2025 Changelog

ClickHouse release v25.8.2.29-lts (874146507b0) FIXME as compared to v25.8.1.5101-lts (4f2b50b8c92)

New Feature

• Backported in #86620: Add system table iceberg_metadata_log to retrieve Iceberg metadata files during SELECT statements. #86152 (Konstantin Vedernikov).

Improvement

• Backported in #86333: Add allow_experimental_delta_lake_writes. #86180 (Kseniia Sumarokova).
• Backported in #86493: Add ability to enable JSON logging only for specific channel, for this set logger.formatting.channel to one of syslog/console/errorlog/log. #86331 (Azat Khuzhin).

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

• Backported in #86614: Shutdown tables properly when recovering database replica. Improper shutdown would lead to LOGICAL_ERROR for some table engines during database replica recovery. #84744 (Antonio Andelic).
• Backported in #86386: Process includes from /etc/metrika.xml as a default when creating disks from SQL. #86232 (alekar).
• Backported in #86653: Fix 416 The range specified is invalid for the current size of the resource. The range specified is invalid for the current size of the resource when reading empty blobs from Azure blob storage for plain_rewritable disk. #86400 (Julia Kartseva).
• Backported in #86457: Fixed a bug in Materialized Views: an MV might not work if it was created, dropped, and then created again with the same name. #86413 (Alexander Tokmakov).
• Backported in #86468: Fix leaking of MergesMutationsMemoryTracking due to Buffer tables and fix query_views_log for streaming from Kafka (and others). #86422 (Azat Khuzhin).
• Backported in #86549: Fix use of uninitialized memory in getSubcolumnType. #86498 (Raúl Marín).
• Backported in #86582: Ignore exceptions during flushing log on shutdown and make shutdown more safe (to avoid SIGSEGV). #86546 (Azat Khuzhin).

NO CL CATEGORY

• Backported in #86570:. #86558 (Nikita Mikhaylov).

NOT FOR CHANGELOG / INSIGNIFICANT

• Backported in #86425: In this PR https://github.com/ClickHouse/ClickHouse/pull/85177, when acquiring the DB lock, we had retrying logic and threw ErrorCodes::TIMEOUT_EXCEEDED when it fails. #86321 (Tuan Pham Anh).
• Backported in #86585: Fix test_multiple_disks::test_system_tables. #86338 (Nikita Taranov).
• Backported in #86550: More verbose error in Iceberg Manifest File Initialization. #86409 (Daniil Ivanik).