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 55.53. pg_statistic_ext
Columns
Column Type Description 

Row identifier 
Table containing the columns described by this object 
Name of the statistics object 
The OID of the namespace that contains this statistics object 
Owner of the statistics object 

An array of attribute numbers, indicating which table columns are
covered by this statistics object;
for example a value of 
An array containing codes for the enabled statistics kinds;
valid values are:

Expression trees (in 
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.