v.19.14Improvement

Better Support of Skip Indexes for Mutations and Replication

Official CH changelog text
Better support of skip indexes for mutations and replication. Support for MATERIALIZE/CLEAR INDEX ... IN PARTITION query. UPDATE x = x recalculates all indices that use column x. #5053 (Nikita Vasilev)
Introduces enhanced support for skip indexes in mutations and replication, including the ability to use MATERIALIZE INDEX ... IN PARTITION and CLEAR INDEX ... IN PARTITION queries. Also, UPDATE x = x statements now recalculate all indices that depend on column x.

Why it matters

This feature addresses the need for better management and maintenance of skip indexes during data mutations and replication processes. It allows users to explicitly materialize or clear skip indexes on specific partitions, improving index consistency and query performance. Additionally, automatically recalculating dependent indices on no-op updates ensures index accuracy without additional manual steps.

How to use it

Users can run the following queries to manage skip indexes on partitions:

MATERIALIZE INDEX index_name IN PARTITION partition_name
CLEAR INDEX index_name IN PARTITION partition_name


To recalculate all indices that depend on a column x, execute:

UPDATE table_name SET x = x WHERE <condition>

This triggers the recalculation of all skip indexes using column x.

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