codekingpro/portable-devtools

1<?xml version="1.0" encoding="UTF-8" standalone="no"?>2<!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>3   The catalog <code class="structname">pg_statistic_ext</code>4   holds definitions of extended planner statistics.5   Each row in this catalog corresponds to a <em class="firstterm">statistics object</em>6   created with <a class="link" href="sql-createstatistics.html" title="CREATE STATISTICS"><code class="command">CREATE STATISTICS</code></a>.7  </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">8       Column Type9      </p>10      <p>11       Description12      </p></th></tr></thead><tbody><tr><td class="catalog_table_entry"><p class="column_definition">13       <code class="structfield">oid</code> <code class="type">oid</code>14      </p>15      <p>16       Row identifier17      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">18       <code class="structfield">stxrelid</code> <code class="type">oid</code>19       (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>)20      </p>21      <p>22       Table containing the columns described by this object23      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">24       <code class="structfield">stxname</code> <code class="type">name</code>25      </p>26      <p>27       Name of the statistics object28      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">29       <code class="structfield">stxnamespace</code> <code class="type">oid</code>30       (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>)31      </p>32      <p>33       The OID of the namespace that contains this statistics object34      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">35       <code class="structfield">stxowner</code> <code class="type">oid</code>36       (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>)37      </p>38      <p>39       Owner of the statistics object40      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">41       <code class="structfield">stxstattarget</code> <code class="type">int4</code>42      </p>43      <p>44       <code class="structfield">stxstattarget</code> controls the level of detail45       of statistics accumulated for this statistics object by46       <a class="link" href="sql-analyze.html" title="ANALYZE"><code class="command">ANALYZE</code></a>.47       A zero value indicates that no statistics should be collected.48       A negative value says to use the maximum of the statistics targets of49       the referenced columns, if set, or the system default statistics target.50       Positive values of <code class="structfield">stxstattarget</code>51       determine the target number of <span class="quote">“<span class="quote">most common values</span>”</span>52       to collect.53      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">54       <code class="structfield">stxkeys</code> <code class="type">int2vector</code>55       (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>)56      </p>57      <p>58       An array of attribute numbers, indicating which table columns are59       covered by this statistics object;60       for example a value of <code class="literal">1 3</code> would61       mean that the first and the third table columns are covered62      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">63       <code class="structfield">stxkind</code> <code class="type">char[]</code>64      </p>65      <p>66       An array containing codes for the enabled statistics kinds;67       valid values are:68       <code class="literal">d</code> for n-distinct statistics,69       <code class="literal">f</code> for functional dependency statistics,70       <code class="literal">m</code> for most common values (MCV) list statistics, and71       <code class="literal">e</code> for expression statistics72      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">73       <code class="structfield">stxexprs</code> <code class="type">pg_node_tree</code>74      </p>75      <p>76       Expression trees (in <code class="function">nodeToString()</code>77       representation) for statistics object attributes that are not simple78       column references.  This is a list with one element per expression.79       Null if all statistics object attributes are simple references.80      </p></td></tr></tbody></table></div></div><br class="table-break" /><p>81   The <code class="structname">pg_statistic_ext</code> entry is filled in82   completely during <a class="link" href="sql-createstatistics.html" title="CREATE STATISTICS"><code class="command">CREATE STATISTICS</code></a>, but the actual83   statistical values are not computed then.84   Subsequent <a class="link" href="sql-analyze.html" title="ANALYZE"><code class="command">ANALYZE</code></a> commands compute the desired values85   and populate an entry in the86   <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>87   catalog.88  </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>