closes #27814. #29276 (Kseniia Sumarokova).
• Fix possible Table columns structure in ZooKeeper is different from local table structure exception while recreating or creating new replicas of ReplicatedMergeTree, when one of table columns have default expressions with case-insensitive functions. #29266 (Anton Popov).
• Send normal Database doesn't exist error (UNKNOWN_DATABASE) to the client (via TCP) instead of Attempt to read after eof (ATTEMPT_TO_READ_AFTER_EOF). #29229 (Azat Khuzhin).
• Fix segfault while inserting into column with type LowCardinality(Nullable) in Avro input format. #29132 (Kruglov Pavel).
• Do not allow to reuse previous credentials in case of inter-server secret (Before INSERT via Buffer/Kafka to Distributed table with interserver secret configured for that cluster, may re-use previously set user for that connection). #29060 (Azat Khuzhin).
• Handle any_join_distinct_right_table_keys when join with dictionary, close #29007. #29014 (Vladimir C).
• Fix "Not found column ... in block" error, when join on alias column, close #26980. #29008 (Vladimir C).
• Fix the number of threads used in GLOBAL IN subquery (it was executed in single threads since #19414 bugfix). #28997 (Nikolai Kochetov).
• Fix bad optimizations of ORDER BY if it contains WITH FILL. This closes #28908. This closes #26049. #28910 (alexey-milovidov).
• Fix higher-order array functions (SIGSEGV for arrayCompact/ILLEGAL_COLUMN for arrayDifference/arrayCumSumNonNegative) with consts. #28904 (Azat Khuzhin).
• Fix waiting for mutation with mutations_sync=2. #28889 (Azat Khuzhin).
• Fix queries to external databases (i.e. MySQL) with multiple columns in IN ( i.e. (k,v) IN ((1, 2)) ) (but note that this has some backward incompatibility for the clickhouse-copier since it uses alias for tuple element). #28888 (Azat Khuzhin).
• Fix bug with LowCardinality in short-curcuit function evaluation. Closes #28884. #28887 (Kruglov Pavel).
• Fix reading of subcolumns from compact parts. #28873 (Anton Popov).
• Fixed a race condition between DROP PART and REPLACE/MOVE PARTITION that might cause replicas to diverge in rare cases. #28864 (tavplubix).
• Fix expressions compilation with short circuit evaluation. #28821 (Azat Khuzhin).
• Fix extremely rare case when ReplicatedMergeTree replicas can diverge after hard reboot of all replicas. The error looks like Part ... intersects (previous|next) part .... #28817 (alesapin).
• Better check for connection usability and also catch any exception in RabbitMQ shutdown just in case. #28797 (Kseniia Sumarokova).
• Fix benign race condition in ReplicatedMergeTreeQueue. Shouldn't be visible for user, but can lead to subtle bugs. #28734 (alesapin).
• Fix possible crash for SELECT with partially created aggregate projection in case of exception. #28700 (Amos Bird).
• Fix the coredump in the creation of distributed tables, when the parameters passed in are wrong. #28686 (Zhiyong Wang).
• Add Settings.Names, Settings.Values aliases for system.processes table. #28685 (Vitaly).
• • Fix the number of arguments required by s2RectAdd and s2RectContains functions. #28663 (Bharat Nallan).
• Fix invalid constant type conversion when nullable or lowcardinality primary key is used. #28636 (Amos Bird).
• Fix "Column is not under aggregate function and not in GROUP BY" with PREWHERE (Fixes: #28461). #28502 (Azat Khuzhin).

NO CL ENTRY

• NO CL ENTRY: 'remove some unneeded header files'. #30722 (flynn).
• NO CL ENTRY: 'Revert "Revert "Improve usability of remote_url_allow_hosts""'. #30708 (Nikolai Kochetov).
• NO CL ENTRY: 'Revert "Improve usability of remote_url_allow_hosts"'. #30707 (Nikolai Kochetov).
• NO CL ENTRY: 'Revert "Fix style regressions on benchmark page"'. #30652 (alesapin).
• NO CL ENTRY: 'add support of window function in antlr grammar'. #30181 (PHaroZ).
• NO CL ENTRY: 'Link FAQ from Debian installation'. #29836 (Federico Ceratto).
• NO CL ENTRY: 'Revert "Add coroutines example."'. #29829 (Nikolai Kochetov).
• NO CL ENTRY: 'Generate test_results.tsv for fasttest'. #29319 (Dmitry Novik).
• NO CL ENTRY: 'Update rounding-functions.md'. #29249 (quoctan132).

Testing Improvement

• Implemented structure-aware fuzzing approach in ClickHouse for select statement parser. #30012 (Paul).

Backward Incompatible Change

• Remove setting odbc_max_field_size because it is not used anymore. Closes #30413. #30778 (Kseniia Sumarokova).
• Change order of json_path and json in sql json function (to be correct). Closes #30449. #30474 (Kseniia Sumarokova).
• Remove MergeTree table setting write_final_mark. It will be always true. #30455 (Kseniia Sumarokova).
• Function bayesAB is removed. This closes #26233. #29934 (alexey-milovidov).
• Now ClickHouse Keeper snapshots compressed with ZSTD codec by default instead of custom ClickHouse LZ4 block compression. This behavior can be turned off with compress_snapshots_with_zstd_format coordination setting (must be equal on all quorum replicas). Backward incompatibility is quite rare and may happen only when new node will send snapshot (happens in case of recovery) to the old node which is unable to read snapshots in ZSTD format. #29417 (alesapin).

