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 '1994-09-01'
	and o_orderdate < cast(date '1994-09-01' + 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=1158550.73..1158550.78 rows=20 width=175) (actual time=23162.045..23162.053 rows=20 loops=1)
   Buffers: shared hit=567374 read=857118 written=441
   ->  Sort  (cost=1158550.73..1159967.71 rows=566790 width=175) (actual time=23162.042..23162.048 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=567374 read=857118 written=441
         ->  HashAggregate  (cost=1137800.76..1143468.66 rows=566790 width=175) (actual time=22788.009..23024.495 rows=378825 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=567371 read=857118 written=441
               ->  Hash Join  (cost=353638.44..1123631.01 rows=566790 width=175) (actual time=3893.823..20897.558 rows=1136858 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=567371 read=857118 written=441
                     ->  Hash Join  (cost=353636.88..1115836.08 rows=566790 width=153) (actual time=3893.789..20505.076 rows=1136858 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=567370 read=857118 written=441
                           ->  Hash Join  (cost=284608.88..1038306.23 rows=566790 width=12) (actual time=2196.894..18076.688 rows=1136858 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=567367 read=821843 written=440
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..691925.05 rows=14961292 width=12) (actual time=0.056..12467.439 rows=14822519 loops=1)
                                       Buffers: shared hit=402318 read=754731 written=440
                                 ->  Hash  (cost=277420.03..277420.03 rows=575073 width=8) (actual time=2190.824..2190.824 rows=568317 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30392kB
                                       Buffers: shared hit=165049 read=67112
                                       ->  Bitmap Heap Scan on orders  (cost=12486.93..277420.03 rows=575073 width=8) (actual time=273.957..1998.197 rows=568317 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-09-01'::date) AND (o_orderdate < '1994-12-01'::date))
                                             Heap Blocks: exact=230516
                                             Buffers: shared hit=165049 read=67112
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12343.16 rows=575073 width=0) (actual time=195.188..195.188 rows=574585 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-09-01'::date) AND (o_orderdate < '1994-12-01'::date))
                                                   Buffers: shared read=1645
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1684.610..1684.610 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=3 read=35275 written=1
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.008..827.161 rows=1500000 loops=1)
                                       Buffers: shared hit=3 read=35275 written=1
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.021..0.021 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: 4.762 ms
 Execution time: 23188.021 ms
(42 rows)

COMMIT;
COMMIT