51.53. 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
,
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 51.53.
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
|