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=3511669.57..3511674.61 rows=144 width=46) (actual time=761630.088..764710.181 rows=175 loops=1)
   Buffers: shared hit=30152438 read=874074 dirtied=64 written=3364
   ->  Sort  (cost=3511669.57..3511669.93 rows=144 width=46) (actual time=761614.971..762495.548 rows=3271939 loops=1)
         Sort Key: nation.n_name, (date_part('year'::text, (orders.o_orderdate)::timestamp without time zone))
         Sort Method: quicksort  Memory: 558421kB
         Buffers: shared hit=30152438 read=874074 dirtied=64 written=3364
         ->  Nested Loop  (cost=2841130.88..3511664.41 rows=144 width=46) (actual time=201943.123..736272.219 rows=3271939 loops=1)
               Buffers: shared hit=30152430 read=874074 dirtied=64 written=3364
               ->  Nested Loop  (cost=2841130.88..3511623.34 rows=144 width=24) (actual time=201943.030..604211.919 rows=3271939 loops=1)
                     Buffers: shared hit=23608552 read=874074 dirtied=64 written=3364
                     ->  Nested Loop  (cost=2841130.88..3511342.33 rows=144 width=24) (actual time=201942.895..359628.737 rows=3271939 loops=1)
                           Buffers: shared hit=10699510 read=677267 written=1094
                           ->  Merge Join  (cost=2841130.88..3511300.40 rows=144 width=28) (actual time=201942.835..230420.450 rows=3271939 loops=1)
                                 Merge Cond: ((partsupp.ps_partkey = lineitem.l_partkey) AND (partsupp.ps_suppkey = lineitem.l_suppkey))
                                 Buffers: shared hit=864997 read=677266 written=1094
                                 ->  Index Scan using pk_partsupp on partsupp  (cost=0.00..603091.29 rows=8000000 width=12) (actual time=0.007..18784.137 rows=7999657 loops=1)
                                       Buffers: shared hit=316691 read=117498 written=1092
                                 ->  Sort  (cost=2841130.85..2850156.47 rows=3610251 width=28) (actual time=201942.655..205930.558 rows=3271939 loops=1)
                                       Sort Key: part.p_partkey, lineitem.l_suppkey
                                       Sort Method: quicksort  Memory: 353925kB
                                       Buffers: shared hit=548306 read=559768 written=2
                                       ->  Hash Join  (cost=67023.64..2447908.31 rows=3610251 width=28) (actual time=2263.311..196912.033 rows=3271939 loops=1)
                                             Hash Cond: (lineitem.l_partkey = part.p_partkey)
                                             Buffers: shared hit=548303 read=559768 written=2
                                             ->  Seq Scan on lineitem  (cost=0.00..1668598.31 rows=60105231 width=24) (actual time=0.032..70907.603 rows=60045603 loops=1)
                                                   Buffers: shared hit=508002 read=559544 written=2
                                             ->  Hash  (cost=65522.00..65522.00 rows=120131 width=4) (actual time=2262.882..2262.882 rows=108866 loops=1)
                                                   Buckets: 16384  Batches: 1  Memory Usage: 3828kB
                                                   Buffers: shared hit=40298 read=224
                                                   ->  Seq Scan on part  (cost=0.00..65522.00 rows=120131 width=4) (actual time=0.022..2186.772 rows=108866 loops=1)
                                                         Filter: ((p_name)::text ~~ '%sky%'::text)
                                                         Rows Removed by Filter: 1891134
                                                         Buffers: shared hit=40298 read=224
                           ->  Index Scan using pk_supplier on supplier  (cost=0.00..0.28 rows=1 width=8) (actual time=0.037..0.038 rows=1 loops=3271939)
                                 Index Cond: (s_suppkey = lineitem.l_suppkey)
                                 Buffers: shared hit=9834513 read=1
                     ->  Index Scan using pk_orders on orders  (cost=0.00..1.94 rows=1 width=8) (actual time=0.073..0.073 rows=1 loops=3271939)
                           Index Cond: (o_orderkey = lineitem.l_orderkey)
                           Buffers: shared hit=12909042 read=196807 dirtied=64 written=2270
               ->  Index Scan using pk_nation on nation  (cost=0.00..0.27 rows=1 width=30) (actual time=0.037..0.037 rows=1 loops=3271939)
                     Index Cond: (n_nationkey = supplier.s_nationkey)
                     Buffers: shared hit=6543878
 Total runtime: 764856.866 ms
(43 rows)

COMMIT;
COMMIT