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+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!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>53.11. pg_class</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-cast.html" title="53.10. pg_cast" /><link rel="next" href="catalog-pg-collation.html" title="53.12. pg_collation" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">53.11. <code class="structname">pg_class</code></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="catalog-pg-cast.html" title="53.10. pg_cast">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 15.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="catalog-pg-collation.html" title="53.12. pg_collation">Next</a></td></tr></table><hr /></div><div class="sect1" id="CATALOG-PG-CLASS"><div class="titlepage"><div><div><h2 class="title" style="clear: both">53.11. <code class="structname">pg_class</code></h2></div></div></div><a id="id-1.10.4.13.2" class="indexterm"></a><p>
+ The catalog <code class="structname">pg_class</code> describes tables and
+ other objects that have columns or are otherwise similar to a
+ table. This includes indexes (but see also <a class="link" href="catalog-pg-index.html" title="53.26. pg_index"><code class="structname">pg_index</code></a>),
+ sequences (but see also <a class="link" href="catalog-pg-sequence.html" title="53.47. pg_sequence"><code class="structname">pg_sequence</code></a>),
+ views, materialized views, composite types, and TOAST tables;
+ see <code class="structfield">relkind</code>.
+ Below, when we mean all of these kinds of objects we speak of
+ <span class="quote">“<span class="quote">relations</span>”</span>. Not all of <code class="structname">pg_class</code>'s
+ columns are meaningful for all relation kinds.
+ </p><div class="table" id="id-1.10.4.13.4"><p class="title"><strong>Table 53.11. <code class="structname">pg_class</code> Columns</strong></p><div class="table-contents"><table class="table" summary="pg_class Columns" border="1"><colgroup><col /></colgroup><thead><tr><th class="catalog_table_entry"><p class="column_definition">
+ Column Type
+ </p>
+ <p>
+ Description
+ </p></th></tr></thead><tbody><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">oid</code> <code class="type">oid</code>
+ </p>
+ <p>
+ Row identifier
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relname</code> <code class="type">name</code>
+ </p>
+ <p>
+ Name of the table, index, view, etc.
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relnamespace</code> <code class="type">oid</code>
+ (references <a class="link" href="catalog-pg-namespace.html" title="53.32. pg_namespace"><code class="structname">pg_namespace</code></a>.<code class="structfield">oid</code>)
+ </p>
+ <p>
+ The OID of the namespace that contains this relation
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">reltype</code> <code class="type">oid</code>
+ (references <a class="link" href="catalog-pg-type.html" title="53.64. pg_type"><code class="structname">pg_type</code></a>.<code class="structfield">oid</code>)
+ </p>
+ <p>
+ The OID of the data type that corresponds to this table's row type,
+ if any; zero for indexes, sequences, and toast tables, which have
+ no <code class="structname">pg_type</code> entry
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">reloftype</code> <code class="type">oid</code>
+ (references <a class="link" href="catalog-pg-type.html" title="53.64. pg_type"><code class="structname">pg_type</code></a>.<code class="structfield">oid</code>)
+ </p>
+ <p>
+ For typed tables, the OID of the underlying composite type;
+ zero for all other relations
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relowner</code> <code class="type">oid</code>
+ (references <a class="link" href="catalog-pg-authid.html" title="53.8. pg_authid"><code class="structname">pg_authid</code></a>.<code class="structfield">oid</code>)
+ </p>
+ <p>
+ Owner of the relation
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relam</code> <code class="type">oid</code>
+ (references <a class="link" href="catalog-pg-am.html" title="53.3. pg_am"><code class="structname">pg_am</code></a>.<code class="structfield">oid</code>)
+ </p>
+ <p>
+ If this is a table or an index, the access method used (heap,
+ B-tree, hash, etc.); otherwise zero (zero occurs for sequences,
+ as well as relations without storage, such as views)
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relfilenode</code> <code class="type">oid</code>
+ </p>
+ <p>
+ Name of the on-disk file of this relation; zero means this
+ is a <span class="quote">“<span class="quote">mapped</span>”</span> relation whose disk file name is determined
+ by low-level state
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">reltablespace</code> <code class="type">oid</code>
+ (references <a class="link" href="catalog-pg-tablespace.html" title="53.56. pg_tablespace"><code class="structname">pg_tablespace</code></a>.<code class="structfield">oid</code>)
+ </p>
+ <p>
+ The tablespace in which this relation is stored. If zero,
+ the database's default tablespace is implied. (Not meaningful
+ if the relation has no on-disk file.)
