## Chapter 54. System Views

In addition to the system catalogs, PostgreSQL provides a number of built-in views. Some system views provide convenient access to some commonly used queries on the system catalogs. Other views provide access to internal server state.

The information schema (Chapter 37) provides an alternative set of views which overlap the functionality of the system views. Since the information schema is SQL-standard whereas the views described here are PostgreSQL-specific, it's usually better to use the information schema if it provides all the information you need.

Table 54.1 lists the system views described here. More detailed documentation of each view follows below. There are some additional views that provide access to accumulated statistics; they are described in Table 28.2.

## 54.1. Overview

Table 54.1 lists the system views. More detailed documentation of each catalog follows below. Except where noted, all the views described here are read-only.

Table 54.1. System Views

View Name | Purpose
--- | ---
`pg_available_extensions` | available extensions
`pg_available_extension_versions` | available versions of extensions
`pg_backend_memory_contexts` | backend memory contexts
`pg_config` | compile-time configuration parameters
`pg_cursors` | open cursors
`pg_file_settings` | summary of configuration file contents
`pg_group` | groups of database users
`pg_hba_file_rules` | summary of client authentication configuration file contents
`pg_ident_file_mappings` | summary of client user name mapping configuration file contents
`pg_indexes` | indexes
`pg_locks` | locks currently held or awaited
`pg_matviews` | materialized views
`pg_policies` | policies
`pg_prepared_statements` | prepared statements
`pg_prepared_xacts` | prepared transactions
`pg_publication_tables` | publications and information of their associated tables
`pg_replication_origin_status` | information about replication origins, including replication progress
`pg_replication_slots` | replication slot information
`pg_roles` | database roles
`pg_rules` | rules
`pg_seclabels` | security labels
`pg_sequences` | sequences
`pg_settings` | parameter settings
`pg_shadow` | database users
`pg_shmem_allocations` | shared memory allocations
`pg_stats` | planner statistics
`pg_stats_ext` | extended planner statistics
`pg_stats_ext_exprs` | extended planner statistics for expressions
`pg_tables` | tables
`pg_timezone_abbrevs` | time zone abbreviations
`pg_timezone_names` | time zone names
`pg_user` | database users
`pg_user_mappings` | user mappings
`pg_views` | views