2025 Changelog

ClickHouse release v25.6.7.23-stable (4efdb9097eb) FIXME as compared to v25.6.6.29-stable (63e6c7573e5)

Improvement

• Backported in #85019: Add 4LW in Keeper, lgrq, for toggling request logging of received requests. #84719 (Antonio Andelic).
• Backported in #84868: Reduce contention on storage lock in Keeper. #84732 (Antonio Andelic).
• Backported in #85016: Limit Keeper log entry cache size by number of entries using keeper_server.coordination_settings.latest_logs_cache_entry_count_threshold and keeper_server.coordination_settings.commit_logs_cache_entry_count_threshold. #84877 (Antonio Andelic).

Bug Fix (user-visible misbehavior in an official stable release)

• Backported in #84831: Fix logger usage in IAccessStorage. #84365 (Konstantin Bogdanov).
• Backported in #84879: Fix CORRUPTED_DATA error when lazy columns are used with external sort. #84738 (János Benjamin Antal).
• Backported in #84993: Fix total watches count returned by Keeper. #84890 (Antonio Andelic).
• Backported in #84960: Fix memory tracking drift from background schedule pool and executor. #84946 (Azat Khuzhin).

NOT FOR CHANGELOG / INSIGNIFICANT

• Backported in #84795: Previously, FilterTransform could stop reading if the expression for any chunk returned a constant false. This can lead to a bug, because constant columns are allowed to appear during the execution, and most function default implementations will preserve constants as well. #83855 (Nikolai Kochetov).
• Backported in #84680: Removing temprary parts may take a while (especially with S3), and currently we do it while holding a global lock in MergeTreeBackgroundExecutor. When we need to restart all tables due to connection loss and we wait for background tasks to finish - tables may even stuck in readonly mode for an hour. But looks like we don't need this lock for calling cancel. #84311 (Alexander Tokmakov).
• Backported in #84837: Add ability to lock/unlock SharedLockGuard explicitly. #84687 (Mikhail Artemenko).