9.30. Statistics Information Functions
PostgreSQL provides a function to inspect complex statistics defined using the CREATE STATISTICS
command.
9.30.1. Inspecting MCV Lists
pg_mcv_list_items
returns a list of all items stored in a multi-column MCV list, and returns the following columns:
Name
Type
Description
index
int
index of the item in the MCV list
values
text[]
values stored in the MCV item
nulls
boolean[]
flags identifying NULL
values
frequency
double precision
frequency of this MCV item
base_frequency
double precision
base frequency of this MCV item
The pg_mcv_list_items
function can be used like this:
Values of the pg_mcv_list
can be obtained only from the pg_statistic_ext_data.stxdmcv
column.
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