DROP INDEX - remove an index
DROP INDEX [ CONCURRENTLY ] [ IF EXISTS ]
name[, ...] [ CASCADE | RESTRICT ]
drops an existing index from the database
system. To execute this command you must be the owner of
Drop the index without locking out concurrent selects, inserts, updates, and deletes on the index's table. A normal
DROP INDEXacquires an
ACCESS EXCLUSIVElock 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
CASCADEoption is not supported. (Thus, an index that supports a
PRIMARY KEYconstraint cannot be dropped this way.) Also, regular
DROP INDEXcommands can be performed within a transaction block, but
DROP INDEX CONCURRENTLYcannot. Lastly, indexes on partitioned tables cannot be dropped using this option.
For temporary tables,
DROP INDEXis always non-concurrent, as no other session can access them, and non-concurrent index drop is cheaper.
Do not throw an error if the index does not exist. A notice is issued in this case.
The name (optionally schema-qualified) of an index to remove.
Automatically drop objects that depend on the index, and in turn all objects that depend on those objects (see Section 5.13 ).
Refuse to drop the index if any objects depend on it. This is the default.
This command will remove the index
DROP INDEX title_idx;
language extension. There
are no provisions for indexes in the SQL standard.