51.51. pg_statistic_ext

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

Table 51.51. pg_statistic_ext Columns

Name Type References Description
stxrelid oid pg_class .oid Table containing the columns described by this object
stxname name Name of the statistics object
stxnamespace oid pg_namespace .oid The OID of the namespace that contains this statistics object
stxowner oid pg_authid .oid Owner of the statistics object
stxkeys int2vector pg_attribute .attnum 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.