9.31. Statistics Information Functions#
Postgres Pro provides a function to inspect complex statistics defined using theCREATE STATISTICS command.
9.31.1. Inspecting MCV Lists#
pg_mcv_list_items(pg_mcv_list) →setof record
The Values of thepg_mcv_list_items returns a set of records describing all items stored in a multi-columnMCV list. It returns the following columns:Name Type Description indexintegerindex of the item in theMCV list valuestext[]values stored in the MCV item nullsboolean[]flags identifying NULL valuesfrequencydouble precisionfrequency of thisMCV item base_frequencydouble precisionbase frequency of thisMCV item pg_mcv_list_items function can be used like this:SELECT m.* FROM pg_statistic_ext join pg_statistic_ext_data on (oid = stxoid), pg_mcv_list_items(stxdmcv) m WHERE stxname = 'stts';
pg_mcv_list type can be obtained only from thepg_statistic_ext_data.stxdmcv column.