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 '%snow%'
	) as profit
group by
	nation,
	o_year
order by
	nation,
	o_year desc;
                                                                                  QUERY PLAN                                                                                   
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 GroupAggregate  (cost=3376492.21..3376496.51 rows=123 width=46) (actual time=255894.272..259412.100 rows=175 loops=1)
   Buffers: shared hit=30218644 read=706220 written=7678
   ->  Sort  (cost=3376492.21..3376492.51 rows=123 width=46) (actual time=255878.931..257001.405 rows=3260185 loops=1)
         Sort Key: nation.n_name, (date_part('year'::text, (orders.o_orderdate)::timestamp without time zone))
         Sort Method: quicksort  Memory: 556768kB
         Buffers: shared hit=30218644 read=706220 written=7678
         ->  Nested Loop  (cost=2709963.84..3376487.94 rows=123 width=46) (actual time=126569.205..232432.059 rows=3260185 loops=1)
               Buffers: shared hit=30218636 read=706220 written=7678
               ->  Nested Loop  (cost=2709963.84..3376452.86 rows=123 width=24) (actual time=126569.143..214898.268 rows=3260185 loops=1)
                     Buffers: shared hit=23698266 read=706220 written=7678
                     ->  Nested Loop  (cost=2709963.84..3376211.21 rows=123 width=24) (actual time=126569.063..159622.289 rows=3260185 loops=1)
                           Buffers: shared hit=10678693 read=667105 written=7647
                           ->  Merge Join  (cost=2709963.84..3376175.39 rows=123 width=28) (actual time=126569.026..139604.613 rows=3260185 loops=1)
                                 Merge Cond: ((partsupp.ps_partkey = lineitem.l_partkey) AND (partsupp.ps_suppkey = lineitem.l_suppkey))
                                 Buffers: shared hit=880088 read=667105 written=7647
                                 ->  Index Scan using pk_partsupp on partsupp  (cost=0.00..603091.33 rows=8000000 width=12) (actual time=0.018..6656.740 rows=7999849 loops=1)
                                       Buffers: shared hit=272213 read=161989 written=2518
                                 ->  Sort  (cost=2709963.83..2717670.17 rows=3082537 width=28) (actual time=126568.960..128856.911 rows=3260185 loops=1)
                                       Sort Key: part.p_partkey, lineitem.l_suppkey
                                       Sort Method: quicksort  Memory: 353006kB
                                       Buffers: shared hit=607875 read=505116 written=5129
                                       ->  Hash Join  (cost=66798.25..2377732.82 rows=3082537 width=28) (actual time=2186.250..122494.523 rows=3260185 loops=1)
                                             Hash Cond: (lineitem.l_partkey = part.p_partkey)
                                             Buffers: shared hit=607872 read=505116 written=5129
                                             ->  Seq Scan on lineitem  (cost=0.00..1676282.10 rows=60382710 width=24) (actual time=0.023..23045.014 rows=59985687 loops=1)
                                                   Buffers: shared hit=601653 read=470810 written=6
                                             ->  Hash  (cost=65522.00..65522.00 rows=102100 width=4) (actual time=2186.041..2186.041 rows=108717 loops=1)
                                                   Buckets: 16384  Batches: 1  Memory Usage: 3823kB
                                                   Buffers: shared hit=6216 read=34306 written=5123
                                                   ->  Seq Scan on part  (cost=0.00..65522.00 rows=102100 width=4) (actual time=0.021..1570.665 rows=108717 loops=1)
                                                         Filter: ((p_name)::text ~~ '%snow%'::text)
                                                         Rows Removed by Filter: 1891283
                                                         Buffers: shared hit=6216 read=34306 written=5123
                           ->  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=3260185)
                                 Index Cond: (s_suppkey = lineitem.l_suppkey)
                                 Buffers: shared hit=9798605
                     ->  Index Scan using pk_orders on orders  (cost=0.00..1.95 rows=1 width=8) (actual time=0.016..0.016 rows=1 loops=3260185)
                           Index Cond: (o_orderkey = lineitem.l_orderkey)
                           Buffers: shared hit=13019573 read=39115 written=31
               ->  Index Scan using pk_nation on nation  (cost=0.00..0.27 rows=1 width=30) (actual time=0.003..0.004 rows=1 loops=3260185)
                     Index Cond: (n_nationkey = supplier.s_nationkey)
                     Buffers: shared hit=6520370
 Total runtime: 259514.148 ms
(43 rows)

COMMIT;
COMMIT