PostgreSQL

52.3. `pg_am`
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52.3. `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 indexes have access methods. The requirements for index access methods are discussed in detail in Chapter 61.

Table 52.3. pg_am Columns

Name Type References Description

Name	Type	References	Description
`oid`	`oid`		Row identifier (hidden attribute; must be explicitly selected)
`amname`	`name`		Name of the access method
`amhandler`	`regproc`	`pg_proc.oid`	OID of a handler function that is responsible for supplying information about the access method
`amtype`	`char`		Currently always `i` to indicate an index access method; other values may be allowed in future

oid

Row identifier (hidden attribute; must be explicitly selected)

amname

name

Name of the access method

amhandler

regproc

pg_proc.oid

OID of a handler function that is responsible for supplying information about the access method

amtype

char

Currently always i to indicate an index access method; other values may be allowed in future

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 9.63.

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52.3. pg_am

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52.3. `pg_am`