about those tables that are readable by the current user.

</para>

<para>

<structname>pg_statistic</structname> should not be readable by the

public, since even statistical information about a table's contents

might be considered sensitive. (Example: minimum and maximum values

of a salary column might be quite interesting.)

<link linkend="view-pg-stats"><structname>pg_stats</structname></link>

is a publicly readable view on

<structname>pg_statistic</structname> that only exposes information

about those tables that are readable by the current user.

</para>

<para>

Similarly, <structname>pg_statistic_ext_data</structname> should not be

readable by the public, since the contents might be considered sensitive.

(Example: most common combination of values in columns might be quite

interesting.)

<link linkend="view-pg-stats-ext"><structname>pg_stats_ext</structname></link>

is a publicly readable view on <structname>pg_statistic_ext_data</structname>

(after joining with <structname>pg_statistic_ext</structname>) that only exposes

information about those tables and columns that are readable by the current user.

</para>

<table>

<title><structname>pg_statistic</structname> Columns</title>

</table>

<para>

The <structfield>stxkind</structfield> field is filled at creation of the

statistics object, indicating which statistic type(s) are desired. The

statistics (once computed by <command>ANALYZE</command>) are stored in

The <structname>pg_statistic_ext</structname> entry is filled in

completely during <command>CREATE STATISTICS</command>, but the actual

statistical values are not computed then.

Subsequent <command>ANALYZE</command> commands compute the desired values

and populate an entry in the

<link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>

catalog.

</para>

created with <xref linkend="sql-createstatistics"/>.

</para>

<para>

Like <structname>pg_statistic</structname>,

<structname>pg_statistic_ext_data</structname> 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.)

<link linkend="view-pg-stats-ext"><structname>pg_stats_ext</structname></link>

is a publicly readable view

on <structname>pg_statistic_ext_data</structname> (after joining

with <structname>pg_statistic_ext</structname>) that only exposes

information about those tables and columns that are readable by the

current user.

</para>

<table>

<title><structname>pg_statistic_ext_data</structname> Columns</title>

<entry><structfield>stxoid</structfield></entry>

<entry><type>oid</type></entry>

<entry><literal><link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>.oid</literal></entry>

<entry>Extended statistic containing the definition for this data.</entry>

<entry>Extended statisticobjectcontaining the definition for this data</entry>

</row>

<row>

<entry></entry>

<entry>

MCV (most-common values) list statistics, serialized as

<structname>pg_mcv_list</structname> type.

<structname>pg_mcv_list</structname> type

</entry>

</row>