DROP INDEX
DROP INDEX — remove an index
Synopsis
DROP INDEX [ CONCURRENTLY ] [ IF EXISTS ] name [, ...] [ CASCADE | RESTRICT ]
Description
DROP INDEX removes an existing index from the database system. To execute this command you must be the owner of the index.
Parameters
CONCURRENTLY
Drop the index without blocking concurrent selects, inserts, updates, and deletes on the index's table. A normal DROP INDEX acquires an exclusive lock on the table, blocking other access until the index drop completes. With this option, the command instead waits until conflicting transactions have completed.
There are several caveats to be aware of when using this option. Only one index name can be specified, and the CASCADE option is not supported (thus, an index that supports a UNIQUE or PRIMARY KEY constraint cannot be dropped this way). Also, regular DROP INDEX commands can be executed within a transaction block, but DROP INDEX CONCURRENTLY cannot. Finally, indexes on partitioned tables cannot be dropped using this option.
For temporary tables, DROP INDEX is always non-concurrent, since no other session can access them, and dropping a non-concurrent index is cheaper.
IF EXISTS
Do not throw an error if the index does not exist. A notice is issued in this case.
name
The name of an index to remove (optionally schema-qualified).
CASCADE
Automatically drop objects that depend on the index, and in turn all objects that depend on those objects.
RESTRICT
Refuse to drop the index if any objects depend on it. This is the default.
Examples
# This command will remove the index title_idx:
DROP INDEX title_idx;