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=3490732.89..3490737.51 rows=132 width=46) (actual time=244343.696..247328.895 rows=175 loops=1)
   Buffers: shared hit=29942860 read=966707 dirtied=215 written=12358
   ->  Sort  (cost=3490732.89..3490733.22 rows=132 width=46) (actual time=244330.587..245108.322 rows=3258195 loops=1)
         Sort Key: nation.n_name, (date_part('year'::text, (orders.o_orderdate)::timestamp without time zone))
         Sort Method: quicksort  Memory: 556488kB
         Buffers: shared hit=29942860 read=966707 dirtied=215 written=12358
         ->  Nested Loop  (cost=2822313.23..3490728.24 rows=132 width=46) (actual time=116529.468..224998.337 rows=3258195 loops=1)
               Buffers: shared hit=29942852 read=966707 dirtied=215 written=12358
               ->  Nested Loop  (cost=2822313.23..3490690.60 rows=132 width=24) (actual time=116529.394..207945.035 rows=3258195 loops=1)
                     Buffers: shared hit=23426462 read=966707 dirtied=215 written=12358
                     ->  Nested Loop  (cost=2822313.23..3490429.96 rows=132 width=24) (actual time=116529.224..147236.703 rows=3258195 loops=1)
                           Buffers: shared hit=10655390 read=687061 written=34
                           ->  Merge Join  (cost=2822313.23..3490391.52 rows=132 width=28) (actual time=116529.143..127905.576 rows=3258195 loops=1)
                                 Merge Cond: ((partsupp.ps_partkey = lineitem.l_partkey) AND (partsupp.ps_suppkey = lineitem.l_suppkey))
                                 Buffers: shared hit=862760 read=686952 written=5
                                 ->  Index Scan using pk_partsupp on partsupp  (cost=0.00..603091.29 rows=8000000 width=12) (actual time=0.009..4800.686 rows=7999933 loops=1)
                                       Buffers: shared hit=434201 read=7
                                 ->  Sort  (cost=2822313.23..2830643.27 rows=3332013 width=28) (actual time=116528.999..118875.858 rows=3258195 loops=1)
                                       Sort Key: part.p_partkey, lineitem.l_suppkey
                                       Sort Method: quicksort  Memory: 352851kB
                                       Buffers: shared hit=428559 read=686945 written=5
                                       ->  Hash Join  (cost=66898.32..2461323.57 rows=3332013 width=28) (actual time=1010.551..112474.511 rows=3258195 loops=1)
                                             Hash Cond: (lineitem.l_partkey = part.p_partkey)
                                             Buffers: shared hit=428556 read=686945 written=5
                                             ->  Seq Scan on lineitem  (cost=0.00..1680213.23 rows=60523723 width=24) (actual time=0.020..19649.714 rows=60044082 loops=1)
                                                   Buffers: shared hit=388031 read=686945 written=5
                                             ->  Hash  (cost=65522.00..65522.00 rows=110106 width=4) (actual time=1010.343..1010.343 rows=108577 loops=1)
                                                   Buckets: 16384  Batches: 1  Memory Usage: 3818kB
                                                   Buffers: shared hit=40522
                                                   ->  Seq Scan on part  (cost=0.00..65522.00 rows=110106 width=4) (actual time=0.022..968.325 rows=108577 loops=1)
                                                         Filter: ((p_name)::text ~~ '%grey%'::text)
                                                         Rows Removed by Filter: 1891423
                                                         Buffers: shared hit=40522
                           ->  Index Scan using pk_supplier on supplier  (cost=0.00..0.28 rows=1 width=8) (actual time=0.004..0.005 rows=1 loops=3258195)
                                 Index Cond: (s_suppkey = lineitem.l_suppkey)
                                 Buffers: shared hit=9792630 read=109 written=29
                     ->  Index Only Scan using orders_o_orderkey_o_orderdate_idx on orders  (cost=0.00..1.96 rows=1 width=8) (actual time=0.017..0.018 rows=1 loops=3258195)
                           Index Cond: (o_orderkey = lineitem.l_orderkey)
                           Heap Fetches: 3258195
                           Buffers: shared hit=12771072 read=279646 dirtied=215 written=12324
               ->  Index Scan using pk_nation on nation  (cost=0.00..0.27 rows=1 width=30) (actual time=0.003..0.003 rows=1 loops=3258195)
                     Index Cond: (n_nationkey = supplier.s_nationkey)
                     Buffers: shared hit=6516390
 Total runtime: 247411.985 ms
(44 rows)

COMMIT;
COMMIT