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 '%khaki%'
	) as profit
group by
	nation,
	o_year
order by
	nation,
	o_year desc;
                                                                                  QUERY PLAN                                                                                   
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 GroupAggregate  (cost=3515582.92..3515587.93 rows=143 width=46) (actual time=261507.396..265025.328 rows=175 loops=1)
   Buffers: shared hit=30226059 read=701091 written=2405
   ->  Sort  (cost=3515582.92..3515583.28 rows=143 width=46) (actual time=261493.135..262579.218 rows=3260509 loops=1)
         Sort Key: nation.n_name, (date_part('year'::text, (orders.o_orderdate)::timestamp without time zone))
         Sort Method: quicksort  Memory: 556814kB
         Buffers: shared hit=30226059 read=701091 written=2405
         ->  Nested Loop  (cost=2845386.45..3515577.80 rows=143 width=46) (actual time=133144.587..240545.026 rows=3260509 loops=1)
               Buffers: shared hit=30226051 read=701091 written=2405
               ->  Nested Loop  (cost=2845386.45..3515537.02 rows=143 width=24) (actual time=133144.501..222900.884 rows=3260509 loops=1)
                     Buffers: shared hit=23705033 read=701091 written=2405
                     ->  Nested Loop  (cost=2845386.45..3515256.08 rows=143 width=24) (actual time=133144.383..166114.772 rows=3260509 loops=1)
                           Buffers: shared hit=10653714 read=692550 written=2401
                           ->  Merge Join  (cost=2845386.45..3515214.44 rows=143 width=28) (actual time=133144.304..146232.277 rows=3260509 loops=1)
                                 Merge Cond: ((partsupp.ps_partkey = lineitem.l_partkey) AND (partsupp.ps_suppkey = lineitem.l_suppkey))
                                 Buffers: shared hit=854291 read=692550 written=2401
                                 ->  Index Scan using pk_partsupp on partsupp  (cost=0.00..603091.33 rows=8000000 width=12) (actual time=0.008..6623.321 rows=7999917 loops=1)
                                       Buffers: shared hit=267190 read=167018 written=2395
                                 ->  Sort  (cost=2845386.32..2854298.45 rows=3564854 width=28) (actual time=133144.241..135425.489 rows=3260509 loops=1)
                                       Sort Key: part.p_partkey, lineitem.l_suppkey
                                       Sort Method: quicksort  Memory: 353032kB
                                       Buffers: shared hit=587101 read=525532 written=6
                                       ->  Hash Join  (cost=66998.45..2457433.75 rows=3564854 width=28) (actual time=1507.259..128109.251 rows=3260509 loops=1)
                                             Hash Cond: (lineitem.l_partkey = part.p_partkey)
                                             Buffers: shared hit=587098 read=525532 written=6
                                             ->  Seq Scan on lineitem  (cost=0.00..1675715.18 rows=60361918 width=24) (actual time=0.023..24415.466 rows=59985687 loops=1)
                                                   Buffers: shared hit=581152 read=490953 written=6
                                             ->  Hash  (cost=65522.00..65522.00 rows=118116 width=4) (actual time=1507.065..1507.065 rows=108775 loops=1)
                                                   Buckets: 16384  Batches: 1  Memory Usage: 3825kB
                                                   Buffers: shared hit=5943 read=34579
                                                   ->  Seq Scan on part  (cost=0.00..65522.00 rows=118116 width=4) (actual time=0.014..1440.828 rows=108775 loops=1)
                                                         Filter: ((p_name)::text ~~ '%khaki%'::text)
                                                         Rows Removed by Filter: 1891225
                                                         Buffers: shared hit=5943 read=34579
                           ->  Index Scan using pk_supplier on supplier  (cost=0.00..0.28 rows=1 width=8) (actual time=0.005..0.005 rows=1 loops=3260509)
                                 Index Cond: (s_suppkey = lineitem.l_suppkey)
                                 Buffers: shared hit=9799423
                     ->  Index Only Scan using orders_o_orderkey_o_orderdate_idx on orders  (cost=0.00..1.95 rows=1 width=8) (actual time=0.016..0.016 rows=1 loops=3260509)
                           Index Cond: (o_orderkey = lineitem.l_orderkey)
                           Heap Fetches: 3260509
                           Buffers: shared hit=13051319 read=8541 written=4
               ->  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=3260509)
                     Index Cond: (n_nationkey = supplier.s_nationkey)
                     Buffers: shared hit=6521018
 Total runtime: 265156.655 ms
(44 rows)

COMMIT;
COMMIT