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<!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>53.26. pg_index</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-foreign-table.html" title="53.25. pg_foreign_table" /><link rel="next" href="catalog-pg-inherits.html" title="53.27. pg_inherits" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">53.26. <code class="structname">pg_index</code></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="catalog-pg-foreign-table.html" title="53.25. pg_foreign_table">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-inherits.html" title="53.27. pg_inherits">Next</a></td></tr></table><hr /></div><div class="sect1" id="CATALOG-PG-INDEX"><div class="titlepage"><div><div><h2 class="title" style="clear: both">53.26. <code class="structname">pg_index</code> <a href="#CATALOG-PG-INDEX" class="id_link">#</a></h2></div></div></div><a id="id-1.10.4.28.2" class="indexterm"></a><p>
The catalog <code class="structname">pg_index</code> contains part of the information
about indexes. The rest is mostly in
<a class="link" href="catalog-pg-class.html" title="53.11. pg_class"><code class="structname">pg_class</code></a>.
</p><div class="table" id="id-1.10.4.28.4"><p class="title"><strong>Table 53.26. <code class="structname">pg_index</code> Columns</strong></p><div class="table-contents"><table class="table" summary="pg_index 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">indexrelid</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>
The OID of the <a class="link" href="catalog-pg-class.html" title="53.11. pg_class"><code class="structname">pg_class</code></a> entry for this index
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indrelid</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>
The OID of the <a class="link" href="catalog-pg-class.html" title="53.11. pg_class"><code class="structname">pg_class</code></a> entry for the table this index is for
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indnatts</code> <code class="type">int2</code>
</p>
<p>
The total number of columns in the index (duplicates
<code class="literal">pg_class.relnatts</code>); this number includes both key and included attributes
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indnkeyatts</code> <code class="type">int2</code>
</p>
<p>
The number of <em class="firstterm">key columns</em> in the index,
not counting any <em class="firstterm">included columns</em>, which are
merely stored and do not participate in the index semantics
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indisunique</code> <code class="type">bool</code>
</p>
<p>
If true, this is a unique index
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indnullsnotdistinct</code> <code class="type">bool</code>
</p>
<p>
This value is only used for unique indexes. If false, this unique
index will consider null values distinct (so the index can contain
multiple null values in a column, the default PostgreSQL behavior). If
it is true, it will consider null values to be equal (so the index can
only contain one null value in a column).
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indisprimary</code> <code class="type">bool</code>
</p>
<p>
If true, this index represents the primary key of the table
(<code class="structfield">indisunique</code> should always be true when this is true)
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indisexclusion</code> <code class="type">bool</code>
</p>
<p>
If true, this index supports an exclusion constraint
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indimmediate</code> <code class="type">bool</code>
</p>
<p>
If true, the uniqueness check is enforced immediately on
insertion
(irrelevant if <code class="structfield">indisunique</code> is not true)
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indisclustered</code> <code class="type">bool</code>
</p>
<p>
If true, the table was last clustered on this index
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indisvalid</code> <code class="type">bool</code>
</p>
<p>
If true, the index is currently valid for queries. False means the
index is possibly incomplete: it must still be modified by
<a class="link" href="sql-insert.html" title="INSERT"><code class="command">INSERT</code></a>/<a class="link" href="sql-update.html" title="UPDATE"><code class="command">UPDATE</code></a> operations, but it cannot safely
be used for queries. If it is unique, the uniqueness property is not
guaranteed true either.
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indcheckxmin</code> <code class="type">bool</code>
</p>
<p>
If true, queries must not use the index until the <code class="structfield">xmin</code>
of this <code class="structname">pg_index</code> row is below their <code class="symbol">TransactionXmin</code>
event horizon, because the table may contain broken <a class="link" href="storage-hot.html" title="73.7. Heap-Only Tuples (HOT)">HOT chains</a> with
incompatible rows that they can see
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indisready</code> <code class="type">bool</code>
</p>
<p>
If true, the index is currently ready for inserts. False means the
index must be ignored by <a class="link" href="sql-insert.html" title="INSERT"><code class="command">INSERT</code></a>/<a class="link" href="sql-update.html" title="UPDATE"><code class="command">UPDATE</code></a>
operations.
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indislive</code> <code class="type">bool</code>
</p>
<p>
If false, the index is in process of being dropped, and should be
ignored for all purposes (including HOT-safety decisions)
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indisreplident</code> <code class="type">bool</code>
</p>
<p>
If true this index has been chosen as <span class="quote">“<span class="quote">replica identity</span>”</span>
using <a class="link" href="sql-altertable.html#SQL-ALTERTABLE-REPLICA-IDENTITY"><code class="command">ALTER TABLE ...
REPLICA IDENTITY USING INDEX ...</code></a>
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indkey</code> <code class="type">int2vector</code>
(references <a class="link" href="catalog-pg-attribute.html" title="53.7. pg_attribute"><code class="structname">pg_attribute</code></a>.<code class="structfield">attnum</code>)
</p>
<p>
This is an array of <code class="structfield">indnatts</code> values that
indicate which table columns this index indexes. For example, a value
of <code class="literal">1 3</code> would mean that the first and the third table
columns make up the index entries. Key columns come before non-key
(included) columns. A zero in this array indicates that the
corresponding index attribute is an expression over the table columns,
rather than a simple column reference.
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indcollation</code> <code class="type">oidvector</code>
(references <a class="link" href="catalog-pg-collation.html" title="53.12. pg_collation"><code class="structname">pg_collation</code></a>.<code class="structfield">oid</code>)
</p>
<p>
For each column in the index key
(<code class="structfield">indnkeyatts</code> values), this contains the OID
of the collation to use for the index, or zero if the column is not of
a collatable data type.
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indclass</code> <code class="type">oidvector</code>
(references <a class="link" href="catalog-pg-opclass.html" title="53.33. pg_opclass"><code class="structname">pg_opclass</code></a>.<code class="structfield">oid</code>)
</p>
<p>
For each column in the index key
(<code class="structfield">indnkeyatts</code> values), this contains the OID
of the operator class to use. See
<a class="link" href="catalog-pg-opclass.html" title="53.33. pg_opclass"><code class="structname">pg_opclass</code></a> for details.
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indoption</code> <code class="type">int2vector</code>
</p>
<p>
This is an array of <code class="structfield">indnkeyatts</code> values that
store per-column flag bits. The meaning of the bits is defined by
the index's access method.
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indexprs</code> <code class="type">pg_node_tree</code>
</p>
<p>
Expression trees (in <code class="function">nodeToString()</code>
representation) for index attributes that are not simple column
references. This is a list with one element for each zero
entry in <code class="structfield">indkey</code>. Null if all index attributes
are simple references.
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">indpred</code> <code class="type">pg_node_tree</code>
</p>
<p>
Expression tree (in <code class="function">nodeToString()</code>
representation) for partial index predicate. Null if not a
partial index.
</p></td></tr></tbody></table></div></div><br class="table-break" /></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="catalog-pg-foreign-table.html" title="53.25. pg_foreign_table">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-inherits.html" title="53.27. pg_inherits">Next</a></td></tr><tr><td width="40%" align="left" valign="top">53.25. <code class="structname">pg_foreign_table</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"> 53.27. <code class="structname">pg_inherits</code></td></tr></table></div></body></html>