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 55.54. 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
|