ClickHouse/docs/changelogs/v21.8.3.44-lts.md

ClickHouse release v21.8.3.44-lts FIXME as compared to v21.8.2.19-prestable

Improvement

• Rename setting. #26844 (ianton-ru).

Bug Fix

• Backported in #27545: Now, scalar subquery always returns Nullable result if it's type can be Nullable. It is needed because in case of empty subquery it's result should be Null. Previously, it was possible to get error about incompatible types (type deduction does not execute scalar subquery, and it could use not-nullable type). Scalar subquery with empty result which can't be converted to Nullable (like Array or Tuple) now throws error. Fixes #25411. #26423 (Nikolai Kochetov).
• Backported in #26856: ParallelFormattingOutputFormat: Use mutex to handle the join to the collector_thread (https://github.com/ClickHouse/ClickHouse/issues/26694). #26703 (Raúl Marín).
• Backported in #26941: Do not remove data on ReplicatedMergeTree table shutdown to avoid creating data to metadata inconsistency. #26716 (nvartolomei).
• Backported in #26981: Aggregate function parameters might be lost when applying some combinators causing exceptions like Conversion from AggregateFunction(topKArray, Array(String)) to AggregateFunction(topKArray(10), Array(String)) is not supported. It's fixed. Fixes #26196 and #26433. #26814 (Alexander Tokmakov).
• Backported in #26909: Fix library-bridge ids load. #26834 (Kseniia Sumarokova).
• Backported in #26945: Fix error Missing columns: 'xxx' when DEFAULT column references other non materialized column without DEFAULT expression. Fixes #26591. #26900 (alesapin).
• Backported in #26997: Fix reading of custom TLDs (stops processing with lower buffer or bigger file). #26948 (Azat Khuzhin).
• Backported in #27030: Now partition ID in queries like ALTER TABLE ... PARTITION ID xxx validates for correctness. Fixes #25718. #26963 (alesapin).
• Backported in #27053: [RFC] Fix possible mutation stack due to race with DROP_RANGE. #27002 (Azat Khuzhin).
• Backported in #27106: Fixed cache, complex_key_cache, ssd_cache, complex_key_ssd_cache configuration parsing. Options allow_read_expired_keys, max_update_queue_size, update_queue_push_timeout_milliseconds, query_wait_timeout_milliseconds were not parsed for dictionaries with non cache type. #27032 (Maksim Kita).
• Backported in #27160: Fix synchronization in GRPCServer This PR fixes #27024. #27064 (Vitaly Baranov).
• Backported in #27365: - Fix uninitialized memory in functions multiSearch* with empty array, close #27169. #27181 (Vladimir C).
• Backported in #27263: In rare cases system.detached_parts table might contain incorrect information for some parts, it's fixed. Fixes #27114. #27183 (Alexander Tokmakov).
• Backported in #27555: Fix mutation stuck on invalid partitions in non-replicated MergeTree. #27248 (Azat Khuzhin).
• Backported in #27411: Fix distributed_group_by_no_merge=2+distributed_push_down_limit=1 or optimize_distributed_group_by_sharding_key=1 with LIMIT BY and LIMIT OFFSET. #27249 (Azat Khuzhin).
• Backported in #27507: Fix errors like Expected ColumnLowCardinality, gotUInt8 or Bad cast from type DB::ColumnVector<char8_t> to DB::ColumnLowCardinality for some queries with LowCardinality in PREWHERE. Fixes #23515. #27298 (Nikolai Kochetov).
• Backported in #27417: Fix Cannot find column error for queries with sampling. Was introduced in #24574. Fixes #26522. #27301 (Nikolai Kochetov).
• Backported in #27414: Fixed incorrect validation of partition id for MergeTree tables that created with old syntax. #27328 (Alexander Tokmakov).
• Backported in #27540: Fix incorrect result for query with row-level security, prewhere and LowCardinality filter. Fixes #27179. #27329 (Nikolai Kochetov).
• Backported in #27419: /proc/info contains metrics like. #27361 (Mike Kot).
• Backported in #27472: fix metric BackgroundMessageBrokerSchedulePoolTask, maybe mistyped。. #27452 (Ben).