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Manipulating Column Statistics

The following operations are available:

  • ALTER TABLE [db].table ADD STATISTIC (columns list) TYPE type - Adds statistic description to tables metadata.

  • ALTER TABLE [db].table DROP STATISTIC (columns list) TYPE type - Removes statistic description from tables metadata and deletes statistic files from disk.

  • ALTER TABLE [db].table CLEAR STATISTIC (columns list) TYPE type - Deletes statistic files from disk.

  • ALTER TABLE [db.]table MATERIALIZE STATISTIC (columns list) TYPE type - Rebuilds the statistic for columns. Implemented as a mutation.

The first two commands are lightweight in a sense that they only change metadata or remove files.

Also, they are replicated, syncing statistics metadata via ZooKeeper.


Statistic manipulation is supported only for tables with *MergeTree engine (including replicated variants).