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=1147360.72..1147360.77 rows=20 width=175) (actual time=27212.917..27212.925 rows=20 loops=1)
   Buffers: shared hit=754118 read=655445 written=4994
   ->  Sort  (cost=1147360.72..1148761.31 rows=560236 width=175) (actual time=27212.913..27212.918 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=754118 read=655445 written=4994
         ->  HashAggregate  (cost=1126850.68..1132453.04 rows=560236 width=175) (actual time=26662.780..27058.661 rows=381529 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=754115 read=655445 written=4994
               ->  Hash Join  (cost=350487.21..1112844.78 rows=560236 width=175) (actual time=4286.765..23296.884 rows=1147540 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=754115 read=655445 written=4994
                     ->  Hash Join  (cost=350485.65..1105139.97 rows=560236 width=153) (actual time=4286.726..22909.505 rows=1147540 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=754114 read=655445 written=4994
                           ->  Hash Join  (cost=281457.65..1027708.43 rows=560236 width=12) (actual time=2473.454..20073.402 rows=1147540 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=754112 read=620169 written=4937
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..685097.79 rows=14813620 width=12) (actual time=0.052..13349.726 rows=14823288 loops=1)
                                       Buffers: shared hit=585116 read=559172 written=4937
                                 ->  Hash  (cost=274351.99..274351.99 rows=568418 width=8) (actual time=2382.549..2382.549 rows=574297 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30626kB
                                       Buffers: shared hit=168996 read=60997
                                       ->  Bitmap Heap Scan on orders  (cost=12050.72..274351.99 rows=568418 width=8) (actual time=261.904..2187.557 rows=574297 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-06-01'::date) AND (o_orderdate < '1993-09-01'::date))
                                             Heap Blocks: exact=228423
                                             Buffers: shared hit=168996 read=60997
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..11908.61 rows=568418 width=0) (actual time=187.170..187.170 rows=574834 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-06-01'::date) AND (o_orderdate < '1993-09-01'::date))
                                                   Buffers: shared read=1570
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1801.468..1801.468 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276 written=57
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.011..896.502 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276 written=57
                     ->  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=0.005..0.009 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.680 ms
 Execution time: 27252.325 ms
(42 rows)

COMMIT;
COMMIT