---
sidebar_position: 1
sidebar_label: 2022
---

# 2022 Changelog

### ClickHouse release v21.5.2.25-prestable FIXME as compared to v21.5.1.6601-prestable

#### Improvement
* Backported in [#23342](https://github.com/ClickHouse/ClickHouse/issues/23342): Disable settings `use_hedged_requests` and `async_socket_for_remote` because there is an evidence that it may cause issues. [#23261](https://github.com/ClickHouse/ClickHouse/pull/23261) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Backported in [#23678](https://github.com/ClickHouse/ClickHouse/issues/23678): Fixed `quantile(s)TDigest`. Added special handling of singleton centroids according to tdunning/t-digest 3.2+. Also a bug with over-compression of centroids in implementation of earlier version of the algorithm was fixed. [#23314](https://github.com/ClickHouse/ClickHouse/pull/23314) ([Vladimir Chebotarev](https://github.com/excitoon)).

#### Bug Fix
* Backported in [#23343](https://github.com/ClickHouse/ClickHouse/issues/23343): This PR fixes a crash on shutdown which happened because of currentConnections() could return zero while some connections were still alive. [#23154](https://github.com/ClickHouse/ClickHouse/pull/23154) ([Vitaly Baranov](https://github.com/vitlibar)).
* Backported in [#23405](https://github.com/ClickHouse/ClickHouse/issues/23405): QueryAliasVisitor to prefer alias for ASTWithAlias if subquery was optimized to constant. Fixes [#22924](https://github.com/ClickHouse/ClickHouse/issues/22924). Fixes [#10401](https://github.com/ClickHouse/ClickHouse/issues/10401). [#23191](https://github.com/ClickHouse/ClickHouse/pull/23191) ([Maksim Kita](https://github.com/kitaisreal)).
* Backported in [#23383](https://github.com/ClickHouse/ClickHouse/issues/23383): Fixed `Not found column` error when selecting from `MaterializeMySQL` with condition on key column. Fixes [#22432](https://github.com/ClickHouse/ClickHouse/issues/22432). [#23200](https://github.com/ClickHouse/ClickHouse/pull/23200) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Backported in [#23386](https://github.com/ClickHouse/ClickHouse/issues/23386): Fixed the behavior when disabling `input_format_with_names_use_header ` setting discards all the input with CSVWithNames format. This fixes [#22406](https://github.com/ClickHouse/ClickHouse/issues/22406). [#23202](https://github.com/ClickHouse/ClickHouse/pull/23202) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Backported in [#23340](https://github.com/ClickHouse/ClickHouse/issues/23340): Add type conversion for optimize_skip_unused_shards_rewrite_in (fixes `use-of-uninitialized-value` with `optimize_skip_unused_shards_rewrite_in`). [#23219](https://github.com/ClickHouse/ClickHouse/pull/23219) ([Azat Khuzhin](https://github.com/azat)).
* Backported in [#23341](https://github.com/ClickHouse/ClickHouse/issues/23341): Fixed simple key dictionary from DDL creation if primary key is not first attribute. Fixes [#23236](https://github.com/ClickHouse/ClickHouse/issues/23236). [#23262](https://github.com/ClickHouse/ClickHouse/pull/23262) ([Maksim Kita](https://github.com/kitaisreal)).
* Backported in [#23449](https://github.com/ClickHouse/ClickHouse/issues/23449): Fixed very rare (distributed) race condition between creation and removal of ReplicatedMergeTree tables. It might cause exceptions like `node doesn't exist` on attempt to create replicated table. Fixes [#21419](https://github.com/ClickHouse/ClickHouse/issues/21419). [#23294](https://github.com/ClickHouse/ClickHouse/pull/23294) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Backported in [#23578](https://github.com/ClickHouse/ClickHouse/issues/23578): Fixed very rare race condition on background cleanup of old blocks. It might cause a block not to be deduplicated if it's too close to the end of deduplication window. [#23301](https://github.com/ClickHouse/ClickHouse/pull/23301) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Backported in [#23427](https://github.com/ClickHouse/ClickHouse/issues/23427): Fix possible crash in case if `unknown packet` was received form remote query (with `async_socket_for_remote` enabled). Maybe fixes [#21167](https://github.com/ClickHouse/ClickHouse/issues/21167). [#23309](https://github.com/ClickHouse/ClickHouse/pull/23309) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Backported in [#23675](https://github.com/ClickHouse/ClickHouse/issues/23675): Don't relax NOT conditions during partition pruning. This fixes [#23305](https://github.com/ClickHouse/ClickHouse/issues/23305) and [#21539](https://github.com/ClickHouse/ClickHouse/issues/21539). [#23310](https://github.com/ClickHouse/ClickHouse/pull/23310) ([Amos Bird](https://github.com/amosbird)).
