diff options
Diffstat (limited to 'doc/src/sgml/man7/ALTER_INDEX.7')
| -rw-r--r-- | doc/src/sgml/man7/ALTER_INDEX.7 | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/doc/src/sgml/man7/ALTER_INDEX.7 b/doc/src/sgml/man7/ALTER_INDEX.7 new file mode 100644 index 0000000..79b3923 --- /dev/null +++ b/doc/src/sgml/man7/ALTER_INDEX.7 @@ -0,0 +1,237 @@ +'\" t +.\" Title: ALTER INDEX +.\" Author: The PostgreSQL Global Development Group +.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/> +.\" Date: 2023 +.\" Manual: PostgreSQL 15.5 Documentation +.\" Source: PostgreSQL 15.5 +.\" Language: English +.\" +.TH "ALTER INDEX" "7" "2023" "PostgreSQL 15.5" "PostgreSQL 15.5 Documentation" +.\" ----------------------------------------------------------------- +.\" * Define some portability stuff +.\" ----------------------------------------------------------------- +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.\" http://bugs.debian.org/507673 +.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.\" ----------------------------------------------------------------- +.\" * set default formatting +.\" ----------------------------------------------------------------- +.\" disable hyphenation +.nh +.\" disable justification (adjust text to left margin only) +.ad l +.\" ----------------------------------------------------------------- +.\" * MAIN CONTENT STARTS HERE * +.\" ----------------------------------------------------------------- +.SH "NAME" +ALTER_INDEX \- change the definition of an index +.SH "SYNOPSIS" +.sp +.nf +ALTER INDEX [ IF EXISTS ] \fIname\fR RENAME TO \fInew_name\fR +ALTER INDEX [ IF EXISTS ] \fIname\fR SET TABLESPACE \fItablespace_name\fR +ALTER INDEX \fIname\fR ATTACH PARTITION \fIindex_name\fR +ALTER INDEX \fIname\fR [ NO ] DEPENDS ON EXTENSION \fIextension_name\fR +ALTER INDEX [ IF EXISTS ] \fIname\fR SET ( \fIstorage_parameter\fR [= \fIvalue\fR] [, \&.\&.\&. ] ) +ALTER INDEX [ IF EXISTS ] \fIname\fR RESET ( \fIstorage_parameter\fR [, \&.\&.\&. ] ) +ALTER INDEX [ IF EXISTS ] \fIname\fR ALTER [ COLUMN ] \fIcolumn_number\fR + SET STATISTICS \fIinteger\fR +ALTER INDEX ALL IN TABLESPACE \fIname\fR [ OWNED BY \fIrole_name\fR [, \&.\&.\&. ] ] + SET TABLESPACE \fInew_tablespace\fR [ NOWAIT ] +.fi +.SH "DESCRIPTION" +.PP +\fBALTER INDEX\fR +changes the definition of an existing index\&. There are several subforms described below\&. Note that the lock level required may differ for each subform\&. An +ACCESS EXCLUSIVE +lock is held unless explicitly noted\&. When multiple subcommands are listed, the lock held will be the strictest one required from any subcommand\&. +.PP +RENAME +.RS 4 +The +RENAME +form changes the name of the index\&. If the index is associated with a table constraint (either +UNIQUE, +PRIMARY KEY, or +EXCLUDE), the constraint is renamed as well\&. There is no effect on the stored data\&. +.sp +Renaming an index acquires a +SHARE UPDATE EXCLUSIVE +lock\&. +.RE +.PP +SET TABLESPACE +.RS 4 +This form changes the index\*(Aqs 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 +\fBALTER DATABASE\fR +or explicit +\fBALTER INDEX\fR +invocations instead if desired\&. See also +\fBCREATE TABLESPACE\fR\&. +.RE +.PP +ATTACH PARTITION +.RS 4 +Causes the named index to become attached to the altered index\&. The named index must be on a partition of the table containing the index being altered, and have an equivalent definition\&. An attached index cannot be dropped by itself, and will automatically be dropped if its parent index is dropped\&. +.RE +.PP +DEPENDS ON EXTENSION \fIextension_name\fR +.br +NO DEPENDS ON EXTENSION \fIextension_name\fR +.RS 4 +This form marks the index as dependent on the extension, or no longer dependent on that extension if +NO +is specified\&. An index that\*(Aqs marked as dependent on an extension is automatically dropped when the extension is dropped\&. +.RE +.PP +SET ( \fIstorage_parameter\fR [= \fIvalue\fR] [, \&.