ClickHouse/docs/changelogs/v21.7.9.7-stable.md

ClickHouse release v21.7.9.7-stable FIXME as compared to v21.7.8.58-stable

Improvement

• Backported in #27892: Allow symlinks for library dictionaty path. #27815 (Kseniia Sumarokova).
• Backported in #28155: Use Multipart copy upload for large S3 objects. #27858 (ianton-ru).

Bug Fix

• Backported in #27976: Bugfix for windowFunnel's "strict" mode. This fixes #27469. #27563 (achimbab).
• Backported in #27780: Fix column filtering with union distinct in subquery. Closes #27578. #27689 (Kseniia Sumarokova).
• Backported in #27866: Prevent crashes for some formats when NULL (tombstone) message was coming from Kafka. Closes #19255. #27794 (filimonov).
• Backported in #28347: Fix a rare bug in DROP PART which can lead to the error Unexpected merged part intersects drop range. #27807 (alesapin).
• Backported in #27955: Fix selecting with extremes from a column of the type LowCardinality(UUID). #27918 (Vitaly Baranov).
• Backported in #27951: 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 #28208: Fix cases, when read buffer fails with 'attempt to read after end of file'. Closes #26149. #28150 (Filatenkov Artur).

Build/Testing/Packaging Improvement

• Backported in #28032: 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 #28116: Fix extremely rare segfaults on shutdown due to incorrect order of context/config reloader shutdown. #28088 (nvartolomei).
• Backported in #28183: Fixed possible excessive number of conditions moved from WHERE to PREWHERE (optimization controlled by settings optimize_move_to_prewhere). #28139 (lthaooo).
• Backported in #28255: Fix incorrect behavior in clickhouse-keeper when list watches (getChildren) triggered with set requests for children. #28190 (alesapin).
• Backported in #28265: Fix possible read of uninitialized memory for queries with Nullable(LowCardinality) type and extremes. Fixes #28165. #28205 (Nikolai Kochetov).
• Backported in #28288: Fix reading of custom TLD w/o new line at EOF. #28213 (Azat Khuzhin).
• Backported in #28295: Fix inconsistent result in queries with ORDER BY and Merge tables with enabled setting optimize_read_in_order. #28266 (Anton Popov).