SYSTEM CATALOG · System catalog

pg_statistic_ext_data

PostgreSQL documentation ↗Source definition ↗

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.

First seen PG 12Last seen PG 19Columns 6

9.0 9.1 9.2 9.3 9.4 9.5 9.6 10 11 12 13 14 15 16 17 18 19^β3

Checked column by column against a PostgreSQL 18.6 instance · Raw measurement record ↗

Columns PostgreSQL 18

pg_statistic_ext_data

COLUMN	TYPE	DESCRIPTION
`stxoid`	`oid`NOT NULL	Extended statistics object containing the definition for this dataReferences:`pg_statistic_ext.oid`
`stxdinherit`	`boolean`NOT NULLDocumented as:`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

Columns marked "implicit" are not included in SELECT *; some early statistics views are completed from same-version source, and the extra provenance is shown in the column description.

Common system columns 6

System attributes PostgreSQL provides, normally not expanded by SELECT *. Kept separately so they are not mixed in with ordinary columns.

Columns	Type	attnum
`tableoid`	`oid`	-6
`cmax`	`cid`	-5
`xmax`	`xid`	-4
`cmin`	`cid`	-3
`xmin`	`xid`	-2
`ctid`	`tid`	-1

Column evolution matrix

Hover a cell for the column type

PresentAdded / type or attribute changeRemoved

COLUMN	9.0	9.1	9.2	9.3	9.4	9.5	9.6	10	11	12	13	14
`stxoid`	–	–	–	–	–	–	–	–	–
`stxdndistinct`	–	–	–	–	–	–	–	–	–
`stxddependencies`	–	–	–	–	–	–	–	–	–
`stxdmcv`	–	–	–	–	–	–	–	–	–
`stxdexpr`	–	–	–	–	–	–	–	–	–	–	–
`stxdinherit`	–	–	–	–	–	–	–	–	–	–	–	–

9.0 is the coverage baseline; a column already present in the baseline is not marked as added. The matrix aligns columns by name, so a rename appears as the old column removed and a new column added.

Evolution timeline

Changes between adjacent majors

PostgreSQL 15 ← 14

+ stxdinheritCatalog description updated

PostgreSQL 14 ← 13

+ stxdexpr1 column description updatesCatalog description updated

PostgreSQL 12 ← 11Catalog added

+ stxoid+ stxdndistinct+ stxddependencies+ stxdmcv

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