# ALTER INDEX

The `ALTER INDEX` statement applies a schema change to an index.

Note:

This statement performs a schema change. For more information about how online schema changes work in CockroachDB, see Online Schema Changes.

For information on using `ALTER INDEX`, see the documents for its relevant subcommands.

Subcommand | Description
--- | ---
`CONFIGURE ZONE` | New in v2.1: Configure replication zones for an index.
`RENAME` | Change the name of an index.
`SPLIT AT` | Force a key-value layer range split at the specified row in the index.