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 '%forest%'
	) as profit
group by
	nation,
	o_year
order by
	nation,
	o_year desc;
                                                                                  QUERY PLAN                                                                                   
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 GroupAggregate  (cost=3388249.75..3388254.27 rows=129 width=46) (actual time=284401.476..287946.980 rows=175 loops=1)
   Buffers: shared hit=30292840 read=611493 dirtied=47 written=2834
   ->  Sort  (cost=3388249.75..3388250.08 rows=129 width=46) (actual time=284387.026..285410.115 rows=3258161 loops=1)
         Sort Key: nation.n_name, (date_part('year'::text, (orders.o_orderdate)::timestamp without time zone))
         Sort Method: quicksort  Memory: 556483kB
         Buffers: shared hit=30292840 read=611493 dirtied=47 written=2834
         ->  Nested Loop  (cost=2720838.90..3388245.23 rows=129 width=46) (actual time=124231.579..262060.210 rows=3258161 loops=1)
               Buffers: shared hit=30292832 read=611493 dirtied=47 written=2834
               ->  Nested Loop  (cost=2720838.90..3388208.44 rows=129 width=24) (actual time=124231.512..240208.404 rows=3258161 loops=1)
                     Buffers: shared hit=23776510 read=611493 dirtied=47 written=2834
                     ->  Nested Loop  (cost=2720838.90..3387955.43 rows=129 width=24) (actual time=124231.474..164689.118 rows=3258161 loops=1)
                           Buffers: shared hit=10850505 read=487051 written=1772
                           ->  Merge Join  (cost=2720838.90..3387917.86 rows=129 width=28) (actual time=124231.436..138406.433 rows=3258161 loops=1)
                                 Merge Cond: ((partsupp.ps_partkey = lineitem.l_partkey) AND (partsupp.ps_suppkey = lineitem.l_suppkey))
                                 Buffers: shared hit=1058426 read=487051 written=1772
                                 ->  Index Scan using pk_partsupp on partsupp  (cost=0.00..603091.29 rows=8000000 width=12) (actual time=0.051..7119.324 rows=7999977 loops=1)
                                       Buffers: shared hit=287866 read=146343 written=1771
                                 ->  Sort  (cost=2720838.34..2728834.02 rows=3198272 width=28) (actual time=124231.325..126946.040 rows=3258161 loops=1)
                                       Sort Key: part.p_partkey, lineitem.l_suppkey
                                       Sort Method: quicksort  Memory: 352848kB
                                       Buffers: shared hit=770560 read=340708 written=1
                                       ->  Hash Join  (cost=66848.30..2375283.26 rows=3198272 width=28) (actual time=1846.307..120220.988 rows=3258161 loops=1)
                                             Hash Cond: (lineitem.l_partkey = part.p_partkey)
                                             Buffers: shared hit=770557 read=340708 written=1
                                             ->  Seq Scan on lineitem  (cost=0.00..1673596.12 rows=60285612 width=24) (actual time=0.033..25654.476 rows=60046221 loops=1)
                                                   Buffers: shared hit=763479 read=307261 written=1
                                             ->  Hash  (cost=65522.00..65522.00 rows=106104 width=4) (actual time=1846.004..1846.004 rows=108543 loops=1)
                                                   Buckets: 16384  Batches: 1  Memory Usage: 3816kB
                                                   Buffers: shared hit=7075 read=33447
                                                   ->  Seq Scan on part  (cost=0.00..65522.00 rows=106104 width=4) (actual time=0.035..1769.890 rows=108543 loops=1)
                                                         Filter: ((p_name)::text ~~ '%forest%'::text)
                                                         Rows Removed by Filter: 1891457
                                                         Buffers: shared hit=7075 read=33447
                           ->  Index Scan using pk_supplier on supplier  (cost=0.00..0.28 rows=1 width=8) (actual time=0.007..0.007 rows=1 loops=3258161)
                                 Index Cond: (s_suppkey = lineitem.l_suppkey)
                                 Buffers: shared hit=9792079
                     ->  Index Scan using pk_orders on orders  (cost=0.00..1.95 rows=1 width=8) (actual time=0.022..0.022 rows=1 loops=3258161)
                           Index Cond: (o_orderkey = lineitem.l_orderkey)
                           Buffers: shared hit=12926005 read=124442 dirtied=47 written=1062
               ->  Index Scan using pk_nation on nation  (cost=0.00..0.27 rows=1 width=30) (actual time=0.004..0.005 rows=1 loops=3258161)
                     Index Cond: (n_nationkey = supplier.s_nationkey)
                     Buffers: shared hit=6516322
 Total runtime: 288067.599 ms
(43 rows)

COMMIT;
COMMIT