v.22.6Improvement

Do not write expired TTL columns after subsequent merges

Do not write expired columns by TTL after subsequent merges (before only first merge/optimize of the part will not write expired by TTL columns, all other will do). #37570 (Azat Khuzhin).
Improves TTL handling by preventing expired columns from being written after subsequent merges, not just the first merge or optimize operation.

Why it matters

Previously, expired columns defined by TTL were only excluded from being written during the first merge or optimize of a data part, while subsequent merges would still write them. This feature ensures that expired columns are consistently excluded from all merges, reducing unnecessary storage and improving query performance.

How to use it

This feature is applied automatically in the merge process and does not require any user configuration. Users benefit from more efficient TTL column expiration handling with no changes in their queries or settings.