BEGIN;
BEGIN
EXPLAIN (ANALYZE, BUFFERS)
select
	n_name,
	sum(l_extendedprice * (1 - l_discount)) as revenue
from
	customer,
	orders,
	lineitem,
	supplier,
	nation,
	region
where
	c_custkey = o_custkey
	and l_orderkey = o_orderkey
	and l_suppkey = s_suppkey
	and c_nationkey = s_nationkey
	and s_nationkey = n_nationkey
	and n_regionkey = r_regionkey
	and r_name = 'AFRICA'
	and o_orderdate >= date '1996-01-01'
	and o_orderdate < date '1996-01-01' + interval '1 year'
group by
	n_name
order by
	revenue desc;
                                                                                              QUERY PLAN                                                                                               
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=2446221.16..2446221.22 rows=25 width=34) (actual time=114148.405..114148.406 rows=5 loops=1)
   Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount))))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=955139 read=532949 written=1
   ->  HashAggregate  (cost=2446220.32..2446220.57 rows=25 width=34) (actual time=114148.324..114148.327 rows=5 loops=1)
         Buffers: shared hit=955136 read=532949 written=1
         ->  Hash Join  (cost=402922.32..2445486.68 rows=73364 width=34) (actual time=18272.243..113883.427 rows=72700 loops=1)
               Hash Cond: ((lineitem.l_suppkey = supplier.s_suppkey) AND (customer.c_nationkey = supplier.s_nationkey))
               Buffers: shared hit=955136 read=532949 written=1
               ->  Hash Join  (cost=398243.32..2403380.98 rows=1834653 width=46) (actual time=18117.343..109134.115 rows=1827789 loops=1)
                     Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                     Buffers: shared hit=952954 read=532949 written=1
                     ->  Seq Scan on lineitem  (cost=0.00..1683567.42 rows=60644742 width=16) (actual time=0.044..43701.338 rows=60044872 loops=1)
                           Buffers: shared hit=591405 read=485715 written=1
                     ->  Hash  (cost=392508.61..392508.61 rows=458777 width=38) (actual time=18116.582..18116.582 rows=456629 loops=1)
                           Buckets: 65536  Batches: 1  Memory Usage: 32107kB
                           Buffers: shared hit=361549 read=47234
                           ->  Hash Join  (cost=88856.52..392508.61 rows=458777 width=38) (actual time=4007.130..17670.246 rows=456629 loops=1)
                                 Hash Cond: (orders.o_custkey = customer.c_custkey)
                                 Buffers: shared hit=361549 read=47234
                                 ->  Bitmap Heap Scan on orders  (cost=49814.30..340276.56 rows=2293884 width=8) (actual time=1391.489..8734.185 rows=2284200 loops=1)
                                       Recheck Cond: ((o_orderdate >= '1996-01-01'::date) AND (o_orderdate < '1997-01-01 00:00:00'::timestamp without time zone))
                                       Buffers: shared hit=222635 read=39998
                                       ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..49240.83 rows=2293884 width=0) (actual time=1300.531..1300.531 rows=2306946 loops=1)
                                             Index Cond: ((o_orderdate >= '1996-01-01'::date) AND (o_orderdate < '1997-01-01 00:00:00'::timestamp without time zone))
                                             Buffers: shared read=6596
                                 ->  Hash  (cost=35292.22..35292.22 rows=300000 width=38) (actual time=2615.219..2615.219 rows=299493 loops=1)
                                       Buckets: 32768  Batches: 1  Memory Usage: 21059kB
                                       Buffers: shared hit=138914 read=7236
                                       ->  Nested Loop  (cost=905.09..35292.22 rows=300000 width=38) (actual time=58.023..2401.036 rows=299493 loops=1)
                                             Buffers: shared hit=138914 read=7236
                                             ->  Nested Loop  (cost=0.00..14.07 rows=5 width=30) (actual time=0.067..0.195 rows=5 loops=1)
                                                   Join Filter: (nation.n_regionkey = region.r_regionkey)
                                                   Rows Removed by Join Filter: 20
                                                   Buffers: shared hit=3
                                                   ->  Index Scan using pk_nation on nation  (cost=0.00..12.63 rows=25 width=34) (actual time=0.012..0.057 rows=25 loops=1)
                                                         Buffers: shared hit=2
                                                   ->  Materialize  (cost=0.00..1.07 rows=1 width=4) (actual time=0.002..0.003 rows=1 loops=25)
                                                         Buffers: shared hit=1
                                                         ->  Seq Scan on region  (cost=0.00..1.06 rows=1 width=4) (actual time=0.032..0.041 rows=1 loops=1)
                                                               Filter: (r_name = 'AFRICA'::bpchar)
                                                               Rows Removed by Filter: 4
                                                               Buffers: shared hit=1
                                             ->  Bitmap Heap Scan on customer  (cost=905.09..6455.63 rows=60000 width=8) (actual time=37.280..457.275 rows=59899 loops=5)
                                                   Recheck Cond: (c_nationkey = nation.n_nationkey)
                                                   Buffers: shared hit=138911 read=7236
                                                   ->  Bitmap Index Scan on customer_c_nationkey_c_custkey_idx  (cost=0.00..890.09 rows=60000 width=0) (actual time=27.512..27.512 rows=59899 loops=5)
                                                         Index Cond: (c_nationkey = nation.n_nationkey)
                                                         Buffers: shared hit=7 read=826
               ->  Hash  (cost=3179.00..3179.00 rows=100000 width=8) (actual time=152.937..152.937 rows=100000 loops=1)
                     Buckets: 16384  Batches: 1  Memory Usage: 3907kB
                     Buffers: shared hit=2179
                     ->  Seq Scan on supplier  (cost=0.00..3179.00 rows=100000 width=8) (actual time=0.016..107.630 rows=100000 loops=1)
                           Buffers: shared hit=2179
 Total runtime: 114163.564 ms
(55 rows)

COMMIT;
COMMIT