2021 Changelog

- Remove socket from epoll before cancelling packet receiver in `HedgedConnections` to prevent possible race. Fixes [#22161](https://github.com/ClickHouse/ClickHouse/issues/22161). [#22443](https://github.com/ClickHouse/ClickHouse/pull/22443) ([Kruglov Pavel](https://github.com/Avogar)).
- Add (missing) memory accounting in parallel parsing routines. In previous versions OOM was possible when the resultset contains very large blocks of data. This closes [#22008](https://github.com/ClickHouse/ClickHouse/issues/22008). [#22425](https://github.com/ClickHouse/ClickHouse/pull/22425) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Fix exception which may happen when `SELECT` has constant `WHERE` condition and source table has columns which names are digits. [#22270](https://github.com/ClickHouse/ClickHouse/pull/22270) ([LiuNeng](https://github.com/liuneng1994)).
- Fix query cancellation with `use_hedged_requests=0` and `async_socket_for_remote=1`. [#22183](https://github.com/ClickHouse/ClickHouse/pull/22183) ([Azat Khuzhin](https://github.com/azat)).
- Fix uncaught exception in `InterserverIOHTTPHandler`. [#22146](https://github.com/ClickHouse/ClickHouse/pull/22146) ([Azat Khuzhin](https://github.com/azat)).
- Fix docker entrypoint in case `http_port` is not in the config. [#22132](https://github.com/ClickHouse/ClickHouse/pull/22132) ([Ewout](https://github.com/devwout)).
- Fix error `Invalid number of rows in Chunk` in `JOIN` with `TOTALS` and `arrayJoin`. Closes [#19303](https://github.com/ClickHouse/ClickHouse/issues/19303). [#22129](https://github.com/ClickHouse/ClickHouse/pull/22129) ([Vladimir](https://github.com/vdimir)).
- Fix the background thread pool name which used to poll message from Kafka. The Kafka engine with the broken thread pool will not consume the message from message queue. [#22122](https://github.com/ClickHouse/ClickHouse/pull/22122) ([fastio](https://github.com/fastio)).
- Fix waiting for `OPTIMIZE` and `ALTER` queries for `ReplicatedMergeTree` table engines. Now the query will not hang when the table was detached or restarted. [#22118](https://github.com/ClickHouse/ClickHouse/pull/22118) ([alesapin](https://github.com/alesapin)).
- Disable `async_socket_for_remote`/`use_hedged_requests` for buggy Linux kernels. [#22109](https://github.com/ClickHouse/ClickHouse/pull/22109) ([Azat Khuzhin](https://github.com/azat)).
- Docker entrypoint: avoid chown of `.` in case when `LOG_PATH` is empty. Closes [#22100](https://github.com/ClickHouse/ClickHouse/issues/22100). [#22102](https://github.com/ClickHouse/ClickHouse/pull/22102) ([filimonov](https://github.com/filimonov)).
- The function `decrypt` was lacking a check for the minimal size of data encrypted in `AEAD` mode. This closes [#21897](https://github.com/ClickHouse/ClickHouse/issues/21897). [#22064](https://github.com/ClickHouse/ClickHouse/pull/22064) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- In rare case, merge for `CollapsingMergeTree` may create granule with `index_granularity + 1` rows. Because of this, internal check, added in [#18928](https://github.com/ClickHouse/ClickHouse/issues/18928) (affects 21.2 and 21.3), may fail with error `Incomplete granules are not allowed while blocks are granules size`. This error did not allow parts to merge. [#21976](https://github.com/ClickHouse/ClickHouse/pull/21976) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
- Reverted [#15454](https://github.com/ClickHouse/ClickHouse/issues/15454) that may cause significant increase in memory usage while loading external dictionaries of hashed type. This closes [#21935](https://github.com/ClickHouse/ClickHouse/issues/21935). [#21948](https://github.com/ClickHouse/ClickHouse/pull/21948) ([Maksim Kita](https://github.com/kitaisreal)).
- Prevent hedged connections overlaps (`Unknown packet 9 from server` error). [#21941](https://github.com/ClickHouse/ClickHouse/pull/21941) ([Azat Khuzhin](https://github.com/azat)).
- Fix reading the HTTP POST request with "multipart/form-data" content type in some cases. [#21936](https://github.com/ClickHouse/ClickHouse/pull/21936) ([Ivan](https://github.com/abyss7)).
