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1<?xml version="1.0" encoding="UTF-8" standalone="no"?>2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>53.3. pg_am</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="catalog-pg-aggregate.html" title="53.2. pg_aggregate" /><link rel="next" href="catalog-pg-amop.html" title="53.4. pg_amop" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">53.3. <code class="structname">pg_am</code></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="catalog-pg-aggregate.html" title="53.2. pg_aggregate">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="catalogs.html" title="Chapter 53. System Catalogs">Up</a></td><th width="60%" align="center">Chapter 53. System Catalogs</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 16.3 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="catalog-pg-amop.html" title="53.4. pg_amop">Next</a></td></tr></table><hr /></div><div class="sect1" id="CATALOG-PG-AM"><div class="titlepage"><div><div><h2 class="title" style="clear: both">53.3. <code class="structname">pg_am</code> <a href="#CATALOG-PG-AM" class="id_link">#</a></h2></div></div></div><a id="id-1.10.4.5.2" class="indexterm"></a><p>3   The catalog <code class="structname">pg_am</code> stores information about4   relation access methods.  There is one row for each access method supported5   by the system.6   Currently, only tables and indexes have access methods. The requirements for table7   and index access methods are discussed in detail in <a class="xref" href="tableam.html" title="Chapter 63. Table Access Method Interface Definition">Chapter 63</a> and8   <a class="xref" href="indexam.html" title="Chapter 64. Index Access Method Interface Definition">Chapter 64</a> respectively.9  </p><div class="table" id="id-1.10.4.5.4"><p class="title"><strong>Table 53.3. <code class="structname">pg_am</code> Columns</strong></p><div class="table-contents"><table class="table" summary="pg_am Columns" border="1"><colgroup><col /></colgroup><thead><tr><th class="catalog_table_entry"><p class="column_definition">10       Column Type11      </p>12      <p>13       Description14      </p></th></tr></thead><tbody><tr><td class="catalog_table_entry"><p class="column_definition">15       <code class="structfield">oid</code> <code class="type">oid</code>16      </p>17      <p>18       Row identifier19      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">20       <code class="structfield">amname</code> <code class="type">name</code>21      </p>22      <p>23       Name of the access method24      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">25       <code class="structfield">amhandler</code> <code class="type">regproc</code>26       (references <a class="link" href="catalog-pg-proc.html" title="53.39. pg_proc"><code class="structname">pg_proc</code></a>.<code class="structfield">oid</code>)27      </p>28      <p>29       OID of a handler function that is responsible for supplying information30       about the access method31      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">32       <code class="structfield">amtype</code> <code class="type">char</code>33      </p>34      <p>35       <code class="literal">t</code> = table (including materialized views),36       <code class="literal">i</code> = index.37      </p></td></tr></tbody></table></div></div><br class="table-break" /><div class="note"><h3 class="title">Note</h3><p>38    Before <span class="productname">PostgreSQL</span> 9.6, <code class="structname">pg_am</code>39    contained many additional columns representing properties of index access40    methods.  That data is now only directly visible at the C code level.41    However, <code class="function">pg_index_column_has_property()</code> and related42    functions have been added to allow SQL queries to inspect index access43    method properties; see <a class="xref" href="functions-info.html#FUNCTIONS-INFO-CATALOG-TABLE" title="Table 9.72. System Catalog Information Functions">Table 9.72</a>.44   </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="catalog-pg-aggregate.html" title="53.2. pg_aggregate">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="catalogs.html" title="Chapter 53. System Catalogs">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="catalog-pg-amop.html" title="53.4. pg_amop">Next</a></td></tr><tr><td width="40%" align="left" valign="top">53.2. <code class="structname">pg_aggregate</code> </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 16.3 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 53.4. <code class="structname">pg_amop</code></td></tr></table></div></body></html>