---
title: "Overview"
id: catalogs-overview
pg_version: "20devel"
---

<a id="catalogs-overview"></a>

## 52.1. Overview

[Table 52.1](catalogs-overview.md#catalog-table) lists the system catalogs. More detailed documentation of each catalog follows below. 

Most system catalogs are copied from the template database during database creation and are thereafter database-specific. A few catalogs are physically shared across all databases in a cluster; these are noted in the descriptions of the individual catalogs. 

<a id="catalog-table"></a>

**System Catalogs**

| Catalog Name | Purpose | 
| --- | --- |
| [pg_aggregate](catalog-pg-aggregate.md) | aggregate functions | 
| [pg_am](catalog-pg-am.md) | relation access methods | 
| [pg_amop](catalog-pg-amop.md) | access method operators | 
| [pg_amproc](catalog-pg-amproc.md) | access method support functions | 
| [pg_attrdef](catalog-pg-attrdef.md) | column default values | 
| [pg_attribute](catalog-pg-attribute.md) | table columns ("attributes") | 
| [pg_authid](catalog-pg-authid.md) | authorization identifiers (roles) | 
| [pg_auth_members](catalog-pg-auth-members.md) | authorization identifier membership relationships | 
| [pg_cast](catalog-pg-cast.md) | casts (data type conversions) | 
| [pg_class](catalog-pg-class.md) | tables, indexes, sequences, views ("relations") | 
| [pg_collation](catalog-pg-collation.md) | collations (locale information) | 
| [pg_constraint](catalog-pg-constraint.md) | check constraints, unique constraints, primary key constraints, foreign key constraints | 
| [pg_conversion](catalog-pg-conversion.md) | encoding conversion information | 
| [pg_database](catalog-pg-database.md) | databases within this database cluster | 
| [pg_db_role_setting](catalog-pg-db-role-setting.md) | per-role and per-database settings | 
| [pg_default_acl](catalog-pg-default-acl.md) | default privileges for object types | 
| [pg_depend](catalog-pg-depend.md) | dependencies between database objects | 
| [pg_description](catalog-pg-description.md) | descriptions or comments on database objects | 
| [pg_enum](catalog-pg-enum.md) | enum label and value definitions | 
| [pg_event_trigger](catalog-pg-event-trigger.md) | event triggers | 
| [pg_extension](catalog-pg-extension.md) | installed extensions | 
| [pg_foreign_data_wrapper](catalog-pg-foreign-data-wrapper.md) | foreign-data wrapper definitions | 
| [pg_foreign_server](catalog-pg-foreign-server.md) | foreign server definitions | 
| [pg_foreign_table](catalog-pg-foreign-table.md) | additional foreign table information | 
| [pg_index](catalog-pg-index.md) | additional index information | 
| [pg_inherits](catalog-pg-inherits.md) | table inheritance hierarchy | 
| [pg_init_privs](catalog-pg-init-privs.md) | object initial privileges | 
| [pg_language](catalog-pg-language.md) | languages for writing functions | 
| [pg_largeobject](catalog-pg-largeobject.md) | data pages for large objects | 
| [pg_largeobject_metadata](catalog-pg-largeobject-metadata.md) | metadata for large objects | 
| [pg_namespace](catalog-pg-namespace.md) | schemas | 
| [pg_opclass](catalog-pg-opclass.md) | access method operator classes | 
| [pg_operator](catalog-pg-operator.md) | operators | 
| [pg_opfamily](catalog-pg-opfamily.md) | access method operator families | 
| [pg_parameter_acl](catalog-pg-parameter-acl.md) | configuration parameters for which privileges have been granted | 
| [pg_partitioned_table](catalog-pg-partitioned-table.md) | information about partition key of tables | 
| [pg_policy](catalog-pg-policy.md) | row-security policies | 
| [pg_proc](catalog-pg-proc.md) | functions and procedures | 
| [pg_propgraph_element](catalog-pg-propgraph-element.md) | property graph elements (vertices and edges) | 
| [pg_propgraph_element_label](catalog-pg-propgraph-element-label.md) | property graph links between elements and labels | 
| [pg_propgraph_label](catalog-pg-propgraph-label.md) | property graph labels | 
| [pg_propgraph_label_property](catalog-pg-propgraph-label-property.md) | property graph label-specific property definitions | 
| [pg_propgraph_property](catalog-pg-propgraph-property.md) | property graph properties | 
| [pg_publication](catalog-pg-publication.md) | publications for logical replication | 
| [pg_publication_namespace](catalog-pg-publication-namespace.md) | schema to publication mapping | 
| [pg_publication_rel](catalog-pg-publication-rel.md) | relation to publication mapping | 
| [pg_range](catalog-pg-range.md) | information about range types | 
| [pg_replication_origin](catalog-pg-replication-origin.md) | registered replication origins | 
| [pg_rewrite](catalog-pg-rewrite.md) | query rewrite rules | 
| [pg_seclabel](catalog-pg-seclabel.md) | security labels on database objects | 
| [pg_sequence](catalog-pg-sequence.md) | information about sequences | 
| [pg_shdepend](catalog-pg-shdepend.md) | dependencies on shared objects | 
| [pg_shdescription](catalog-pg-shdescription.md) | comments on shared objects | 
| [pg_shseclabel](catalog-pg-shseclabel.md) | security labels on shared database objects | 
| [pg_statistic](catalog-pg-statistic.md) | planner statistics | 
| [pg_statistic_ext](catalog-pg-statistic-ext.md) | extended planner statistics (definition) | 
| [pg_statistic_ext_data](catalog-pg-statistic-ext-data.md) | extended planner statistics (built statistics) | 
| [pg_subscription](catalog-pg-subscription.md) | logical replication subscriptions | 
| [pg_subscription_rel](catalog-pg-subscription-rel.md) | relation state for subscriptions | 
| [pg_tablespace](catalog-pg-tablespace.md) | tablespaces within this database cluster | 
| [pg_transform](catalog-pg-transform.md) | transforms (data type to procedural language conversions) | 
| [pg_trigger](catalog-pg-trigger.md) | triggers | 
| [pg_ts_config](catalog-pg-ts-config.md) | text search configurations | 
| [pg_ts_config_map](catalog-pg-ts-config-map.md) | text search configurations' token mappings | 
| [pg_ts_dict](catalog-pg-ts-dict.md) | text search dictionaries | 
| [pg_ts_parser](catalog-pg-ts-parser.md) | text search parsers | 
| [pg_ts_template](catalog-pg-ts-template.md) | text search templates | 
| [pg_type](catalog-pg-type.md) | data types | 
| [pg_user_mapping](catalog-pg-user-mapping.md) | mappings of users to foreign servers |