# pg_extension

The system catalog table `pg_extension` stores information about installed extensions.

Table 1. `pg_catalog.pg_exttable`

| column            | type    | references            | description                                                  |
| :---------------- | :------ | :-------------------- | :----------------------------------------------------------- |
|`oid`|	oid ||		The object ID
|`extname`|	name||		Name of the extension
|`extowner`|	oid|	pg_authid.oid|	Owner of the extension
|`extnamespace`|	oid|	pg_namespace.oid|	Schema containing the extension exported objects
|`extrelocatable`|	boolean		||True if the extension can be relocated to another schema
|`extversion`|	text||		Version name for the extension
|`extconfig`|	oid[]|	pg_class.oid |	Array of regclass OIDs for the extension configuration tables, or NULL if none.
|`extcondition`|	text[]||		Array of WHERE-clause filter conditions for the extension configuration tables, or NULL if none.

Unlike most catalogs with a namespace column, `extnamespace` does not imply that the extension belongs to that schema. Extension names are never schema-qualified. The `extnamespace` schema indicates the schema that contains most or all of the extension objects. If `extrelocatable` is `true`, then this schema must contain all schema-qualifiable objects that belong to the extension.