Help Center/ GaussDB/ Developer Guide(Centralized_V2.0-2.x)/ System Catalogs and System Views/ System Catalogs/ PG_STATISTIC_EXT
Updated on 2025-07-22 GMT+08:00
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PG_STATISTIC_EXT

PG_STATISTIC_EXT records extended statistics about tables in a database. You can specify the extended statistics to be collected. This system catalog is accessible only to users with the SYSADMIN permission.

Table 1 PG_STATISTIC_EXT columns

Name

Type

Description

starelid

oid

Table or index that the described column belongs to.

starelkind

char

Type of the object to which a table belongs. c indicates an ordinary table, and p indicates a partitioned table.

stainherit

Boolean

Specifies whether to collect statistics for objects that have inheritance relationship.

stanullfrac

real

Percentage of column entries that are null.

stawidth

integer

Average stored width, in bytes, of non-null entries.

stadistinct

real
Number of distinct, non-null data values in the column for database nodes.
  • A value greater than 0 is the actual number of distinct values.
  • A value less than 0 is the ratio of the distinct value to the total number of rows. For example, if stadistinct is -0.5, the actual distinct value is the total number of rows multiplied by 0.5.
  • The value 0 indicates that the number of distinct values is unknown.

stadndistinct

real
Number of unique non-null data values in the DN1 column.
  • A value greater than 0 is the actual number of distinct values.
  • A value less than 0 is the ratio of the distinct value to the total number of rows. For example, if stadistinct is -0.5, the actual distinct value is the total number of rows multiplied by 0.5.
  • The value 0 indicates that the number of distinct values is unknown.

stakindN

smallint

Code number stating that the type of statistics is stored in slot N of the pg_statistic row.

The value of N ranges from 1 to 5.

staopN

oid

Operator used to generate the statistics stored in slot N. For example, a histogram slot shows the < operator that defines the sort order of the data.

The value of N ranges from 1 to 5.

stakey

int2vector

Array of a column ID.

stanumbersN

real[]

Numerical statistics of the appropriate type for slot N. The value is NULL if the slot does not involve numerical values.

The value of N ranges from 1 to 5.

stavaluesN

anyarray

Column data values of the appropriate type for slot N. The value is NULL if the slot type does not store any data values. Each array's element values are actually of the specific column's data type, so there is no way to define these columns' type more specifically than anyarray.

The value of N ranges from 1 to 5.

staexprs

pg_node_tree

Expression corresponding to the extended statistics information.

PG_STATISTIC_EXT stores sensitive information about statistical objects, such as MCVs. Users with the SYSADMIN permission and authorized users can access the PG_STATISTIC_EXT system catalog to query the sensitive information about the statistical objects.

Parent topic: System Catalogs