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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>53.53. pg_statistic_ext_data</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-ext.html" title="53.52. pg_statistic_ext" /><link rel="next" href="catalog-pg-subscription.html" title="53.54. pg_subscription" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">53.53. <code class="structname">pg_statistic_ext_data</code></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="catalog-pg-statistic-ext.html" title="53.52. pg_statistic_ext">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 15.7 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="catalog-pg-subscription.html" title="53.54. pg_subscription">Next</a></td></tr></table><hr /></div><div class="sect1" id="CATALOG-PG-STATISTIC-EXT-DATA"><div class="titlepage"><div><div><h2 class="title" style="clear: both">53.53. <code class="structname">pg_statistic_ext_data</code></h2></div></div></div><a id="id-1.10.4.55.2" class="indexterm"></a><p>
The catalog <code class="structname">pg_statistic_ext_data</code>
holds data for extended planner statistics defined in
<a class="link" href="catalog-pg-statistic-ext.html" title="53.52. pg_statistic_ext"><code class="structname">pg_statistic_ext</code></a>.
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><p>
Normally there is one entry, with <code class="structfield">stxdinherit</code> =
<code class="literal">false</code>, for each statistics object that has been analyzed.
If the table has inheritance children or partitions, a second entry with
<code class="structfield">stxdinherit</code> = <code class="literal">true</code> is also created.
This row represents the statistics object over the inheritance tree, i.e.,
statistics for the data you'd see with
<code class="literal">SELECT * FROM <em class="replaceable"><code>table</code></em>*</code>,
whereas the <code class="structfield">stxdinherit</code> = <code class="literal">false</code> row
represents the results of
<code class="literal">SELECT * FROM ONLY <em class="replaceable"><code>table</code></em></code>.
</p><p>
Like <a class="link" href="catalog-pg-statistic.html" title="53.51. pg_statistic"><code class="structname">pg_statistic</code></a>,
<code class="structname">pg_statistic_ext_data</code> should not be
readable by the public, since the contents might be considered sensitive.
(Example: most common combinations of values in columns might be quite
interesting.)
<a class="link" href="view-pg-stats-ext.html" title="54.28. pg_stats_ext"><code class="structname">pg_stats_ext</code></a>
is a publicly readable view
on <code class="structname">pg_statistic_ext_data</code> (after joining
with <a class="link" href="catalog-pg-statistic-ext.html" title="53.52. pg_statistic_ext"><code class="structname">pg_statistic_ext</code></a>) that only exposes
information about tables the current user owns.
</p><div class="table" id="id-1.10.4.55.6"><p class="title"><strong>Table 53.53. <code class="structname">pg_statistic_ext_data</code> Columns</strong></p><div class="table-contents"><table class="table" summary="pg_statistic_ext_data 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">stxoid</code> <code class="type">oid</code>
(references <a class="link" href="catalog-pg-statistic-ext.html" title="53.52. pg_statistic_ext"><code class="structname">pg_statistic_ext</code></a>.<code class="structfield">oid</code>)
</p>
<p>
Extended statistics object containing the definition for this data
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">stxdinherit</code> <code class="type">bool</code>
</p>
<p>
If true, the stats include values from child tables, not just the
values in the specified relation
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">stxdndistinct</code> <code class="type">pg_ndistinct</code>
</p>
<p>
N-distinct counts, serialized as <code class="structname">pg_ndistinct</code> type
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">stxddependencies</code> <code class="type">pg_dependencies</code>
</p>
<p>
Functional dependency statistics, serialized
as <code class="structname">pg_dependencies</code> type
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">stxdmcv</code> <code class="type">pg_mcv_list</code>
</p>
<p>
MCV (most-common values) list statistics, serialized as
<code class="structname">pg_mcv_list</code> type
</p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
<code class="structfield">stxdexpr</code> <code class="type">pg_statistic[]</code>
</p>
<p>
Per-expression statistics, serialized as an array of
<code class="structname">pg_statistic</code> type
</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-statistic-ext.html" title="53.52. pg_statistic_ext">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-subscription.html" title="53.54. pg_subscription">Next</a></td></tr><tr><td width="40%" align="left" valign="top">53.52. <code class="structname">pg_statistic_ext</code> </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 15.7 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 53.54. <code class="structname">pg_subscription</code></td></tr></table></div></body></html>
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