### ClickHouse release v21.12.3.32-stable FIXME as compared to v21.12.2.17-stable

#### Bug Fix
* Backported in [#33018](https://github.com/ClickHouse/ClickHouse/issues/33018): - Clickhouse Keeper handler should remove operation when response sent. [#32988](https://github.com/ClickHouse/ClickHouse/pull/32988) ([JackyWoo](https://github.com/JackyWoo)).

#### Bug Fix (user-visible misbehaviour in official stable or prestable release)

* Backported in [#32890](https://github.com/ClickHouse/ClickHouse/issues/32890): Fix LOGICAL_ERROR when the target of a materialized view is a JOIN or a SET table. [#32669](https://github.com/ClickHouse/ClickHouse/pull/32669) ([Raúl Marín](https://github.com/Algunenano)).
* Backported in [#33183](https://github.com/ClickHouse/ClickHouse/issues/33183): Server might fail to start if database with `MySQL` engine cannot connect to MySQL server, it's fixed. Fixes [#14441](https://github.com/ClickHouse/ClickHouse/issues/14441). [#32802](https://github.com/ClickHouse/ClickHouse/pull/32802) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Backported in [#32904](https://github.com/ClickHouse/ClickHouse/issues/32904): `MergeTree` table engine might silently skip some mutations if there are too many running mutations or in case of high memory consumption, it's fixed. Fixes [#17882](https://github.com/ClickHouse/ClickHouse/issues/17882). [#32814](https://github.com/ClickHouse/ClickHouse/pull/32814) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Backported in [#33047](https://github.com/ClickHouse/ClickHouse/issues/33047): Fix optimization with lazy seek for async reads from remote fs. Closes [#32803](https://github.com/ClickHouse/ClickHouse/issues/32803). [#32835](https://github.com/ClickHouse/ClickHouse/pull/32835) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Backported in [#32932](https://github.com/ClickHouse/ClickHouse/issues/32932): Close [#32487](https://github.com/ClickHouse/ClickHouse/issues/32487). [#32914](https://github.com/ClickHouse/ClickHouse/pull/32914) ([Vladimir C](https://github.com/vdimir)).
* Backported in [#32962](https://github.com/ClickHouse/ClickHouse/issues/32962): Fix a regression in `replaceRegexpAll` function. The function worked incorrectly when matched substring was empty. This closes [#32777](https://github.com/ClickHouse/ClickHouse/issues/32777). This closes [#30245](https://github.com/ClickHouse/ClickHouse/issues/30245). [#32945](https://github.com/ClickHouse/ClickHouse/pull/32945) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Backported in [#33067](https://github.com/ClickHouse/ClickHouse/issues/33067): Fix hdfs url check that didn't allow using HA namenode address. Bug was introduced in https://github.com/ClickHouse/ClickHouse/pull/31042. [#32976](https://github.com/ClickHouse/ClickHouse/pull/32976) ([Kruglov Pavel](https://github.com/Avogar)).
* Backported in [#33100](https://github.com/ClickHouse/ClickHouse/issues/33100): Fix Context leak in case of cancel_http_readonly_queries_on_client_close (i.e. leaking of external tables that had been uploaded the the server and other resources). [#32982](https://github.com/ClickHouse/ClickHouse/pull/32982) ([Azat Khuzhin](https://github.com/azat)).
* Backported in [#33123](https://github.com/ClickHouse/ClickHouse/issues/33123): Fix error `Invalid version for SerializationLowCardinality key column` in case of reading from `LowCardinality` column with `local_filesystem_read_prefetch` or `remote_filesystem_read_prefetch` enabled. [#33046](https://github.com/ClickHouse/ClickHouse/pull/33046) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).