9.29. Statistics Information Functions
PostgreSQL provides a function to inspect complex statistics defined using theCREATE STATISTICS command.
9.29.1. Inspecting MCV Lists
The Values of thepg_mcv_list_items returns a list of all items stored in a multi-columnMCV list, and returns the following columns:Name Type Description indexintindex 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 can be obtained only from thepg_statistic_ext_data.stxdmcv column.