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 |
---|---|---|---|

`stxrelid` |
oid | pg_class.oid | The table containing the columns described by this object |

`stxname` |
name | The name of the statistics object | |

`stxnamespace` |
pg_namespace.oid | The object identifier of the namespace that contains this statistics object | |

`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