\&.\&. ] ) +.RS 4 +This form changes one or more index\-method\-specific storage parameters for the index\&. See +\fBCREATE INDEX\fR +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 +\fBREINDEX\fR +to get the desired effects\&. +.RE +.PP +RESET ( \fIstorage_parameter\fR [, \&.\&.\&. ] ) +.RS 4 +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\&. +.RE +.PP +ALTER [ COLUMN ] \fIcolumn_number\fR SET STATISTICS \fIinteger\fR +.RS 4 +This form sets the per\-column statistics\-gathering target for subsequent +\fBANALYZE\fR +operations, though can be used only on index columns that are defined as an expression\&. Since expressions lack a unique name, we refer to them using the ordinal number of the index column\&. The target can be set in the range 0 to 10000; alternatively, set it to \-1 to revert to using the system default statistics target (default_statistics_target)\&. For more information on the use of statistics by the +PostgreSQL +query planner, refer to +Section\ \&14.2\&. +.RE +.SH "PARAMETERS" +.PP +IF EXISTS +.RS 4 +Do not throw an error if the index does not exist\&. A notice is issued in this case\&. +.RE +.PP +\fIcolumn_number\fR +.RS 4 +The ordinal number refers to the ordinal (left\-to\-right) position of the index column\&. +.RE +.PP +\fIname\fR +.RS 4 +The name (possibly schema\-qualified) of an existing index to alter\&. +.RE +.PP +\fInew_name\fR +.RS 4 +The new name for the index\&. +.RE +.PP +\fItablespace_name\fR +.RS 4 +The tablespace to which the index will be moved\&. +.RE +.PP +\fIextension_name\fR +.RS 4 +The name of the extension that the index is to depend on\&. +.RE +.PP +\fIstorage_parameter\fR +.RS 4 +The name of an index\-method\-specific storage parameter\&. +.RE +.PP +\fIvalue\fR +.RS 4 +The new value for an index\-method\-specific storage parameter\&. This might be a number or a word depending on the parameter\&. +.RE +.SH "NOTES" +.PP +These operations are also possible using +\fBALTER TABLE\fR\&. +\fBALTER INDEX\fR +is in fact just an alias for the forms of +\fBALTER TABLE\fR +that apply to indexes\&. +.PP +There was formerly an +\fBALTER INDEX OWNER\fR +variant, but this is now ignored (with a warning)\&. An index cannot have an owner different from its table\*(Aqs owner\&. Changing the table\*(Aqs owner automatically changes the index as well\&. +.PP +Changing any part of a system catalog index is not permitted\&. +.SH "EXAMPLES" +.PP +To rename an existing index: +.sp +.if n \{\ +.RS 4 +.\} +.nf +ALTER INDEX distributors RENAME TO suppliers; +.fi +.if n \{\ +.RE +.\} +.PP +To move an index to a different tablespace: +.sp +.if n \{\ +.RS 4 +.\} +.nf +ALTER INDEX distributors SET TABLESPACE fasttablespace; +.fi +.if n \{\ +.RE +.\} +.PP +To change an index\*(Aqs fill factor (assuming that the index method supports it): +.sp +.if n \{\ +.RS 4 +.\} +.nf +ALTER INDEX distributors SET (fillfactor = 75); +REINDEX INDEX distributors; +.fi +.if n \{\ +.RE +.\} +.PP +Set the statistics\-gathering target for an expression index: +.sp +.if n \{\ +.RS 4 +.\} +.nf +CREATE INDEX coord_idx ON measured (x, y, (z + t)); +ALTER INDEX coord_idx ALTER COLUMN 3 SET STATISTICS 1000; +.fi +.if n \{\ +.RE +.\} +.SH "COMPATIBILITY" +.PP +\fBALTER INDEX\fR +is a +PostgreSQL +extension\&. +.SH "SEE ALSO" +CREATE INDEX (\fBCREATE_INDEX\fR(7)), \fBREINDEX\fR(7) |