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 '1994-07-01'
	and o_orderdate < cast(date '1994-07-01' + 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=1194418.60..1194418.65 rows=20 width=175) (actual time=27101.620..27101.628 rows=20 loops=1)
   Buffers: shared hit=1133822 read=299169 dirtied=1583 written=1580
   ->  Sort  (cost=1194418.60..1195880.21 rows=584643 width=175) (actual time=27101.617..27101.624 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=1133822 read=299169 dirtied=1583 written=1580
         ->  HashAggregate  (cost=1173015.03..1178861.46 rows=584643 width=175) (actual time=26600.815..26949.243 rows=381507 loops=1)
               Buffers: shared hit=1133819 read=299169 dirtied=1583 written=1580
               ->  Hash Join  (cost=402363.99..1158398.96 rows=584643 width=175) (actual time=4254.368..22141.323 rows=1147138 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1133819 read=299169 dirtied=1583 written=1580
                     ->  Hash Join  (cost=402362.42..1150358.56 rows=584643 width=153) (actual time=4254.330..21646.625 rows=1147138 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1133818 read=299169 dirtied=1583 written=1580
                           ->  Merge Join  (cost=333334.42..1069637.70 rows=584643 width=12) (actual time=2327.386..17187.561 rows=1147138 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=1125076 read=272633 dirtied=1583 written=1580
                                 ->  Sort  (cost=333334.39..334812.69 rows=591320 width=8) (actual time=2327.254..2470.705 rows=573910 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51479kB
                                       Buffers: shared hit=229299 read=2260 dirtied=229
                                       ->  Bitmap Heap Scan on orders  (cost=12734.98..276645.78 rows=591320 width=8) (actual time=298.395..1918.207 rows=573910 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-07-01'::date) AND (o_orderdate < '1994-10-01'::date))
                                             Buffers: shared hit=229299 read=2260 dirtied=229
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12587.15 rows=591320 width=0) (actual time=215.830..215.830 rows=577379 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-07-01'::date) AND (o_orderdate < '1994-10-01'::date))
                                                   Buffers: shared hit=73 read=1568
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..690165.84 rows=14934397 width=12) (actual time=0.107..12261.349 rows=14822937 loops=1)
                                       Buffers: shared hit=895777 read=270373 dirtied=1354 written=1580
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1925.430..1925.430 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=8742 read=26536
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.004..832.754 rows=1500000 loops=1)
                                       Buffers: shared hit=8742 read=26536
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.023..0.023 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=0.010..0.015 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 27162.790 ms
(40 rows)

COMMIT;
COMMIT