New Feature

• Support ALTER TABLE for tables in Memory databases. #30866 (tavplubix).
• New function mapExtractKeyLike to get the map only kept elements matched specified pattern. #30793 (凌涛).
• CompiledExpressionCache limit elements size using compiled_expression_cache_elements_size setting. #30667 (Maksim Kita).
• Add ability to change nodes configuration (in .xml file) for ClickHouse Keeper. #30372 (alesapin).
• Added HashedArray dictionary type. Closes #30236. #30242 (Maksim Kita).
• Added new JSONExtractKeys function ... #30056 (Vitaly).
• Added function tokens. That allow to split string into tokens using non-alpha numeric ASCII characters as separators. #29981 (Maksim Kita).
• Add support for FreeBSD aarch64. #29952 (MikaelUrankar).
• User can now create dictionaries with comments: CREATE DICTIONARY ... COMMENT 'vaue' ... #29899 (Vasily Nemkov).
• Added columns data_compressed_bytes, data_uncompressed_bytes, marks_bytes into system.data_skipping_indices. Added columns secondary_indices_compressed_bytes, secondary_indices_uncompressed_bytes, secondary_indices_marks_bytes into system.parts. Closes #29697. #29896 (Maksim Kita).
• Add table alias to system.tables and database alias to system.databases #29677. #29882 (kevin wan).
• Predefined configuration for table function remote. Closes #29756. #29774 (Kseniia Sumarokova).
• Returns String with OS Kernel version. #29755 (Memo).
• Added function ngram. Closes #29699. #29738 (Maksim Kita).
• Support EXISTS(subquery). Closes #6852. #29731 (Kseniia Sumarokova).
• • Added MD4 and SHA384 functions. #29602 (Nikita Tikhomirov).
• Clickhouse HTTP Server can enable HSTS by set hsts_max_age in config.xml with a positive number. #29516 (凌涛).
• Huawei OBS Storage support. Closes #24294. #29511 (kevin wan).
• New function mapContainsKeyLike to get the map that key matches a simple regular expression. #29471 (凌涛).
• Users now can set comments to database in CREATE DATABASE statement ... #29429 (Vasily Nemkov).
• clickhouse-format support option --query. #29325 (凌涛).
• Add CapnProto output format, refactor CapnProto input format. #29291 (Kruglov Pavel).
• Implemented ALTER TABLE x MODIFY COMMENT. #29264 (Vasily Nemkov).
• Adds H3 inspection functions that are missing from ClickHouse but are available via the H3 api: https://h3geo.org/docs/api/inspection. #29209 (Bharat Nallan).
• Allow non-replicated ALTER TABLE FETCH and ATTACH in Replicated databases. #29202 (Kevin Michel).
• Added a setting output_format_csv_null_representation: This is the same as output_format_tsv_null_representation but is for CSV output. #29123 (PHO).
• Added function zookeeperSessionUptime() which returns uptime of current ZooKeeper session in seconds. #28983 (tavplubix).
• Implements the h3ToGeoBoundary function. #28952 (Ivan Veselov).
• Add aggregate function exponentialMovingAverage that can be used as window function. This closes #27511. #28914 (alexey-milovidov).
• Allow to include subcolumns of table columns into DESCRIBE query result (can be enabled by setting describe_include_subcolumns). #28905 (Anton Popov).
• Executable, ExecutablePool added option send_chunk_header. If this option is true then chunk rows_count with line break will be sent to client before chunk. #28833 (Maksim Kita).
• Added executable user defined functions. #28803 (Maksim Kita).
• Added INFORMATION_SCHEMA database with SCHEMATA, TABLES, VIEWS and COLUMNS views to the corresponding tables in system database. Closes #9770. #28691 (tavplubix).
• Add normalizeUTF8NFC, normalizeUTF8NFD, normalizeUTF8NFKC, normalizeUTF8NFKD functions. #28633 (darkkeks).
• Allow predefined connections to external data sources. Closes #28367. #28577 (Kseniia Sumarokova).
• tokenbf_v1 and ngram support Map with key of String of FixedSring type. It enhance data skipping in query with map key filter. sql CREATE TABLE map_tokenbf ( row_id UInt32, map Map(String, String), INDEX map_tokenbf map TYPE ngrambf_v1(4,256,2,0) GRANULARITY 1 ) Engine=MergeTree() Order by id With table above, the query select * from map_tokebf where map['K']='V' will skip the granule that doesn't contain key A . Of course, how many rows will skipped is depended on the granularity and index_granularity you set. #28511 (凌涛).
• Send profile events from server to client. New packet type ProfileEvents was introduced. Closes #26177. #28364 (Dmitry Novik).
• This closes #27763. #28325 (小路).
• Support adding / deleting tables to replication from PostgreSQL dynamically in database engine MaterializedPostgreSQL. Support alter for database settings. Closes #27573. #28301 (Kseniia Sumarokova).
• This fully closes #4509 and even more. #27933 (Alexey Boykov).
• Add sparkbar aggregate function. This closes #26175. #27481 (小路).
• Add interactive mode for clickhouse-local. Also merge code of clickhouse-client and clickhouse-local together. Closes #7203. Closes #25516. Closes #22401. #26231 (Kseniia Sumarokova).
• Implementation of a table engine to consume application log files in ClickHouse. closes #6953. #25969 (flynn).
• Added an ability to suspend and resume a process of a merge. This is needed for a better scheduling and controlling of merges execution. #22381. #25165 (Nikita Mikhaylov).
• Added function accurateCastOrDefault(x, T). Closes #21330. Authors @taiyang-li. #23028 (Maksim Kita).
• Logging all successful and failed login, and logout events to a new system.session_log table. ... #22415 (Vasily Nemkov).
• • Add Function toUUIDOrDefault, toUInt8/16/32/64/256OrDefault, toInt8/16/32/64/128/256OrDefault, which enables user defining default value(not null) when string parsing is failed. #21330 (taiyang-li).
• Queries with JOIN ON support OR. #21320 (Ilya Golshtein).
• New asynchronous insert mode allows to accumulate inserted data and store it in a single batch in background. On server-side it controlled by settings async_insert_threads, async_insert_max_data_size and async_insert_busy_timeout_ms. For client it can be enabled by setting async_insert for INSERT queries with data inlined in query or in separate buffer (e.g. for INSERT queries via HTTP protocol). If wait_for_async_insert is true (by default) the client will wait until data will be flushed to table. Implements #18282. #20557 (Ivan).

