NAME
ALTER INDEX - change the definition of an index
SYNOPSIS
ALTER INDEX name RENAME TO new_name
ALTER INDEX name SET TABLESPACE tablespace_name
ALTER INDEX name SET ( storage_parameter = value [, ... ] )
ALTER INDEX name RESET ( storage_parameter [, ... ] )
DESCRIPTION
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. See also CREATE TABLESPACE
[create_tablespace(7)].
SET ( storage_parameter = value [, ... ] )
This form changes one or more index-method-specific storage
parameters for the index. See CREATE INDEX [create_index(7)] 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 [reindex(7)] 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.
PARAMETERS
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.
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.
NOTES
These operations are also possible using ALTER TABLE [alter_table(7)].
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.
EXAMPLES
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;
COMPATIBILITY
ALTER INDEX is a PostgreSQL extension.
SEE ALSO
CREATE INDEX [create_index(7)], REINDEX [reindex(7)]