ClickHouse/docs/changelogs/v21.3.8.76-lts.md

### ClickHouse release v21.3.8.76-lts FIXME as compared to v21.3.7.62-stable

#### Improvement
* Backported in [#23396](https://github.com/ClickHouse/ClickHouse/issues/23396): If tuple of NULLs, e.g. `(NULL, NULL)` is on the left hand side of `IN` operator with tuples of non-NULLs on the right hand side, e.g. `SELECT (NULL, NULL) IN ((0, 0), (3, 1))` return 0 instead of throwing an exception about incompatible types. The expression may also appear due to optimization of something like `SELECT (NULL, NULL) = (8, 0) OR (NULL, NULL) = (3, 2) OR (NULL, NULL) = (0, 0) OR (NULL, NULL) = (3, 1)`. This closes [#22017](https://github.com/ClickHouse/ClickHouse/issues/22017). [#22063](https://github.com/ClickHouse/ClickHouse/pull/22063) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Backported in [#23272](https://github.com/ClickHouse/ClickHouse/issues/23272): 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)).

#### Bug Fix
* Backported in [#23232](https://github.com/ClickHouse/ClickHouse/issues/23232): Server might fail to start if `data_type_default_nullable` setting is enabled in default profile, it's fixed. Fixes [#22573](https://github.com/ClickHouse/ClickHouse/issues/22573). [#23185](https://github.com/ClickHouse/ClickHouse/pull/23185) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Backported in [#23406](https://github.com/ClickHouse/ClickHouse/issues/23406): 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 [#23381](https://github.com/ClickHouse/ClickHouse/issues/23381): 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 [#23284](https://github.com/ClickHouse/ClickHouse/issues/23284): 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 [#23450](https://github.com/ClickHouse/ClickHouse/issues/23450): 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 [#23500](https://github.com/ClickHouse/ClickHouse/issues/23500): 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 [#23468](https://github.com/ClickHouse/ClickHouse/issues/23468): `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 [#23544](https://github.com/ClickHouse/ClickHouse/issues/23544): 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 [#23479](https://github.com/ClickHouse/ClickHouse/issues/23479): 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 [#23499](https://github.com/ClickHouse/ClickHouse/issues/23499): - 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 [#23493](https://github.com/ClickHouse/ClickHouse/issues/23493): 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 [#23536](https://github.com/ClickHouse/ClickHouse/issues/23536): 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 [#23533](https://github.com/ClickHouse/ClickHouse/issues/23533): 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)).