Performance Improvement

• Queries with INTO OUTFILE in clickhouse-client will use multiple threads. Fix the issue with flickering progress-bar when using INTO OUTFILE. This closes #30873. This closes #30872. #30886 (alexey-milovidov).
• • Improve filter bitmask generator function all in one with sse/avx2/avx512 instructions. #30670 (jasperzhu).
• Dictionaries support read from multiple threads. #30500 (Maksim Kita).
• ColumnDecimal improve performance for filter operation. #30431 (Jun Jin).
• Improve performance of aggregation in order of primary key (with enabled setting optimize_aggregation_in_order). #30266 (Anton Popov).
• • To take advantage of X86_64 feature, Use AVX2/AVX512 instructions to accelerate filter operation. #30014 (jasperzhu).
• • Remove branchy code in filter operation with a better implementation with popcnt/ctz which have better performance. #29881 (Jun Jin).
• Improve the performance of SUM of nullable floating point numbers. #28906 (Raúl Marín).
• Attempt to improve performance of string comparison. #28767 (alexey-milovidov).
• Reduce default settings for S3 multipart upload part size. #28679 (ianton-ru).
• Speed up bitmapAnd function. #28332 (dddounaiking).
• Removed sub-optimal mutation notifications in StorageMergeTree when merges are still going. #27552 (Vladimir Chebotarev).
• If query has multiple quantile aggregate functions with the same arguments but different level parameter:. #26657 (hexiaoting).

