v.25.8Improvement

Add profile event MutationAffectedRowsUpperBound that shows

Official CH changelog text
Added profile event MutationAffectedRowsUpperBound that shows the number of affected rows in a mutation (e.g., the total number of rows that satisfy the condition in ALTER UPDATE or ALTER DELETE query. #83978 (Anton Popov).
Added a profile event MutationAffectedRowsUpperBound that reports the number of rows affected by a mutation query, such as the total rows matching the condition in ALTER UPDATE or ALTER DELETE statements.

Why it matters

This feature provides users with insight into how many rows are affected by mutation queries, helping in monitoring and debugging by revealing the upper bound of impacted rows during ALTER UPDATE and ALTER DELETE commands.

How to use it

Users can access the MutationAffectedRowsUpperBound profile event after executing mutation queries to see the count of affected rows. This event is automatically recorded and available in the query profiling data without any additional configuration.

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