> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cockroachlabs.com/llms.txt
> Use this file to discover all available pages before exploring further.

# pg_extension

The `pg_extension` [system catalogs](/docs/stable/system-catalogs.md) provide information about CockroachDB extensions.

This page describes the `pg_extension` system catalog schema. For information about supported `CREATE EXTENSION` statements and PostgreSQL extension-compatible functionality, see [SQL Feature Support > PostgreSQL extensions](/docs/stable/sql-feature-support.md#postgresql-extensions).

## Data exposed by `pg_extension`

In CockroachDB , `pg_extension` contains the following tables, all of which provide information about CockroachDB's [spatial extension](/docs/stable/spatial-data-overview.md):

* `geography_columns`
* `geometry_columns`
* `spatial_ref_sys`

> [!NOTE]
>
> `pg_extension` tables are read-only.

To see the list of tables in `pg_extension` for the [current database](/docs/stable/sql-name-resolution.md#current-database), use the following [`SHOW TABLES`](/docs/stable/show-tables) statement:

```sql theme={"theme":{"light":"catppuccin-mocha","dark":"catppuccin-mocha"}}
> SHOW TABLES FROM pg_extension;
```

```
  schema_name  |    table_name     | type  | owner | estimated_row_count
---------------+-------------------+-------+-------+----------------------
  pg_extension | geography_columns | table | NULL  |                NULL
  pg_extension | geometry_columns  | table | NULL  |                NULL
  pg_extension | spatial_ref_sys   | table | NULL  |                NULL
(3 rows)
```

## Querying `pg_extension` tables

You can run [`SELECT` queries](/docs/stable/selection-queries) on the tables in `pg_extension`.

> [!TIP]
>
> To ensure that you can view all of the tables in `pg_extension`, query the tables as a user with [`admin` privileges](/docs/stable/security-reference/authorization#admin-role).

> [!NOTE]
>
> Unless specified otherwise, queries to `pg_extension` assume the [current database](/docs/stable/sql-name-resolution.md#current-database).

For example, to return the `pg_extension` table with additional information about indexes in the `movr` database, you can query the `pg_extension.pg_indexes` table:

```sql theme={"theme":{"light":"catppuccin-mocha","dark":"catppuccin-mocha"}}
> SELECT * FROM movr.pg_extension.pg_indexes;
```

```
   crdb_oid  | schemaname |         tablename          |                   indexname                   | tablespace |                                                            indexdef
-------------+------------+----------------------------+-----------------------------------------------+------------+---------------------------------------------------------------------------------------------------------------------------------
  2055313241 | public     | users                      | users_pkey                                    | NULL       | CREATE UNIQUE INDEX users_pkey ON movr.public.users USING btree (city ASC, id ASC)
  1795576970 | public     | vehicles                   | vehicles_pkey                                 | NULL       | CREATE UNIQUE INDEX vehicles_pkey ON movr.public.vehicles USING btree (city ASC, id ASC)
  1795576969 | public     | vehicles                   | vehicles_auto_index_fk_city_ref_users         | NULL       | CREATE INDEX vehicles_auto_index_fk_city_ref_users ON movr.public.vehicles USING btree (city ASC, owner_id ASC)
   450499963 | public     | rides                      | rides_pkey                                    | NULL       | CREATE UNIQUE INDEX rides_pkey ON movr.public.rides USING btree (city ASC, id ASC)
   450499960 | public     | rides                      | rides_auto_index_fk_city_ref_users            | NULL       | CREATE INDEX rides_auto_index_fk_city_ref_users ON movr.public.rides USING btree (city ASC, rider_id ASC)
   450499961 | public     | rides                      | rides_auto_index_fk_vehicle_city_ref_vehicles | NULL       | CREATE INDEX rides_auto_index_fk_vehicle_city_ref_vehicles ON movr.public.rides USING btree (vehicle_city ASC, vehicle_id ASC)
  2315049508 | public     | vehicle_location_histories | vehicle_location_histories_pkey               | NULL       | CREATE UNIQUE vehicle_location_histories_pkey ON movr.public.vehicle_location_histories USING btree (city ASC, ride_id ASC, "timestamp" ASC)
   969972501 | public     | promo_codes                | promo_codes_pkey                              | NULL       | CREATE UNIQUE INDEX promo_codes_pkey ON movr.public.promo_codes USING btree (code ASC)
   710236230 | public     | user_promo_codes           | user_promo_codes_pkey                         | NULL       | CREATE UNIQUE INDEX user_promo_codes_pkey ON movr.public.user_promo_codes USING btree (city ASC, user_id ASC, code ASC)
(9 rows)
```

## See also

* [`SHOW`](/docs/stable/show-vars)
* [`SHOW DATABASES`](/docs/stable/show-databases)
* [`SHOW SCHEMAS`](/docs/stable/show-schemas)
* [`SHOW TABLES`](/docs/stable/show-tables)
* [SQL Name Resolution](/docs/stable/sql-name-resolution.md)
* [System Catalogs](/docs/stable/system-catalogs.md)