Improvement

• Rename the columns of SessionLog: session_id -> auth_id, session_name -> session_id, changed_settings -> settings. #30882 (Vitaly Baranov).
• Allow to parse values of Date data type in text formats as YYYYMMDD in addition to YYYY-MM-DD. This closes #30870. #30871 (alexey-milovidov).
• Arrays of all serializable types are now supported by arrayStringConcat. #30840 (Nickita Taranov).
• SQLUserDefinedFunctions support ON CLUSTER. Example CREATE FUNCTION test_function ON CLUSTER 'cluster' AS x -> x + 1;. Closes #30666. #30734 (Maksim Kita).
• Get memory amount with Docker/cgroups limitations. See #25662. #30574 (Pavel Medvedev).
• Make query, which fetched table structure for PostgreSQL database because, more reliable. #30477 (Kseniia Sumarokova).
• SQLUserDefinedFunctions support CREATE OR REPLACE, CREATE IF NOT EXISTS syntaxes. #30454 (Maksim Kita).
• SQLUserDefinedFunctions added DROP IF EXISTS support. Example DROP FUNCTION IF EXISTS test_function. #30437 (Maksim Kita).
• SQLUserDefinedFunctions support lambdas. Example CREATE FUNCTION lambda_function AS x -> arrayMap(element -> element * 2, x);. #30435 (Maksim Kita).
• More full support of positional arguments. #30433 (Kseniia Sumarokova).
• Allow extract non-string element as string using JSONExtractString. This is for https://github.com/ClickHouse/ClickHouse/pull/25452#issuecomment-927123287. #30426 (Amos Bird).
• Added an ability to use FINAL clause in SELECT queries from GraphiteMergeTree. #30360 (Nikita Mikhaylov).
• Minor improvements in replica cloning and enqueuing fetch for broken parts, that should avoid extremely rare hanging of GET_PART entries in replication queue. #30346 (tavplubix).
• Allow symlinks to files in user_files directory for file table function. #30309 (Kseniia Sumarokova).
• Fixed comparison of Date32 with Date, DateTime, DateTime64, String. #30219 (liang.huang).
• Allow to remove SAMPLE BY expression from MergeTree tables (ALTER TABLE <table> REMOVE SAMPLE BY). #30180 (Anton Popov).
• Support SQL user defined functions for clickhouse-local. #30179 (Maksim Kita).
• Now Keeper (as part of clickhouse-server) will start asynchronously if it can connect to some other node. #30170 (alesapin).
• Now clickhouse-client supports native multi-line editing. #30143 (Amos Bird).
• PolygonDictionary added support for read method if setting store_polygon_key_column = true. Closes #30090. #30142 (Maksim Kita).
• Reduce amount of redundant compressed data read from disk for some types SELECT queries (only for MergeTree engines family). #30111 (alesapin).
• Improve solution https://github.com/ClickHouse/ClickHouse/pull/28853 See also https://github.com/ClickHouse/ClickHouse/pull/29928. #30084 (Vitaly Baranov).
• Add ability to print raw profile events to clickhouse-client (This can be useful for debugging and for testing). #30064 (Azat Khuzhin).
• ProfileEvents::Counters snapshot doesn't store data in std::atomic anymore. #30000 (Dmitry Novik).
• Now clickhouse use DNS cache while communicating with external S3. #29999 (alesapin).
• Fix data-race between flush() and startup() in StorageBuffer. #29930 (Azat Khuzhin).
• Fix lock-order-inversion between DROP TABLE for DatabaseMemory and LiveView. #29929 (Azat Khuzhin).
• Fix lock-order-inversion between periodic dictionary reload and config reload. #29928 (Azat Khuzhin).
• Better exception message while reading column from Arrow-supported formats like Arrow, ArrowStream, Parquet and ORC. This closes #29926. #29927 (alexey-milovidov).
• Update zoneinfo files to 2021c. #29925 (alexey-milovidov).
• Add ability to configure retries and delays between them for clickhouse-copier. #29921 (Azat Khuzhin).
• Now min-max aggregation over the first expression of primary key is optimized by projection. This is for https://github.com/ClickHouse/ClickHouse/issues/329. #29918 (Amos Bird).
• Add shutdown_wait_unfinished_queries server setting to allowing waiting for running queries up to shutdown_wait_unfinished time. This is for #24451 . #29914 (Amos Bird).
• Remove unused variable in s3cluster. #29912 (taiyang-li).
• Add ability to trace peak memory usage (with new trace_type - MemoryPeak). #29858 (Azat Khuzhin).
• Added partitioned table prefix 'p' for the query for fetching replica identity index. #29828 (Shoh Jahon).
• Web UI: render bars in table cells. #29792 (alexey-milovidov).
• Remove some redundant seek calls while reading compressed blocks in MergeTree table engines family. #29766 (alesapin).
• Apply max_untracked_memory/memory_profiler_step/memory_profiler_sample_probability during mutate/merge. #29681 (Azat Khuzhin).
• Add ClickHouse logo to Play UI. #29674 (alexey-milovidov).
• Make url table function to process multiple URLs in parallel. This closes #29670 and closes #29671. #29673 (alexey-milovidov).
• Query obfuscator clickhouse-format --obfuscate now works with more types of queries. #29672 (alexey-milovidov).
• Fixed the issue: clickhouse-format --obfuscate cannot process queries with embedded dictionaries (functions regionTo...). #29667 (alexey-milovidov).
• Fix incorrect nullable processing of JSONFunctions. This fixes #29615 . Mark as improvement because https://github.com/ClickHouse/ClickHouse/pull/28012 is not released. #29659 (Amos Bird).
• Increase listen_backlog by default (to match default in newer linux kernel). #29643 (Azat Khuzhin).
• Allow user to change log levels without restart. #29586 (Nikolay Degterinsky).
• Reload dictionaries, models, user defined executable functions if servers config dictionaries_config, models_config, user_defined_executable_functions_config changes. Closes #28142. #29529 (Maksim Kita).
• Get rid of pointless restriction on projection name. Now projection name can start with tmp_. #29520 (Amos Bird).
