ClickHouse/docs/changelogs/v21.9.2.17-stable.md

ClickHouse release v21.9.2.17-stable FIXME as compared to v21.9.1.8000-prestable

Improvement

• Backported in #27894: Allow symlinks for library dictionaty path. #27815 (Kseniia Sumarokova).
• Backported in #28153: Use Multipart copy upload for large S3 objects. #27858 (ianton-ru).
• Backported in #28643: Fix strange sessions expiration logic in Keeper. Probably it should help in CI: https://clickhouse-test-reports.s3.yandex.net/0/6bd9b82141c98dcd7796fd9d08326831095ba519/stress_test_(debug).html#fail1. #28519 (alesapin).

Bug Fix

• Backported in #27981: Bugfix for windowFunnel's "strict" mode. This fixes #27469. #27563 (achimbab).
• Backported in #27922: After https://github.com/ClickHouse/ClickHouse/pull/26864. Fix shutdown of NamedSessionStorage: session contexts stored in NamedSessionStorage are now destroyed before destroying the global context. #27875 (Vitaly Baranov).
• Backported in #27926: Fix PostgreSQL-style cast (:: operator) with negative numbers. #27876 (Anton Popov).
• Backported in #27959: Fix selecting with extremes from a column of the type LowCardinality(UUID). #27918 (Vitaly Baranov).
• Backported in #27954: Check cluster name before creating Distributed table, do not allow to create a table with incorrect cluster name. Fixes #27832. #27927 (Alexander Tokmakov).
• Backported in #28000: Fix checking access grants when executing GRANT WITH REPLACE statement with ON CLUSTER clause. This PR improves fix https://github.com/ClickHouse/ClickHouse/pull/27701. #27983 (Vitaly Baranov).
• Backported in #28210: Fix cases, when read buffer fails with 'attempt to read after end of file'. Closes #26149. #28150 (Filatenkov Artur).
• Backported in #28750: 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 (Anton Popov).

Build/Testing/Packaging Improvement

• Backported in #28029: Temporarily switched ubuntu apt repository to mirror ru.archive.ubuntu.com as default one(archive.ubuntu.com) is not responding from our CI. #28016 (Ilya Yatsishin).

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

• Backported in #27973: Fix handling null value with type of Nullable(String) in function JSONExtract. This fixes #27929 and #27930 . This was introduced in https://github.com/ClickHouse/ClickHouse/pull/25452 . #27939 (Amos Bird).
• Backported in #28118: Fix extremely rare segfaults on shutdown due to incorrect order of context/config reloader shutdown. #28088 (nvartolomei).
• Backported in #28182: Fixed possible excessive number of conditions moved from WHERE to PREWHERE (optimization controlled by settings optimize_move_to_prewhere). #28139 (lthaooo).
• Backported in #28260: Multiple small fixes for projections. See detailed description in pr. #28178 (Amos Bird).
• Backported in #28257: Fix incorrect behavior in clickhouse-keeper when list watches (getChildren) triggered with set requests for children. #28190 (alesapin).
• Backported in #28343: Fix a rare bug in clickhouse-keeper when the client can receive a watch response before request-response. #28197 (alesapin).
• Backported in #28261: Fix possible read of uninitialized memory for queries with Nullable(LowCardinality) type and extremes. Fixes #28165. #28205 (Nikolai Kochetov).
• Backported in #28253: Fix reading of custom TLD w/o new line at EOF. #28213 (Azat Khuzhin).
• Backported in #28294: Fix inconsistent result in queries with ORDER BY and Merge tables with enabled setting optimize_read_in_order. #28266 (Anton Popov).
• Backported in #28401: Fix intersecting parts due to new part had been replaced with an empty part. #28310 (Azat Khuzhin).
• Backported in #28688: Fix NOT-IN index optimization when not all key columns are used. This fixes #28120. #28315 (Amos Bird).
• Backported in #28435: Fix non joined rows from nullable column. Close #27691. #28349 (Vladimir C).
• Backported in #28645: Fix rare case when changes of clickhouse-keeper settings may lead to lost logs and server hung. #28360 (alesapin).
• Backported in #28507: Fix lack of quotes for table names in MaterializedPostgreSQL engine. Closes #28316. #28433 (Kseniia Sumarokova).
• Backported in #28480: Fixed possible ZooKeeper watches leak on background processing of distributed DDL queue. Closes #26036. #28446 (Alexander Tokmakov).
• Backported in #28572: Fix bug which can lead to error Existing table metadata in ZooKeeper differs in sorting key expression. after alter of ReplicatedVersionedCollapsingMergeTree. Fixes #28515. #28528 (alesapin).
• Backported in #28594: Fix There is no subcolumn error, while select from tables, which have Nested columns and scalar columns with dot in name and the same prefix as Nested (e.g. n.id UInt32, n.arr1 Array(UInt64), n.arr2 Array(UInt64)). #28531 (Anton Popov).
• Backported in #28657: Fix UUID overlap in DROP TABLE for internal DDL from MaterializeMySQL. #28533 (Azat Khuzhin).
• Backported in #28568: Fix endless loop for truncated bzip2 archive. #28543 (Azat Khuzhin).
• Backported in #28704: - Fix the number of arguments required by s2RectAdd and s2RectContains functions. #28663 (Bharat Nallan).
• Backported in #28715: Add Settings.Names, Settings.Values aliases for system.processes table. #28685 (Vitaly Orlov).
• Backported in #28744: Fix the coredump in the creation of distributed tables, when the parameters passed in are wrong. #28686 (Zhiyong Wang).