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 '1994-08-01'
	and o_orderdate < cast(date '1994-08-01' + 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=1160903.36..1160903.41 rows=20 width=175) (actual time=26675.418..26675.423 rows=20 loops=1)
   Buffers: shared hit=705570 read=719289 dirtied=214 written=1178
   ->  Sort  (cost=1160903.36..1162338.28 rows=573966 width=175) (actual time=26675.415..26675.418 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=705570 read=719289 dirtied=214 written=1178
         ->  HashAggregate  (cost=1139890.68..1145630.34 rows=573966 width=175) (actual time=26297.964..26536.055 rows=381528 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=705567 read=719289 dirtied=214 written=1178
               ->  Hash Join  (cost=353935.01..1125541.53 rows=573966 width=175) (actual time=5097.766..24209.288 rows=1146630 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=705567 read=719289 dirtied=214 written=1178
                     ->  Hash Join  (cost=353933.45..1117647.93 rows=573966 width=153) (actual time=5097.725..23806.368 rows=1146630 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=705566 read=719289 dirtied=214 written=1178
                           ->  Hash Join  (cost=284905.45..1040010.44 rows=573966 width=12) (actual time=3279.901..21188.670 rows=1146630 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=705564 read=684013 dirtied=214 written=1027
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..693132.30 rows=14995592 width=12) (actual time=0.056..14259.625 rows=14822519 loops=1)
                                       Buffers: shared hit=586963 read=570087 written=728
                                 ->  Hash  (cost=277642.24..277642.24 rows=581022 width=8) (actual time=3274.150..3274.150 rows=573761 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30605kB
                                       Buffers: shared hit=118601 read=113926 dirtied=214 written=299
                                       ->  Bitmap Heap Scan on orders  (cost=12619.91..277642.24 rows=581022 width=8) (actual time=310.155..2954.632 rows=573761 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-08-01'::date) AND (o_orderdate < '1994-11-01'::date))
                                             Heap Blocks: exact=230866
                                             Buffers: shared hit=118601 read=113926 dirtied=214 written=299
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12474.66 rows=581022 width=0) (actual time=225.283..225.283 rows=580045 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-08-01'::date) AND (o_orderdate < '1994-11-01'::date))
                                                   Buffers: shared read=1661 written=6
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1805.780..1805.780 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276 written=151
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.010..944.583 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276 written=151
                     ->  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=0.009..0.013 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 5.460 ms
 Execution time: 26697.424 ms
(42 rows)

COMMIT;
COMMIT