• Fixed There is no query or query context has expired error in mutations with nested subqueries. Do not allow subqueries in mutation if table is replicated and allow_nondeterministic_mutations setting is disabled. #29495 (tavplubix).
• Add support for IS NULL/IS NOT NULL for external dbs (i.e. MySQL). #29463 (Azat Khuzhin).
• Enable per-query memory profiler (set to memory_profiler_step=4MiB) globally. #29455 (Azat Khuzhin).
• Transform isNull/isNotNull to IS NULL/IS NOT NULL (for external dbs, i.e. MySQL). #29446 (Azat Khuzhin).
• Apply config changes to max_concurrent_queries during runtime (no need to restart). #29414 (Raúl Marín).
• Added setting use_skip_indexes. #29405 (Maksim Kita).
• fix lost in memory part when freeze. #29376 (Mo Xuan).
• Pass through initial query_id for clickhouse-benchmark (previously if you run remote query via clickhouse-benchmark, queries on shards will not be linked to the initial query via initial_query_id). #29364 (Azat Khuzhin).
• Allow to write number in query as binary literal. Example SELECT 0b001;. #29304 (Maksim Kita).
• Primary key index and partition filter can work in tuple. #29281 (凌涛).
• Skip indexes tokenbf_v1 and ngrambf_v1 added support for Array data type with key of String of FixedString type. #29280 (Maksim Kita).
• Function has added support for map data type. #29267 (Maksim Kita).
• Add compress_logs settings for clickhouse-keeper which allow to compress clickhouse-keeper logs in ZSTD . Implements: #26977. #29223 (alesapin).
• Skip indexes tokenbf_v1 and ngrambf_v1 added support for Map data type with key of String of FixedString type. Author @lingtaolf. #29220 (Maksim Kita).
• Add ability to disable converting expressions to local filter for external queries (external_table_strict_query=true). #29206 (Azat Khuzhin).
• Allow to asynchronous reads for remote fs disks. #29205 (Kseniia Sumarokova).
• Add CORS support. Add headers for preflight options request. Closes #18693. #29155 (Filatenkov Artur).
• Added an ability to execute more merges and mutations than the number of threads in background pool. Merges and mutations will be executed step by step according to their sizes (lower is more prioritized). The ratio of the number of tasks to threads to execute is controlled by a setting background_merges_mutations_concurrency_ratio, 2 by default. #29140 (Nikita Mikhaylov).
• Disable projections when ARRAY JOIN is used. Currently projection analysis will break array join aliases. #29139 (Amos Bird).
• Fix possible LogicalError, support more types in MsgPack input/output format. #29077 (Kruglov Pavel).
• Allow to input and output LowCardinality columns in ORC input/output format. #29062 (Kruglov Pavel).
• Select from system.distributed_ddl_queue might show incorrect values, it's fixed. #29061 (tavplubix).
• Correct behaviour with unknown methods for http connection. Solves #29050. #29057 (Filatenkov Artur).
• Fix bug in clickhouse-keeper-converter which can lead to some data loss while restoring from ZooKeeper logs (not snapshot). #29030 (小路).
• Apply settings from CREATE AS SELECT queries (fixes: #28810). #28962 (Azat Khuzhin).
• add default database setting for alter table ... on cluster ... replace/move partition from/to ... #28955 (anneji-dev).
• gRPC: Allow change server-side compression from client. #28953 (Vitaly Baranov).
• Add time dependency for clickhouse-server unit (systemd and sysvinit init). #28891 (Azat Khuzhin).
• Skip "no data" exception when reading thermal sensors for asynchronous metrics. This closes #28852. #28882 (alexey-milovidov).
• Fixed race condition that might cause Dictionary not found error for existing dictionary in rare cases. #28853 (tavplubix).
• Relax nested function for If-combinator check (but forbid nested identical combinators). #28828 (Azat Khuzhin).
• Fix uncaught exception during server termination. #28761 (Azat Khuzhin).
• Forbid cleaning of tmp directories that can be used by an active mutation/merge. #28760 (Azat Khuzhin).
• Allow optimization : optimize_arithmetic_operations_in_aggregate_functions = 1 when alias is used. I cannot figure out why it was disabled. We set aliases in all other TreeOptimizers, except this one. Maybe I'm missing something important) @4ertus2 could you give a bad example?. #28746 (Amos Bird).
• Implement detach_not_byte_identical_parts setting for ReplicatedMergeTree, that will detach instead of remove not byte-identical parts (after mege/mutate). #28708 (Azat Khuzhin).
• Implement max_suspicious_broken_parts_bytes setting for MergeTree (to limit total size of all broken parts, default is 1GiB). #28707 (Azat Khuzhin).
• This PR enables expanding macros in RabbitMQ settings, for example:. #28683 (Vitaly Baranov).
• Resolve table dependencies on metadata loading. Closes #8004, closes #15170. #28373 (tavplubix).
• Speed up part loading process with multiple disks are in use. The idea is similar to https://github.com/ClickHouse/ClickHouse/pull/16423 . Prod env shows improvement: 24 min -> 16 min . #28363 (Amos Bird).
• Avoid error "Division by zero" when denominator is Nullable in functions divide, intDiv and modulo. Closes #22621. #28352 (Kruglov Pavel).
• Reload stacktrace cache when symbol is reloaded. #28137 (Amos Bird).
• This PR allows reading data of a table using the Log engine in multiple threads. #28125 (Vitaly Baranov).
• Fix misbehavior of NULL column handling in json functions. This fixes #27930. #28012 (Amos Bird).
• Add dedicated Mark/Uncompressed cache for skip indices. Not sure how to test it properly. #27961 (Amos Bird).
• Correct Codec(AES_128_GCM_SIV). #27476 (Filatenkov Artur).
• Add compression for INTO OUTPUT and FROM INFILE with additional optional parameter. #27135 (Filatenkov Artur).
• • Allow to mix using join with other join types. #23881 (darkkeks).

