v.25.8Improvement
Add a limit
Added a limit (table setting max_uncompressed_bytes_in_patches) for total uncompressed bytes in patch parts. It prevents significant slowdowns of SELECT queries after lightweight updates and prevents possible misuse of lightweight updates. #85641 (Anton Popov).Why it matters
This feature prevents significant slowdowns ofSELECT queries which can occur after performing lightweight updates. It also helps to avoid potential misuse of lightweight updates by controlling the amount of uncompressed data in patches.How to use it
Users can enable or configure this feature by setting the table-level settingmax_uncompressed_bytes_in_patches to a desired byte limit. This setting will then enforce the maximum allowed uncompressed bytes in patch parts to maintain query performance.