2021 Changelog

- Functions for case-insensitive search in UTF-8 strings like `positionCaseInsensitiveUTF8` and `countSubstringsCaseInsensitiveUTF8` might find substrings that actually does not match in very rare cases, it's fixed. [#30663](https://github.com/ClickHouse/ClickHouse/pull/30663) ([tavplubix](https://github.com/tavplubix)).
- Fix reading from empty file on encrypted disk. [#30494](https://github.com/ClickHouse/ClickHouse/pull/30494) ([Vitaly Baranov](https://github.com/vitlibar)).
- Fix transformation of disjunctions chain to `IN` (controlled by settings `optimize_min_equality_disjunction_chain_length`) in distributed queries with settings `legacy_column_name_of_tuple_literal = 0`. [#28658](https://github.com/ClickHouse/ClickHouse/pull/28658) ([Anton Popov](https://github.com/CurtizJ)).
- Allow using a materialized column as the sharding key in a distributed table even if `insert_allow_materialized_columns=0`:. [#28637](https://github.com/ClickHouse/ClickHouse/pull/28637) ([Vitaly Baranov](https://github.com/vitlibar)).
- 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)).
- 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)).
- Fix crash when projection with hashing function is materialized. This fixes [#30861](https://github.com/ClickHouse/ClickHouse/issues/30861) . The issue is similar to <https://github.com/ClickHouse/ClickHouse/pull/28560> which is a lack of proper understanding of the invariant of header's emptyness. [#30877](https://github.com/ClickHouse/ClickHouse/pull/30877) ([Amos Bird](https://github.com/amosbird)).
- 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) ([tavplubix](https://github.com/tavplubix)).
- Clean temporary directory when localBackup failed by some reason. [#30797](https://github.com/ClickHouse/ClickHouse/pull/30797) ([ianton-ru](https://github.com/ianton-ru)).
- 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) ([tavplubix](https://github.com/tavplubix)).
- Fix PREWHERE with WHERE in case of always true PREWHERE. [#30668](https://github.com/ClickHouse/ClickHouse/pull/30668) ([Azat Khuzhin](https://github.com/azat)).
- 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)).
- Add missing parenthesis for `isNotNull`/`isNull` rewrites to `IS [NOT] NULL` (fixes queries that has something like `isNotNull(1)+isNotNull(2)`). [#30520](https://github.com/ClickHouse/ClickHouse/pull/30520) ([Azat Khuzhin](https://github.com/azat)).
- 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)).
- Fixed segfault which might happen if session expired during execution of REPLACE PARTITION. [#30432](https://github.com/ClickHouse/ClickHouse/pull/30432) ([tavplubix](https://github.com/tavplubix)).
- Queries with condition like `IN (subquery)` could return incorrect result in case if aggregate projection applied. Fixed creation of sets for projections. [#30310](https://github.com/ClickHouse/ClickHouse/pull/30310) ([Amos Bird](https://github.com/amosbird)).
- Fix column alias resolution of JOIN queries when projection is enabled. This fixes [#30146](https://github.com/ClickHouse/ClickHouse/issues/30146). [#30293](https://github.com/ClickHouse/ClickHouse/pull/30293) ([Amos Bird](https://github.com/amosbird)).
- Fix some deficiency in `replaceRegexpAll` function. [#30292](https://github.com/ClickHouse/ClickHouse/pull/30292) ([Memo](https://github.com/Joeywzr)).
- Fix ComplexKeyHashedDictionary, ComplexKeySparseHashedDictionary parsing `preallocate` option from layout config. [#30246](https://github.com/ClickHouse/ClickHouse/pull/30246) ([Maksim Kita](https://github.com/kitaisreal)).
- 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)).
- Fix crash with shortcircuit and lowcardinality in multiIf. [#30243](https://github.com/ClickHouse/ClickHouse/pull/30243) ([Raúl Marín](https://github.com/Algunenano)).
- FlatDictionary, HashedDictionary fix bytes\_allocated calculation for nullable attributes. [#30238](https://github.com/ClickHouse/ClickHouse/pull/30238) ([Maksim Kita](https://github.com/kitaisreal)).
- Allow identifiers starting with numbers in multiple joins. [#30230](https://github.com/ClickHouse/ClickHouse/pull/30230) ([Vladimir C](https://github.com/vdimir)).
- Fix reading from `MergeTree` with `max_read_buffer_size = 0` (when the user wants to shoot himself in the foot) (can lead to exceptions `Can't adjust last granule`, `LOGICAL_ERROR`, or even data loss). [#30192](https://github.com/ClickHouse/ClickHouse/pull/30192) ([Azat Khuzhin](https://github.com/azat)).
- 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)).
- Fix INSERT SELECT incorrectly fills MATERIALIZED column based of Nullable column. [#30189](https://github.com/ClickHouse/ClickHouse/pull/30189) ([Azat Khuzhin](https://github.com/azat)).
- Support nullable arguments in function `initializeAggregation`. [#30177](https://github.com/ClickHouse/ClickHouse/pull/30177) ([Anton Popov](https://github.com/CurtizJ)).
- 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)).
- Fix race between MOVE PARTITION and merges/mutations for MergeTree. [#30074](https://github.com/ClickHouse/ClickHouse/pull/30074) ([Azat Khuzhin](https://github.com/azat)).
- Dropped `Memory` database might reappear after server restart, it's fixed ([#29795](https://github.com/ClickHouse/ClickHouse/issues/29795)). Also added `force_remove_data_recursively_on_drop` setting as a workaround for `Directory not empty` error when dropping `Ordinary` database (because it's not possible to remove data leftovers manually in cloud environment). [#30054](https://github.com/ClickHouse/ClickHouse/pull/30054) ([tavplubix](https://github.com/tavplubix)).
- Fix crash of sample by `tuple()`, closes [#30004](https://github.com/ClickHouse/ClickHouse/issues/30004). [#30016](https://github.com/ClickHouse/ClickHouse/pull/30016) ([flynn](https://github.com/ucasfl)).
- try to close issue: [#29965](https://github.com/ClickHouse/ClickHouse/issues/29965). [#29976](https://github.com/ClickHouse/ClickHouse/pull/29976) ([hexiaoting](https://github.com/hexiaoting)).
- Fix possible data-race between `FileChecker` and `StorageLog`/`StorageStripeLog`. [#29959](https://github.com/ClickHouse/ClickHouse/pull/29959) ([Azat Khuzhin](https://github.com/azat)).