BEGIN;
BEGIN
EXPLAIN (ANALYZE, BUFFERS)
select
	supp_nation,
	cust_nation,
	l_year,
	sum(volume) as revenue
from
	(
		select
			n1.n_name as supp_nation,
			n2.n_name as cust_nation,
			extract(year from l_shipdate) as l_year,
			l_extendedprice * (1 - l_discount) as volume
		from
			supplier,
			lineitem,
			orders,
			customer,
			nation n1,
			nation n2
		where
			s_suppkey = l_suppkey
			and o_orderkey = l_orderkey
			and c_custkey = o_custkey
			and s_nationkey = n1.n_nationkey
			and c_nationkey = n2.n_nationkey
			and (
				(n1.n_name = 'CHINA' and n2.n_name = 'ALGERIA')
				or (n1.n_name = 'ALGERIA' and n2.n_name = 'CHINA')
			)
			and l_shipdate between date '1995-01-01' and date '1996-12-31'
	) as shipping
group by
	supp_nation,
	cust_nation,
	l_year
order by
	supp_nation,
	cust_nation,
	l_year;
                                                                                       QUERY PLAN                                                                                        
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=2001926.69..2001934.39 rows=3080 width=64) (actual time=23840.247..23840.247 rows=4 loops=1)
   Sort Key: n1.n_name, n2.n_name, (date_part('year'::text, (lineitem.l_shipdate)::timestamp without time zone))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=5284459 read=257580 written=32
   ->  HashAggregate  (cost=2001702.03..2001748.23 rows=3080 width=64) (actual time=23840.151..23840.164 rows=4 loops=1)
         Group Key: n1.n_name, n2.n_name, date_part('year'::text, (lineitem.l_shipdate)::timestamp without time zone)
         Buffers: shared hit=5284451 read=257580 written=32
         ->  Hash Join  (cost=62340.37..2000787.00 rows=61002 width=64) (actual time=1048.114..23757.454 rows=57815 loops=1)
               Hash Cond: (lineitem.l_suppkey = supplier.s_suppkey)
               Join Filter: (((n1.n_name = 'CHINA'::bpchar) AND (n2.n_name = 'ALGERIA'::bpchar)) OR ((n1.n_name = 'ALGERIA'::bpchar) AND (n2.n_name = 'CHINA'::bpchar)))
               Rows Removed by Join Filter: 58030
               Buffers: shared hit=5284451 read=257580 written=32
               ->  Nested Loop  (cost=58604.97..1988898.77 rows=1467331 width=42) (actual time=997.714..22703.503 rows=1462858 loops=1)
                     Buffers: shared hit=5282268 read=257580 written=32
                     ->  Hash Join  (cost=58604.40..531536.45 rows=1203596 width=30) (actual time=997.555..13267.975 rows=1202499 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=246307 read=43000 written=1
                           ->  Seq Scan on orders  (cost=0.00..404477.52 rows=15044952 width=8) (actual time=0.008..3320.045 rows=15015000 loops=1)
                                 Buffers: shared hit=246304 read=7724 written=1
                           ->  Hash  (cost=57104.40..57104.40 rows=120000 width=30) (actual time=996.648..996.648 rows=119981 loops=1)
                                 Buckets: 131072  Batches: 1  Memory Usage: 8289kB
                                 Buffers: shared hit=3 read=35276
                                 ->  Hash Join  (cost=1.40..57104.40 rows=120000 width=30) (actual time=0.065..939.773 rows=119981 loops=1)
                                       Hash Cond: (customer.c_nationkey = n2.n_nationkey)
                                       Buffers: shared hit=3 read=35276
                                       ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=8) (actual time=0.012..704.482 rows=1500000 loops=1)
                                             Buffers: shared hit=2 read=35276
                                       ->  Hash  (cost=1.38..1.38 rows=2 width=30) (actual time=0.033..0.033 rows=2 loops=1)
                                             Buckets: 1024  Batches: 1  Memory Usage: 9kB
                                             Buffers: shared hit=1
                                             ->  Seq Scan on nation n2  (cost=0.00..1.38 rows=2 width=30) (actual time=0.014..0.021 rows=2 loops=1)
                                                   Filter: ((n_name = 'ALGERIA'::bpchar) OR (n_name = 'CHINA'::bpchar))
                                                   Rows Removed by Filter: 23
                                                   Buffers: shared hit=1
                     ->  Index Scan using lineitem_l_orderkey_l_linenumber_l_shipdate_idx on lineitem  (cost=0.56..1.16 rows=5 width=20) (actual time=0.007..0.007 rows=1 loops=1202499)
                           Index Cond: ((l_orderkey = orders.o_orderkey) AND (l_shipdate >= '1995-01-01'::date) AND (l_shipdate <= '1996-12-31'::date))
                           Buffers: shared hit=5035961 read=214580 written=31
               ->  Hash  (cost=3635.40..3635.40 rows=8000 width=30) (actual time=50.010..50.010 rows=7922 loops=1)
                     Buckets: 8192  Batches: 1  Memory Usage: 544kB
                     Buffers: shared hit=2180
                     ->  Hash Join  (cost=1.40..3635.40 rows=8000 width=30) (actual time=0.046..47.482 rows=7922 loops=1)
                           Hash Cond: (supplier.s_nationkey = n1.n_nationkey)
                           Buffers: shared hit=2180
                           ->  Seq Scan on supplier  (cost=0.00..3179.00 rows=100000 width=8) (actual time=0.007..30.343 rows=100000 loops=1)
                                 Buffers: shared hit=2179
                           ->  Hash  (cost=1.38..1.38 rows=2 width=30) (actual time=0.023..0.023 rows=2 loops=1)
                                 Buckets: 1024  Batches: 1  Memory Usage: 9kB
                                 Buffers: shared hit=1
                                 ->  Seq Scan on nation n1  (cost=0.00..1.38 rows=2 width=30) (actual time=0.007..0.014 rows=2 loops=1)
                                       Filter: ((n_name = 'CHINA'::bpchar) OR (n_name = 'ALGERIA'::bpchar))
                                       Rows Removed by Filter: 23
                                       Buffers: shared hit=1
 Planning time: 6.518 ms
 Execution time: 23840.868 ms
(54 rows)

COMMIT;
COMMIT