2026 Changelog

ClickHouse release v25.8.19.20-lts (228561f7659) FIXME as compared to v25.8.18.1-lts (557fdf60f81)

Improvement

• Backported in #96432: //github.com/ClickHouse/ClickHouse/blob/master/docs/changelog_entry_guidelines.md) of the changes that goes into CHANGELOG.md): Skip object storage reads when querying DeltaLake tables from system.tables. #95899 (Antonio Andelic).

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

• Backported in #96153: //github.com/ClickHouse/ClickHouse/blob/master/docs/changelog_entry_guidelines.md) of the changes that goes into CHANGELOG.md): Fix use-of-uninitialized-value in formatDateTime with non-fixed-width formatters, such as MySQL and JODA-style. #96133 (Alexey Milovidov).
• Backported in #96515: //github.com/ClickHouse/ClickHouse/blob/master/docs/changelog_entry_guidelines.md) of the changes that goes into CHANGELOG.md): Fix null pointer dereference in certain expressions with lambda functions. #96479 (Alexey Milovidov).
• Backported in #97045: //github.com/ClickHouse/ClickHouse/blob/master/docs/changelog_entry_guidelines.md) of the changes that goes into CHANGELOG.md):. #96878 (Alexey Milovidov).
• Backported in #97363: //github.com/ClickHouse/ClickHouse/blob/master/docs/changelog_entry_guidelines.md) of the changes that goes into CHANGELOG.md): Fix segfault in StorageKeeperMap backup due to use-after-free of dangling storage pointer in lazy backup batch. #97336 (Alexey Milovidov).
• Backported in #98029: //github.com/ClickHouse/ClickHouse/blob/master/docs/changelog_entry_guidelines.md) of the changes that goes into CHANGELOG.md): Remove incorrect replaceRegexpOne to extract query rewrite that produced wrong results when the regexp didn't match; also fix exception when replaceRegexpOne is used with GROUP BY ... WITH CUBE and group_by_use_nulls=1. #97546 (Alexey Milovidov).
• Backported in #98219: //github.com/ClickHouse/ClickHouse/blob/master/docs/changelog_entry_guidelines.md) of the changes that goes into CHANGELOG.md): Fix possible crashes during reading of empty granules in advanced shared data in JSON. Closes #97563. #97778 (Pavel Kruglov).
• Backported in #98017: //github.com/ClickHouse/ClickHouse/blob/master/docs/changelog_entry_guidelines.md) of the changes that goes into CHANGELOG.md): - Fixed ClickHouse server crash/assert in call to mapContainsKey/mapContainsKeyLike with tokenbf_v1 skip index. #97826 (Shankar Iyer).
• Backported in #98716: //github.com/ClickHouse/ClickHouse/blob/master/docs/changelog_entry_guidelines.md) of the changes that goes into CHANGELOG.md): Enforce READ ON FILE checks for scalar file() and DESCRIBE TABLE file(). #98115 (Nikolay Degterinsky).
• Backported in #98924: //github.com/ClickHouse/ClickHouse/blob/master/docs/changelog_entry_guidelines.md) of the changes that goes into CHANGELOG.md): * Fix unexpected result with read_in_order_use_virtual_row and monotonic functions, close #97837. #98514 (Vladimir Cherkasov).
• Backported in #98645: //github.com/ClickHouse/ClickHouse/blob/master/docs/changelog_entry_guidelines.md) of the changes that goes into CHANGELOG.md): Fix column rollback in Buffer engine during handling an exception during appending a new block. Old logic could lead to corrupted in-memory state of columns. #98551 (Pavel Kruglov).
• Backported in #99414: //github.com/ClickHouse/ClickHouse/blob/master/docs/changelog_entry_guidelines.md) of the changes that goes into CHANGELOG.md): Fix reverseUTF8 exception on invalid (truncated) UTF-8 input. #98770 (Alexey Milovidov).
• Backported in #99767: Fix server crash (std::terminate) when executing ALTER TABLE ... DROP PART on a patch part after a schema change (e.g. ADD COLUMN). The crash was caused by missing system columns (_part) in the empty coverage part metadata, leading to an uncaught exception inside a NOEXCEPT_SCOPE. #99036 (Peng Jian).
• Backported in #99665: //github.com/ClickHouse/ClickHouse/blob/master/docs/changelog_entry_guidelines.md) of the changes that goes into CHANGELOG.md): Fix heap-use-after-free in INTERSECT/EXCEPT when the query produces duplicate column names. #99471 (Alexey Milovidov).
• Backported in #99893: //github.com/ClickHouse/ClickHouse/blob/master/docs/changelog_entry_guidelines.md) of the changes that goes into CHANGELOG.md): Fix query:. #99739 (Konstantin Vedernikov).

Build/Testing/Packaging Improvement

• Backported in #98751: Use mongo-c-driver 2.2.2. #98304 (Konstantin Bogdanov).
• Backported in #98590: //github.com/ClickHouse/ClickHouse/blob/master/docs/changelog_entry_guidelines.md) of the changes that goes into CHANGELOG.md): Use postgres REL_18_3. #98306 (Konstantin Bogdanov).

NOT FOR CHANGELOG / INSIGNIFICANT

• Backported in #98760: CI: skip all jobs for release PRs in filter_job hook. #98740 (Max Kainov).
• Accept COMMENT before AS SELECT in view parser for forward compatibility with newer versions. #99562 (Alexey Milovidov).