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 '%steel%'
	) as profit
group by
	nation,
	o_year
order by
	nation,
	o_year desc;
                                                                                  QUERY PLAN                                                                                   
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 GroupAggregate  (cost=3493008.66..3493013.45 rows=137 width=46) (actual time=212434.194..215975.689 rows=175 loops=1)
   Buffers: shared hit=30377133 read=580971 dirtied=27 written=5014
   ->  Sort  (cost=3493008.66..3493009.00 rows=137 width=46) (actual time=212418.314..213541.910 rows=3264234 loops=1)
         Sort Key: nation.n_name, (date_part('year'::text, (orders.o_orderdate)::timestamp without time zone))
         Sort Method: quicksort  Memory: 557337kB
         Buffers: shared hit=30377133 read=580971 dirtied=27 written=5014
         ->  Nested Loop  (cost=2823802.27..3493003.80 rows=137 width=46) (actual time=103241.412..191499.942 rows=3264234 loops=1)
               Buffers: shared hit=30377125 read=580971 dirtied=27 written=5014
               ->  Nested Loop  (cost=2823802.27..3492964.72 rows=137 width=24) (actual time=103241.341..178290.723 rows=3264234 loops=1)
                     Buffers: shared hit=23848657 read=580971 dirtied=27 written=5014
                     ->  Nested Loop  (cost=2823802.27..3492696.47 rows=137 width=24) (actual time=103241.308..129217.611 rows=3264234 loops=1)
                           Buffers: shared hit=10841871 read=512922 written=384
                           ->  Merge Join  (cost=2823802.27..3492656.57 rows=137 width=28) (actual time=103241.266..114031.174 rows=3264234 loops=1)
                                 Merge Cond: ((partsupp.ps_partkey = lineitem.l_partkey) AND (partsupp.ps_suppkey = lineitem.l_suppkey))
                                 Buffers: shared hit=1031583 read=512819 written=384
                                 ->  Index Scan using pk_partsupp on partsupp  (cost=0.00..603091.26 rows=8000000 width=12) (actual time=0.008..4824.610 rows=7999945 loops=1)
                                       Buffers: shared hit=341681 read=92527 written=354
                                 ->  Sort  (cost=2823797.20..2832387.75 rows=3436219 width=28) (actual time=103241.118..105539.859 rows=3264234 loops=1)
                                       Sort Key: part.p_partkey, lineitem.l_suppkey
                                       Sort Method: quicksort  Memory: 353323kB
                                       Buffers: shared hit=689902 read=420292 written=30
                                       ->  Hash Join  (cost=66948.41..2450754.56 rows=3436219 width=28) (actual time=1303.087..99862.719 rows=3264234 loops=1)
                                             Hash Cond: (lineitem.l_partkey = part.p_partkey)
                                             Buffers: shared hit=689899 read=420292 written=30
                                             ->  Seq Scan on lineitem  (cost=0.00..1671914.45 rows=60224845 width=24) (actual time=0.017..17493.441 rows=60045303 loops=1)
                                                   Buffers: shared hit=677037 read=392629 written=5
                                             ->  Hash  (cost=65522.00..65522.00 rows=114113 width=4) (actual time=1302.844..1302.844 rows=108737 loops=1)
                                                   Buckets: 16384  Batches: 1  Memory Usage: 3823kB
                                                   Buffers: shared hit=12859 read=27663 written=25
                                                   ->  Seq Scan on part  (cost=0.00..65522.00 rows=114113 width=4) (actual time=0.026..1241.329 rows=108737 loops=1)
                                                         Filter: ((p_name)::text ~~ '%steel%'::text)
                                                         Rows Removed by Filter: 1891263
                                                         Buffers: shared hit=12859 read=27663 written=25
                           ->  Index Scan using pk_supplier on supplier  (cost=0.00..0.28 rows=1 width=8) (actual time=0.003..0.004 rows=1 loops=3264234)
                                 Index Cond: (s_suppkey = lineitem.l_suppkey)
                                 Buffers: shared hit=9810288 read=103
                     ->  Index Scan using pk_orders on orders  (cost=0.00..1.95 rows=1 width=8) (actual time=0.014..0.014 rows=1 loops=3264234)
                           Index Cond: (o_orderkey = lineitem.l_orderkey)
                           Buffers: shared hit=13006786 read=68049 dirtied=27 written=4630
               ->  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=3264234)
                     Index Cond: (n_nationkey = supplier.s_nationkey)
                     Buffers: shared hit=6528468
 Total runtime: 216099.426 ms
(43 rows)

COMMIT;
COMMIT