Bug Fix

• Fix reading from empty file on encrypted disk. #30494 (Vitaly Baranov).
• Fix releasing query ID and session ID at the end of query processing while handing gRPC call. This PR fixes flaky test test_grpc_protocol/test.py::test_session. #29954 (Vitaly Baranov).
• Fix shutdown of AccessControlManager. Now there can't be reloading of the configuration after AccessControlManager has been destroyed. This PR fixes the flaky test test_user_directories/test.py::test_relative_path. #29951 (Vitaly Baranov).
• Fix bug in clickhouse-keeper-converter which can lead to incorrect ZooKeeper log deserialization. #29071 (小路).
• Fix transformation of disjunctions chain to IN (controlled by settings optimize_min_equality_disjunction_chain_length) in distributed queries with settings legacy_column_name_of_tuple_literal = 0. #28658 (Anton Popov).
• Allow using a materialized column as the sharding key in a distributed table even if insert_allow_materialized_columns=0:. #28637 (Vitaly Baranov).

Build/Testing/Packaging Improvement

• Recursive submodules are no longer needed for ClickHouse. #30315 (alexey-milovidov).
• ClickHouse can be statically built with Musl. This is added as experiment, it does not support building odbc-bridge, library-bridge, integration with CatBoost and some libraries. #30248 (alexey-milovidov).
• Add tests for encrypted disk & encryption codec and ReplicatedMergeTree. #30172 (Vitaly Baranov).
• Enable Protobuf, Arrow, ORC, Parquet for AArch64 and Darwin builds. This closes #29248. This closes #28018. #30015 (alexey-milovidov).
• Add cross-build for PowerPC (powerpc64le). This closes #9589. Enable support for interaction with MySQL for AArch64 and PowerPC. This closes #26301. #30010 (alexey-milovidov).
• Leave only required files in cross-compile toolchains. Include them as submodules (earlier they were downloaded as tarballs). #29974 (alexey-milovidov).
• Fix an build error because of Rename "common" to "base". #29688 (Sergei Semin).
• Turning on experimental constexpr expressions evaluator for clang to speed up template code compilation. #29668 (myrrc).
• Add ability to compile using newer version fo glibc w/o using new symbols. #29594 (Azat Khuzhin).
• N/A Detailed description / Documentation draft:. #29367 (kevin wan).
• Add a test for https://github.com/ClickHouse/ClickHouse/pull/28683. #28934 (Vitaly Baranov).
• Convert skip_list .json into first line comments. #28909 (Vitaly Baranov).
• Reduce Debug build binary size by clang optimization. #28736 (flynn).
• Now all images for CI will be placed in the separate dockerhub repo. #28656 (alesapin).
• Improve support for build with clang-13. #28046 (Sergei Semin).
• Switch clang builds to 12 version. #20495 (Ilya Yatsishin).

Bug Fix (user-visible misbehaviour in official stable or prestable release

• Fix ORDER BY ... WITH FILL with set TO and FROM and no rows in result set. #30888 (Anton Popov).

Bug Fix (user-visible misbehaviour in official stable or prestable release)

