## 52.50. `pg_statistic_ext`

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 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`](sql-createstatistics.html).

**Table 52.50. `pg_statistic_ext` Columns**

|                                                                                                                                                                                                                          Column Type<br/><br/> Description                                                                                                                                                                                                                         |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|                                                                                                                                                                                                                        `oid` `oid`<br/><br/> Row identifier                                                                                                                                                                                                                        |
|                                                                                                                                                                      `stxrelid` `oid` (references [`pg_class`](catalog-pg-class.html).`oid`)<br/><br/> Table containing the columns described by this object                                                                                                                                                                       |
|                                                                                                                                                                                                              `stxname` `name`<br/><br/> Name of the statistics object                                                                                                                                                                                                              |
|                                                                                                                                                            `stxnamespace` `oid` (references [`pg_namespace`](catalog-pg-namespace.html).`oid`)<br/><br/> The OID of the namespace that contains this statistics object                                                                                                                                                             |
|                                                                                                                                                                                 `stxowner` `oid` (references [`pg_authid`](catalog-pg-authid.html).`oid`)<br/><br/> Owner of the statistics object                                                                                                                                                                                 |
|`stxstattarget` `int4`<br/><br/>`stxstattarget` controls the level of detail of statistics accumulated for this statistics object by [`ANALYZE`](sql-analyze.html). A zero value indicates that no statistics should be collected. A negative 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.|
|                                                                                       `stxkeys` `int2vector` (references [`pg_attribute`](catalog-pg-attribute.html).`attnum`)<br/><br/> 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[]`<br/><br/> 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`<br/><br/> 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.                                                                                                  |

 The `pg_statistic_ext` entry is filled in completely during [`CREATE STATISTICS`](sql-createstatistics.html), but the actual statistical values are not computed then. Subsequent [`ANALYZE`](sql-analyze.html) commands compute the desired values and populate an entry in the [`pg_statistic_ext_data`](catalog-pg-statistic-ext-data.html) catalog.