* Backported in [#23581](https://github.com/ClickHouse/ClickHouse/issues/23581): * Fix bug in dict join with join_algorithm = 'auto'. Close [#23002](https://github.com/ClickHouse/ClickHouse/issues/23002). [#23312](https://github.com/ClickHouse/ClickHouse/pull/23312) ([Vladimir C](https://github.com/vdimir)).
* Backported in [#23428](https://github.com/ClickHouse/ClickHouse/issues/23428): Fix possible `Block structure mismatch` error for queries with `UNION` which could possibly happen after filter-push-down optimization. Fixes [#23029](https://github.com/ClickHouse/ClickHouse/issues/23029). [#23359](https://github.com/ClickHouse/ClickHouse/pull/23359) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Backported in [#23642](https://github.com/ClickHouse/ClickHouse/issues/23642): Fix incompatible constant expression generation during partition pruning based on virtual columns. This fixes https://github.com/ClickHouse/ClickHouse/pull/21401#discussion_r611888913. [#23366](https://github.com/ClickHouse/ClickHouse/pull/23366) ([Amos Bird](https://github.com/amosbird)).
* Backported in [#23453](https://github.com/ClickHouse/ClickHouse/issues/23453): `ORDER BY` with `COLLATE` was not working correctly if the column is in primary key (or is a monotonic function of it) and the setting `optimize_read_in_order` is not turned off. This closes [#22379](https://github.com/ClickHouse/ClickHouse/issues/22379). Workaround for older versions: turn the setting `optimize_read_in_order` off. [#23375](https://github.com/ClickHouse/ClickHouse/pull/23375) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Backported in [#23510](https://github.com/ClickHouse/ClickHouse/issues/23510): Remove support for `argMin` and `argMax` for single `Tuple` argument. The code was not memory-safe. The feature was added by mistake and it is confusing for people. These functions can be reintroduced under different names later. This fixes [#22384](https://github.com/ClickHouse/ClickHouse/issues/22384) and reverts [#17359](https://github.com/ClickHouse/ClickHouse/issues/17359). [#23393](https://github.com/ClickHouse/ClickHouse/pull/23393) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Backported in [#23584](https://github.com/ClickHouse/ClickHouse/issues/23584): Allow to move more conditions to `PREWHERE` as it was before version 21.1. Insufficient number of moved condtions could lead to worse performance. [#23397](https://github.com/ClickHouse/ClickHouse/pull/23397) ([Anton Popov](https://github.com/CurtizJ)).
* Backported in [#23477](https://github.com/ClickHouse/ClickHouse/issues/23477): Kafka storage may support `arrow` and `arrowstream` format messages. [#23415](https://github.com/ClickHouse/ClickHouse/pull/23415) ([Chao Ma](https://github.com/godliness)).
* Backported in [#23587](https://github.com/ClickHouse/ClickHouse/issues/23587): Fixed `Cannot unlink file` error on unsuccessful creation of ReplicatedMergeTree table with multidisk configuration. This closes [#21755](https://github.com/ClickHouse/ClickHouse/issues/21755). [#23433](https://github.com/ClickHouse/ClickHouse/pull/23433) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Backported in [#23497](https://github.com/ClickHouse/ClickHouse/issues/23497): - Bug fix for `deltaSum` aggregate function in counter reset case ... [#23437](https://github.com/ClickHouse/ClickHouse/pull/23437) ([Russ Frank](https://github.com/rf)).
* Backported in [#23491](https://github.com/ClickHouse/ClickHouse/issues/23491): Fix bug that does not allow cast from empty array literal, to array with dimensions greater than 1. Closes [#14476](https://github.com/ClickHouse/ClickHouse/issues/14476). [#23456](https://github.com/ClickHouse/ClickHouse/pull/23456) ([Maksim Kita](https://github.com/kitaisreal)).
* Backported in [#23589](https://github.com/ClickHouse/ClickHouse/issues/23589): Fix corner cases in vertical merges with `ReplacingMergeTree`. In rare cases they could lead to fails of merges with exceptions like `Incomplete granules are not allowed while blocks are granules size`. [#23459](https://github.com/ClickHouse/ClickHouse/pull/23459) ([Anton Popov](https://github.com/CurtizJ)).
