PostgreSQL 15 ← 14
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.
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 |
|---|---|---|
tableoid | oid | -6 |
cmax | cid | -5 |
xmax | xid | -4 |
cmin | cid | -3 |
xmin | xid | -2 |
ctid | tid | -1 |
字段演化矩阵
悬停查看字段类型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 14 ← 13
PostgreSQL 12 ← 11新增目录
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。