ClickHouse/docs/changelogs/v21.5.2.25-prestable.md

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

Improvement

• Backported in #23342: Disable settings use_hedged_requests and async_socket_for_remote because there is an evidence that it may cause issues. #23261 (Alexey Milovidov).
• Backported in #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 (Vladimir Chebotarev).

Bug Fix

• Backported in #23343: This PR fixes a crash on shutdown which happened because of currentConnections() could return zero while some connections were still alive. #23154 (Vitaly Baranov).
• Backported in #23405: QueryAliasVisitor to prefer alias for ASTWithAlias if subquery was optimized to constant. Fixes #22924. Fixes #10401. #23191 (Maksim Kita).
• Backported in #23383: Fixed Not found column error when selecting from MaterializeMySQL with condition on key column. Fixes #22432. #23200 (Alexander Tokmakov).
• Backported in #23386: Fixed the behavior when disabling input_format_with_names_use_header setting discards all the input with CSVWithNames format. This fixes #22406. #23202 (Nikita Mikhaylov).
• Backported in #23340: Add type conversion for optimize_skip_unused_shards_rewrite_in (fixes use-of-uninitialized-value with optimize_skip_unused_shards_rewrite_in). #23219 (Azat Khuzhin).
• Backported in #23341: Fixed simple key dictionary from DDL creation if primary key is not first attribute. Fixes #23236. #23262 (Maksim Kita).
• Backported in #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. #23294 (Alexander Tokmakov).
• Backported in #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 (Alexander Tokmakov).
• Backported in #23427: Fix possible crash in case if unknown packet was received form remote query (with async_socket_for_remote enabled). Maybe fixes #21167. #23309 (Nikolai Kochetov).
• Backported in #23675: Don't relax NOT conditions during partition pruning. This fixes #23305 and #21539. #23310 (Amos Bird).
• Backported in #23581: * Fix bug in dict join with join_algorithm = 'auto'. Close #23002. #23312 (Vladimir C).
• Backported in #23428: Fix possible Block structure mismatch error for queries with UNION which could possibly happen after filter-push-down optimization. Fixes #23029. #23359 (Nikolai Kochetov).
• Backported in #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 (Amos Bird).
• Backported in #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. Workaround for older versions: turn the setting optimize_read_in_order off. #23375 (Alexey Milovidov).
• Backported in #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 and reverts #17359. #23393 (Alexey Milovidov).
• Backported in #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 (Anton Popov).
• Backported in #23477: Kafka storage may support arrow and arrowstream format messages. #23415 (Chao Ma).
• Backported in #23587: Fixed Cannot unlink file error on unsuccessful creation of ReplicatedMergeTree table with multidisk configuration. This closes #21755. #23433 (Alexander Tokmakov).
• Backported in #23497: - Bug fix for deltaSum aggregate function in counter reset case ... #23437 (Russ Frank).
• Backported in #23491: Fix bug that does not allow cast from empty array literal, to array with dimensions greater than 1. Closes #14476. #23456 (Maksim Kita).
• Backported in #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 (Anton Popov).
• Backported in #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 (hexiaoting).
• Backported in #23532: Fix columns function when multiple joins in select query. Closes #22736. #23501 (Maksim Kita).
• Backported in #23613: Fix restart / stop command hanging. Closes #20214. #23552 (filimonov).
• Backported in #23627: Fix misinterpretation of some LIKE expressions with escape sequences. #23610 (Alexey Milovidov).
• Backported in #23692: Fixed server fault when inserting data through HTTP caused an exception. This fixes #23512. #23643 (Nikita Mikhaylov).
• Backported in #23694: Added an exception in case of completely the same values in both samples in aggregate function mannWhitneyUTest. This fixes #23646. #23654 (Nikita Mikhaylov).
• Backported in #23757: Avoid possible "Cannot schedule a task" error (in case some exception had been occurred) on INSERT into Distributed. #23744 (Azat Khuzhin).

NO CL CATEGORY

• Backported in #23347:. #23334 (Alexey Milovidov).