# 52.51. pg\_statistic\_ext

目錄 pg\_statistic\_ext 包含了延伸的計劃程序統計資訊。此目錄中的每一個資料列相對應於使用 [CREATE STATISTICS](/11/reference/sql-commands/create-statistics.md) 所建立的統計資訊物件。

#### **Table 52.51. `pg_statistic_ext` Columns**

| 欄位                | 型別                | 參考                                                                     | 說明                                                        |
| ----------------- | ----------------- | ---------------------------------------------------------------------- | --------------------------------------------------------- |
| `stxrelid`        | `oid`             | [`pg_class`](/11/internals/system-catalogs/pg_class.md).oid            | 包含此物件包含欄位的所屬資料表                                           |
| `stxname`         | `name`            |                                                                        | 統計物件的名稱                                                   |
| `stxnamespace`    | `oid`             | [`pg_namespace`](/11/internals/system-catalogs/pg_namespace.md).oid    | 包含此統計資訊物件在命名空間裡的 OID                                      |
| `stxowner`        | `oid`             | [`pg_authid`](/11/internals/system-catalogs/pg_authid.md).oid          | 統計物件的所有者                                                  |
| `stxkeys`         | `int2vector`      | [`pg_attribute`](/11/internals/system-catalogs/pg_attribute.md).attnum | 一組陣列表示的屬性數字，指示此統計物件覆蓋哪些資料表欄位；例如，值為 1 3 意味著覆蓋了第一個和第三個資料表欄位 |
| `stxkind`         | `char[]`          |                                                                        | 包含已啟用統計類型的代碼的陣列；有效值為：d 表示 n-distinct 統計資訊，f 表示功能相依統計資訊    |
| `stxndistinct`    | `pg_ndistinct`    |                                                                        | N-distinct 計數，序列化為 pg\_ndistinct 型別                       |
| `stxdependencies` | `pg_dependencies` |                                                                        | 功能相依統計資訊，序列化為 pg\_dependencies 型別                         |

stxkind 欄位會在建立統計物件時填入，指示需要哪種統計類型。在它之後的欄位最初為 NULL，僅在 ANALYZE 計算出相對應的統計量時才填入內容。


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