Look at Index

select correlation from pg_stats where tablename = 'empCodeToPosition' and attname = 'positionId';

CREATE EXTENSION IF NOT EXISTS pageinspect;
SELECT bt.ctid as corr_heap_ctid, e."positionId", e."empCodeId" FROM bt_page_items('"empCodeToPosition_empCodeId_idx"', 21) as bt INNER JOIN "empCodeToPosition" e on e.ctid = bt.ctid LIMIT 100 OFFSET 1;