Another suggestion, try to cluster the table using the index for the "field" column, then analyze. If you're on a spinning disk it will help if you sort your search "field" during bulk insert.
On Fri, Jul 19, 2019 at 07:43:26PM +0530, mayank rupareliya wrote: >Well, you haven't shown us the execution plan, so it's hard to check why >it did not help much and give you further advice. > > >This is the latest query execution with explain after adding indexing on >both columns. > >Aggregate (cost=174173.57..174173.58 rows=1 width=8) (actual >time=65087.657..65087.658 rows=1 loops=1) > -> Bitmap Heap Scan on fields (cost=1382.56..174042.61 rows=52386 >width=0) (actual time=160.340..65024.533 rows=31857 loops=1) > Recheck Cond: ((field)::text = 'Champlin'::text) > Heap Blocks: exact=31433 > -> Bitmap Index Scan on index_field (cost=0.00..1369.46 >rows=52386 width=0) (actual time=125.078..125.079 rows=31857 loops=1) > Index Cond: ((field)::text = 'Champlin'::text) >Planning Time: 8.595 ms >Execution Time: 65093.508 ms >
That very clearly does not use the index-only scan, so it's not surprising it's not any faster. You need to find out why the planner makes that decision.
regards
-- Tomas Vondra http://www.2ndQuadrant.com PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
