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=1197221.92..1197221.97 rows=20 width=175) (actual time=97262.594..97262.602 rows=20 loops=1)
   Buffers: shared hit=603824 read=824386 written=20922
   ->  Sort  (cost=1197221.92..1198630.31 rows=563353 width=175) (actual time=97262.589..97262.595 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=603824 read=824386 written=20922
         ->  HashAggregate  (cost=1176597.77..1182231.30 rows=563353 width=175) (actual time=96725.532..97087.819 rows=372826 loops=1)
               Buffers: shared hit=603821 read=824386 written=20922
               ->  Hash Join  (cost=401035.61..1162513.95 rows=563353 width=175) (actual time=12774.241..91972.074 rows=1113678 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=603821 read=824386 written=20922
                     ->  Hash Join  (cost=401034.05..1154766.28 rows=563353 width=153) (actual time=12774.183..90974.300 rows=1113678 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=603820 read=824386 written=20922
                           ->  Merge Join  (cost=332006.05..1074471.22 rows=563353 width=12) (actual time=7534.715..82397.281 rows=1113678 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=603814 read=789114 written=20922
                                 ->  Sort  (cost=332006.05..333426.92 rows=568351 width=8) (actual time=7532.036..7783.267 rows=555675 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 50624kB
                                       Buffers: shared hit=226538 read=4494
                                       ->  Bitmap Heap Scan on orders  (cost=12343.59..277681.86 rows=568351 width=8) (actual time=632.786..7229.149 rows=555675 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-02-01'::date) AND (o_orderdate < '1993-05-01'::date))
                                             Buffers: shared hit=226538 read=4494
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12201.50 rows=568351 width=0) (actual time=520.807..520.807 rows=562824 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-02-01'::date) AND (o_orderdate < '1993-05-01'::date))
                                                   Buffers: shared read=1612
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..696301.26 rows=15076134 width=12) (actual time=2.594..70653.030 rows=14822450 loops=1)
                                       Buffers: shared hit=377276 read=784620 written=20922
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=5236.948..5236.948 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=6 read=35272
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.017..3646.282 rows=1500000 loops=1)
                                       Buffers: shared hit=6 read=35272
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.031..0.031 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=0.009..0.015 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 97345.002 ms
(40 rows)

COMMIT;
COMMIT