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 '1993-07-01'
	and o_orderdate < cast(date '1993-07-01' + 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=1157972.50..1157972.55 rows=20 width=175) (actual time=28118.607..28118.615 rows=20 loops=1)
   Buffers: shared hit=1055591 read=364291 dirtied=110 written=3580
   ->  Sort  (cost=1157972.50..1159408.46 rows=574385 width=175) (actual time=28118.603..28118.606 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=1055591 read=364291 dirtied=110 written=3580
         ->  HashAggregate  (cost=1136944.47..1142688.32 rows=574385 width=175) (actual time=27560.034..27948.968 rows=381627 loops=1)
               Group Key: customer.c_custkey, customer.c_name, customer.c_acctbal, customer.c_phone, nation.n_name, customer.c_address, customer.c_comment
               Buffers: shared hit=1055588 read=364291 dirtied=110 written=3580
               ->  Hash Join  (cost=353192.40..1122584.84 rows=574385 width=175) (actual time=4636.299..23231.475 rows=1147179 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1055588 read=364291 dirtied=110 written=3580
                     ->  Hash Join  (cost=353190.83..1114685.49 rows=574385 width=153) (actual time=4636.256..22818.817 rows=1147179 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1055587 read=364291 dirtied=110 written=3580
                           ->  Hash Join  (cost=284162.83..1037041.71 rows=574385 width=12) (actual time=2925.483..20211.750 rows=1147179 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=1022986 read=361614 dirtied=110 written=3576
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..691069.52 rows=14950919 width=12) (actual time=0.062..13228.142 rows=14807964 loops=1)
                                       Buffers: shared hit=880274 read=272627 written=3104
                                 ->  Hash  (cost=276894.20..276894.20 rows=581456 width=8) (actual time=2919.485..2919.485 rows=573808 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30607kB
                                       Buffers: shared hit=142712 read=88987 dirtied=110 written=472
                                       ->  Bitmap Heap Scan on orders  (cost=12624.36..276894.20 rows=581456 width=8) (actual time=324.008..2707.083 rows=573808 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-07-01'::date) AND (o_orderdate < '1993-10-01'::date))
                                             Heap Blocks: exact=230048
                                             Buffers: shared hit=142712 read=88987 dirtied=110 written=472
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12479.00 rows=581456 width=0) (actual time=232.872..232.872 rows=578778 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-07-01'::date) AND (o_orderdate < '1993-10-01'::date))
                                                   Buffers: shared read=1651 written=2
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1698.396..1698.396 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=32601 read=2677 written=4
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.020..723.411 rows=1500000 loops=1)
                                       Buffers: shared hit=32601 read=2677 written=4
                     ->  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: 10kB
                           Buffers: shared hit=1
                           ->  Seq Scan on nation  (cost=0.00..1.25 rows=25 width=30) (actual time=0.008..0.010 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 5.541 ms
 Execution time: 28144.581 ms
(42 rows)

COMMIT;
COMMIT