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SYSTEM CATALOG · 系统目录

pg_statistic_ext_data

The catalog pg_statistic_ext_data holds data for extended planner statistics defined in pg_statistic_ext. Each row in this catalog corresponds to a statistics object created with CREATE STATISTICS. Normally there is one entry, with stxdinherit = false, for each statistics object that has been analyzed. If the table has inheritance children or partitions, a second entry with stxdinherit = true is also created. This row represents the statistics object over the inheritance tree, i.e., statistics for the data you'd see with SELECT * FROM table*, whereas the stxdinherit = false row represents the results of SELECT * FROM ONLY table. Like pg_statistic, pg_statistic_ext_data should not be readable by the public, since the contents might be considered sensitive. (Example: most common combinations of values in columns might be quite interesting.) pg_stats_ext is a publicly readable view on pg_statistic_ext_data (after joining with pg_statistic_ext) that only exposes information about tables the current user owns.

首次收录 PG 12最近收录 PG 19当前字段 6

已与 PostgreSQL 18.6 实例逐字段核对 · 原始实测记录 ↗

字段结构 PostgreSQL 18

pg_statistic_ext_data
字段 / COLUMN类型 / TYPE说明 / DESCRIPTION
stxoid oidNOT NULL Extended statistics object containing the definition for this data引用:pg_statistic_ext.oid
stxdinherit booleanNOT NULL文档原写法:bool If true, the stats include values from child tables, not just the values in the specified relation
stxdndistinct pg_ndistinct N-distinct counts, serialized as pg_ndistinct type
stxddependencies pg_dependencies Functional dependency statistics, serialized as pg_dependencies type
stxdmcv pg_mcv_list MCV (most-common values) list statistics, serialized as pg_mcv_list type
stxdexpr pg_statistic[] Per-expression statistics, serialized as an array of pg_statistic type

标记“隐式列”的字段不包含在 SELECT * 中;部分早期统计视图由同版本源码补全,额外来源会显示在字段说明中。

通用系统列 6

PostgreSQL 提供的系统属性,通常不在 SELECT * 中展开。单独保留,不与普通字段混算。

字段类型attnum
tableoidoid-6
cmaxcid-5
xmaxxid-4
cmincid-3
xminxid-2
ctidtid-1

字段演化矩阵

悬停查看字段类型
存在新增 / 类型或属性变化移除
字段 / COLUMN9.09.19.29.39.49.59.610111213141516171819
stxoid
stxdndistinct
stxddependencies
stxdmcv
stxdexpr
stxdinherit

9.0 是收录基线;基线中已存在的字段不标记为新增。矩阵按字段名称对齐,重命名显示为旧字段移除与新字段新增。

演化时间线

相邻大版本的变化

PostgreSQL 15 ← 14

+ stxdinherit目录说明更新

PostgreSQL 14 ← 13

+ stxdexpr1 处字段说明更新目录说明更新

PostgreSQL 12 ← 11新增目录

+ stxoid+ stxdndistinct+ stxddependencies+ stxdmcv

比较任意两个版本

选择两个版本,查看字段的新增、移除与类型变化。交互比较需要 JavaScript;演化时间线可直接阅读。