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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>52.26. 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="52.25. pg_foreign_table" /><link rel="next" href="catalog-pg-inherits.html" title="52.27. pg_inherits" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">52.26. <code xmlns="http://www.w3.org/1999/xhtml" class="structname">pg_index</code></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="catalog-pg-foreign-table.html" title="52.25. pg_foreign_table">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="catalogs.html" title="Chapter 52. System Catalogs">Up</a></td><th width="60%" align="center">Chapter 52. System Catalogs</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 11.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="catalog-pg-inherits.html" title="52.27. pg_inherits">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="CATALOG-PG-INDEX"><div class="titlepage"><div><div><h2 class="title" style="clear: both">52.26. <code class="structname">pg_index</code></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
<code class="structname">pg_class</code>.
</p><div class="table" id="id-1.10.4.28.4"><p class="title"><strong>Table 52.26. <code class="structname">pg_index</code> Columns</strong></p><div class="table-contents"><table class="table" summary="pg_index Columns" border="1"><colgroup><col /><col /><col /><col /></colgroup><thead><tr><th>Name</th><th>Type</th><th>References</th><th>Description</th></tr></thead><tbody><tr><td><code class="structfield">indexrelid</code></td><td><code class="type">oid</code></td><td><code class="literal"><a class="link" href="catalog-pg-class.html" title="52.11. pg_class"><code class="structname">pg_class</code></a>.oid</code></td><td>The OID of the <code class="structname">pg_class</code> entry for this index</td></tr><tr><td><code class="structfield">indrelid</code></td><td><code class="type">oid</code></td><td><code class="literal"><a class="link" href="catalog-pg-class.html" title="52.11. pg_class"><code class="structname">pg_class</code></a>.oid</code></td><td>The OID of the <code class="structname">pg_class</code> entry for the table this index is for</td></tr><tr><td><code class="structfield">indnatts</code></td><td><code class="type">int2</code></td><td> </td><td>The total number of columns in the index (duplicates
<code class="literal">pg_class.relnatts</code>); this number includes both key and included attributes</td></tr><tr><td><code class="structfield">indnkeyatts</code></td><td><code class="type">int2</code></td><td> </td><td>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</td></tr><tr><td><code class="structfield">indisunique</code></td><td><code class="type">bool</code></td><td> </td><td>If true, this is a unique index</td></tr><tr><td><code class="structfield">indisprimary</code></td><td><code class="type">bool</code></td><td> </td><td>If true, this index represents the primary key of the table
(<code class="structfield">indisunique</code> should always be true when this is true)</td></tr><tr><td><code class="structfield">indisexclusion</code></td><td><code class="type">bool</code></td><td> </td><td>If true, this index supports an exclusion constraint</td></tr><tr><td><code class="structfield">indimmediate</code></td><td><code class="type">bool</code></td><td> </td><td>If true, the uniqueness check is enforced immediately on
insertion
(irrelevant if <code class="structfield">indisunique</code> is not true)</td></tr><tr><td><code class="structfield">indisclustered</code></td><td><code class="type">bool</code></td><td> </td><td>If true, the table was last clustered on this index</td></tr><tr><td><code class="structfield">indisvalid</code></td><td><code class="type">bool</code></td><td> </td><td>
If true, the index is currently valid for queries. False means the
index is possibly incomplete: it must still be modified by
<code class="command">INSERT</code>/<code class="command">UPDATE</code> operations, but it cannot safely
be used for queries. If it is unique, the uniqueness property is not
guaranteed true either.
</td></tr><tr><td><code class="structfield">indcheckxmin</code></td><td><code class="type">bool</code></td><td> </td><td>
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 HOT chains with
incompatible rows that they can see
</td></tr><tr><td><code class="structfield">indisready</code></td><td><code class="type">bool</code></td><td> </td><td>
If true, the index is currently ready for inserts. False means the
index must be ignored by <code class="command">INSERT</code>/<code class="command">UPDATE</code>
operations.
</td></tr><tr><td><code class="structfield">indislive</code></td><td><code class="type">bool</code></td><td> </td><td>
If false, the index is in process of being dropped, and should be
ignored for all purposes (including HOT-safety decisions)
</td></tr><tr><td><code class="structfield">indisreplident</code></td><td><code class="type">bool</code></td><td> </td><td>
If true this index has been chosen as <span class="quote">“<span class="quote">replica identity</span>”</span>
using <code class="command">ALTER TABLE ... REPLICA IDENTITY USING INDEX
...</code>
</td></tr><tr><td><code class="structfield">indkey</code></td><td><code class="type">int2vector</code></td><td><code class="literal"><a class="link" href="catalog-pg-attribute.html" title="52.7. pg_attribute"><code class="structname">pg_attribute</code></a>.attnum</code></td><td>
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.
</td></tr><tr><td><code class="structfield">indcollation</code></td><td><code class="type">oidvector</code></td><td><code class="literal"><a class="link" href="catalog-pg-collation.html" title="52.12. pg_collation"><code class="structname">pg_collation</code></a>.oid</code></td><td>
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.
</td></tr><tr><td><code class="structfield">indclass</code></td><td><code class="type">oidvector</code></td><td><code class="literal"><a class="link" href="catalog-pg-opclass.html" title="52.33. pg_opclass"><code class="structname">pg_opclass</code></a>.oid</code></td><td>
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="52.33. pg_opclass"><code class="structname">pg_opclass</code></a> for details.
</td></tr><tr><td><code class="structfield">indoption</code></td><td><code class="type">int2vector</code></td><td> </td><td>
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.
</td></tr><tr><td><code class="structfield">indexprs</code></td><td><code class="type">pg_node_tree</code></td><td> </td><td>
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.
</td></tr><tr><td><code class="structfield">indpred</code></td><td><code class="type">pg_node_tree</code></td><td> </td><td>
Expression tree (in <code class="function">nodeToString()</code>
representation) for partial index predicate. Null if not a
partial index.
</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">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="catalogs.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="catalog-pg-inherits.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">52.25. <code class="structname">pg_foreign_table</code> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> 52.27. <code class="structname">pg_inherits</code></td></tr></table></div></body></html>
