pg_statistic_ext — PostgreSQL system catalog

The PostgreSQL pg_statistic_ext system catalog: full column reference (names, types, descriptions), catalog relationships and version support.

The Sev-1 Admin
The Sev-1 Admin  ·  2 min read

Summary

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.

(Description quoted from the official PostgreSQL documentation.)

Columns

The pg_statistic_ext system catalog exposes the following columns (names, types and descriptions are taken verbatim from the PostgreSQL documentation):

  • oid oid
    Row identifier
  • stxrelid oid references pg_class.oid
    Table containing the columns described by this object
  • stxname name
    Name of the statistics object
  • stxnamespace oid references pg_namespace.oid
    The OID of the namespace that contains this statistics object
  • stxowner oid references pg_authid.oid
    Owner of the statistics object
  • stxkeys int2vector references 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
  • stxstattarget int2
    stxstattarget controls the level of detail of statistics accumulated for this statistics object by ANALYZE. A zero value indicates that no statistics should be collected. A null value says to use the maximum of the statistics targets of the referenced columns, if set, or the system default statistics target. Positive values of stxstattarget determine the target number of “most common values” to collect.
  • stxkind char[]
    An array containing codes for the enabled statistics kinds; valid values are: d for n-distinct statistics, f for functional dependency statistics, m for most common values (MCV) list statistics, and e for expression statistics
  • stxexprs pg_node_tree
    Expression trees (in nodeToString() representation) for statistics object attributes that are not simple column references. This is a list with one element per expression. Null if all statistics object attributes are simple references.

Related catalogs

This object references the following other system catalogs:

Version applicability

Present in PostgreSQL 17, 18, 19 (verified against each release’s documentation). This is a long-standing system object that also exists in earlier PostgreSQL releases.

Related & references

Reference: PostgreSQL documentation — pg_statistic_ext.