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52.51. pg_statistic_ext

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

Table 52.51. 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
stxndistinct pg_ndistinct   N-distinct counts, serialized as pg_ndistinct type
stxdependencies pg_dependencies   Functional dependency statistics, serialized as pg_dependencies type

The stxkind field is filled at creation of the statistics object, indicating which statistic type(s) are desired. The fields after it are initially NULL and are filled only when the corresponding statistic has been computed by ANALYZE.