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 '%grey%'
	) as profit
group by
	nation,
	o_year
order by
	nation,
	o_year desc;
                                                                                  QUERY PLAN                                                                                   
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 GroupAggregate  (cost=3501397.01..3501401.87 rows=139 width=46) (actual time=292867.746..296517.956 rows=175 loops=1)
   Buffers: shared hit=30071444 read=835524 written=1562
   ->  Sort  (cost=3501397.01..3501397.35 rows=139 width=46) (actual time=292855.209..293925.775 rows=3258141 loops=1)
         Sort Key: nation.n_name, (date_part('year'::text, (orders.o_orderdate)::timestamp without time zone))
         Sort Method: quicksort  Memory: 556481kB
         Buffers: shared hit=30071444 read=835524 written=1562
         ->  Nested Loop  (cost=2832097.99..3501392.06 rows=139 width=46) (actual time=140158.011..271977.210 rows=3258141 loops=1)
               Buffers: shared hit=30071436 read=835524 written=1562
               ->  Nested Loop  (cost=2832097.99..3501352.41 rows=139 width=24) (actual time=140157.927..249870.392 rows=3258141 loops=1)
                     Buffers: shared hit=23555154 read=835524 written=1562
                     ->  Nested Loop  (cost=2832097.99..3501078.88 rows=139 width=24) (actual time=140157.865..180833.613 rows=3258141 loops=1)
                           Buffers: shared hit=10510011 read=830172 written=1550
                           ->  Merge Join  (cost=2832097.99..3501038.40 rows=139 width=28) (actual time=140157.815..154449.700 rows=3258141 loops=1)
                                 Merge Cond: ((partsupp.ps_partkey = lineitem.l_partkey) AND (partsupp.ps_suppkey = lineitem.l_suppkey))
                                 Buffers: shared hit=717420 read=830172 written=1550
                                 ->  Index Scan using pk_partsupp on partsupp  (cost=0.00..603091.29 rows=8000000 width=12) (actual time=0.015..7433.402 rows=7999933 loops=1)
                                       Buffers: shared hit=298165 read=136043 written=1546
                                 ->  Sort  (cost=2832097.43..2840713.56 rows=3446453 width=28) (actual time=140157.588..142546.710 rows=3258141 loops=1)
                                       Sort Key: part.p_partkey, lineitem.l_suppkey
                                       Sort Method: quicksort  Memory: 352847kB
                                       Buffers: shared hit=419255 read=694129 written=4
                                       ->  Hash Join  (cost=66948.40..2457869.82 rows=3446453 width=28) (actual time=1516.949..135448.584 rows=3258141 loops=1)
                                             Hash Cond: (lineitem.l_partkey = part.p_partkey)
                                             Buffers: shared hit=419252 read=694129 written=4
                                             ->  Seq Scan on lineitem  (cost=0.00..1676903.48 rows=60404748 width=24) (actual time=0.031..31764.124 rows=60045310 loops=1)
                                                   Buffers: shared hit=419247 read=653609 written=4
                                             ->  Hash  (cost=65522.00..65522.00 rows=114112 width=4) (actual time=1516.621..1516.621 rows=108577 loops=1)
                                                   Buckets: 16384  Batches: 1  Memory Usage: 3818kB
                                                   Buffers: shared hit=2 read=40520
                                                   ->  Seq Scan on part  (cost=0.00..65522.00 rows=114112 width=4) (actual time=0.031..1451.457 rows=108577 loops=1)
                                                         Filter: ((p_name)::text ~~ '%grey%'::text)
                                                         Rows Removed by Filter: 1891423
                                                         Buffers: shared hit=2 read=40520
                           ->  Index Scan using pk_supplier on supplier  (cost=0.00..0.28 rows=1 width=8) (actual time=0.007..0.007 rows=1 loops=3258141)
                                 Index Cond: (s_suppkey = lineitem.l_suppkey)
                                 Buffers: shared hit=9792591
                     ->  Index Scan using pk_orders on orders  (cost=0.00..1.96 rows=1 width=8) (actual time=0.020..0.020 rows=1 loops=3258141)
                           Index Cond: (o_orderkey = lineitem.l_orderkey)
                           Buffers: shared hit=13045143 read=5352 written=12
               ->  Index Scan using pk_nation on nation  (cost=0.00..0.27 rows=1 width=30) (actual time=0.004..0.005 rows=1 loops=3258141)
                     Index Cond: (n_nationkey = supplier.s_nationkey)
                     Buffers: shared hit=6516282
 Total runtime: 296636.364 ms
(43 rows)

COMMIT;
COMMIT