postgresql/doc/src/sgml/ref/create_materialized_view.sgml

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<!--
doc/src/sgml/ref/create_materialized_view.sgml
PostgreSQL documentation
-->
<refentry id="sql-creatematerializedview">
<indexterm zone="sql-creatematerializedview">
<primary>CREATE MATERIALIZED VIEW</primary>
</indexterm>
<refmeta>
<refentrytitle>CREATE MATERIALIZED VIEW</refentrytitle>
<manvolnum>7</manvolnum>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
<refnamediv>
<refname>CREATE MATERIALIZED VIEW</refname>
<refpurpose>define a new materialized view</refpurpose>
</refnamediv>
<refsynopsisdiv>
<synopsis>
CREATE MATERIALIZED VIEW [ IF NOT EXISTS ] <replaceable>table_name</replaceable>
[ (<replaceable>column_name</replaceable> [, ...] ) ]
[ USING <replaceable class="parameter">method</replaceable> ]
[ WITH ( <replaceable class="parameter">storage_parameter</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] ) ]
[ TABLESPACE <replaceable class="parameter">tablespace_name</replaceable> ]
AS <replaceable>query</replaceable>
[ WITH [ NO ] DATA ]
</synopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
<command>CREATE MATERIALIZED VIEW</command> defines a materialized view of
a query. The query is executed and used to populate the view at the time
the command is issued (unless <command>WITH NO DATA</command> is used) and may be
refreshed later using <command>REFRESH MATERIALIZED VIEW</command>.
</para>
<para>
<command>CREATE MATERIALIZED VIEW</command> is similar to
<command>CREATE TABLE AS</command>, except that it also remembers the query used
to initialize the view, so that it can be refreshed later upon demand.
A materialized view has many of the same properties as a table, but there
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-21 00:36:57 +01:00
is no support for temporary materialized views.
</para>
<para>
<command>CREATE MATERIALIZED VIEW</command> requires
<literal>CREATE</literal> privilege on the schema used for the materialized
view.
</para>
</refsect1>
<refsect1>
<title>Parameters</title>
2014-12-13 20:16:16 +01:00
<variablelist>
<varlistentry>
<term><literal>IF NOT EXISTS</literal></term>
<listitem>
<para>
Do not throw an error if a materialized view with the same name already
exists. A notice is issued in this case. Note that there is no guarantee
that the existing materialized view is anything like the one that would
have been created.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable>table_name</replaceable></term>
<listitem>
<para>
The name (optionally schema-qualified) of the materialized view to be
created. The name must be distinct from the name of any other relation
(table, sequence, index, view, materialized view, or foreign table) in
the same schema.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable>column_name</replaceable></term>
<listitem>
<para>
The name of a column in the new materialized view. If column names are
not provided, they are taken from the output column names of the query.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>USING <replaceable class="parameter">method</replaceable></literal></term>
<listitem>
<para>
This optional clause specifies the table access method to use to store
the contents for the new materialized view; the method needs be an
access method of type <literal>TABLE</literal>. See <xref
linkend="tableam"/> for more information. If this option is not
specified, the default table access method is chosen for the new
materialized view. See <xref linkend="guc-default-table-access-method"/>
for more information.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>WITH ( <replaceable class="parameter">storage_parameter</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] )</literal></term>
<listitem>
<para>
This clause specifies optional storage parameters for the new
2020-05-11 20:15:49 +02:00
materialized view; see
<xref linkend="sql-createtable-storage-parameters"/> in the
<xref linkend="sql-createtable"/> documentation for more
information. All parameters supported for <literal>CREATE
TABLE</literal> are also supported for <literal>CREATE MATERIALIZED
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-21 00:36:57 +01:00
VIEW</literal>.
See <xref linkend="sql-createtable"/> for more information.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>TABLESPACE <replaceable class="parameter">tablespace_name</replaceable></literal></term>
<listitem>
<para>
The <replaceable class="parameter">tablespace_name</replaceable> is the name
of the tablespace in which the new materialized view is to be created.
If not specified, <xref linkend="guc-default-tablespace"/> is consulted.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable>query</replaceable></term>
<listitem>
<para>
Improve <xref> vs. <command> formatting in the documentation SQL commands are generally marked up as <command>, except when a link to a reference page is used using <xref>. But the latter doesn't create monospace markup, so this looks strange especially when a paragraph contains a mix of links and non-links. We considered putting <command> in the <refentrytitle> on the target side, but that creates some formatting side effects elsewhere. Generally, it seems safer to solve this on the link source side. We can't put the <xref> inside the <command>; the DTD doesn't allow this. DocBook 5 would allow the <command> to have the linkend attribute itself, but we are not there yet. So to solve this for now, convert the <xref>s to <link> plus <command>. This gives the correct look and also gives some more flexibility what we can put into the link text (e.g., subcommands or other clauses). In the future, these could then be converted to DocBook 5 style. I haven't converted absolutely all xrefs to SQL command reference pages, only those where we care about the appearance of the link text or where it was otherwise appropriate to make the appearance match a bit better. Also in some cases, the links where repetitive, so in those cases the links where just removed and replaced by a plain <command>. In cases where we just want the link and don't specifically care about the generated link text (typically phrased "for further information see <xref ...>") the xref is kept. Reported-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org> Discussion: https://www.postgresql.org/message-id/flat/87o8pco34z.fsf@wibble.ilmari.org
2020-10-03 16:16:51 +02:00
A <link linkend="sql-select"><command>SELECT</command></link>, <link linkend="sql-table"><command>TABLE</command></link>,
or <link linkend="sql-values"><command>VALUES</command></link> command. This query will run within a
security-restricted operation; in particular, calls to functions that
themselves create temporary tables will fail.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>WITH [ NO ] DATA</literal></term>
<listitem>
<para>
This clause specifies whether or not the materialized view should be
populated at creation time. If not, the materialized view will be
flagged as unscannable and cannot be queried until <command>REFRESH
MATERIALIZED VIEW</command> is used.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Compatibility</title>
<para>
<command>CREATE MATERIALIZED VIEW</command> is a
<productname>PostgreSQL</productname> extension.
</para>
</refsect1>
<refsect1>
<title>See Also</title>
<simplelist type="inline">
<member><xref linkend="sql-altermaterializedview"/></member>
<member><xref linkend="sql-createtableas"/></member>
<member><xref linkend="sql-createview"/></member>
<member><xref linkend="sql-dropmaterializedview"/></member>
<member><xref linkend="sql-refreshmaterializedview"/></member>
</simplelist>
</refsect1>
</refentry>