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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>53.52. pg_statistic_ext</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-statistic.html" title="53.51. pg_statistic" /><link rel="next" href="catalog-pg-statistic-ext-data.html" title="53.53. pg_statistic_ext_data" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">53.52. <code class="structname">pg_statistic_ext</code></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="catalog-pg-statistic.html" title="53.51. pg_statistic">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-statistic-ext-data.html" title="53.53. pg_statistic_ext_data">Next</a></td></tr></table><hr /></div><div class="sect1" id="CATALOG-PG-STATISTIC-EXT"><div class="titlepage"><div><div><h2 class="title" style="clear: both">53.52. <code class="structname">pg_statistic_ext</code> <a href="#CATALOG-PG-STATISTIC-EXT" class="id_link">#</a></h2></div></div></div><a id="id-1.10.4.54.2" class="indexterm"></a><p>
The catalog <code class="structname">pg_statistic_ext</code>
holds definitions of extended planner statistics.
Each row in this catalog corresponds to a <em class="firstterm">statistics object</em>
created with <a class="link" href="sql-createstatistics.html" title="CREATE STATISTICS"><code class="command">CREATE STATISTICS</code></a>.
</p><div class="table" id="id-1.10.4.54.4"><p class="title"><strong>Table 53.52. <code class="structname">pg_statistic_ext</code> Columns</strong></p><div class="table-contents"><table class="table" summary="pg_statistic_ext 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">stxrelid</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>
Table containing the columns described by this object
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">stxname</code> <code class="type">name</code>
</p>
<p>
Name of the statistics object
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">stxnamespace</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 statistics object
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">stxowner</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 statistics object
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">stxstattarget</code> <code class="type">int4</code>
</p>
<p>
<code class="structfield">stxstattarget</code> controls the level of detail
of statistics accumulated for this statistics object by
<a class="link" href="sql-analyze.html" title="ANALYZE"><code class="command">ANALYZE</code></a>.
A zero value indicates that no statistics should be collected.
A negative value says to use the maximum of the statistics targets of
the referenced columns, if set, or the system default statistics target.
Positive values of <code class="structfield">stxstattarget</code>
determine the target number of <span class="quote">“<span class="quote">most common values</span>”</span>
to collect.
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">stxkeys</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>
An array of attribute numbers, indicating which table columns are
covered by this statistics object;
for example a value of <code class="literal">1 3</code> would
mean that the first and the third table columns are covered
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">stxkind</code> <code class="type">char[]</code>
</p>
<p>
An array containing codes for the enabled statistics kinds;
valid values are:
<code class="literal">d</code> for n-distinct statistics,
<code class="literal">f</code> for functional dependency statistics,
<code class="literal">m</code> for most common values (MCV) list statistics, and
<code class="literal">e</code> for expression statistics
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">stxexprs</code> <code class="type">pg_node_tree</code>
</p>
<p>
Expression trees (in <code class="function">nodeToString()</code>
representation) for statistics object attributes that are not simple
column references. This is a list with one element per expression.
Null if all statistics object attributes are simple references.
</p></td></tr></tbody></table></div></div><br class="table-break" /><p>
The <code class="structname">pg_statistic_ext</code> entry is filled in
completely during <a class="link" href="sql-createstatistics.html" title="CREATE STATISTICS"><code class="command">CREATE STATISTICS</code></a>, but the actual
statistical values are not computed then.
Subsequent <a class="link" href="sql-analyze.html" title="ANALYZE"><code class="command">ANALYZE</code></a> commands compute the desired values
and populate an entry in the
<a class="link" href="catalog-pg-statistic-ext-data.html" title="53.53. pg_statistic_ext_data"><code class="structname">pg_statistic_ext_data</code></a>
catalog.
</p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="catalog-pg-statistic.html" title="53.51. pg_statistic">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-statistic-ext-data.html" title="53.53. pg_statistic_ext_data">Next</a></td></tr><tr><td width="40%" align="left" valign="top">53.51. <code class="structname">pg_statistic</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"> 53.53. <code class="structname">pg_statistic_ext_data</code></td></tr></table></div></body></html>