1ALTER INDEX(7)           PostgreSQL 11.6 Documentation          ALTER INDEX(7)
2
3
4

NAME

6       ALTER_INDEX - change the definition of an index
7

SYNOPSIS

9       ALTER INDEX [ IF EXISTS ] name RENAME TO new_name
10       ALTER INDEX [ IF EXISTS ] name SET TABLESPACE tablespace_name
11       ALTER INDEX name ATTACH PARTITION index_name
12       ALTER INDEX name DEPENDS ON EXTENSION extension_name
13       ALTER INDEX [ IF EXISTS ] name SET ( storage_parameter = value [, ... ] )
14       ALTER INDEX [ IF EXISTS ] name RESET ( storage_parameter [, ... ] )
15       ALTER INDEX [ IF EXISTS ] name ALTER [ COLUMN ] column_number
16           SET STATISTICS integer
17       ALTER INDEX ALL IN TABLESPACE name [ OWNED BY role_name [, ... ] ]
18           SET TABLESPACE new_tablespace [ NOWAIT ]
19

DESCRIPTION

21       ALTER INDEX changes the definition of an existing index. There are
22       several subforms:
23
24       RENAME
25           The RENAME form changes the name of the index. If the index is
26           associated with a table constraint (either UNIQUE, PRIMARY KEY, or
27           EXCLUDE), the constraint is renamed as well. There is no effect on
28           the stored data.
29
30       SET TABLESPACE
31           This form changes the index's tablespace to the specified
32           tablespace and moves the data file(s) associated with the index to
33           the new tablespace. To change the tablespace of an index, you must
34           own the index and have CREATE privilege on the new tablespace. All
35           indexes in the current database in a tablespace can be moved by
36           using the ALL IN TABLESPACE form, which will lock all indexes to be
37           moved and then move each one. This form also supports OWNED BY,
38           which will only move indexes owned by the roles specified. If the
39           NOWAIT option is specified then the command will fail if it is
40           unable to acquire all of the locks required immediately. Note that
41           system catalogs will not be moved by this command, use ALTER
42           DATABASE or explicit ALTER INDEX invocations instead if desired.
43           See also CREATE TABLESPACE (CREATE_TABLESPACE(7)).
44
45       ATTACH PARTITION
46           Causes the named index to become attached to the altered index. The
47           named index must be on a partition of the table containing the
48           index being altered, and have an equivalent definition. An attached
49           index cannot be dropped by itself, and will automatically be
50           dropped if its parent index is dropped.
51
52       DEPENDS ON EXTENSION
53           This form marks the index as dependent on the extension, such that
54           if the extension is dropped, the index will automatically be
55           dropped as well.
56
57       SET ( storage_parameter = value [, ... ] )
58           This form changes one or more index-method-specific storage
59           parameters for the index. See CREATE INDEX (CREATE_INDEX(7)) for
60           details on the available parameters. Note that the index contents
61           will not be modified immediately by this command; depending on the
62           parameter you might need to rebuild the index with REINDEX(7) to
63           get the desired effects.
64
65       RESET ( storage_parameter [, ... ] )
66           This form resets one or more index-method-specific storage
67           parameters to their defaults. As with SET, a REINDEX might be
68           needed to update the index entirely.
69
70       ALTER [ COLUMN ] column_number SET STATISTICS integer
71           This form sets the per-column statistics-gathering target for
72           subsequent ANALYZE(7) operations, though can be used only on index
73           columns that are defined as an expression. Since expressions lack a
74           unique name, we refer to them using the ordinal number of the index
75           column. The target can be set in the range 0 to 10000;
76           alternatively, set it to -1 to revert to using the system default
77           statistics target (default_statistics_target). For more information
78           on the use of statistics by the PostgreSQL query planner, refer to
79           Section 14.2.
80

PARAMETERS

82       IF EXISTS
83           Do not throw an error if the index does not exist. A notice is
84           issued in this case.
85
86       column_number
87           The ordinal number refers to the ordinal (left-to-right) position
88           of the index column.
89
90       name
91           The name (possibly schema-qualified) of an existing index to alter.
92
93       new_name
94           The new name for the index.
95
96       tablespace_name
97           The tablespace to which the index will be moved.
98
99       extension_name
100           The name of the extension that the index is to depend on.
101
102       storage_parameter
103           The name of an index-method-specific storage parameter.
104
105       value
106           The new value for an index-method-specific storage parameter. This
107           might be a number or a word depending on the parameter.
108

NOTES

110       These operations are also possible using ALTER TABLE (ALTER_TABLE(7)).
111       ALTER INDEX is in fact just an alias for the forms of ALTER TABLE that
112       apply to indexes.
113
114       There was formerly an ALTER INDEX OWNER variant, but this is now
115       ignored (with a warning). An index cannot have an owner different from
116       its table's owner. Changing the table's owner automatically changes the
117       index as well.
118
119       Changing any part of a system catalog index is not permitted.
120

EXAMPLES

122       To rename an existing index:
123
124           ALTER INDEX distributors RENAME TO suppliers;
125
126       To move an index to a different tablespace:
127
128           ALTER INDEX distributors SET TABLESPACE fasttablespace;
129
130       To change an index's fill factor (assuming that the index method
131       supports it):
132
133           ALTER INDEX distributors SET (fillfactor = 75);
134           REINDEX INDEX distributors;
135
136       Set the statistics-gathering target for an expression index:
137
138           CREATE INDEX coord_idx ON measured (x, y, (z + t));
139           ALTER INDEX coord_idx ALTER COLUMN 3 SET STATISTICS 1000;
140

COMPATIBILITY

142       ALTER INDEX is a PostgreSQL extension.
143

SEE ALSO

145       CREATE INDEX (CREATE_INDEX(7)), REINDEX(7)
146
147
148
149PostgreSQL 11.6                      2019                       ALTER INDEX(7)
Impressum