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 '1993-06-01'
	and o_orderdate < cast(date '1993-06-01' + 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=1189473.49..1189473.54 rows=20 width=175) (actual time=31227.621..31227.629 rows=20 loops=1)
   Buffers: shared hit=1241676 read=186301 dirtied=270 written=60
   ->  Sort  (cost=1189473.49..1190909.03 rows=574215 width=175) (actual time=31227.616..31227.619 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=1241676 read=186301 dirtied=270 written=60
         ->  HashAggregate  (cost=1168451.69..1174193.84 rows=574215 width=175) (actual time=30721.095..31047.232 rows=381503 loops=1)
               Buffers: shared hit=1241673 read=186301 dirtied=270 written=60
               ->  Hash Join  (cost=400736.14..1154096.31 rows=574215 width=175) (actual time=4819.993..25685.533 rows=1147592 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1241673 read=186301 dirtied=270 written=60
                     ->  Hash Join  (cost=400734.58..1146199.29 rows=574215 width=153) (actual time=4819.937..24970.939 rows=1147592 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1241672 read=186301 dirtied=270 written=60
                           ->  Merge Join  (cost=331706.58..1065686.99 rows=574215 width=12) (actual time=2599.915..20380.133 rows=1147592 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=1206396 read=186299 dirtied=270 written=60
                                 ->  Sort  (cost=331699.07..333154.74 rows=582267 width=8) (actual time=2599.739..2778.634 rows=574262 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51495kB
                                       Buffers: shared hit=226432 read=4495
                                       ->  Bitmap Heap Scan on orders  (cost=12422.16..275943.16 rows=582267 width=8) (actual time=580.279..2370.916 rows=574262 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-06-01'::date) AND (o_orderdate < '1993-09-01'::date))
                                             Buffers: shared hit=226432 read=4495
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12276.59 rows=582267 width=0) (actual time=377.813..377.813 rows=577112 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-06-01'::date) AND (o_orderdate < '1993-09-01'::date))
                                                   Buffers: shared hit=2 read=1593
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..688131.38 rows=14881228 width=12) (actual time=0.110..14315.901 rows=14823275 loops=1)
                                       Buffers: shared hit=979964 read=181804 dirtied=270 written=60
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=2215.949..2215.949 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=35276 read=2
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.023..983.402 rows=1500000 loops=1)
                                       Buffers: shared hit=35276 read=2
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.025..0.025 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=0.008..0.013 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 31279.764 ms
(40 rows)

COMMIT;
COMMIT