51.51. `pg_statistic_ext`
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## 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 statistic 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.

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