- Fix wrong `ORDER BY` results when a query contains window functions, and optimization for reading in primary key order is applied. Fixes [#21828](https://github.com/ClickHouse/ClickHouse/issues/21828). [#21915](https://github.com/ClickHouse/ClickHouse/pull/21915) ([Alexander Kuzmenkov](https://github.com/akuzm)).
- Fix deadlock in first catboost model execution. Closes [#13832](https://github.com/ClickHouse/ClickHouse/issues/13832). [#21844](https://github.com/ClickHouse/ClickHouse/pull/21844) ([Kruglov Pavel](https://github.com/Avogar)).
- Fix incorrect query result (and possible crash) which could happen when `WHERE` or `HAVING` condition is pushed before `GROUP BY`. Fixes [#21773](https://github.com/ClickHouse/ClickHouse/issues/21773). [#21841](https://github.com/ClickHouse/ClickHouse/pull/21841) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
- Better error handling and logging in `WriteBufferFromS3`. [#21836](https://github.com/ClickHouse/ClickHouse/pull/21836) ([Pavel Kovalenko](https://github.com/Jokser)).
- Fix possible crashes in aggregate functions with combinator `Distinct`, while using two-level aggregation. This is a follow-up fix of [#18365](https://github.com/ClickHouse/ClickHouse/pull/18365) . Can only reproduced in production env. [#21818](https://github.com/ClickHouse/ClickHouse/pull/21818) ([Amos Bird](https://github.com/amosbird)).
- Fix scalar subquery index analysis. This fixes [#21717](https://github.com/ClickHouse/ClickHouse/issues/21717) , which was introduced in [#18896](https://github.com/ClickHouse/ClickHouse/pull/18896). [#21766](https://github.com/ClickHouse/ClickHouse/pull/21766) ([Amos Bird](https://github.com/amosbird)).
- Fix bug for `ReplicatedMerge` table engines when `ALTER MODIFY COLUMN` query doesn't change the type of `Decimal` column if its size (32 bit or 64 bit) doesn't change. [#21728](https://github.com/ClickHouse/ClickHouse/pull/21728) ([alesapin](https://github.com/alesapin)).
- Fix possible infinite waiting when concurrent `OPTIMIZE` and `DROP` are run for `ReplicatedMergeTree`. [#21716](https://github.com/ClickHouse/ClickHouse/pull/21716) ([Azat Khuzhin](https://github.com/azat)).
- Fix function `arrayElement` with type `Map` for constant integer arguments. [#21699](https://github.com/ClickHouse/ClickHouse/pull/21699) ([Anton Popov](https://github.com/CurtizJ)).
- Fix SIGSEGV on not existing attributes from `ip_trie` with `access_to_key_from_attributes`. [#21692](https://github.com/ClickHouse/ClickHouse/pull/21692) ([Azat Khuzhin](https://github.com/azat)).
- Server now start accepting connections only after `DDLWorker` and dictionaries initialization. [#21676](https://github.com/ClickHouse/ClickHouse/pull/21676) ([Azat Khuzhin](https://github.com/azat)).
- Add type conversion for keys of tables of type `Join` (previously led to SIGSEGV). [#21646](https://github.com/ClickHouse/ClickHouse/pull/21646) ([Azat Khuzhin](https://github.com/azat)).
- Fix distributed requests cancellation (for example simple select from multiple shards with limit, i.e. `select * from remote('127.{2,3}', system.numbers) limit 100`) with `async_socket_for_remote=1`. [#21643](https://github.com/ClickHouse/ClickHouse/pull/21643) ([Azat Khuzhin](https://github.com/azat)).
- Fix `fsync_part_directory` for horizontal merge. [#21642](https://github.com/ClickHouse/ClickHouse/pull/21642) ([Azat Khuzhin](https://github.com/azat)).
- Remove unknown columns from joined table in `WHERE` for queries to external database engines (MySQL, PostgreSQL). close [#14614](https://github.com/ClickHouse/ClickHouse/issues/14614), close [#19288](https://github.com/ClickHouse/ClickHouse/issues/19288) (dup), close [#19645](https://github.com/ClickHouse/ClickHouse/issues/19645) (dup). [#21640](https://github.com/ClickHouse/ClickHouse/pull/21640) ([Vladimir](https://github.com/vdimir)).