---
title: "pg_statistic_ext"
id: catalog-pg-statistic-ext
pg_version: "20devel"
---

<a id="catalog-pg-statistic-ext"></a>

## 52.57. 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`](sql-createstatistics.md). 

**pg_statistic_ext Columns**

| Column Type | Description | 
| --- | --- |
| `oid` `oid` | Row identifier |
| `stxrelid` `oid` (references [pg_class](catalog-pg-class.md).`oid`) | Table containing the columns described by this object |
| `stxname` `name` | Name of the statistics object |
| `stxnamespace` `oid` (references [pg_namespace](catalog-pg-namespace.md).`oid`) | The OID of the namespace that contains this statistics object |
| `stxowner` `oid` (references [pg_authid](catalog-pg-authid.md).`oid`) | Owner of the statistics object |
| `stxkeys` `int2vector` (references [pg_attribute](catalog-pg-attribute.md).`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`](sql-analyze.md). 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. |

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