* Backported in [#23535](https://github.com/ClickHouse/ClickHouse/issues/23535): When modify column's default value without datatype, and this column is used as ReplacingMergeTree's parameter like column `b` in the below example, then the server will core dump: ``` CREATE TABLE alter_test (a Int32, b DateTime) ENGINE = ReplacingMergeTree(b) ORDER BY a; ALTER TABLE alter_test MODIFY COLUMN `b` DEFAULT now(); ``` the sever throw error: ``` 2021.04.22 09:48:00.685317 [ 2607 ] {} <Trace> BaseDaemon: Received signal 11 2021.04.22 09:48:00.686110 [ 2705 ] {} <Fatal> BaseDaemon: ######################################## 2021.04.22 09:48:00.686336 [ 2705 ] {} <Fatal> BaseDaemon: (version 21.6.1.1, build id: 6459E84DFCF8E778546C5AD2FFE91B3AD71E1B1B) (from thread 2619) (no query) Received signal Segmentation fault (11) 2021.04.22 09:48:00.686572 [ 2705 ] {} <Fatal> BaseDaemon: Address: NULL pointer. Access: read. Address not mapped to object. 2021.04.22 09:48:00.686686 [ 2705 ] {} <Fatal> BaseDaemon: Stack trace: 0x1c2585d7 0x1c254f66 0x1bb7e403 0x1bb58923 0x1bb56a85 0x1c6840ef 0x1c691148 0x2061a05c 0x2061a8e4 0x20775a03 0x207722bd 0x20771048 0x7f6e5c25be25 0x7f6e5bd81bad 2021.04.22 09:48:02.283045 [ 2705 ] {} <Fatal> BaseDaemon: 4. /mnt/disk4/hewenting/ClickHouse/src/src/Storages/MergeTree/MergeTreeData.cpp:1449: DB::(anonymous namespace)::checkVersionColumnTypesConversion(DB::IDataType const*, DB::IDataType const*, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >) @ 0x1c2585d7 in /mnt/disk4/hewenting/ClickHouse/build-dbgsrc-clang-dev-nested/programs/clickhouse-server 2021.04.22 09:48:03.714451 [ 2705 ] {} <Fatal> BaseDaemon: 5. /mnt/disk4/hewenting/ClickHouse/src/src/Storages/MergeTree/MergeTreeData.cpp:1582: DB::MergeTreeData::checkAlterIsPossible(DB::AlterCommands const&, std::__1::shared_ptr<DB::Context>) const @ 0x1c254f66 in /mnt/disk4/hewenting/ClickHouse/build-dbgsrc-clang-dev-nested/programs/clickhouse-server 2021.04.22 09:48:04.692949 [ 2705 ] {} <Fatal> BaseDaemon: 6. /mnt/disk4/hewenting/ClickHouse/src/src/Interpreters/InterpreterAlterQuery.cpp:144: DB::InterpreterAlterQuery::execute() @ 0x1bb7e403 in /mnt/disk4/hewenting/ClickHouse/build-dbgsrc-clang-dev-nested/programs/clickhouse-server ```. [#23483](https://github.com/ClickHouse/ClickHouse/pull/23483) ([hexiaoting](https://github.com/hexiaoting)).
* Backported in [#23532](https://github.com/ClickHouse/ClickHouse/issues/23532): Fix `columns` function when multiple joins in select query. Closes [#22736](https://github.com/ClickHouse/ClickHouse/issues/22736). [#23501](https://github.com/ClickHouse/ClickHouse/pull/23501) ([Maksim Kita](https://github.com/kitaisreal)).
* Backported in [#23613](https://github.com/ClickHouse/ClickHouse/issues/23613): Fix restart / stop command hanging. Closes [#20214](https://github.com/ClickHouse/ClickHouse/issues/20214). [#23552](https://github.com/ClickHouse/ClickHouse/pull/23552) ([filimonov](https://github.com/filimonov)).
* Backported in [#23627](https://github.com/ClickHouse/ClickHouse/issues/23627): Fix misinterpretation of some `LIKE` expressions with escape sequences. [#23610](https://github.com/ClickHouse/ClickHouse/pull/23610) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Backported in [#23692](https://github.com/ClickHouse/ClickHouse/issues/23692): Fixed server fault when inserting data through HTTP caused an exception. This fixes [#23512](https://github.com/ClickHouse/ClickHouse/issues/23512). [#23643](https://github.com/ClickHouse/ClickHouse/pull/23643) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Backported in [#23694](https://github.com/ClickHouse/ClickHouse/issues/23694): Added an exception in case of completely the same values in both samples in aggregate function `mannWhitneyUTest`. This fixes [#23646](https://github.com/ClickHouse/ClickHouse/issues/23646). [#23654](https://github.com/ClickHouse/ClickHouse/pull/23654) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Backported in [#23757](https://github.com/ClickHouse/ClickHouse/issues/23757): Avoid possible "Cannot schedule a task" error (in case some exception had been occurred) on INSERT into Distributed. [#23744](https://github.com/ClickHouse/ClickHouse/pull/23744) ([Azat Khuzhin](https://github.com/azat)).

#### NO CL CATEGORY

* Backported in [#23347](https://github.com/ClickHouse/ClickHouse/issues/23347):. [#23334](https://github.com/ClickHouse/ClickHouse/pull/23334) ([Alexey Milovidov](https://github.com/alexey-milovidov)).

#### NOT FOR CHANGELOG / INSIGNIFICANT

* Fix logical error in stress tests [#23197](https://github.com/ClickHouse/ClickHouse/pull/23197) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Zlib use attribute constructor for functable initialization [#23266](https://github.com/ClickHouse/ClickHouse/pull/23266) ([Maksim Kita](https://github.com/kitaisreal)).
* Fix integration tests for Hedged requests [#23275](https://github.com/ClickHouse/ClickHouse/pull/23275) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* System dictionaries virtual key column [#23458](https://github.com/ClickHouse/ClickHouse/pull/23458) ([Maksim Kita](https://github.com/kitaisreal)).