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relpages</code> <code class="type">int4</code>
+ </p>
+ <p>
+ Size of the on-disk representation of this table in pages (of size
+ <code class="symbol">BLCKSZ</code>). This is only an estimate used by the
+ planner. It is updated by <a class="link" href="sql-vacuum.html" title="VACUUM"><code class="command">VACUUM</code></a>,
+ <a class="link" href="sql-analyze.html" title="ANALYZE"><code class="command">ANALYZE</code></a>, and a few DDL commands such as
+ <a class="link" href="sql-createindex.html" title="CREATE INDEX"><code class="command">CREATE INDEX</code></a>.
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">reltuples</code> <code class="type">float4</code>
+ </p>
+ <p>
+ Number of live rows in the table. This is only an estimate used by
+ the planner. It is updated by <a class="link" href="sql-vacuum.html" title="VACUUM"><code class="command">VACUUM</code></a>,
+ <a class="link" href="sql-analyze.html" title="ANALYZE"><code class="command">ANALYZE</code></a>, and a few DDL commands such as
+ <a class="link" href="sql-createindex.html" title="CREATE INDEX"><code class="command">CREATE INDEX</code></a>.
+ If the table has never yet been vacuumed or
+ analyzed, <code class="structfield">reltuples</code>
+ contains <code class="literal">-1</code> indicating that the row count is
+ unknown.
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relallvisible</code> <code class="type">int4</code>
+ </p>
+ <p>
+ Number of pages that are marked all-visible in the table's
+ visibility map. This is only an estimate used by the
+ planner. It is updated by <a class="link" href="sql-vacuum.html" title="VACUUM"><code class="command">VACUUM</code></a>,
+ <a class="link" href="sql-analyze.html" title="ANALYZE"><code class="command">ANALYZE</code></a>, and a few DDL commands such as
+ <a class="link" href="sql-createindex.html" title="CREATE INDEX"><code class="command">CREATE INDEX</code></a>.
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">reltoastrelid</code> <code class="type">oid</code>
+ (references <a class="link" href="catalog-pg-class.html" title="53.11. pg_class"><code class="structname">pg_class</code></a>.<code class="structfield">oid</code>)
+ </p>
+ <p>
+ OID of the TOAST table associated with this table, zero if none. The
+ TOAST table stores large attributes <span class="quote">“<span class="quote">out of line</span>”</span> in a
+ secondary table.
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relhasindex</code> <code class="type">bool</code>
+ </p>
+ <p>
+ True if this is a table and it has (or recently had) any indexes
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relisshared</code> <code class="type">bool</code>
+ </p>
+ <p>
+ True if this table is shared across all databases in the cluster. Only
+ certain system catalogs (such as <a class="link" href="catalog-pg-database.html" title="53.15. pg_database"><code class="structname">pg_database</code></a>)
+ are shared.
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relpersistence</code> <code class="type">char</code>
+ </p>
+ <p>
+ <code class="literal">p</code> = permanent table/sequence, <code class="literal">u</code> = unlogged table/sequence,
+ <code class="literal">t</code> = temporary table/sequence
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relkind</code> <code class="type">char</code>
+ </p>
+ <p>
+ <code class="literal">r</code> = ordinary table,
+ <code class="literal">i</code> = index,
+ <code class="literal">S</code> = sequence,
+ <code class="literal">t</code> = TOAST table,
+ <code class="literal">v</code> = view,
+ <code class="literal">m</code> = materialized view,
+ <code class="literal">c</code> = composite type,
+ <code class="literal">f</code> = foreign table,
+ <code class="literal">p</code> = partitioned table,
+ <code class="literal">I</code> = partitioned index
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relnatts</code> <code class="type">int2</code>
+ </p>
+ <p>
+ Number of user columns in the relation (system columns not
+ counted). There must be this many corresponding entries in
+ <a class="link" href="catalog-pg-attribute.html" title="53.7. pg_attribute"><code class="structname">pg_attribute</code></a>. See also
+ <code class="structname">pg_attribute</code>.<code class="structfield">attnum</code>.
