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 '1993-09-01'
	and o_orderdate < cast(date '1993-09-01' + 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=1153896.84..1153896.89 rows=20 width=175) (actual time=27594.857..27594.864 rows=20 loops=1)
   Buffers: shared hit=788378 read=632780 written=618
   ->  Sort  (cost=1153896.84..1155296.62 rows=559912 width=175) (actual time=27594.854..27594.856 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=788378 read=632780 written=618
         ->  HashAggregate  (cost=1133398.67..1138997.79 rows=559912 width=175) (actual time=27155.912..27445.546 rows=378890 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=788375 read=632780 written=618
               ->  Hash Join  (cost=352236.37..1119400.87 rows=559912 width=175) (actual time=4869.040..24487.561 rows=1136419 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=788375 read=632780 written=618
                     ->  Hash Join  (cost=352234.81..1111700.51 rows=559912 width=153) (actual time=4869.000..24053.239 rows=1136419 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=788374 read=632780 written=618
                           ->  Hash Join  (cost=283206.81..1034273.83 rows=559912 width=12) (actual time=2877.664..21226.958 rows=1136419 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=753166 read=632710 written=618
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..689546.95 rows=14912372 width=12) (actual time=0.087..14554.590 rows=14823054 loops=1)
                                       Buffers: shared hit=595753 read=559267 written=529
                                 ->  Hash  (cost=276110.04..276110.04 rows=567707 width=8) (actual time=2870.584..2870.584 rows=567958 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30378kB
                                       Buffers: shared hit=157413 read=73443 written=89
                                       ->  Bitmap Heap Scan on orders  (cost=12299.43..276110.04 rows=567707 width=8) (actual time=402.948..2643.149 rows=567958 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-09-01'::date) AND (o_orderdate < '1993-12-01'::date))
                                             Heap Blocks: exact=229228
                                             Buffers: shared hit=157413 read=73443 written=89
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12157.50 rows=567707 width=0) (actual time=289.671..289.671 rows=571833 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-09-01'::date) AND (o_orderdate < '1993-12-01'::date))
                                                   Buffers: shared read=1628
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1979.529..1979.529 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=35208 read=70
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.020..900.434 rows=1500000 loops=1)
                                       Buffers: shared hit=35208 read=70
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.023..0.023 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=0.007..0.013 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 5.571 ms
 Execution time: 27616.192 ms
(42 rows)

COMMIT;
COMMIT