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 '1993-09-01'
	and o_orderdate < cast(date '1993-09-01' + 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=1193692.57..1193692.62 rows=20 width=175) (actual time=29936.232..29936.240 rows=20 loops=1)
   Buffers: shared hit=1212110 read=214210 written=13265
   ->  Sort  (cost=1193692.57..1195121.54 rows=571589 width=175) (actual time=29936.228..29936.234 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=1212110 read=214210 written=13265
         ->  HashAggregate  (cost=1172766.90..1178482.79 rows=571589 width=175) (actual time=29400.273..29768.439 rows=378639 loops=1)
               Buffers: shared hit=1212107 read=214210 written=13265
               ->  Hash Join  (cost=401072.12..1158477.18 rows=571589 width=175) (actual time=4818.584..26189.724 rows=1135414 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1212107 read=214210 written=13265
                     ->  Hash Join  (cost=401070.56..1150616.27 rows=571589 width=153) (actual time=4818.545..25489.851 rows=1135414 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1212106 read=214210 written=13265
                           ->  Merge Join  (cost=332042.56..1070156.49 rows=571589 width=12) (actual time=2818.519..21260.839 rows=1135414 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=1176828 read=214210 written=13265
                                 ->  Sort  (cost=332042.56..333486.81 rows=577699 width=8) (actual time=2818.447..3003.856 rows=567457 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51176kB
                                       Buffers: shared hit=229419 read=1679
                                       ->  Bitmap Heap Scan on orders  (cost=12543.40..276756.88 rows=577699 width=8) (actual time=400.710..2537.510 rows=567457 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-09-01'::date) AND (o_orderdate < '1993-12-01'::date))
                                             Buffers: shared hit=229419 read=1679
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12398.97 rows=577699 width=0) (actual time=290.723..290.723 rows=572935 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-09-01'::date) AND (o_orderdate < '1993-12-01'::date))
                                                   Buffers: shared hit=102 read=1538
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..692074.55 rows=14974894 width=12) (actual time=0.054..15142.259 rows=14807964 loops=1)
                                       Buffers: shared hit=947409 read=212531 written=13265
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1997.864..1997.864 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=35278
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.013..865.902 rows=1500000 loops=1)
                                       Buffers: shared hit=35278
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.019..0.019 rows=25 loops=1)
                           Buckets: 1024  Batches: 1  Memory Usage: 2kB
                           Buffers: shared hit=1
                           ->  Seq Scan on nation  (cost=0.00..1.25 rows=25 width=30) (actual time=0.004..0.006 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 29981.988 ms
(40 rows)

COMMIT;
COMMIT