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 '%violet%'
	) as profit
group by
	nation,
	o_year
order by
	nation,
	o_year desc;
                                                                                  QUERY PLAN                                                                                   
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 GroupAggregate  (cost=3477157.15..3477161.77 rows=132 width=46) (actual time=275389.631..279063.652 rows=175 loops=1)
   Buffers: shared hit=30440837 read=579891 written=3072
   ->  Sort  (cost=3477157.15..3477157.48 rows=132 width=46) (actual time=275375.640..276488.010 rows=3270804 loops=1)
         Sort Key: nation.n_name, (date_part('year'::text, (orders.o_orderdate)::timestamp without time zone))
         Sort Method: quicksort  Memory: 558261kB
         Buffers: shared hit=30440837 read=579891 written=3072
         ->  Nested Loop  (cost=2809239.04..3477152.50 rows=132 width=46) (actual time=127174.189..254125.512 rows=3270804 loops=1)
               Buffers: shared hit=30440829 read=579891 written=3072
               ->  Nested Loop  (cost=2809239.04..3477114.85 rows=132 width=24) (actual time=127174.104..233708.088 rows=3270804 loops=1)
                     Buffers: shared hit=23899221 read=579891 written=3072
                     ->  Nested Loop  (cost=2809239.04..3477076.71 rows=131 width=28) (actual time=127174.070..209703.178 rows=3270804 loops=1)
                           Buffers: shared hit=14068826 read=579891 written=3072
                           ->  Merge Join  (cost=2809239.04..3476818.91 rows=131 width=28) (actual time=127173.996..141145.663 rows=3270804 loops=1)
                                 Merge Cond: ((partsupp.ps_partkey = lineitem.l_partkey) AND (partsupp.ps_suppkey = lineitem.l_suppkey))
                                 Buffers: shared hit=970273 read=577319 written=3064
                                 ->  Index Scan using pk_partsupp on partsupp  (cost=0.00..603091.29 rows=8000000 width=12) (actual time=0.010..7009.092 rows=7999953 loops=1)
                                       Buffers: shared hit=306296 read=127912 written=3061
                                 ->  Sort  (cost=2809238.48..2817401.13 rows=3265058 width=28) (actual time=127173.612..129714.185 rows=3270804 loops=1)
                                       Sort Key: part.p_partkey, lineitem.l_suppkey
                                       Sort Method: quicksort  Memory: 353836kB
                                       Buffers: shared hit=663977 read=449407 written=3
                                       ->  Hash Join  (cost=66873.32..2455980.80 rows=3265058 width=28) (actual time=2255.246..122069.035 rows=3270804 loops=1)
                                             Hash Cond: (lineitem.l_partkey = part.p_partkey)
                                             Buffers: shared hit=663974 read=449407 written=3
                                             ->  Seq Scan on lineitem  (cost=0.00..1676903.48 rows=60404748 width=24) (actual time=0.027..27181.840 rows=60045310 loops=1)
                                                   Buffers: shared hit=656039 read=416817 written=3
                                             ->  Hash  (cost=65522.00..65522.00 rows=108106 width=4) (actual time=2255.030..2255.030 rows=108908 loops=1)
                                                   Buckets: 16384  Batches: 1  Memory Usage: 3829kB
                                                   Buffers: shared hit=7932 read=32590
                                                   ->  Seq Scan on part  (cost=0.00..65522.00 rows=108106 width=4) (actual time=0.057..2168.926 rows=108908 loops=1)
                                                         Filter: ((p_name)::text ~~ '%violet%'::text)
                                                         Rows Removed by Filter: 1891092
                                                         Buffers: shared hit=7932 read=32590
                           ->  Index Scan using pk_orders on orders  (cost=0.00..1.96 rows=1 width=8) (actual time=0.019..0.020 rows=1 loops=3270804)
                                 Index Cond: (o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=13098553 read=2572 written=8
                     ->  Index Scan using pk_supplier on supplier  (cost=0.00..0.28 rows=1 width=8) (actual time=0.006..0.006 rows=1 loops=3270804)
                           Index Cond: (s_suppkey = lineitem.l_suppkey)
                           Buffers: shared hit=9830395
               ->  Index Scan using pk_nation on nation  (cost=0.00..0.27 rows=1 width=30) (actual time=0.004..0.004 rows=1 loops=3270804)
                     Index Cond: (n_nationkey = supplier.s_nationkey)
                     Buffers: shared hit=6541608
 Total runtime: 279193.751 ms
(43 rows)

COMMIT;
COMMIT