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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>52.90. pg_stats_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="view-pg-stats.html" title="52.89. pg_stats" /><link rel="next" href="view-pg-stats-ext-exprs.html" title="52.91. pg_stats_ext_exprs" /></head><body id="docContent" class="container-fluid col-10"><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">52.90. <code xmlns="http://www.w3.org/1999/xhtml" class="structname">pg_stats_ext</code></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="view-pg-stats.html" title="52.89. pg_stats">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 14.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="view-pg-stats-ext-exprs.html" title="52.91. pg_stats_ext_exprs">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="VIEW-PG-STATS-EXT"><div class="titlepage"><div><div><h2 class="title" style="clear: both">52.90. <code class="structname">pg_stats_ext</code></h2></div></div></div><a id="id-1.10.4.92.2" class="indexterm"></a><p>
+ The view <code class="structname">pg_stats_ext</code> provides access to
+ information about each extended statistics object in the database,
+ combining information stored in the <a class="link" href="catalog-pg-statistic-ext.html" title="52.50. pg_statistic_ext"><code class="structname">pg_statistic_ext</code></a>
+ and <a class="link" href="catalog-pg-statistic-ext-data.html" title="52.51. pg_statistic_ext_data"><code class="structname">pg_statistic_ext_data</code></a>
+ catalogs. This view allows access only to rows of
+ <a class="link" href="catalog-pg-statistic-ext.html" title="52.50. pg_statistic_ext"><code class="structname">pg_statistic_ext</code></a> and <a class="link" href="catalog-pg-statistic-ext-data.html" title="52.51. pg_statistic_ext_data"><code class="structname">pg_statistic_ext_data</code></a>
+ that correspond to tables the user has permission to read, and therefore
+ it is safe to allow public read access to this view.
+ </p><p>
+ <code class="structname">pg_stats_ext</code> is also designed to present the
+ information in a more readable format than the underlying catalogs
+ — at the cost that its schema must be extended whenever new types
+ of extended statistics are added to <a class="link" href="catalog-pg-statistic-ext.html" title="52.50. pg_statistic_ext"><code class="structname">pg_statistic_ext</code></a>.
+ </p><div class="table" id="id-1.10.4.92.5"><p class="title"><strong>Table 52.91. <code class="structname">pg_stats_ext</code> Columns</strong></p><div class="table-contents"><table class="table" summary="pg_stats_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">schemaname</code> <code class="type">name</code>
+ (references <a class="link" href="catalog-pg-namespace.html" title="52.32. pg_namespace"><code class="structname">pg_namespace</code></a>.<code class="structfield">nspname</code>)
+ </p>
+ <p>
+ Name of schema containing table
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">tablename</code> <code class="type">name</code>
+ (references <a class="link" href="catalog-pg-class.html" title="52.11. pg_class"><code class="structname">pg_class</code></a>.<code class="structfield">relname</code>)
+ </p>
+ <p>
+ Name of table
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">statistics_schemaname</code> <code class="type">name</code>
+ (references <a class="link" href="catalog-pg-namespace.html" title="52.32. pg_namespace"><code class="structname">pg_namespace</code></a>.<code class="structfield">nspname</code>)
+ </p>
+ <p>
+ Name of schema containing extended statistics object
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">statistics_name</code> <code class="type">name</code>
+ (references <a class="link" href="catalog-pg-statistic-ext.html" title="52.50. pg_statistic_ext"><code class="structname">pg_statistic_ext</code></a>.<code class="structfield">stxname</code>)
+ </p>
+ <p>
+ Name of extended statistics object
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">statistics_owner</code> <code class="type">name</code>
+ (references <a class="link" href="catalog-pg-authid.html" title="52.8. pg_authid"><code class="structname">pg_authid</code></a>.<code class="structfield">rolname</code>)
+ </p>
+ <p>
+ Owner of the extended statistics object
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">attnames</code> <code class="type">name[]</code>
+ (references <a class="link" href="catalog-pg-attribute.html" title="52.7. pg_attribute"><code class="structname">pg_attribute</code></a>.<code class="structfield">attname</code>)
+ </p>
+ <p>
+ Names of the columns included in the extended statistics object
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">exprs</code> <code class="type">text[]</code>
+ </p>
+ <p>
+ Expressions included in the extended statistics object
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">kinds</code> <code class="type">char[]</code>
+ </p>
+ <p>
+ Types of extended statistics object enabled for this record
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">n_distinct</code> <code class="type">pg_ndistinct</code>
+ </p>
+ <p>
+ N-distinct counts for combinations of column values. If greater
+ than zero, the estimated number of distinct values in the combination.
+ If less than zero, the negative of the number of distinct values divided
+ by the number of rows.
+ (The negated form is used when <code class="command">ANALYZE</code> believes that
+ the number of distinct values is likely to increase as the table grows;
+ the positive form is used when the column seems to have a fixed number
+ of possible values.) For example, -1 indicates a unique combination of
+ columns in which the number of distinct combinations is the same as the
+ number of rows.
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">dependencies</code> <code class="type">pg_dependencies</code>
+ </p>
+ <p>
+ Functional dependency statistics
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">most_common_vals</code> <code class="type">text[]</code>
+ </p>
+ <p>
+ A list of the most common combinations of values in the columns.
+ (Null if no combinations seem to be more common than any others.)
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">most_common_val_nulls</code> <code class="type">bool[]</code>
+ </p>
+ <p>
+ A list of NULL flags for the most common combinations of values.
+ (Null when <code class="structfield">most_common_vals</code> is.)
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">most_common_freqs</code> <code class="type">float8[]</code>
+ </p>
+ <p>
+ A list of the frequencies of the most common combinations,
+ i.e., number of occurrences of each divided by total number of rows.
+ (Null when <code class="structfield">most_common_vals</code> is.)
+ </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
+ <code class="structfield">most_common_base_freqs</code> <code class="type">float8[]</code>
+ </p>
+ <p>
+ A list of the base frequencies of the most common combinations,
+ i.e., product of per-value frequencies.
+ (Null when <code class="structfield">most_common_vals</code> is.)
+ </p></td></tr></tbody></table></div></div><br class="table-break" /><p>
+ The maximum number of entries in the array fields can be controlled on a
+ column-by-column basis using the <a class="link" href="sql-altertable.html" title="ALTER TABLE"><code class="command">ALTER
+ TABLE SET STATISTICS</code></a> command, or globally by setting the
+ <a class="xref" href="runtime-config-query.html#GUC-DEFAULT-STATISTICS-TARGET">default_statistics_target</a> run-time parameter.
+ </p></div><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navfooter"><hr></hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="view-pg-stats.html" title="52.89. pg_stats">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="catalogs.html" title="Chapter 52. System Catalogs">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="view-pg-stats-ext-exprs.html" title="52.91. pg_stats_ext_exprs">Next</a></td></tr><tr><td width="40%" align="left" valign="top">52.89. <code xmlns="http://www.w3.org/1999/xhtml" class="structname">pg_stats</code> </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 14.5 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 52.91. <code xmlns="http://www.w3.org/1999/xhtml" class="structname">pg_stats_ext_exprs</code></td></tr></table></div></body></html> \ No newline at end of file
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