Apply mask of deleted rows

Documentation for Apply mask of deleted rows

ALTER TABLE [db].name [ON CLUSTER cluster] APPLY DELETED MASK [IN PARTITION partition_id]

The command applies mask created by lightweight delete and forcefully removes rows marked as deleted from disk. This command is a heavyweight mutation, and it semantically equals to query ALTER TABLE [db].name DELETE WHERE _row_exists = 0.

It only works for tables in the MergeTree family (including replicated tables).

See also

• Lightweight deletes
• Heavyweight deletes