• Fix set index not used in AND/OR expressions when there are more than two operands. This fixes #30416 . #30887 (Amos Bird).
• Fix crash when projection with hashing function is materialized. This fixes #30861 . The issue is similar to https://github.com/ClickHouse/ClickHouse/pull/28560 which is a lack of proper understanding of the invariant of header's emptyness. #30877 (Amos Bird).
• Fixed ambiguity when extracting auxiliary ZooKeeper name from ZooKeeper path in ReplicatedMergeTree. Previously server might fail to start with Unknown auxiliary ZooKeeper name if ZooKeeper path contains a colon. Fixes #29052. Also it was allowed to specify ZooKeeper path that does not start with slash, but now it's deprecated and creation of new tables with such path is not allowed. Slashes and colons in auxiliary ZooKeeper names are not allowed too. #30822 (tavplubix).
• Clean temporary directory when localBackup failed by some reason. #30797 (ianton-ru).
• Fixed a race condition between REPLACE/MOVE PARTITION and background merge in non-replicated MergeTree that might cause a part of moved/replaced data to remain in partition. Fixes #29327. #30717 (tavplubix).
• Fix PREWHERE with WHERE in case of always true PREWHERE. #30668 (Azat Khuzhin).
• Functions for case-insensitive search in UTF8 strings like positionCaseInsensitiveUTF8 and countSubstringsCaseInsensitiveUTF8 might find substrings that actually does not match, it's fixed. #30663 (tavplubix).
• Update aws-sdk submodule for throttling in Yandex.S3. #30646 (ianton-ru).
• Limit push down optimization could cause a error Cannot find column. Fixes #30438. #30562 (Nikolai Kochetov).
• Add missing parenthesis for isNotNull/isNull rewrites to IS [NOT] NULL (fixes queries that has something like isNotNull(1)+isNotNull(2)). #30520 (Azat Khuzhin).
• • Fix deadlock on ALTER with scalar subquery to the same table, close #30461. #30492 (Vladimir C).
• Fixed segfault which might happen if session expired during execution of REPLACE PARTITION. #30432 (tavplubix).
• Makes #30162 less possible ... #30370 (Vasily Nemkov).
• Queries with condition like IN (subquery) could return incorrect result in case if aggregate projection applied. Fixed creation of sets for projections. #30310 (Amos Bird).
• Fix column alias resolution of JOIN queries when projection is enabled. This fixes #30146. #30293 (Amos Bird).
• fix replaceRegexpAll bug. #30292 (Memo).
• Fix ComplexKeyHashedDictionary, ComplexKeySparseHashedDictionary parsing preallocate option from layout config. #30246 (Maksim Kita).
• Fix [I]LIKE function. Closes #28661. #30244 (Nikolay Degterinsky).
• Fix crash with shortcircuit and lowcardinality in multiIf. #30243 (Raúl Marín).
• FlatDictionary, HashedDictionary fix bytes_allocated calculation for nullable attributes. #30238 (Maksim Kita).
• • Allow identifiers staring with numbers in multiple joins. #30230 (Vladimir C).
• Fix reading from MergeTree with max_read_buffer_size=0 (can lead to Can't adjust last granule LOGICAL_ERROR, or even data loss). #30192 (Azat Khuzhin).
• Fix pread_fake_async/pread_threadpool with min_bytes_to_use_direct_io. #30191 (Azat Khuzhin).
• Fix INSERT SELECT incorrectly fills MATERIALIZED column based of Nullable column. #30189 (Azat Khuzhin).
• Support nullable arguments in function initializeAggregation. #30177 (Anton Popov).
• Fix error Port is already connected for queries with GLOBAL IN and WITH TOTALS. Only for 21.9 and 21.10. #30086 (Nikolai Kochetov).
• Fix race between MOVE PARTITION and merges/mutations for MergeTree. #30074 (Azat Khuzhin).
• Dropped Memory database might reappear after server restart, it's fixed (#29795). Also added force_remove_data_recursively_on_drop setting as a workaround for Directory not empty error when dropping Ordinary database (because it's not possible to remove data leftovers manually in cloud environment). #30054 (tavplubix).
• Fix crash of sample by tuple(), closes #30004. #30016 (flynn).
• try to close issue: #29965. #29976 (hexiaoting).
• Fix possible data-race between FileChecker and StorageLog/StorageStripeLog. #29959 (Azat Khuzhin).
• Fix data-race between LogSink::writeMarks() and LogSource in StorageLog. #29946 (Azat Khuzhin).
• Fix potential resource leak of the concurrent query limit of merge tree tables introduced in https://github.com/ClickHouse/ClickHouse/pull/19544 . #29879 (Amos Bird).
• Fix system tables recreation check (fails to detect changes in enum values). #29857 (Azat Khuzhin).
• MaterializedMySQL: Fix an issue where if the connection to MySQL was lost, only parts of a transaction could be processed. #29837 (Håvard Kvålen).
• Avoid Timeout exceeded: elapsed 18446744073.709553 seconds error that might happen in extremely rare cases, presumably due to some bug in kernel. Fixes #29154. #29811 (tavplubix).
• Fix bad cast in ATTACH TABLE ... FROM 'path' query when non-string literal is used instead of path. It may lead to reading of uninitialized memory. #29790 (alexey-milovidov).
• Fix concurrent access to LowCardinality during GROUP BY (leads to SIGSEGV). #29782 (Azat Khuzhin).
• Fix incorrect GROUP BY (multiple rows with the same keys in result) in case of distributed query when shards had mixed versions <= 21.3 and >= 21.4, GROUP BY key had several columns all with fixed size, and two-level aggregation was activated (see group_by_two_level_threshold and group_by_two_level_threshold_bytes). Fixes #29580. #29735 (Nikolai Kochetov).
• Fixed incorrect behaviour of setting materialized_postgresql_tables_list at server restart. Found in #28529. #29686 (Kseniia Sumarokova).
• Condition in filter predicate could be lost after push-down optimisation. #29625 (Nikolai Kochetov).
• Fix JIT expression compilation with aliases and short-circuit expression evaluation. Closes #29403. #29574 (Maksim Kita).
• Fix rare segfault in ALTER MODIFY query when using incorrect table identifier in DEFAULT expression like x.y.z... Fixes #29184. #29573 (alesapin).
