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 '1994-11-01'
	and o_orderdate < cast(date '1994-11-01' + 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=1149223.33..1149223.38 rows=20 width=175) (actual time=33211.003..33211.011 rows=20 loops=1)
   Buffers: shared hit=881299 read=536598 written=4636
   ->  Sort  (cost=1149223.33..1150629.73 rows=562559 width=175) (actual time=33210.998..33211.001 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=881299 read=536598 written=4636
         ->  HashAggregate  (cost=1128628.25..1134253.84 rows=562559 width=175) (actual time=32670.919..33053.378 rows=382144 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=881296 read=536598 written=4636
               ->  Hash Join  (cost=350825.86..1114564.27 rows=562559 width=175) (actual time=4755.591..27137.366 rows=1149256 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=881296 read=536598 written=4636
                     ->  Hash Join  (cost=350824.30..1106827.53 rows=562559 width=153) (actual time=4755.545..26663.489 rows=1149256 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=881295 read=536598 written=4636
                           ->  Hash Join  (cost=281796.30..1029361.14 rows=562559 width=12) (actual time=3104.241..23644.392 rows=1149256 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=848902 read=533713 written=4568
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..686283.29 rows=14841706 width=12) (actual time=0.078..14390.905 rows=14808453 loops=1)
                                       Buffers: shared hit=712540 read=439530 written=1459
                                 ->  Hash  (cost=274667.58..274667.58 rows=570263 width=8) (actual time=3097.895..3097.895 rows=575122 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30658kB
                                       Buffers: shared hit=136362 read=94183 written=3109
                                       ->  Bitmap Heap Scan on orders  (cost=12085.63..274667.58 rows=570263 width=8) (actual time=305.113..2884.622 rows=575122 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-11-01'::date) AND (o_orderdate < '1995-02-01'::date))
                                             Heap Blocks: exact=228970
                                             Buffers: shared hit=136362 read=94183 written=3109
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..11943.07 rows=570263 width=0) (actual time=222.973..222.973 rows=576903 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-11-01'::date) AND (o_orderdate < '1995-02-01'::date))
                                                   Buffers: shared read=1575 written=60
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1638.975..1638.975 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=32393 read=2885 written=68
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.016..736.431 rows=1500000 loops=1)
                                       Buffers: shared hit=32393 read=2885 written=68
                     ->  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=0.007..0.009 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.987 ms
 Execution time: 33239.069 ms
(42 rows)

COMMIT;
COMMIT