### ClickHouse release v21.10.3.9-stable FIXME as compared to v21.10.2.15-stable

#### New Feature
* Backported in [#30712](https://github.com/ClickHouse/ClickHouse/issues/30712): CompiledExpressionCache limit elements size using `compiled_expression_cache_elements_size` setting. [#30667](https://github.com/ClickHouse/ClickHouse/pull/30667) ([Maksim Kita](https://github.com/kitaisreal)).

#### Improvement
* Backported in [#30453](https://github.com/ClickHouse/ClickHouse/issues/30453): Allow symlinks to files in user_files directory for file table function. [#30309](https://github.com/ClickHouse/ClickHouse/pull/30309) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Backported in [#30635](https://github.com/ClickHouse/ClickHouse/issues/30635): More full support of positional arguments. [#30433](https://github.com/ClickHouse/ClickHouse/pull/30433) ([Kseniia Sumarokova](https://github.com/kssenii)).

#### Bug Fix
* Backported in [#30620](https://github.com/ClickHouse/ClickHouse/issues/30620): Fix reading from empty file on encrypted disk. [#30494](https://github.com/ClickHouse/ClickHouse/pull/30494) ([Vitaly Baranov](https://github.com/vitlibar)).
* Backported in [#31369](https://github.com/ClickHouse/ClickHouse/issues/31369): Fix SHOW GRANTS when partial revokes are used. This PR fixes [#31138](https://github.com/ClickHouse/ClickHouse/issues/31138). [#31249](https://github.com/ClickHouse/ClickHouse/pull/31249) ([Vitaly Baranov](https://github.com/vitlibar)).

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

* Backported in [#30915](https://github.com/ClickHouse/ClickHouse/issues/30915): Fix `ORDER BY ... WITH FILL` with set `TO` and `FROM` and no rows in result set. [#30888](https://github.com/ClickHouse/ClickHouse/pull/30888) ([Anton Popov](https://github.com/CurtizJ)).

