Manipulating Data Skipping Indices
The following operations are available:
ALTER TABLE [db].name ADD INDEX name expression TYPE type GRANULARITY value AFTER name [AFTER name2]
- Adds index description to tables metadata.ALTER TABLE [db].name DROP INDEX name
- Removes index description from tables metadata and deletes index files from disk.ALTER TABLE [db.]table MATERIALIZE INDEX name IN PARTITION partition_name
- The query rebuilds the secondary indexname
in the partitionpartition_name
. Implemented as a mutation.
The first two commands areare lightweight in a sense that they only change metadata or remove files.
Also, they are replicated, syncing indices metadata via ZooKeeper.
Note
Index manipulation is supported only for tables with *MergeTree
engine (including
replicated variants).