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 '%sky%'
	) as profit
group by
	nation,
	o_year
order by
	nation,
	o_year desc;
                                                                                  QUERY PLAN                                                                                   
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 GroupAggregate  (cost=3765423.04..3765429.17 rows=175 width=46) (actual time=185611.292..189218.436 rows=175 loops=1)
   Buffers: shared hit=30534701 read=494342 written=2303
   ->  Sort  (cost=3765423.04..3765423.48 rows=175 width=46) (actual time=185598.297..186742.015 rows=3271991 loops=1)
         Sort Key: nation.n_name, (date_part('year'::text, (orders.o_orderdate)::timestamp without time zone))
         Sort Method: quicksort  Memory: 558428kB
         Buffers: shared hit=30534701 read=494342 written=2303
         ->  Nested Loop  (cost=3089325.92..3765416.53 rows=175 width=46) (actual time=97098.296..166619.579 rows=3271991 loops=1)
               Buffers: shared hit=30534693 read=494342 written=2303
               ->  Nested Loop  (cost=3089325.92..3765366.62 rows=175 width=24) (actual time=97098.222..156770.643 rows=3271991 loops=1)
                     Buffers: shared hit=23990711 read=494342 written=2303
                     ->  Nested Loop  (cost=3089325.92..3765023.95 rows=175 width=24) (actual time=97098.175..117667.565 rows=3271991 loops=1)
                           Buffers: shared hit=10909717 read=469322 written=389
                           ->  Merge Join  (cost=3089325.92..3764972.99 rows=175 width=28) (actual time=97098.120..106004.563 rows=3271991 loops=1)
                                 Merge Cond: ((partsupp.ps_partkey = lineitem.l_partkey) AND (partsupp.ps_suppkey = lineitem.l_suppkey))
                                 Buffers: shared hit=1075315 read=469068 written=387
                                 ->  Index Scan using pk_partsupp on partsupp  (cost=0.00..603091.29 rows=8000000 width=12) (actual time=0.010..3919.689 rows=7999657 loops=1)
                                       Buffers: shared hit=401112 read=33077 written=382
                                 ->  Sort  (cost=3089323.75..3100175.87 rows=4340847 width=28) (actual time=97097.993..99078.772 rows=3271991 loops=1)
                                       Sort Key: part.p_partkey, lineitem.l_suppkey
                                       Sort Method: quicksort  Memory: 353929kB
                                       Buffers: shared hit=674203 read=435991 written=5
                                       ->  Hash Join  (cost=67323.91..2610755.24 rows=4340847 width=28) (actual time=1192.936..93673.434 rows=3271991 loops=1)
                                             Hash Cond: (lineitem.l_partkey = part.p_partkey)
                                             Buffers: shared hit=674200 read=435991 written=5
                                             ->  Seq Scan on lineitem  (cost=0.00..1671921.52 rows=60225552 width=24) (actual time=0.026..15212.649 rows=60045303 loops=1)
                                                   Buffers: shared hit=661440 read=408226 written=5
                                             ->  Hash  (cost=65522.00..65522.00 rows=144153 width=4) (actual time=1192.777..1192.777 rows=108866 loops=1)
                                                   Buckets: 16384  Batches: 1  Memory Usage: 3828kB
                                                   Buffers: shared hit=12757 read=27765
                                                   ->  Seq Scan on part  (cost=0.00..65522.00 rows=144153 width=4) (actual time=0.022..1139.713 rows=108866 loops=1)
                                                         Filter: ((p_name)::text ~~ '%sky%'::text)
                                                         Rows Removed by Filter: 1891134
                                                         Buffers: shared hit=12757 read=27765
                           ->  Index Scan using pk_supplier on supplier  (cost=0.00..0.28 rows=1 width=8) (actual time=0.003..0.003 rows=1 loops=3271991)
                                 Index Cond: (s_suppkey = lineitem.l_suppkey)
                                 Buffers: shared hit=9834402 read=254 written=2
                     ->  Index Scan using pk_orders on orders  (cost=0.00..1.95 rows=1 width=8) (actual time=0.011..0.011 rows=1 loops=3271991)
                           Index Cond: (o_orderkey = lineitem.l_orderkey)
                           Buffers: shared hit=13080994 read=25020 written=1914
               ->  Index Scan using pk_nation on nation  (cost=0.00..0.27 rows=1 width=30) (actual time=0.002..0.002 rows=1 loops=3271991)
                     Index Cond: (n_nationkey = supplier.s_nationkey)
                     Buffers: shared hit=6543982
 Total runtime: 189340.283 ms
(43 rows)

COMMIT;
COMMIT