CREATE EXTENSION(7) PostgreSQL 15.7 Documentation CREATE EXTENSION(7)
NAME
CREATE_EXTENSION - install an extension
SYNOPSIS
CREATE EXTENSION [ IF NOT EXISTS ] extension_name
[ WITH ] [ SCHEMA schema_name ]
[ VERSION version ]
[ CASCADE ]
DESCRIPTION
CREATE EXTENSION loads a new extension into the current database. There
must not be an extension of the same name already loaded.
Loading an extension essentially amounts to running the extension's
script file. The script will typically create new SQL objects such as
functions, data types, operators and index support methods. CREATE
EXTENSION additionally records the identities of all the created
objects, so that they can be dropped again if DROP EXTENSION is issued.
The user who runs CREATE EXTENSION becomes the owner of the extension
for purposes of later privilege checks, and normally also becomes the
owner of any objects created by the extension's script.
Loading an extension ordinarily requires the same privileges that would
be required to create its component objects. For many extensions this
means superuser privileges are needed. However, if the extension is
marked trusted in its control file, then it can be installed by any
user who has CREATE privilege on the current database. In this case the
extension object itself will be owned by the calling user, but the
contained objects will be owned by the bootstrap superuser (unless the
extension's script explicitly assigns them to the calling user). This
configuration gives the calling user the right to drop the extension,
but not to modify individual objects within it.
PARAMETERS
IF NOT EXISTS
Do not throw an error if an extension with the same name already
exists. A notice is issued in this case. Note that there is no
guarantee that the existing extension is anything like the one that
would have been created from the currently-available script file.
extension_name
The name of the extension to be installed. PostgreSQL will create
the extension using details from the file
SHAREDIR/extension/extension_name.control.
schema_name
The name of the schema in which to install the extension's objects,
given that the extension allows its contents to be relocated. The
named schema must already exist. If not specified, and the
extension's control file does not specify a schema either, the
current default object creation schema is used.
If the extension specifies a schema parameter in its control file,
then that schema cannot be overridden with a SCHEMA clause.
Normally, an error will be raised if a SCHEMA clause is given and
it conflicts with the extension's schema parameter. However, if the
CASCADE clause is also given, then schema_name is ignored when it
conflicts. The given schema_name will be used for installation of
any needed extensions that do not specify schema in their control
files.
Remember that the extension itself is not considered to be within
any schema: extensions have unqualified names that must be unique
database-wide. But objects belonging to the extension can be within
schemas.
version
The version of the extension to install. This can be written as
either an identifier or a string literal. The default version is
whatever is specified in the extension's control file.
CASCADE
Automatically install any extensions that this extension depends on
that are not already installed. Their dependencies are likewise
automatically installed, recursively. The SCHEMA clause, if given,
applies to all extensions that get installed this way. Other
options of the statement are not applied to automatically-installed
extensions; in particular, their default versions are always
selected.
NOTES
Before you can use CREATE EXTENSION to load an extension into a
database, the extension's supporting files must be installed.
Information about installing the extensions supplied with PostgreSQL
can be found in Additional Supplied Modules.
The extensions currently available for loading can be identified from
the pg_available_extensions or pg_available_extension_versions system
views.
Caution
Installing an extension as superuser requires trusting that the
extension's author wrote the extension installation script in a
secure fashion. It is not terribly difficult for a malicious user
to create trojan-horse objects that will compromise later execution
of a carelessly-written extension script, allowing that user to
acquire superuser privileges. However, trojan-horse objects are
only hazardous if they are in the search_path during script
execution, meaning that they are in the extension's installation
target schema or in the schema of some extension it depends on.
Therefore, a good rule of thumb when dealing with extensions whose
scripts have not been carefully vetted is to install them only into
schemas for which CREATE privilege has not been and will not be
granted to any untrusted users. Likewise for any extensions they
depend on.
The extensions supplied with PostgreSQL are believed to be secure
against installation-time attacks of this sort, except for a few
that depend on other extensions. As stated in the documentation for
those extensions, they should be installed into secure schemas, or
installed into the same schemas as the extensions they depend on,
or both.
For information about writing new extensions, see Section 38.17.
EXAMPLES
Install the hstore extension into the current database, placing its
objects in schema addons:
CREATE EXTENSION hstore SCHEMA addons;
Another way to accomplish the same thing:
SET search_path = addons;
CREATE EXTENSION hstore;
COMPATIBILITY
CREATE EXTENSION is a PostgreSQL extension.
SEE ALSO
ALTER EXTENSION (ALTER_EXTENSION(7)), DROP EXTENSION
(DROP_EXTENSION(7))
PostgreSQL 15.7 2024 CREATE EXTENSION(7)
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