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 '1993-02-01'
	and o_orderdate < cast(date '1993-02-01' + 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=1157288.04..1157288.09 rows=20 width=175) (actual time=25271.773..25271.780 rows=20 loops=1)
   Buffers: shared hit=704435 read=721948 dirtied=1153 written=12718
   ->  Sort  (cost=1157288.04..1158683.98 rows=558376 width=175) (actual time=25271.770..25271.776 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=704435 read=721948 dirtied=1153 written=12718
         ->  HashAggregate  (cost=1136846.09..1142429.85 rows=558376 width=175) (actual time=24834.117..25130.710 rows=372603 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=704432 read=721948 dirtied=1153 written=12718
               ->  Hash Join  (cost=353220.17..1122886.69 rows=558376 width=175) (actual time=4522.585..22936.376 rows=1112803 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=704432 read=721948 dirtied=1153 written=12718
                     ->  Hash Join  (cost=353218.60..1115207.46 rows=558376 width=153) (actual time=4522.543..22556.284 rows=1112803 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=704431 read=721948 dirtied=1153 written=12718
                           ->  Hash Join  (cost=284190.60..1037803.82 rows=558376 width=12) (actual time=2810.508..20137.754 rows=1112803 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=686521 read=704580 dirtied=1153 written=12696
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..691925.05 rows=14961292 width=12) (actual time=0.061..13169.545 rows=14807680 loops=1)
                                       Buffers: shared hit=534629 read=625898 dirtied=1153 written=9508
                                 ->  Hash  (cost=277108.47..277108.47 rows=566536 width=8) (actual time=2801.493..2801.493 rows=555199 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 29880kB
                                       Buffers: shared hit=151892 read=78682 written=3188
                                       ->  Bitmap Heap Scan on orders  (cost=12303.43..277108.47 rows=566536 width=8) (actual time=342.468..2553.823 rows=555199 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-02-01'::date) AND (o_orderdate < '1993-05-01'::date))
                                             Heap Blocks: exact=228964
                                             Buffers: shared hit=151892 read=78682 written=3188
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12161.80 rows=566536 width=0) (actual time=252.029..252.029 rows=561765 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-02-01'::date) AND (o_orderdate < '1993-05-01'::date))
                                                   Buffers: shared read=1610 written=1
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1701.766..1701.766 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=17910 read=17368 written=22
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.022..827.248 rows=1500000 loops=1)
                                       Buffers: shared hit=17910 read=17368 written=22
                     ->  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=0.012..0.014 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.241 ms
 Execution time: 25295.811 ms
(42 rows)

COMMIT;
COMMIT