BEGIN;
BEGIN
EXPLAIN (ANALYZE, BUFFERS)
select
	nation,
	o_year,
	sum(amount) as sum_profit
from
	(
		select
			n_name as nation,
			extract(year from o_orderdate) as o_year,
			l_extendedprice * (1 - l_discount) - ps_supplycost * l_quantity as amount
		from
			part,
			supplier,
			lineitem,
			partsupp,
			orders,
			nation
		where
			s_suppkey = l_suppkey
			and ps_suppkey = l_suppkey
			and ps_partkey = l_partkey
			and p_partkey = l_partkey
			and o_orderkey = l_orderkey
			and s_nationkey = n_nationkey
			and p_name like '%chocolate%'
	) as profit
group by
	nation,
	o_year
order by
	nation,
	o_year desc;
                                                                                  QUERY PLAN                                                                                   
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 GroupAggregate  (cost=3366790.44..3366794.64 rows=120 width=46) (actual time=215464.620..218946.440 rows=175 loops=1)
   Buffers: shared hit=30075888 read=1066918 dirtied=23 written=10573
   ->  Sort  (cost=3366790.44..3366790.74 rows=120 width=46) (actual time=215449.968..216509.350 rows=3284484 loops=1)
         Sort Key: nation.n_name, (date_part('year'::text, (orders.o_orderdate)::timestamp without time zone))
         Sort Method: quicksort  Memory: 560185kB
         Buffers: shared hit=30075888 read=1066918 dirtied=23 written=10573
         ->  Nested Loop  (cost=2700747.15..3366786.29 rows=120 width=46) (actual time=97599.377..194078.569 rows=3284484 loops=1)
               Buffers: shared hit=30075880 read=1066918 dirtied=23 written=10573
               ->  Nested Loop  (cost=2700747.15..3366752.07 rows=120 width=24) (actual time=97599.288..180386.837 rows=3284484 loops=1)
                     Buffers: shared hit=23506912 read=1066918 dirtied=23 written=10573
                     ->  Nested Loop  (cost=2700747.15..3366516.32 rows=120 width=24) (actual time=97599.167..124223.187 rows=3284484 loops=1)
                           Buffers: shared hit=10819651 read=598271 written=2933
                           ->  Merge Join  (cost=2700747.15..3366481.37 rows=120 width=28) (actual time=97599.077..108646.553 rows=3284484 loops=1)
                                 Merge Cond: ((partsupp.ps_partkey = lineitem.l_partkey) AND (partsupp.ps_suppkey = lineitem.l_suppkey))
                                 Buffers: shared hit=948840 read=597688 written=2901
                                 ->  Index Scan using pk_partsupp on partsupp  (cost=0.00..603091.26 rows=8000000 width=12) (actual time=0.009..5118.431 rows=7999845 loops=1)
                                       Buffers: shared hit=289061 read=145141 written=2901
                                 ->  Sort  (cost=2700742.09..2708292.66 rows=3020231 width=28) (actual time=97599.015..99888.259 rows=3284484 loops=1)
                                       Sort Key: part.p_partkey, lineitem.l_suppkey
                                       Sort Method: quicksort  Memory: 354905kB
                                       Buffers: shared hit=659779 read=452547
                                       ->  Hash Join  (cost=66773.24..2375671.19 rows=3020231 width=28) (actual time=1580.050..92851.614 rows=3284484 loops=1)
                                             Hash Cond: (lineitem.l_partkey = part.p_partkey)
                                             Buffers: shared hit=659776 read=452547
                                             ->  Seq Scan on lineitem  (cost=0.00..1675246.82 rows=60344882 width=24) (actual time=0.030..15755.127 rows=60045826 loops=1)
                                                   Buffers: shared hit=637298 read=434500
                                             ->  Hash  (cost=65522.00..65522.00 rows=100099 width=4) (actual time=1579.839..1579.839 rows=109369 loops=1)
                                                   Buckets: 16384  Batches: 1  Memory Usage: 3846kB
                                                   Buffers: shared hit=22475 read=18047
                                                   ->  Seq Scan on part  (cost=0.00..65522.00 rows=100099 width=4) (actual time=0.018..1502.666 rows=109369 loops=1)
                                                         Filter: ((p_name)::text ~~ '%chocolate%'::text)
                                                         Rows Removed by Filter: 1890631
                                                         Buffers: shared hit=22475 read=18047
                           ->  Index Scan using pk_supplier on supplier  (cost=0.00..0.28 rows=1 width=8) (actual time=0.004..0.004 rows=1 loops=3284484)
                                 Index Cond: (s_suppkey = lineitem.l_suppkey)
                                 Buffers: shared hit=9870811 read=583 written=32
                     ->  Index Scan using pk_orders on orders  (cost=0.00..1.95 rows=1 width=8) (actual time=0.016..0.016 rows=1 loops=3284484)
                           Index Cond: (o_orderkey = lineitem.l_orderkey)
                           Buffers: shared hit=12687261 read=468647 dirtied=23 written=7640
               ->  Index Scan using pk_nation on nation  (cost=0.00..0.27 rows=1 width=30) (actual time=0.002..0.003 rows=1 loops=3284484)
                     Index Cond: (n_nationkey = supplier.s_nationkey)
                     Buffers: shared hit=6568968
 Total runtime: 219125.603 ms
(43 rows)

COMMIT;
COMMIT