PostgreSQL 13 Documentation: 51.3. pg_am

51.3. `pg_am`
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51.3. `pg_am`

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 Chapter 60 and Chapter 61 respectively.

Table 51.3. pg_am Columns

Column Type Description
`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.

Column Type

Description

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.

Note

Before PostgreSQL 9.6, pg_am contained many additional columns representing properties of index access methods. That data is now only directly visible at the C code level. However, pg_index_column_has_property() and related functions have been added to allow SQL queries to inspect index access method properties; see Table 9.68.

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