• Fix null deference for GROUP BY WITH TOTALS HAVING (when the column from HAVING wasn't selected). #29553 (Azat Khuzhin).
• Avoid deadlocks when reading and writting on JOIN Engine tables at the same time. #29544 (Raúl Marín).
• Fix bug in check pathStartsWith becuase there was bug with the usage of std::mismatch: The behavior is undefined if the second range is shorter than the first range.. #29531 (Kseniia Sumarokova).
• In ODBC bridge add retries for error Invalid cursor state. It is a retriable error. Closes #29473. #29518 (Kseniia Sumarokova).
• Fixed incorrect table name parsing on loading of Lazy database. Fixes #29456. #29476 (tavplubix).
• Fix possible Block structure mismatch for subqueries with pushed-down HAVING predicate. Fixes #29010. #29475 (Nikolai Kochetov).
• Fix Logical error Cannot capture columns in functions greatest/least. Closes #29334. #29454 (Kruglov Pavel).
• rocksdb: fix race condition during multiple DB opening (and get back some tests that triggers the problem on CI). #29393 (Azat Khuzhin).
• Fix replicated access storage not shutting down cleanly when misconfigured. #29388 (Kevin Michel).
• Remove window function nth_value as it is not memory-safe. This closes #29347. #29348 (alexey-milovidov).
• Fix vertical merges of projection parts. This fixes #29253 . This PR also fixes several projection merge/mutation issues introduced in https://github.com/ClickHouse/ClickHouse/pull/25165. #29337 (Amos Bird).
• Fix hanging DDL queries on Replicated database while adding a new replica. #29328 (Kevin Michel).
• Fix connection timeouts (send_timeout/receive_timeout). #29282 (Azat Khuzhin).
• Fix failed assertion in ReadBufferFromHDFS. Update libhdfs3 library to be able to run in tests in debug. Closes #29251. Closes #27814. #29276 (Kseniia Sumarokova).
• Fix possible Table columns structure in ZooKeeper is different from local table structure exception while recreating or creating new replicas of ReplicatedMergeTree, when one of table columns have default expressions with case-insensitive functions. #29266 (Anton Popov).
• Send normal Database doesn't exist error (UNKNOWN_DATABASE) to the client (via TCP) instead of Attempt to read after eof (ATTEMPT_TO_READ_AFTER_EOF). #29229 (Azat Khuzhin).
• Fix segfault while inserting into column with type LowCardinality(Nullable) in Avro input format. #29132 (Kruglov Pavel).
• Do not allow to reuse previous credentials in case of inter-server secret (Before INSERT via Buffer/Kafka to Distributed table with interserver secret configured for that cluster, may re-use previously set user for that connection). #29060 (Azat Khuzhin).
• Handle any_join_distinct_right_table_keys when join with dictionary, close #29007. #29014 (Vladimir C).
• Fix "Not found column ... in block" error, when join on alias column, close #26980. #29008 (Vladimir C).
• Fix the number of threads used in GLOBAL IN subquery (it was executed in single threads since #19414 bugfix). #28997 (Nikolai Kochetov).
• Fix bad optimizations of ORDER BY if it contains WITH FILL. This closes #28908. This closes #26049. #28910 (alexey-milovidov).
• Fix higher-order array functions (SIGSEGV for arrayCompact/ILLEGAL_COLUMN for arrayDifference/arrayCumSumNonNegative) with consts. #28904 (Azat Khuzhin).
• Fix waiting for mutation with mutations_sync=2. #28889 (Azat Khuzhin).
• Fix queries to external databases (i.e. MySQL) with multiple columns in IN ( i.e. (k,v) IN ((1, 2)) ) (but note that this has some backward incompatibility for the clickhouse-copier since it uses alias for tuple element). #28888 (Azat Khuzhin).
• Fix bug with LowCardinality in short-curcuit function evaluation. Closes #28884. #28887 (Kruglov Pavel).
• Fix reading of subcolumns from compact parts. #28873 (Anton Popov).
• Fixed a race condition between DROP PART and REPLACE/MOVE PARTITION that might cause replicas to diverge in rare cases. #28864 (tavplubix).
• Fix expressions compilation with short circuit evaluation. #28821 (Azat Khuzhin).
• Fix extremely rare case when ReplicatedMergeTree replicas can diverge after hard reboot of all replicas. The error looks like Part ... intersects (previous|next) part .... #28817 (alesapin).
• Better check for connection usability and also catch any exception in RabbitMQ shutdown just in case. #28797 (Kseniia Sumarokova).
• Fix benign race condition in ReplicatedMergeTreeQueue. Shouldn't be visible for user, but can lead to subtle bugs. #28734 (alesapin).
• Fix possible crash for SELECT with partially created aggregate projection in case of exception. #28700 (Amos Bird).
• Fix the coredump in the creation of distributed tables, when the parameters passed in are wrong. #28686 (Zhiyong Wang).
• Add Settings.Names, Settings.Values aliases for system.processes table. #28685 (Vitaly).
• • Fix the number of arguments required by s2RectAdd and s2RectContains functions. #28663 (Bharat Nallan).
• Fix invalid constant type conversion when nullable or lowcardinality primary key is used. #28636 (Amos Bird).
• Fix "Column is not under aggregate function and not in GROUP BY" with PREWHERE (Fixes: #28461). #28502 (Azat Khuzhin).

NO CL ENTRY

• NO CL ENTRY: 'remove some unneeded header files'. #30722 (flynn).
• NO CL ENTRY: 'Revert "Revert "Improve usability of remote_url_allow_hosts""'. #30708 (Nikolai Kochetov).
• NO CL ENTRY: 'Revert "Improve usability of remote_url_allow_hosts"'. #30707 (Nikolai Kochetov).
• NO CL ENTRY: 'Revert "Fix style regressions on benchmark page"'. #30652 (alesapin).
• NO CL ENTRY: 'add support of window function in antlr grammar'. #30181 (PHaroZ).
• NO CL ENTRY: 'Link FAQ from Debian installation'. #29836 (Federico Ceratto).
• NO CL ENTRY: 'Revert "Add coroutines example."'. #29829 (Nikolai Kochetov).
• NO CL ENTRY: 'Generate test_results.tsv for fasttest'. #29319 (Dmitry Novik).
• NO CL ENTRY: 'Update rounding-functions.md'. #29249 (quoctan132).

Testing Improvement

• Implemented structure-aware fuzzing approach in ClickHouse for select statement parser. #30012 (Paul).