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 '%gainsboro%'
	) as profit
group by
	nation,
	o_year
order by
	nation,
	o_year desc;
                                                                                   QUERY PLAN                                                                                   
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 GroupAggregate  (cost=3482669.57..3482674.12 rows=130 width=46) (actual time=430673.790..434284.485 rows=175 loops=1)
   Buffers: shared hit=29841788 read=949925 dirtied=51 written=3558
   ->  Sort  (cost=3482669.57..3482669.90 rows=130 width=46) (actual time=430660.402..431721.247 rows=3245136 loops=1)
         Sort Key: nation.n_name, (date_part('year'::text, (orders.o_orderdate)::timestamp without time zone))
         Sort Method: quicksort  Memory: 554652kB
         Buffers: shared hit=29841788 read=949925 dirtied=51 written=3558
         ->  Nested Loop  (cost=2814705.79..3482665.01 rows=130 width=46) (actual time=148109.593..407524.749 rows=3245136 loops=1)
               Buffers: shared hit=29841780 read=949925 dirtied=51 written=3558
               ->  Nested Loop  (cost=2814705.79..3482627.93 rows=130 width=24) (actual time=148109.532..375417.523 rows=3245136 loops=1)
                     Buffers: shared hit=23351508 read=949925 dirtied=51 written=3558
                     ->  Nested Loop  (cost=2814705.79..3482371.25 rows=130 width=24) (actual time=148109.429..225476.506 rows=3245136 loops=1)
                           Buffers: shared hit=10567319 read=735930 written=1769
                           ->  Merge Join  (cost=2814705.79..3482333.39 rows=130 width=28) (actual time=148109.383..166406.015 rows=3245136 loops=1)
                                 Merge Cond: ((partsupp.ps_partkey = lineitem.l_partkey) AND (partsupp.ps_suppkey = lineitem.l_suppkey))
                                 Buffers: shared hit=813782 read=735930 written=1769
                                 ->  Index Scan using pk_partsupp on partsupp  (cost=0.00..603091.29 rows=8000000 width=12) (actual time=0.009..10630.691 rows=7999949 loops=1)
                                       Buffers: shared hit=333747 read=100461 written=1769
                                 ->  Sort  (cost=2814705.65..2822884.49 rows=3271536 width=28) (actual time=148109.317..150807.437 rows=3245136 loops=1)
                                       Sort Key: part.p_partkey, lineitem.l_suppkey
                                       Sort Method: quicksort  Memory: 351831kB
                                       Buffers: shared hit=480035 read=635469
                                       ->  Hash Join  (cost=66873.34..2460700.31 rows=3271536 width=28) (actual time=3127.106..143585.115 rows=3245136 loops=1)
                                             Hash Cond: (lineitem.l_partkey = part.p_partkey)
                                             Buffers: shared hit=480032 read=635469
                                             ->  Seq Scan on lineitem  (cost=0.00..1680216.29 rows=60524029 width=24) (actual time=0.016..34137.162 rows=60044082 loops=1)
                                                   Buffers: shared hit=479908 read=595068
                                             ->  Hash  (cost=65522.00..65522.00 rows=108107 width=4) (actual time=3126.839..3126.839 rows=108037 loops=1)
                                                   Buckets: 16384  Batches: 1  Memory Usage: 3799kB
                                                   Buffers: shared hit=121 read=40401
                                                   ->  Seq Scan on part  (cost=0.00..65522.00 rows=108107 width=4) (actual time=0.018..2819.458 rows=108037 loops=1)
                                                         Filter: ((p_name)::text ~~ '%gainsboro%'::text)
                                                         Rows Removed by Filter: 1891963
                                                         Buffers: shared hit=121 read=40401
                           ->  Index Scan using pk_supplier on supplier  (cost=0.00..0.28 rows=1 width=8) (actual time=0.016..0.017 rows=1 loops=3245136)
                                 Index Cond: (s_suppkey = lineitem.l_suppkey)
                                 Buffers: shared hit=9753537
                     ->  Index Only Scan using orders_o_orderkey_o_orderdate_idx on orders  (cost=0.00..1.96 rows=1 width=8) (actual time=0.045..0.045 rows=1 loops=3245136)
                           Index Cond: (o_orderkey = lineitem.l_orderkey)
                           Heap Fetches: 3245136
                           Buffers: shared hit=12784189 read=213995 dirtied=51 written=1789
               ->  Index Scan using pk_nation on nation  (cost=0.00..0.27 rows=1 width=30) (actual time=0.007..0.007 rows=1 loops=3245136)
                     Index Cond: (n_nationkey = supplier.s_nationkey)
                     Buffers: shared hit=6490272
 Total runtime: 434383.331 ms
(44 rows)

COMMIT;
COMMIT