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 '1993-08-01'
	and o_orderdate < cast(date '1993-08-01' + 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=1161164.56..1161164.61 rows=20 width=175) (actual time=26476.825..26476.834 rows=20 loops=1)
   Buffers: shared hit=800131 read=623795 written=9267
   ->  Sort  (cost=1161164.56..1162602.49 rows=575172 width=175) (actual time=26476.822..26476.826 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=800131 read=623795 written=9267
         ->  HashAggregate  (cost=1140107.72..1145859.44 rows=575172 width=175) (actual time=25976.286..26330.718 rows=381864 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=800128 read=623795 written=9267
               ->  Hash Join  (cost=353685.79..1125728.42 rows=575172 width=175) (actual time=4190.980..23516.213 rows=1147521 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=800128 read=623795 written=9267
                     ->  Hash Join  (cost=353684.23..1117818.25 rows=575172 width=153) (actual time=4190.942..23126.421 rows=1147521 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=800127 read=623795 written=9267
                           ->  Hash Join  (cost=284656.23..1040162.67 rows=575172 width=12) (actual time=2300.879..20180.885 rows=1147521 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=800125 read=588519 written=9266
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..693468.85 rows=15009681 width=12) (actual time=0.065..13191.509 rows=14822651 loops=1)
                                       Buffers: shared hit=599580 read=557001 written=9266
                                 ->  Hash  (cost=277391.77..277391.77 rows=581122 width=8) (actual time=2294.089..2294.089 rows=574383 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30629kB
                                       Buffers: shared hit=200545 read=31518
                                       ->  Bitmap Heap Scan on orders  (cost=12620.94..277391.77 rows=581122 width=8) (actual time=352.179..2081.039 rows=574383 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-08-01'::date) AND (o_orderdate < '1993-11-01'::date))
                                             Heap Blocks: exact=230403
                                             Buffers: shared hit=200545 read=31518
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12475.66 rows=581122 width=0) (actual time=256.783..256.783 rows=579920 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-08-01'::date) AND (o_orderdate < '1993-11-01'::date))
                                                   Buffers: shared read=1660
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1877.641..1877.641 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276 written=1
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.013..926.610 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276 written=1
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.024..0.024 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..0.013 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.792 ms
 Execution time: 26501.631 ms
(42 rows)

COMMIT;
COMMIT