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=1189223.08..1189223.13 rows=20 width=175) (actual time=70738.181..70738.191 rows=20 loops=1)
   Buffers: shared hit=1165237 read=259611 written=20879
   ->  Sort  (cost=1189223.08..1190631.81 rows=563493 width=175) (actual time=70738.177..70738.183 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=1165237 read=259611 written=20879
         ->  HashAggregate  (cost=1168593.80..1174228.73 rows=563493 width=175) (actual time=70099.989..70545.021 rows=381379 loops=1)
               Buffers: shared hit=1165234 read=259611 written=20879
               ->  Hash Join  (cost=398807.60..1154506.48 rows=563493 width=175) (actual time=12724.377..65359.109 rows=1147350 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1165234 read=259611 written=20879
                     ->  Hash Join  (cost=398806.03..1146756.89 rows=563493 width=153) (actual time=12724.303..64479.342 rows=1147350 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1165233 read=259611 written=20879
                           ->  Merge Join  (cost=329778.03..1066459.03 rows=563493 width=12) (actual time=9380.990..58531.613 rows=1147350 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=1129955 read=259611 written=20879
                                 ->  Sort  (cost=329778.03..331199.26 rows=568492 width=8) (actual time=9380.846..9587.347 rows=573472 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51458kB
                                       Buffers: shared hit=229278 read=1606
                                       ->  Bitmap Heap Scan on orders  (cost=12124.96..275439.34 rows=568492 width=8) (actual time=681.562..9081.350 rows=573472 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-05-01'::date) AND (o_orderdate < '1993-08-01'::date))
                                             Buffers: shared hit=229278 read=1606
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..11982.84 rows=568492 width=0) (actual time=545.979..545.979 rows=576962 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-05-01'::date) AND (o_orderdate < '1993-08-01'::date))
                                                   Buffers: shared read=1596
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..690812.26 rows=14957221 width=12) (actual time=0.101..45222.181 rows=14808400 loops=1)
                                       Buffers: shared hit=900677 read=258005 written=20879
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=3340.717..3340.717 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=0.022..1971.870 rows=1500000 loops=1)
                                       Buffers: shared hit=35278
                     ->  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: 70788.420 ms
(40 rows)

COMMIT;
COMMIT