SQL Commands / Indexes & Statistics

DROP INDEX

remove an index

Reading PG 18current·documented in 30 of 30 versions, 6.4 to 20

6.4 6.5 7.0 7.1 7.2 7.3 7.4 8.0 8.1 8.2 8.3 8.4 9.0 9.1 9.2 9.3 9.4 9.5 9.6 10 11 12 13 14 15 16 17 18 19 20

Lock modes

These modes are associated with DROP INDEX in PostgreSQL 18. The affected object, command options and execution phase determine which locks are acquired. Open a mode for its conditions and conflicts.

SHARE UPDATE EXCLUSIVE Table lock ACCESS EXCLUSIVE Table lock

All command variants and compatibility matrices

Syntax

DROP INDEX [ CONCURRENTLY ] [ IF EXISTS ] name [, ...] [ CASCADE | RESTRICT ]

Syntax diagrams

Read left to right. Branches are choices, bypasses are optional, loops repeat. Select an underlined parameter to open its rule.

Description

DROP INDEX drops 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 locking out concurrent selects, inserts, updates, and deletes on the index's table. A normal DROP INDEX acquires an ACCESS EXCLUSIVE lock on the table, blocking other accesses until the index drop can be completed. 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 performed within a transaction block, but DROP INDEX CONCURRENTLY cannot. Lastly, indexes on partitioned tables cannot be dropped using this option.

For temporary tables, DROP INDEX is always non-concurrent, as no other session can access them, and non-concurrent index drop 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 (optionally schema-qualified) of an index to remove.

CASCADE

Automatically drop objects that depend on the index, and in turn all objects that depend on those objects (see Section 5.15).

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;

Compatibility

DROP INDEX is a PostgreSQL language extension. There are no provisions for indexes in the SQL standard.

Related entries

CREATE INDEX

Definition snapshot: b7bd9cda · English manual source