ClickHouse/docs/changelogs/v20.11.5.18-stable.md

ClickHouse release v20.11.5.18-stable FIXME as compared to v20.11.4.13-stable

Performance Improvement

• Backported in #17592: Fix performance of reading from Merge tables over huge number of MergeTree tables. Fixes #7748. #16988 (Anton Popov).

Bug Fix

• Backported in #17629: Throw error when use ColumnTransformer replace non exist column. #16183 (hexiaoting).
• Backported in #17158: Fixed uncontrolled growth of TDigest. #16680 (hrissan).
• Backported in #17313: Return number of affected rows for INSERT queries via MySQL protocol. Previously ClickHouse used to always return 0, it's fixed. Fixes #16605. #16715 (Winter Zhang).
• Backported in #17342: TODO. #16866 (Alexander Tokmakov).
• Backported in #17588: Fix optimization of group by with enabled setting optimize_aggregators_of_group_by_keys and joins. Fixes #12604. #16951 (Anton Popov).
• Backported in #17595: Fix order by optimization with monotonous functions. Fixes #16107. #16956 (Anton Popov).
• Backported in #17430: Bug fix for funciton fuzzBits, related issue: #16980. #17051 (hexiaoting).
• Backported in #17194: Fix ColumnConst comparison which leads to crash. This fixed #17088 . #17135 (Amos Bird).
• Backported in #17558: Fix possible wrong index analysis when the types of the index comparison are different. This fixes #17122. #17145 (Amos Bird).
• Backported in #17396: Fix #15235. When clickhouse-copier handle non-partitioned table, throws segfault error. #17248 (Qi Chen).
• Backported in #17408: Fix set index invalidation when there are const columns in the subquery. This fixes #17246 . #17249 (Amos Bird).
• Backported in #17490: Fix crash while reading from JOIN table with LowCardinality types. Fixes #17228. #17397 (Nikolai Kochetov).
• Backported in #17494: Fix duplicates after DISTINCT which were possible because of incorrect optimization. Fixes #17294. #17296 (li chengxiang). #17439 (Nikolai Kochetov).
• Backported in #17521: Fix ORDER BY with enabled setting optimize_redundant_functions_in_order_by. #17471 (Anton Popov).
• Backported in #17534: Fix bug when mark cache size was underestimated by clickhouse. It may happen when there are a lot of tiny files with marks. #17496 (alesapin).
• Backported in #17628: Fix alter query hang when the corresponding mutation was killed on the different replica. Fixes #16953. #17499 (alesapin).
• Backported in #17610: When clickhouse-client is used in interactive mode with multiline queries, single line comment was erronously extended till the end of query. This fixes #13654. #17565 (Alexey Milovidov).
• Backported in #17684: Exception fmt::v7::format_error can be logged in background for MergeTree tables. This fixes #17613. #17615 (Alexey Milovidov).
• Backported in #17696: In might be determined incorrectly if cluster is circular- (cross-) replicated or not when executing ON CLUSTER query due to race condition when pool_size > 1. It's fixed. #17640 (Alexander Tokmakov).
• Fix optimize_trivial_count_query with partition predicate (backport #16767 to 20.11). #17644 (Azat Khuzhin).
• Backported in #17728: Fixed Function not implemented error when executing RENAME query in Atomic database with ClickHouse running on Windows Subsystem for Linux. Fixes #17661. #17664 (Alexander Tokmakov).
• Backported in #17785: Fixed problem when ClickHouse fails to resume connection to MySQL servers. #17681 (Alexander Kazakov).
• Backported in #17815: Do not restore parts from WAL if in_memory_parts_enable_wal is disabled. #17802 (detailyang).

Build/Testing/Packaging Improvement

• Backported in #17290: Update embedded timezone data to version 2020d (also update cctz to the latest master). #17204 (filimonov).