BEGIN;
BEGIN
EXPLAIN (ANALYZE, BUFFERS)
select
	c_custkey,
	c_name,
	sum(l_extendedprice * (1 - l_discount)) as revenue,
	c_acctbal,
	n_name,
	c_address,
	c_phone,
	c_comment
from
	customer,
	orders,
	lineitem,
	nation
where
	c_custkey = o_custkey
	and l_orderkey = o_orderkey
	and o_orderdate >= date '1993-04-01'
	and o_orderdate < cast(date '1993-04-01' + interval '3 month' as date)
	and l_returnflag = 'R'
	and c_nationkey = n_nationkey
group by
	c_custkey,
	c_name,
	c_acctbal,
	c_phone,
	n_name,
	c_address,
	c_comment
order by
	revenue desc
LIMIT 20;
                                                                                                QUERY PLAN                                                                                                 
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Limit  (cost=1151029.62..1151029.67 rows=20 width=175) (actual time=22152.478..22152.485 rows=20 loops=1)
   Buffers: shared hit=705309 read=701849
   ->  Sort  (cost=1151029.62..1152451.45 rows=568734 width=175) (actual time=22152.474..22152.478 rows=20 loops=1)
         Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount))))
         Sort Method: top-N heapsort  Memory: 30kB
         Buffers: shared hit=705309 read=701849
         ->  HashAggregate  (cost=1130208.47..1135895.81 rows=568734 width=175) (actual time=21835.212..22025.332 rows=378497 loops=1)
               Group Key: customer.c_custkey, customer.c_name, customer.c_acctbal, customer.c_phone, nation.n_name, customer.c_address, customer.c_comment
               Buffers: shared hit=705306 read=701849
               ->  Hash Join  (cost=351694.38..1115990.12 rows=568734 width=175) (actual time=3684.542..19925.767 rows=1135365 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=705306 read=701849
                     ->  Hash Join  (cost=351692.82..1108168.46 rows=568734 width=153) (actual time=3684.504..19555.735 rows=1135365 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=705305 read=701849
                           ->  Hash Join  (cost=282664.82..1030609.45 rows=568734 width=12) (actual time=2352.894..17572.790 rows=1135365 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=670030 read=701846
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..686598.50 rows=14842461 width=12) (actual time=0.079..12087.514 rows=14808721 loops=1)
                                       Buffers: shared hit=520250 read=621674
                                 ->  Hash  (cost=275443.87..275443.87 rows=577641 width=8) (actual time=2347.650..2347.650 rows=567679 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30367kB
                                       Buffers: shared hit=149780 read=80172
                                       ->  Bitmap Heap Scan on orders  (cost=12245.26..275443.87 rows=577641 width=8) (actual time=218.657..2163.500 rows=567679 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-04-01'::date) AND (o_orderdate < '1993-07-01'::date))
                                             Heap Blocks: exact=228391
                                             Buffers: shared hit=149780 read=80172
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12100.84 rows=577641 width=0) (actual time=151.012..151.012 rows=570567 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-04-01'::date) AND (o_orderdate < '1993-07-01'::date))
                                                   Buffers: shared read=1561
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1321.331..1321.331 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=35275 read=3
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.013..568.762 rows=1500000 loops=1)
                                       Buffers: shared hit=35275 read=3
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.027..0.027 rows=25 loops=1)
                           Buckets: 1024  Batches: 1  Memory Usage: 10kB
                           Buffers: shared hit=1
                           ->  Seq Scan on nation  (cost=0.00..1.25 rows=25 width=30) (actual time=0.010..0.014 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 3.886 ms
 Execution time: 22169.961 ms
(42 rows)

COMMIT;
COMMIT