bidder=# explain analyze select auction_id, count(auction_id) from impressions where impressiondate >= '2019-02-26' and impressiondate < '2019-02-28' group by auction_id having count(auction_id) > 1;
                                                                                QUERY PLAN                                                                                 
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Finalize GroupAggregate  (cost=119605.15..119657.32 rows=67 width=40) (actual time=17366.948..30768.250 rows=3426 loops=1)
   Group Key: impressions_y2019m02d27.auction_id
   Filter: (count(impressions_y2019m02d27.auction_id) > 1)
   Rows Removed by Filter: 6313438
   ->  Gather Merge  (cost=119605.15..119651.82 rows=400 width=40) (actual time=17366.912..29118.310 rows=6318045 loops=1)
         Workers Planned: 2
         Workers Launched: 2
         ->  Sort  (cost=118605.13..118605.63 rows=200 width=40) (actual time=13319.406..16766.156 rows=2106015 loops=3)
               Sort Key: impressions_y2019m02d27.auction_id
               Sort Method: external merge  Disk: 103624kB
               Worker 0:  Sort Method: external merge  Disk: 102392kB
               Worker 1:  Sort Method: external merge  Disk: 149696kB
               ->  Partial HashAggregate  (cost=118595.48..118597.48 rows=200 width=40) (actual time=1554.139..2065.507 rows=2106015 loops=3)
                     Group Key: impressions_y2019m02d27.auction_id
                     ->  Parallel Append  (cost=0.00..105426.59 rows=2633779 width=32) (actual time=0.197..756.503 rows=2107041 loops=3)
                           ->  Parallel Seq Scan on impressions_y2019m02d27  (cost=0.00..48494.71 rows=1384714 width=32) (actual time=0.024..158.109 rows=1107716 loops=3)
                                 Filter: ((impressiondate >= '2019-02-26'::date) AND (impressiondate < '2019-02-28'::date))
                           ->  Parallel Seq Scan on impressions_y2019m02d26  (cost=0.00..43762.98 rows=1249065 width=32) (actual time=0.282..685.301 rows=1498986 loops=2)
                                 Filter: ((impressiondate >= '2019-02-26'::date) AND (impressiondate < '2019-02-28'::date))
 Planning Time: 0.480 ms
 Execution Time: 30812.092 ms
(21 rows)