SYSTEM VIEW · System view

pg_stats_ext

The view pg_stats_ext provides access to information about each extended statistics object in the database, combining information stored in the pg_statistic_ext and pg_statistic_ext_data catalogs. This view allows access only to rows of pg_statistic_ext and pg_statistic_ext_data that correspond to tables the user owns, and therefore it is safe to allow public read access to this view. pg_stats_ext is also designed to present the information in a more readable format than the underlying catalogs — at the cost that its schema must be extended whenever new types of extended statistics are added to pg_statistic_ext.

First seen PG 12Last seen PG 19Columns 15

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_stats_ext

COLUMN	TYPE	DESCRIPTION
`schemaname`	`name`	Name of schema containing tableReferences:`pg_namespace.nspname`
`tablename`	`name`	Name of tableReferences:`pg_class.relname`
`statistics_schemaname`	`name`	Name of schema containing extended statistics objectReferences:`pg_namespace.nspname`
`statistics_name`	`name`	Name of extended statistics objectReferences:`pg_statistic_ext.stxname`
`statistics_owner`	`name`	Owner of the extended statistics objectReferences:`pg_authid.rolname`
`attnames`	`name[]`	Names of the columns included in the extended statistics objectReferences:`pg_attribute.attname`
`exprs`	`text[]`	Expressions included in the extended statistics object
`kinds`	`"char"[]`Documented as:`char[]`	Types of extended statistics object enabled for this record
`inherited`	`boolean`Documented as:`bool`	If true, the stats include values from child tables, not just the values in the specified relationReferences:`pg_statistic_ext_data.stxdinherit`
`n_distinct`	`pg_ndistinct`	N-distinct counts for combinations of column values. If greater than zero, the estimated number of distinct values in the combination. If less than zero, the negative of the number of distinct values divided by the number of rows. (The negated form is used when ANALYZE believes that the number of distinct values is likely to increase as the table grows; the positive form is used when the column seems to have a fixed number of possible values.) For example, -1 indicates a unique combination of columns in which the number of distinct combinations is the same as the number of rows.
`dependencies`	`pg_dependencies`	Functional dependency statistics
`most_common_vals`	`text[]`	A list of the most common combinations of values in the columns. (Null if no combinations seem to be more common than any others.)
`most_common_val_nulls`	`boolean[]`Documented as:`bool[]`	A list of NULL flags for the most common combinations of values. (Null when most_common_vals is.)
`most_common_freqs`	`double precision[]`Documented as:`float8[]`	A list of the frequencies of the most common combinations, i.e., number of occurrences of each divided by total number of rows. (Null when most_common_vals is.)
`most_common_base_freqs`	`double precision[]`Documented as:`float8[]`	A list of the base frequencies of the most common combinations, i.e., product of per-value frequencies. (Null when most_common_vals is.)

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.

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	15	16	17	18
`schemaname`	–	–	–	–	–	–	–	–	–
`tablename`	–	–	–	–	–	–	–	–	–
`statistics_schemaname`	–	–	–	–	–	–	–	–	–
`statistics_name`	–	–	–	–	–	–	–	–	–
`statistics_owner`	–	–	–	–	–	–	–	–	–
`attnames`	–	–	–	–	–	–	–	–	–
`kinds`	–	–	–	–	–	–	–	–	–
`n_distinct`	–	–	–	–	–	–	–	–	–
`dependencies`	–	–	–	–	–	–	–	–	–
`most_common_vals`	–	–	–	–	–	–	–	–	–
`most_common_val_nulls`	–	–	–	–	–	–	–	–	–
`most_common_freqs`	–	–	–	–	–	–	–	–	–
`most_common_base_freqs`	–	–	–	–	–	–	–	–	–
`exprs`	–	–	–	–	–	–	–	–	–	–	–
`inherited`	–	–	–	–	–	–	–	–	–	–	–	–
`tableid`	–	–	–	–	–	–	–	–	–	–	–	–	–	–	–	–
`statistics_id`	–	–	–	–	–	–	–	–	–	–	–	–	–	–	–	–

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 19 ← 18

+ tableid+ statistics_id

PostgreSQL 15 ← 14

+ inherited

PostgreSQL 14 ← 13

+ exprs5 column description updatesCatalog description updated

PostgreSQL 12 ← 11Catalog added

+ schemaname+ tablename+ statistics_schemaname+ statistics_name+ statistics_owner+ attnames+ kinds+ n_distinct+ dependencies+ most_common_vals+ most_common_val_nulls+ most_common_freqs+ most_common_base_freqs

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FROMTOInclude description updates

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