2021 Changelog

- Multiple fixes for hedged requests. Fixed an error `Can't initialize pipeline with empty pipe` for queries with `GLOBAL IN/JOIN` when the setting `use_hedged_requests` is enabled. Fixes [#23431](https://github.com/ClickHouse/ClickHouse/issues/23431). [#23805](https://github.com/ClickHouse/ClickHouse/pull/23805) ([Nikolai Kochetov](https://github.com/KochetovNicolai)). Fixed a race condition in hedged connections which leads to crash. This fixes [#22161](https://github.com/ClickHouse/ClickHouse/issues/22161). [#22443](https://github.com/ClickHouse/ClickHouse/pull/22443) ([Kruglov Pavel](https://github.com/Avogar)). Fix possible crash in case if `unknown packet` was received from remote query (with `async_socket_for_remote` enabled). Fixes [#21167](https://github.com/ClickHouse/ClickHouse/issues/21167). [#23309](https://github.com/ClickHouse/ClickHouse/pull/23309) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
- 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)).
- Fixed remote JDBC bridge timeout connection issue. Closes [#9609](https://github.com/ClickHouse/ClickHouse/issues/9609). [#23771](https://github.com/ClickHouse/ClickHouse/pull/23771) ([Maksim Kita](https://github.com/kitaisreal), [alexey-milovidov](https://github.com/alexey-milovidov)).
- Fix the logic of initial load of `complex_key_hashed` if `update_field` is specified. Closes [#23800](https://github.com/ClickHouse/ClickHouse/issues/23800). [#23824](https://github.com/ClickHouse/ClickHouse/pull/23824) ([Maksim Kita](https://github.com/kitaisreal)).
- Fixed crash when `PREWHERE` and row policy filter are both in effect with empty result. [#23763](https://github.com/ClickHouse/ClickHouse/pull/23763) ([Amos Bird](https://github.com/amosbird)).
- 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)).
- 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)).
- 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)).
- Fixed misinterpretation of some `LIKE` expressions with escape sequences. [#23610](https://github.com/ClickHouse/ClickHouse/pull/23610) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Fixed 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)).
- Fixed `COLUMNS` matcher in case of 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)).
- Fixed a crash when modifying column's default value when a column itself is used as `ReplacingMergeTree`'s parameter. [#23483](https://github.com/ClickHouse/ClickHouse/pull/23483) ([hexiaoting](https://github.com/hexiaoting)).
- Fixed 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)).
- Fixed bug that does not allow cast from empty array literal, to array with dimensions greater than 1, e.g. `CAST([] AS Array(Array(String)))`. Closes [#14476](https://github.com/ClickHouse/ClickHouse/issues/14476). [#23456](https://github.com/ClickHouse/ClickHouse/pull/23456) ([Maksim Kita](https://github.com/kitaisreal)).
- Fixed a bug when `deltaSum` aggregate function produced incorrect result after resetting the counter. [#23437](https://github.com/ClickHouse/ClickHouse/pull/23437) ([Russ Frank](https://github.com/rf)).
- 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) ([tavplubix](https://github.com/tavplubix)).
- Fixed 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)).
- Fixed a crash when setting join\_algorithm is set to 'auto' and Join is performed with a Dictionary. Close [#23002](https://github.com/ClickHouse/ClickHouse/issues/23002). [#23312](https://github.com/ClickHouse/ClickHouse/pull/23312) ([Vladimir](https://github.com/vdimir)).
- 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)).
- 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) ([tavplubix](https://github.com/tavplubix)).
- 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) ([tavplubix](https://github.com/tavplubix)).
- 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)).
- Fixed reading from ODBC when there are many long column names in a table. Closes [#8853](https://github.com/ClickHouse/ClickHouse/issues/8853). [#23215](https://github.com/ClickHouse/ClickHouse/pull/23215) ([Kseniia Sumarokova](https://github.com/kssenii)).
- MaterializeMySQL (experimental feature): 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) ([tavplubix](https://github.com/tavplubix)).
- Correct aliases handling 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)).
- 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) ([tavplubix](https://github.com/tavplubix)).
- Fixed a crash on shutdown which happened because of wrong accounting of current connections. [#23154](https://github.com/ClickHouse/ClickHouse/pull/23154) ([Vitaly Baranov](https://github.com/vitlibar)).