pg_am — PostgreSQL system catalog

Summary

The catalog pg_am stores information about relation access methods. There is one row for each access method supported by the system. Currently, only tables and indexes have access methods. The requirements for table and index access methods are discussed in detail in tableam and indexam respectively.

(Description quoted from the official PostgreSQL documentation.)

Columns

The pg_am system catalog exposes the following columns (names, types and descriptions are taken verbatim from the PostgreSQL documentation):

• oid oid
  Row identifier
• amname name
  Name of the access method
• amhandler regproc references pg_proc.oid
  OID of a handler function that is responsible for supplying information about the access method
• amtype char
  t = table (including materialized views), i = index.

Related catalogs

This object references the following other system catalogs:

• amhandler → pg_proc

Version applicability

Present in PostgreSQL 17, 18, 19 (verified against each release’s documentation). This is a long-standing system object that also exists in earlier PostgreSQL releases.

Related & references

• PostgreSQL system catalog & view index
• Built-in function reference

Reference: PostgreSQL documentation — pg_am.