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 '1993-05-01'
	and o_orderdate < cast(date '1993-05-01' + 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=1150894.72..1150894.77 rows=20 width=176) (actual time=30375.023..30375.032 rows=20 loops=1)
   Buffers: shared hit=669024 read=749671 dirtied=217 written=34
   ->  Sort  (cost=1150894.72..1152326.52 rows=572719 width=176) (actual time=30375.019..30375.023 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=669024 read=749671 dirtied=217 written=34
         ->  HashAggregate  (cost=1129927.68..1135654.87 rows=572719 width=176) (actual time=29962.564..30232.808 rows=381659 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=669021 read=749671 dirtied=217 written=34
               ->  Hash Join  (cost=351611.21..1115609.71 rows=572719 width=176) (actual time=4971.772..26297.999 rows=1148505 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=669021 read=749671 dirtied=217 written=34
                     ->  Hash Join  (cost=351609.64..1107733.26 rows=572719 width=154) (actual time=4971.733..25878.294 rows=1148505 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=669020 read=749671 dirtied=217 written=34
                           ->  Hash Join  (cost=282581.64..1030114.47 rows=572719 width=12) (actual time=3257.682..22904.788 rows=1148505 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=633747 read=749666 dirtied=217 written=34
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..686174.32 rows=14835136 width=12) (actual time=0.095..13972.811 rows=14823114 loops=1)
                                       Buffers: shared hit=513387 read=639631 written=34
                                 ->  Hash  (cost=275313.73..275313.73 rows=581398 width=8) (actual time=3244.333..3244.333 rows=574090 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30618kB
                                       Buffers: shared hit=120360 read=110035 dirtied=217
                                       ->  Bitmap Heap Scan on orders  (cost=12311.76..275313.73 rows=581398 width=8) (actual time=562.584..2976.857 rows=574090 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-05-01'::date) AND (o_orderdate < '1993-08-01'::date))
                                             Heap Blocks: exact=228825
                                             Buffers: shared hit=120360 read=110035 dirtied=217
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12166.41 rows=581398 width=0) (actual time=427.902..427.902 rows=575830 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-05-01'::date) AND (o_orderdate < '1993-08-01'::date))
                                                   Buffers: shared hit=1 read=1569
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=1702.612..1702.612 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=35273 read=5
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.017..669.245 rows=1500000 loops=1)
                                       Buffers: shared hit=35273 read=5
                     ->  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..0.009 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.440 ms
 Execution time: 30406.213 ms
(42 rows)

COMMIT;
COMMIT