ClickHouse/docs/changelogs/v21.3.18.4-lts.md

ClickHouse release v21.3.18.4-lts FIXME as compared to v21.3.17.2-lts

Improvement

• Backported in #30355: Use separate clickhouse-bridge group and user for bridge processes. Set oom_score_adj so the bridges will be first subjects for OOM killer. Set set maximum RSS to 1 GiB. Closes #23861. #25280 (Kseniia Sumarokova).
• Backported in #29945: Update zoneinfo files to 2021c. #29925 (Alexey Milovidov).

Bug Fix

• Backported in #30041: Fix shutdown of AccessControlManager. Now there can't be reloading of the configuration after AccessControlManager has been destroyed. This PR fixes the flaky test test_user_directories/test.py::test_relative_path. #29951 (Vitaly Baranov).

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

• Backported in #29260: Fix invalid constant type conversion when nullable or lowcardinality primary key is used. #28636 (Amos Bird).
• Backported in #29026: Fix the number of threads used in GLOBAL IN subquery (it was executed in single threads since #19414 bugfix). #28997 (Nikolai Kochetov).
• Backported in #29194: Fix segfault while inserting into column with type LowCardinality(Nullable) in Avro input format. #29132 (Kruglov Pavel).
• Backported in #29360: Fix possible Table columns structure in ZooKeeper is different from local table structure exception while recreating or creating new replicas of ReplicatedMergeTree, when one of table columns have default expressions with case-insensitive functions. #29266 (Anton Popov).
• Backported in #29300: Fix connection timeouts (send_timeout/receive_timeout). #29282 (Azat Khuzhin).
• Backported in #30042: Condition in filter predicate could be lost after push-down optimisation. #29625 (Nikolai Kochetov).
• Backported in #29848: Fix concurrent access to LowCardinality during GROUP BY (leads to SIGSEGV). #29782 (Azat Khuzhin).
• Backported in #30066: Fix crash of sample by tuple(), closes #30004. #30016 (flynn).
• Backported in #30332: * Allow identifiers staring with numbers in multiple joins. #30230 (Vladimir C).
• Backported in #30379: fix replaceRegexpAll bug. #30292 (Memo).