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

* Backported in [#30824](https://github.com/ClickHouse/ClickHouse/issues/30824): Fix "Column is not under aggregate function and not in GROUP BY" with PREWHERE (Fixes: [#28461](https://github.com/ClickHouse/ClickHouse/issues/28461)). [#28502](https://github.com/ClickHouse/ClickHouse/pull/28502) ([Azat Khuzhin](https://github.com/azat)).
* Backported in [#30766](https://github.com/ClickHouse/ClickHouse/issues/30766): Fix hanging DDL queries on Replicated database while adding a new replica. [#29328](https://github.com/ClickHouse/ClickHouse/pull/29328) ([Kevin Michel](https://github.com/kmichel-aiven)).
* Backported in [#30504](https://github.com/ClickHouse/ClickHouse/issues/30504): Fixed incorrect behaviour of setting `materialized_postgresql_tables_list` at server restart. Found in [#28529](https://github.com/ClickHouse/ClickHouse/issues/28529). [#29686](https://github.com/ClickHouse/ClickHouse/pull/29686) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Backported in [#30137](https://github.com/ClickHouse/ClickHouse/issues/30137): Fix error `Port is already connected` for queries with `GLOBAL IN` and `WITH TOTALS`. Only for 21.9 and 21.10. [#30086](https://github.com/ClickHouse/ClickHouse/pull/30086) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Backported in [#30465](https://github.com/ClickHouse/ClickHouse/issues/30465): Support nullable arguments in function `initializeAggregation`. [#30177](https://github.com/ClickHouse/ClickHouse/pull/30177) ([Anton Popov](https://github.com/CurtizJ)).
* Backported in [#30353](https://github.com/ClickHouse/ClickHouse/issues/30353): Fix `pread_fake_async`/`pread_threadpool` with `min_bytes_to_use_direct_io`. [#30191](https://github.com/ClickHouse/ClickHouse/pull/30191) ([Azat Khuzhin](https://github.com/azat)).
* Backported in [#30334](https://github.com/ClickHouse/ClickHouse/issues/30334): * Allow identifiers staring with numbers in multiple joins. [#30230](https://github.com/ClickHouse/ClickHouse/pull/30230) ([Vladimir C](https://github.com/vdimir)).
* Backported in [#30654](https://github.com/ClickHouse/ClickHouse/issues/30654): Fix `[I]LIKE` function. Closes [#28661](https://github.com/ClickHouse/ClickHouse/issues/28661). [#30244](https://github.com/ClickHouse/ClickHouse/pull/30244) ([Nikolay Degterinsky](https://github.com/evillique)).
* Backported in [#30378](https://github.com/ClickHouse/ClickHouse/issues/30378): fix replaceRegexpAll bug. [#30292](https://github.com/ClickHouse/ClickHouse/pull/30292) ([Memo](https://github.com/Joeywzr)).
* Backported in [#30526](https://github.com/ClickHouse/ClickHouse/issues/30526): Fixed segfault which might happen if session expired during execution of REPLACE PARTITION. [#30432](https://github.com/ClickHouse/ClickHouse/pull/30432) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Backported in [#30587](https://github.com/ClickHouse/ClickHouse/issues/30587): * Fix deadlock on ALTER with scalar subquery to the same table, close [#30461](https://github.com/ClickHouse/ClickHouse/issues/30461). [#30492](https://github.com/ClickHouse/ClickHouse/pull/30492) ([Vladimir C](https://github.com/vdimir)).
* Backported in [#30608](https://github.com/ClickHouse/ClickHouse/issues/30608): Limit push down optimization could cause a error `Cannot find column`. Fixes [#30438](https://github.com/ClickHouse/ClickHouse/issues/30438). [#30562](https://github.com/ClickHouse/ClickHouse/pull/30562) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Backported in [#30747](https://github.com/ClickHouse/ClickHouse/issues/30747): Update aws-sdk submodule for throttling in Yandex.S3. [#30646](https://github.com/ClickHouse/ClickHouse/pull/30646) ([ianton-ru](https://github.com/ianton-ru)).
* Backported in [#30751](https://github.com/ClickHouse/ClickHouse/issues/30751): Functions for case-insensitive search in UTF8 strings like `positionCaseInsensitiveUTF8` and `countSubstringsCaseInsensitiveUTF8` might find substrings that actually does not match, it's fixed. [#30663](https://github.com/ClickHouse/ClickHouse/pull/30663) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Backported in [#30709](https://github.com/ClickHouse/ClickHouse/issues/30709): Fix PREWHERE with WHERE in case of always true PREWHERE. [#30668](https://github.com/ClickHouse/ClickHouse/pull/30668) ([Azat Khuzhin](https://github.com/azat)).
* Backported in [#30771](https://github.com/ClickHouse/ClickHouse/issues/30771): Fixed a race condition between `REPLACE/MOVE PARTITION` and background merge in non-replicated `MergeTree` that might cause a part of moved/replaced data to remain in partition. Fixes [#29327](https://github.com/ClickHouse/ClickHouse/issues/29327). [#30717](https://github.com/ClickHouse/ClickHouse/pull/30717) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Backported in [#30859](https://github.com/ClickHouse/ClickHouse/issues/30859): Fixed ambiguity when extracting auxiliary ZooKeeper name from ZooKeeper path in `ReplicatedMergeTree`. Previously server might fail to start with `Unknown auxiliary ZooKeeper name` if ZooKeeper path contains a colon. Fixes [#29052](https://github.com/ClickHouse/ClickHouse/issues/29052). Also it was allowed to specify ZooKeeper path that does not start with slash, but now it's deprecated and creation of new tables with such path is not allowed. Slashes and colons in auxiliary ZooKeeper names are not allowed too. [#30822](https://github.com/ClickHouse/ClickHouse/pull/30822) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Backported in [#30926](https://github.com/ClickHouse/ClickHouse/issues/30926): Fix set index not used in AND/OR expressions when there are more than two operands. This fixes [#30416](https://github.com/ClickHouse/ClickHouse/issues/30416) . [#30887](https://github.com/ClickHouse/ClickHouse/pull/30887) ([Amos Bird](https://github.com/amosbird)).
* Backported in [#31289](https://github.com/ClickHouse/ClickHouse/issues/31289): Fix some corner cases with intersect/except. Closes [#30803](https://github.com/ClickHouse/ClickHouse/issues/30803). [#30965](https://github.com/ClickHouse/ClickHouse/pull/30965) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Backported in [#31152](https://github.com/ClickHouse/ClickHouse/issues/31152): Skip max_partition_size_to_drop check in case of ATTACH PARTITION ... FROM and MOVE PARTITION ... [#30995](https://github.com/ClickHouse/ClickHouse/pull/30995) ([Amr Alaa](https://github.com/amralaa-MSFT)).
* Backported in [#31041](https://github.com/ClickHouse/ClickHouse/issues/31041): Using `formatRow` function with not row formats led to segfault. Don't allow to use this function with such formats (because it doesn't make sense). [#31001](https://github.com/ClickHouse/ClickHouse/pull/31001) ([Kruglov Pavel](https://github.com/Avogar)).
* Backported in [#31203](https://github.com/ClickHouse/ClickHouse/issues/31203): Fix abort in debug server and `DB::Exception: std::out_of_range: basic_string` error in release server in case of bad hdfs url by adding additional check of hdfs url structure. [#31042](https://github.com/ClickHouse/ClickHouse/pull/31042) ([Kruglov Pavel](https://github.com/Avogar)).
* Backported in [#31373](https://github.com/ClickHouse/ClickHouse/issues/31373): Fix StorageMerge with aliases and where (it did not work before at all). Closes [#28802](https://github.com/ClickHouse/ClickHouse/issues/28802). [#31044](https://github.com/ClickHouse/ClickHouse/pull/31044) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Backported in [#31255](https://github.com/ClickHouse/ClickHouse/issues/31255): Fix bug in Keeper which can lead to inability to start when some coordination logs was lost and we have more fresh snapshot than our latest log. [#31150](https://github.com/ClickHouse/ClickHouse/pull/31150) ([alesapin](https://github.com/alesapin)).
* Backported in [#31436](https://github.com/ClickHouse/ClickHouse/issues/31436): Fix bug with group by and positional arguments. Closes [#31280](https://github.com/ClickHouse/ClickHouse/issues/31280)#issuecomment-968696186. [#31420](https://github.com/ClickHouse/ClickHouse/pull/31420) ([Kseniia Sumarokova](https://github.com/kssenii)).