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 '1994-07-01'
	and o_orderdate < cast(date '1994-07-01' + 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=1158266.41..1158266.46 rows=20 width=175) (actual time=28765.003..28765.009 rows=20 loops=1)
   Buffers: shared hit=747435 read=674670 dirtied=90 written=8941
   ->  Sort  (cost=1158266.41..1159706.39 rows=575994 width=175) (actual time=28764.999..28765.002 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=747435 read=674670 dirtied=90 written=8941
         ->  HashAggregate  (cost=1137179.47..1142939.41 rows=575994 width=175) (actual time=28315.825..28618.169 rows=381193 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=747432 read=674670 dirtied=90 written=8941
               ->  Hash Join  (cost=352938.31..1122779.62 rows=575994 width=175) (actual time=4785.091..25610.500 rows=1145938 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=747432 read=674670 dirtied=90 written=8941
                     ->  Hash Join  (cost=352936.75..1114858.14 rows=575994 width=153) (actual time=4785.052..25224.194 rows=1145938 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=747431 read=674670 dirtied=90 written=8941
                           ->  Hash Join  (cost=283908.75..1037190.23 rows=575994 width=12) (actual time=2765.828..22043.097 rows=1145938 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=747429 read=639394 dirtied=90 written=8912
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..691403.00 rows=14965061 width=12) (actual time=0.056..13954.121 rows=14808205 loops=1)
                                       Buffers: shared hit=579991 read=575029 written=8830
                                 ->  Hash  (cost=276633.85..276633.85 rows=581957 width=8) (actual time=2757.110..2757.110 rows=573359 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30589kB
                                       Buffers: shared hit=167438 read=64365 dirtied=90 written=82
                                       ->  Bitmap Heap Scan on orders  (cost=12609.49..276633.85 rows=581957 width=8) (actual time=460.089..2519.321 rows=573359 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-07-01'::date) AND (o_orderdate < '1994-10-01'::date))
                                             Heap Blocks: exact=230150
                                             Buffers: shared hit=167438 read=64365 dirtied=90 written=82
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12464.00 rows=581957 width=0) (actual time=340.119..340.119 rows=577964 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-07-01'::date) AND (o_orderdate < '1994-10-01'::date))
                                                   Buffers: shared read=1653
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=2000.844..2000.844 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276 written=29
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.023..965.488 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276 written=29
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.022..0.022 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=0.007..0.011 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 5.142 ms
 Execution time: 28787.164 ms
(42 rows)

COMMIT;
COMMIT