2025 Changelog

Backported in #79981: Fix deserialization of variant discriminators with basic format in compact parts. It was introduced in https://github.com/ClickHouse/ClickHouse/pull/55518. #79000 (Pavel Kruglov).
Backported in #79715: Fix using incorrect paths when renaming an Atomic database. #79569 (Tuan Pham Anh).
Backported in #80049: Fixes the result of SQL function formatDateTime if a variable-size formatter (e.g. %W aka. weekday Monday Tuesday, etc.) is followed by a compound formatter (a formatter that prints multiple components at once, e.g. %D aka. the American date 05/04/25). #79835 (Robert Schulze).
Backported in #80113: IcebergS3 supports count optimization, but IcebergS3Cluster does not. As a result, the count() result returned in cluster mode may be a multiple of the number of replicas. #79844 (wxybear).
Backported in #80078: Allow materialized views with UNIONs to work correctly on new replicas. #80037 (Samay Sharma).
Backported in #80185: Fix warnings Cannot find 'kernel' in '[...]/memory.stat' in ClickHouse's log (issue #77410). #80129 (Robert Schulze).

Backported in #79811: Better introspection for index analysis performance. #79347 (Nikita Taranov).
Backported in #80222: Make test_check_replicated_does_not_block_shutdown less flaky and faster. #79552 (Raúl Marín).
Backported in #80099: enable_user_name_access_type must not affect DEFINER access type. #80026 (pufit).
Backported in #80202: Disable CPU overload checks for all tests. #80166 (Alexander Gololobov).
Backported in #80230: Disable CPU overload check in server settings by default. #80211 (Alexander Gololobov).