Table of Contents
This appendix and the next one contain information regarding the modules that
can be found in the contrib
directory of the
PostgreSQL distribution.
These include porting tools, analysis utilities,
and plug-in features that are not part of the core PostgreSQL system,
mainly because they address a limited audience or are too experimental
to be part of the main source tree. This does not preclude their
usefulness.
This appendix covers extensions and other server plug-in modules found in
contrib
. Appendix G covers utility
programs.
When building from the source distribution, these components are not built automatically, unless you build the "world" target (see Step 2). You can build and install all of them by running:
make
make install
in the contrib
directory of a configured source tree;
or to build and install
just one selected module, do the same in that module's subdirectory.
Many of the modules have regression tests, which can be executed by
running:
make check
before installation or
make installcheck
once you have a PostgreSQL server running.
If you are using a pre-packaged version of PostgreSQL,
these modules are typically made available as a separate subpackage,
such as postgresql-contrib
.
Many modules supply new user-defined functions, operators, or types. To make use of one of these modules, after you have installed the code you need to register the new SQL objects in the database system. In PostgreSQL 9.1 and later, this is done by executing a CREATE EXTENSION command. In a fresh database, you can simply do
CREATE EXTENSION module_name
;
This command must be run by a database superuser. This registers the
new SQL objects in the current database only, so you need to run this
command in each database that you want
the module's facilities to be available in. Alternatively, run it in
database template1
so that the extension will be copied into
subsequently-created databases by default.
Many modules allow you to install their objects in a schema of your
choice. To do that, add SCHEMA
to the schema_name
CREATE EXTENSION
command. By default, the objects will be placed in your current creation
target schema, which in turn defaults to public
.
If your database was brought forward by dump and reload from a pre-9.1 version of PostgreSQL, and you had been using the pre-9.1 version of the module in it, you should instead do
CREATE EXTENSION module_name
FROM unpackaged;
This will update the pre-9.1 objects of the module into a proper extension object. Future updates to the module will be managed by ALTER EXTENSION. For more information about extension updates, see Section 38.17.
Note, however, that some of these modules are not “extensions” in this sense, but are loaded into the server in some other way, for instance by way of shared_preload_libraries. See the documentation of each module for details.