try.py

print("Finalize GroupAggregate  (cost=240784.44..240786.40 rows=6 width=236) (actual time=1779.154..1780.426 rows=4 loops=1)\n  Output: l_returnflag, l_linestatus, sum(l_quantity), sum(l_extendedprice), sum((l_extendedprice * ('1'::numeric - l_discount))), sum(((l_extendedprice * ('1'::numeric - l_discount)) * ('1'::numeric + l_tax))), avg(l_quantity), avg(l_extendedprice), avg(l_discount), count(*)\n  Group Key: lineitem.l_returnflag, lineitem.l_linestatus\n  Buffers: shared hit=2862 read=119357\n  ->  Gather Merge  (cost=240784.44..240785.84 rows=12 width=236) (actual time=1779.134..1780.365 rows=12 loops=1)\n        Output: l_returnflag, l_linestatus, (PARTIAL sum(l_quantity)), (PARTIAL sum(l_extendedprice)), (PARTIAL sum((l_extendedprice * ('1'::numeric - l_discount)))), (PARTIAL sum(((l_extendedprice * ('1'::numeric - l_discount)) * ('1'::numeric + l_tax)))), (PARTIAL avg(l_quantity)), (PARTIAL avg(l_extendedprice)), (PARTIAL avg(l_discount)), (PARTIAL count(*))\n        Workers Planned: 2\n        Workers Launched: 2\n        Buffers: shared hit=2862 read=119357\n        ->  Sort  (cost=239784.42..239784.44 rows=6 width=236) (actual time=1773.163..1773.164 rows=4 loops=3)\n              Output: l_returnflag, l_linestatus, (PARTIAL sum(l_quantity)), (PARTIAL sum(l_extendedprice)), (PARTIAL sum((l_extendedprice * ('1'::numeric - l_discount)))), (PARTIAL sum(((l_extendedprice * ('1'::numeric - l_discount)) * ('1'::numeric + l_tax)))), (PARTIAL avg(l_quantity)), (PARTIAL avg(l_extendedprice)), (PARTIAL avg(l_discount)), (PARTIAL count(*))\n              Sort Key: lineitem.l_returnflag, lineitem.l_linestatus\n              Sort Method: quicksort  Memory: 27kB\n              Buffers: shared hit=2862 read=119357\n              Worker 0:  actual time=1769.754..1769.755 rows=4 loops=1\n                Sort Method: quicksort  Memory: 27kB\n                Buffers: shared hit=954 read=39635\n              Worker 1:  actual time=1770.909..1770.910 rows=4 loops=1\n                Sort Method: quicksort  Memory: 27kB\n                Buffers: shared hit=944 read=39858\n              ->  Partial HashAggregate  (cost=239784.21..239784.34 rows=6 width=236) (actual time=1773.064..1773.070 rows=4 loops=3)\n                    Output: l_returnflag, l_linestatus, PARTIAL sum(l_quantity), PARTIAL sum(l_extendedprice), PARTIAL sum((l_extendedprice * ('1'::numeric - l_discount))), PARTIAL sum(((l_extendedprice * ('1'::numeric - l_discount)) * ('1'::numeric + l_tax))), PARTIAL avg(l_quantity), PARTIAL avg(l_extendedprice), PARTIAL avg(l_discount), PARTIAL count(*)\n                    Group Key: lineitem.l_returnflag, lineitem.l_linestatus\n                    Batches: 1  Memory Usage: 32kB\n                    Buffers: shared hit=2848 read=119357\n                    Worker 0:  actual time=1769.693..1769.700 rows=4 loops=1\n                      Batches: 1  Memory Usage: 32kB\n                      Buffers: shared hit=947 read=39635\n                    Worker 1:  actual time=1770.685..1770.691 rows=4 loops=1\n                      Batches: 1  Memory Usage: 32kB\n                      Buffers: shared hit=937 read=39858\n                    ->  Parallel Seq Scan on public.lineitem  (cost=0.00..153460.94 rows=2466379 width=25) (actual time=0.126..328.322 rows=1972197 loops=3)\n                          Output: l_orderkey, l_partkey, l_suppkey, l_linenumber, l_quantity, l_extendedprice, l_discount, l_tax, l_returnflag, l_linestatus, l_shipdate, l_commitdate, l_receiptdate, l_shipinstruct, l_shipmode, l_comment, dummy\n                          Filter: (lineitem.l_shipdate <= '1998-09-02 00:00:00'::timestamp without time zone)\n                          Rows Removed by Filter: 28208\n                          Buffers: shared hit=2848 read=119357\n                          Worker 0:  actual time=0.124..326.768 rows=1964866 loops=1\n                            Buffers: shared hit=947 read=39635\n                          Worker 1:  actual time=0.187..328.018 rows=1974983 loops=1\n                            Buffers: shared hit=937 read=39858\nPlanning:\n  Buffers: shared hit=111\nPlanning Time: 0.667 ms\nExecution Time: 1780.536 ms")