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relchecks</code> <code class="type">int2</code>
+ </p>
+ <p>
+ Number of <code class="literal">CHECK</code> constraints on the table; see
+ <a class="link" href="catalog-pg-constraint.html" title="53.13. pg_constraint"><code class="structname">pg_constraint</code></a> catalog
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relhasrules</code> <code class="type">bool</code>
+ </p>
+ <p>
+ True if table has (or once had) rules; see
+ <a class="link" href="catalog-pg-rewrite.html" title="53.45. pg_rewrite"><code class="structname">pg_rewrite</code></a> catalog
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relhastriggers</code> <code class="type">bool</code>
+ </p>
+ <p>
+ True if table has (or once had) triggers; see
+ <a class="link" href="catalog-pg-trigger.html" title="53.58. pg_trigger"><code class="structname">pg_trigger</code></a> catalog
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relhassubclass</code> <code class="type">bool</code>
+ </p>
+ <p>
+ True if table or index has (or once had) any inheritance children or partitions
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relrowsecurity</code> <code class="type">bool</code>
+ </p>
+ <p>
+ True if table has row-level security enabled; see
+ <a class="link" href="catalog-pg-policy.html" title="53.38. pg_policy"><code class="structname">pg_policy</code></a> catalog
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relforcerowsecurity</code> <code class="type">bool</code>
+ </p>
+ <p>
+ True if row-level security (when enabled) will also apply to table owner; see
+ <a class="link" href="catalog-pg-policy.html" title="53.38. pg_policy"><code class="structname">pg_policy</code></a> catalog
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relispopulated</code> <code class="type">bool</code>
+ </p>
+ <p>
+ True if relation is populated (this is true for all
+ relations other than some materialized views)
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relreplident</code> <code class="type">char</code>
+ </p>
+ <p>
+ Columns used to form <span class="quote">“<span class="quote">replica identity</span>”</span> for rows:
+ <code class="literal">d</code> = default (primary key, if any),
+ <code class="literal">n</code> = nothing,
+ <code class="literal">f</code> = all columns,
+ <code class="literal">i</code> = index with
+ <code class="structfield">indisreplident</code> set (same as nothing if the
+ index used has been dropped)
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relispartition</code> <code class="type">bool</code>
+ </p>
+ <p>
+ True if table or index is a partition
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relrewrite</code> <code class="type">oid</code>
+ (references <a class="link" href="catalog-pg-class.html" title="53.11. pg_class"><code class="structname">pg_class</code></a>.<code class="structfield">oid</code>)
+ </p>
+ <p>
+ For new relations being written during a DDL operation that requires a
+ table rewrite, this contains the OID of the original relation;
+ otherwise zero. That state is only visible internally; this field should
+ never contain anything other than zero for a user-visible relation.
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relfrozenxid</code> <code class="type">xid</code>
+ </p>
+ <p>
+ All transaction IDs before this one have been replaced with a permanent
+ (<span class="quote">“<span class="quote">frozen</span>”</span>) transaction ID in this table. This is used to track
+ whether the table needs to be vacuumed in order to prevent transaction
+ ID wraparound or to allow <code class="literal">pg_xact</code> to be shrunk. Zero
+ (<code class="symbol">InvalidTransactionId</code>) if the relation is not a table.
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relminmxid</code> <code class="type">xid</code>
+ </p>
+ <p>
+ All multixact IDs before this one have been replaced by a
+ transaction ID in this table. This is used to track
+ whether the table needs to be vacuumed in order to prevent multixact ID
+ wraparound or to allow <code class="literal">pg_multixact</code> to be shrunk. Zero
+ (<code class="symbol">InvalidMultiXactId</code>) if the relation is not a table.
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relacl</code> <code class="type">aclitem[]</code>
+ </p>
+ <p>
+ Access privileges; see <a class="xref" href="ddl-priv.html" title="5.7. Privileges">Section 5.7</a> for details
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">reloptions</code> <code class="type">text[]</code>
+ </p>
+ <p>
+ Access-method-specific options, as <span class="quote">“<span class="quote">keyword=value</span>”</span> strings
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">relpartbound</code> <code class="type">pg_node_tree</code>
+ </p>
+ <p>
+ If table is a partition (see <code class="structfield">relispartition</code>),
+ internal representation of the partition bound
+ </p></td></tr></tbody></table></div></div><br class="table-break" /><p>
+ Several of the Boolean flags in <code class="structname">pg_class</code> are maintained
+ lazily: they are guaranteed to be true if that's the correct state, but
+ may not be reset to false immediately when the condition is no longer
+ true. For example, <code class="structfield">relhasindex</code> is set by
+ <a class="link" href="sql-createindex.html" title="CREATE INDEX"><code class="command">CREATE INDEX</code></a>, but it is never cleared by
+ <a class="link" href="sql-dropindex.html" title="DROP INDEX"><code class="command">DROP INDEX</code></a>. Instead, <a class="link" href="sql-vacuum.html" title="VACUUM"><code class="command">VACUUM</code></a> clears
+ <code class="structfield">relhasindex</code> if it finds the table has no indexes. This
+ arrangement avoids race conditions and improves concurrency.
+ </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="catalog-pg-cast.html" title="53.10. pg_cast">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-collation.html" title="53.12. pg_collation">Next</a></td></tr><tr><td width="40%" align="left" valign="top">53.10. <code class="structname">pg_cast</code> </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 53.12. <code class="structname">pg_collation</code></td></tr></table></div></body></html> \ No newline at end of file
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