55.55. 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 , whereas the table*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 55.55. pg_statistic_ext_data Columns
Column Type Description |
|---|
Extended statistics object containing the definition for this data |
If true, the stats include values from child tables, not just the values in the specified relation |
N-distinct counts, serialized as |
Functional dependency statistics, serialized as |
MCV (most-common values) list statistics, serialized as |
Per-expression statistics, serialized as an array of |