pg_statistic_ext

The pg_statistic_ext system catalog table holds definitions of extended planner statistics. Each row in this catalog corresponds to a statistics object created with CREATE STATISTICS.

column	type	references	description
oid	oid		The object ID
stxrelid	oid	pg_class.oid	The table containing the columns described by this object
stxname	name		The name of the statistics object
stxnamespace	oid	pg_namespace.oid
stxowner	oid	pg_authid.oid	The owner of the statistics object
stxkeys	int2vector	pg_attribute.oid	An array of attribute numbers, indicating which table columns are covered by this statistics object; for example, a value of 1 3 would mean that the first and the third table columns are covered
stxkind	char[]		An array containing codes for the enabled statistics kinds; valid values are: d for n-distinct statistics, f for functional dependency statistics, and m for most common values (MCV) list statistics

The pg_statistic_ext entry is filled in completely during CREATE STATISTICS, but the actual statistical values are not computed then. Subsequent ANALYZE commands compute the desired values and populate an entry in the pg_statistic_ext_data catalog.

Parent topic: System Catalogs Definitions