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 '1994-04-01'
	and o_orderdate < cast(date '1994-04-01' + 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=1196779.13..1196779.18 rows=20 width=175) (actual time=34679.627..34679.634 rows=20 loops=1)
   Buffers: shared hit=785820 read=643669 dirtied=234 written=1280
   ->  Sort  (cost=1196779.13..1198207.63 rows=571400 width=175) (actual time=34679.623..34679.628 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=785820 read=643669 dirtied=234 written=1280
         ->  HashAggregate  (cost=1175860.38..1181574.38 rows=571400 width=175) (actual time=34160.970..34523.529 rows=378972 loops=1)
               Buffers: shared hit=785817 read=643669 dirtied=234 written=1280
               ->  Hash Join  (cost=402588.50..1161575.38 rows=571400 width=175) (actual time=7185.039..30961.034 rows=1138040 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=785817 read=643669 dirtied=234 written=1280
                     ->  Hash Join  (cost=402586.94..1153717.07 rows=571400 width=153) (actual time=7184.981..30311.213 rows=1138040 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=785816 read=643669 dirtied=234 written=1280
                           ->  Merge Join  (cost=333558.94..1073261.07 rows=571400 width=12) (actual time=4703.655..25663.827 rows=1138040 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=750538 read=643669 dirtied=234 written=1280
                                 ->  Sort  (cost=333551.39..334999.92 rows=579414 width=8) (actual time=4703.453..4878.465 rows=568587 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51229kB
                                       Buffers: shared hit=99762 read=132551 dirtied=234 written=1173
                                       ->  Bitmap Heap Scan on orders  (cost=12584.99..278089.20 rows=579414 width=8) (actual time=354.698..4374.617 rows=568587 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-04-01'::date) AND (o_orderdate < '1994-07-01'::date))
                                             Buffers: shared hit=99762 read=132551 dirtied=234 written=1173
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12440.13 rows=579414 width=0) (actual time=274.981..274.981 rows=576045 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-04-01'::date) AND (o_orderdate < '1994-07-01'::date))
                                                   Buffers: shared hit=83 read=1565 written=12
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..693599.80 rows=14999536 width=12) (actual time=0.145..17804.822 rows=14822420 loops=1)
                                       Buffers: shared hit=650776 read=511118 written=107
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=2478.929..2478.929 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=0.019..1090.414 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=0.010..0.019 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 34728.741 ms
(40 rows)

COMMIT;
COMMIT