2026 Changelog

ClickHouse release v25.11.8.25-stable (4081364020e) FIXME as compared to v25.11.7.41-stable (d635abf3eae)

Improvement

• Backported in #94933: Force purging of jemalloc arenas in case the ratio of dirty pages size to max_server_memory_usage exceeds memory_worker_purge_dirty_pages_threshold_ratio. #93500 (Eduard Karacharov).
• Backported in #94729: Add support for SQL-defined named collections in BACKUP/RESTORE for S3 and Azure Blob Storage. Closes #94604. #94605 (Pablo Marcos).
• Backported in #95166: Run purging of jemalloc dirty pages in a different thread from main thread of MemoryWorker. If purging is slow, it could delay updates of RSS usage which could lead to out of memory kills of the process. Introduce new config memory_worker_purge_total_memory_threshold_ratio to start purging dirty pages based on ratio of total memory usage. #94902 (Antonio Andelic).

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

• Backported in #94765: Fix join results when the right-side join key is a sparse column. This closes #92920. I can only reproduce the bug with set compatibility='23.3'. Not sure if it should be backported. #93038 (Amos Bird).
• Backported in #94886: Fix attaching Replicated DBs when the interserver host changed after restarting. #93779 (Tuan Pham Anh).
• Backported in #94592: Fix type conversion to super type during the join operation of the storage Join with USING clause. Fixes #91672. Fixes #78572. #94000 (Dmitry Novik).
• Backported in #94357: Fix bad check for typed paths in JSON. Checj was introduced in https://github.com/ClickHouse/ClickHouse/pull/92842 and can lead to error during existing tables startup. #94070 (Pavel Kruglov).
• Backported in #95202: Fix function to subcolumns optimization not applied to subcolumns. #94323 (Pavel Kruglov).
• Backported in #94718: Fix a crash during ANY LEFT JOIN optimization when isNotNull is evaluated on a missing column. #94600 (Molly).
• Backported in #94813: Fix permission issues in BACKUP/RESTORE operations. #94617 (Pablo Marcos).
• Backported in #94844: Fixes https://github.com/ClickHouse/clickhouse-core-incidents/issues/1250. Likely due to a mix-up, data_type (which may be DataTypeNullable*) is static_cast-ed to DataTypeDateTime64*. Instead, we should cast check_type (the nested type variable). #94627 (Miсhael Stetsyuk).
• Backported in #94796: Fix possibly incorrect RIGHT join result when using complex ON conditions. Close #92913. #94680 (Vladimir Cherkasov).
• Backported in #94786: Preserve constant index granularity (use_const_adaptive_granularity) after Vertical merges. #94725 (Azat Khuzhin).
• Backported in #95150: The getURLHostRFC function was missing bounds checks before dereferencing pointers. When an empty string was passed to domainRFC, it would read uninitialized memory, triggering MSan errors. #94851 (Alexey Milovidov).
• Backported in #94994: Fix readonlyness of encrypted disks. #94852 (Azat Khuzhin).
• Backported in #95034: Fix logical error in fractional LIMIT/OFFSET when using the old analyzer with Distributed tables. Closes #94712. #94999 (Ahmed Gouda).
• Backported in #95215: Fix crash under some conditions when join runtime filters are enabled by default. #95000 (Alexander Gololobov).

Build/Testing/Packaging Improvement

• Backported in #94947: Use curl 8.18.0. #94742 (Konstantin Bogdanov).
• Backported in #95242: Use postgres to REL_18_1. #95189 (Konstantin Bogdanov).
• Backported in #95255: Use libexpat 2.7.3. #95218 (Konstantin Bogdanov).

NO CL CATEGORY

• Backported in #95039:. #95005 (Azat Khuzhin).

NOT FOR CHANGELOG / INSIGNIFICANT

• Backported in #94724: If some files in data part are missing, we can end up with inconsistent in-memory state of some columns which can lead to crashes. It's better to throw logical errors in this case. #92076 (Pavel Kruglov).
• Backported in #94872: Add index out of range check in advanced shared data in JSON. #94855 (Pavel Kruglov).
• Backported in #95273: CI: BackportCI to check PR content is valid. #95190 (Max Kainov).