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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:19:15 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:19:15 +0000 |
commit | 6eb9c5a5657d1fe77b55cc261450f3538d35a94d (patch) | |
tree | 657d8194422a5daccecfd42d654b8a245ef7b4c8 /doc/src/sgml/html/view-pg-stats-ext.html | |
parent | Initial commit. (diff) | |
download | postgresql-13-upstream.tar.xz postgresql-13-upstream.zip |
Adding upstream version 13.4.upstream/13.4upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'doc/src/sgml/html/view-pg-stats-ext.html')
-rw-r--r-- | doc/src/sgml/html/view-pg-stats-ext.html | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/doc/src/sgml/html/view-pg-stats-ext.html b/doc/src/sgml/html/view-pg-stats-ext.html new file mode 100644 index 0000000..f50e171 --- /dev/null +++ b/doc/src/sgml/html/view-pg-stats-ext.html @@ -0,0 +1,111 @@ +<?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>51.89. 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 V1.79.1" /><link rel="prev" href="view-pg-stats.html" title="51.88. pg_stats" /><link rel="next" href="view-pg-tables.html" title="51.90. pg_tables" /></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">51.89. <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="51.88. pg_stats">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="catalogs.html" title="Chapter 51. System Catalogs">Up</a></td><th width="60%" align="center">Chapter 51. System Catalogs</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 13.4 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="view-pg-tables.html" title="51.90. pg_tables">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">51.89. <code class="structname">pg_stats_ext</code></h2></div></div></div><a id="id-1.10.4.91.2" class="indexterm"></a><p> + The view <code class="structname">pg_stats_ext</code> provides access to + the information stored in the <a class="link" href="catalog-pg-statistic-ext.html" title="51.50. pg_statistic_ext"><code class="structname">pg_statistic_ext</code></a> + and <a class="link" href="catalog-pg-statistic-ext-data.html" title="51.51. pg_statistic_ext_data"><code class="structname">pg_statistic_ext_data</code></a> + catalogs. This view allows access only to rows of + <code class="structname">pg_statistic_ext</code> and <code class="structname">pg_statistic_ext_data</code> + 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 <code class="structname">pg_statistic_ext</code>. + </p><div class="table" id="id-1.10.4.91.5"><p class="title"><strong>Table 51.90. <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="51.32. 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="51.11. 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="51.32. pg_namespace"><code class="structname">pg_namespace</code></a>.<code class="structfield">nspname</code>) + </p> + <p> + Name of schema containing extended statistic + </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="51.50. pg_statistic_ext"><code class="structname">pg_statistic_ext</code></a>.<code class="structfield">stxname</code>) + </p> + <p> + Name of extended statistics + </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="51.8. pg_authid"><code class="structname">pg_authid</code></a>.<code class="structfield">rolname</code>) + </p> + <p> + Owner of the extended statistics + </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="51.7. pg_attribute"><code class="structname">pg_attribute</code></a>.<code class="structfield">attname</code>) + </p> + <p> + Names of the columns the extended statistics is defined on + </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 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 <code class="command">ALTER TABLE SET STATISTICS</code> + 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="51.88. pg_stats">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="catalogs.html" title="Chapter 51. System Catalogs">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="view-pg-tables.html" title="51.90. pg_tables">Next</a></td></tr><tr><td width="40%" align="left" valign="top">51.88. <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 13.4 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 51.90. <code xmlns="http://www.w3.org/1999/xhtml" class="structname">pg_tables</code></td></tr></table></div></body></html>
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