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=3395682.38..3395686.86 rows=128 width=46) (actual time=667637.860..671212.020 rows=175 loops=1)
   Buffers: shared hit=30299471 read=578723 dirtied=683 written=2077
   ->  Sort  (cost=3395682.38..3395682.70 rows=128 width=46) (actual time=667624.303..668653.539 rows=3254853 loops=1)
         Sort Key: nation.n_name, (date_part('year'::text, (orders.o_orderdate)::timestamp without time zone))
         Sort Method: quicksort  Memory: 556018kB
         Buffers: shared hit=30299471 read=578723 dirtied=683 written=2077
         ->  Nested Loop  (cost=2728206.77..3395677.90 rows=128 width=46) (actual time=193573.636..646440.140 rows=3254853 loops=1)
               Buffers: shared hit=30299463 read=578723 dirtied=683 written=2077
               ->  Nested Loop  (cost=2728206.77..3395641.39 rows=128 width=24) (actual time=193573.561..536193.839 rows=3254853 loops=1)
                     Buffers: shared hit=23789757 read=578723 dirtied=683 written=2077
                     ->  Nested Loop  (cost=2728206.77..3395389.51 rows=128 width=24) (actual time=193572.967..329896.423 rows=3254853 loops=1)
                           Buffers: shared hit=10793562 read=537569 dirtied=677 written=1315
                           ->  Merge Join  (cost=2728206.77..3395352.23 rows=128 width=28) (actual time=193572.918..218143.558 rows=3254853 loops=1)
                                 Merge Cond: ((partsupp.ps_partkey = lineitem.l_partkey) AND (partsupp.ps_suppkey = lineitem.l_suppkey))
                                 Buffers: shared hit=1010860 read=537569 dirtied=677 written=1315
                                 ->  Index Scan using pk_partsupp on partsupp  (cost=0.00..603091.29 rows=8000000 width=12) (actual time=0.008..15817.370 rows=7999933 loops=1)
                                       Buffers: shared hit=342644 read=91564 written=719
                                 ->  Sort  (cost=2728206.75..2736224.40 rows=3207063 width=28) (actual time=193572.711..196992.804 rows=3254853 loops=1)
                                       Sort Key: part.p_partkey, lineitem.l_suppkey
                                       Sort Method: quicksort  Memory: 352590kB
                                       Buffers: shared hit=668216 read=446005 dirtied=677 written=596
                                       ->  Hash Join  (cost=66848.30..2381638.35 rows=3207063 width=28) (actual time=2089.756..188689.704 rows=3254853 loops=1)
                                             Hash Cond: (lineitem.l_partkey = part.p_partkey)
                                             Buffers: shared hit=668213 read=446005 dirtied=677 written=596
                                             ->  Seq Scan on lineitem  (cost=0.00..1678206.21 rows=60451321 width=24) (actual time=0.035..62532.363 rows=59984909 loops=1)
                                                   Buffers: shared hit=627688 read=446005 dirtied=677 written=596
                                             ->  Hash  (cost=65522.00..65522.00 rows=106104 width=4) (actual time=2089.434..2089.434 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=106104 width=4) (actual time=0.029..2012.869 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=0.032..0.033 rows=1 loops=3254853)
                                 Index Cond: (s_suppkey = lineitem.l_suppkey)
                                 Buffers: shared hit=9782702
                     ->  Index Scan using pk_orders on orders  (cost=0.00..1.96 rows=1 width=8) (actual time=0.061..0.062 rows=1 loops=3254853)
                           Index Cond: (o_orderkey = lineitem.l_orderkey)
                           Buffers: shared hit=12996195 read=41154 dirtied=6 written=762
               ->  Index Scan using pk_nation on nation  (cost=0.00..0.27 rows=1 width=30) (actual time=0.030..0.031 rows=1 loops=3254853)
                     Index Cond: (n_nationkey = supplier.s_nationkey)
                     Buffers: shared hit=6509706
 Total runtime: 671336.828 ms
(43 rows)

COMMIT;
COMMIT