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 '1994-10-01'
	and o_orderdate < cast(date '1994-10-01' + 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=1160195.73..1160195.78 rows=20 width=175) (actual time=23902.525..23902.532 rows=20 loops=1)
   Buffers: shared hit=767394 read=656973 dirtied=681 written=10974
   ->  Sort  (cost=1160195.73..1161635.42 rows=575878 width=175) (actual time=23902.523..23902.526 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=767394 read=656973 dirtied=681 written=10974
         ->  HashAggregate  (cost=1139113.04..1144871.82 rows=575878 width=175) (actual time=23526.084..23760.034 rows=381733 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=767391 read=656973 dirtied=681 written=10974
               ->  Hash Join  (cost=353775.13..1124716.09 rows=575878 width=175) (actual time=4229.912..21585.063 rows=1149944 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=767391 read=656973 dirtied=681 written=10974
                     ->  Hash Join  (cost=353773.57..1116796.20 rows=575878 width=153) (actual time=4229.873..21188.053 rows=1149944 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=767390 read=656973 dirtied=681 written=10974
                           ->  Hash Join  (cost=284745.57..1039130.03 rows=575878 width=12) (actual time=2282.702..18472.608 rows=1149944 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=767388 read=621697 dirtied=681 written=10970
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..692448.35 rows=14980738 width=12) (actual time=0.053..12777.616 rows=14807792 loops=1)
                                       Buffers: shared hit=588151 read=568430 dirtied=681 written=10913
                                 ->  Hash  (cost=277458.15..277458.15 rows=582959 width=8) (actual time=2276.109..2276.109 rows=574234 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30624kB
                                       Buffers: shared hit=179237 read=53267 written=57
                                       ->  Bitmap Heap Scan on orders  (cost=12659.76..277458.15 rows=582959 width=8) (actual time=294.567..2086.402 rows=574234 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-10-01'::date) AND (o_orderdate < '1995-01-01'::date))
                                             Heap Blocks: exact=230842
                                             Buffers: shared hit=179237 read=53267 written=57
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12514.02 rows=582959 width=0) (actual time=213.736..213.736 rows=580648 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-10-01'::date) AND (o_orderdate < '1995-01-01'::date))
                                                   Buffers: shared read=1662 written=1
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1751.013..1751.013 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276 written=4
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.019..843.410 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276 written=4
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.023..0.023 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=0.006..0.010 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 5.189 ms
 Execution time: 23927.299 ms
(42 rows)

COMMIT;
COMMIT