v.23.3New Feature
Add max_number_of_mutations_for_replica Setting to Limit Part Mutations per Replica
Add a merge tree setting max_number_of_mutations_for_replica. It limits the number of part mutations per replica to the specified amount. Zero means no limit on the number of mutations per replica (the execution can still be constrained by other settings). #48047 (Vladimir C).Why it matters
This feature allows users to control and cap the number of mutations running on a single replica, preventing resource overload and improving stability during mutation-heavy workloads. Setting the limit helps manage mutation execution more predictably, while a value of zero disables the limit.How to use it
Set themax_number_of_mutations_for_replica parameter in the MergeTree table settings to the desired maximum number of concurrent mutations per replica. For example, to limit to 3 mutations, use:ALTER TABLE <table_name> MODIFY SETTING max_number_of_mutations_for_replica = 3Setting it to 0 removes the limit.