53.53. 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.

Table 53.53. pg_statistic_ext_data Columns

Column Type


stxoid oid (references pg_statistic_ext . oid )

Extended statistics object containing the definition for this data

stxdinherit 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