51.51. pg_statistic_ext
The catalog
pg_statistic_ext
holds definitions of extended planner statistics.
Each row in this catalog corresponds to a
statistics object
created with
CREATE STATISTICS
.
Table 51.51.
pg_statistic_ext
Columns
| Name | Type | References | Description |
|---|---|---|---|
stxrelid
|
oid
|
|
Table containing the columns described by this object |
stxname
|
name
|
Name of the statistics object | |
stxnamespace
|
oid
|
|
The OID of the namespace that contains this statistics object |
stxowner
|
oid
|
|
Owner of the statistics object |
stxkeys
|
int2vector
|
|
An array of attribute numbers, indicating which table columns are
covered by this statistics object;
for example a value of
1 3
would
mean that the first and the third table columns are covered
|
stxkind
|
char[]
|
An array containing codes for the enabled statistic kinds;
valid values are:
d
for n-distinct statistics,
f
for functional dependency statistics, and
m
for most common values (MCV) list statistics
|
The
pg_statistic_ext
entry is filled in
completely during
CREATE STATISTICS
, but the actual
statistical values are not computed then.
Subsequent
ANALYZE
commands compute the desired values
and populate an entry in the
pg_statistic_ext_data
catalog.