ALTER INDEX — change the definition of an index
ALTER INDEX [ IF EXISTS ]name
RENAME TOnew_name
ALTER INDEX [ IF EXISTS ]name
SET TABLESPACEtablespace_name
ALTER INDEXname
DEPENDS ON EXTENSIONextension_name
ALTER INDEX [ IF EXISTS ]name
SET (storage_parameter
=value
[, ... ] ) ALTER INDEX [ IF EXISTS ]name
RESET (storage_parameter
[, ... ] ) ALTER INDEX ALL IN TABLESPACEname
[ OWNED BYrole_name
[, ... ] ] SET TABLESPACEnew_tablespace
[ NOWAIT ]
ALTER INDEX
changes the definition of an existing index.
There are several subforms:
RENAME
The RENAME
form changes the name of the index.
There is no effect on the stored data.
SET TABLESPACE
This form changes the index's tablespace to the specified tablespace and
moves the data file(s) associated with the index to the new tablespace.
To change the tablespace of an index, you must own the index and have
CREATE
privilege on the new tablespace.
All indexes in the current database in a tablespace can be moved by using
the ALL IN TABLESPACE
form, which will lock all
indexes to be moved and then move each one. This form also supports
OWNED BY
, which will only move indexes owned by the
roles specified. If the NOWAIT
option is specified
then the command will fail if it is unable to acquire all of the locks
required immediately. Note that system catalogs will not be moved by
this command, use ALTER DATABASE
or explicit
ALTER INDEX
invocations instead if desired.
See also
CREATE TABLESPACE.
DEPENDS ON EXTENSION
This form marks the index as dependent on the extension, such that if the extension is dropped, the index will automatically be dropped as well.
SET ( storage_parameter
= value
[, ... ] )
This form changes one or more index-method-specific storage parameters for the index. See CREATE INDEX for details on the available parameters. Note that the index contents will not be modified immediately by this command; depending on the parameter you might need to rebuild the index with REINDEX to get the desired effects.
RESET ( storage_parameter
[, ... ] )
This form resets one or more index-method-specific storage parameters to
their defaults. As with SET
, a REINDEX
might be needed to update the index entirely.
IF EXISTS
Do not throw an error if the index does not exist. A notice is issued in this case.
name
The name (possibly schema-qualified) of an existing index to alter.
new_name
The new name for the index.
tablespace_name
The tablespace to which the index will be moved.
extension_name
The name of the extension that the index is to depend on.
storage_parameter
The name of an index-method-specific storage parameter.
value
The new value for an index-method-specific storage parameter. This might be a number or a word depending on the parameter.
These operations are also possible using
ALTER TABLE.
ALTER INDEX
is in fact just an alias for the forms
of ALTER TABLE
that apply to indexes.
There was formerly an ALTER INDEX OWNER
variant, but
this is now ignored (with a warning). An index cannot have an owner
different from its table's owner. Changing the table's owner
automatically changes the index as well.
Changing any part of a system catalog index is not permitted.
To rename an existing index:
ALTER INDEX distributors RENAME TO suppliers;
To move an index to a different tablespace:
ALTER INDEX distributors SET TABLESPACE fasttablespace;
To change an index's fill factor (assuming that the index method supports it):
ALTER INDEX distributors SET (fillfactor = 75); REINDEX INDEX distributors;
ALTER INDEX
is a PostgreSQL
extension.