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 '1993-10-01'
	and o_orderdate < cast(date '1993-10-01' + 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=1157910.78..1157910.83 rows=20 width=175) (actual time=30416.117..30416.127 rows=20 loops=1)
   Buffers: shared hit=752187 read=671859 dirtied=5 written=655
   ->  Sort  (cost=1157910.78..1159327.15 rows=566550 width=175) (actual time=30416.112..30416.119 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=752187 read=671859 dirtied=5 written=655
         ->  HashAggregate  (cost=1137169.58..1142835.08 rows=566550 width=175) (actual time=29808.767..30219.327 rows=381460 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=752184 read=671859 dirtied=5 written=655
               ->  Hash Join  (cost=353357.28..1123005.83 rows=566550 width=175) (actual time=4799.343..26705.300 rows=1148455 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=752184 read=671859 dirtied=5 written=655
                     ->  Hash Join  (cost=353355.72..1115214.21 rows=566550 width=153) (actual time=4799.299..26231.967 rows=1148455 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=752183 read=671859 dirtied=5 written=655
                           ->  Hash Join  (cost=284327.72..1037687.96 rows=566550 width=12) (actual time=2951.641..23354.058 rows=1148455 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=752181 read=636583 dirtied=5 written=646
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..691607.05 rows=14956835 width=12) (actual time=0.075..15421.062 rows=14822651 loops=1)
                                       Buffers: shared hit=611394 read=545187 written=570
                                 ->  Hash  (cost=277146.87..277146.87 rows=574433 width=8) (actual time=2942.808..2942.808 rows=573892 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30610kB
                                       Buffers: shared hit=140787 read=91396 dirtied=5 written=76
                                       ->  Bitmap Heap Scan on orders  (cost=12476.37..277146.87 rows=574433 width=8) (actual time=326.646..2725.822 rows=573892 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-10-01'::date) AND (o_orderdate < '1994-01-01'::date))
                                             Heap Blocks: exact=230527
                                             Buffers: shared hit=140787 read=91396 dirtied=5 written=76
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12332.76 rows=574433 width=0) (actual time=239.774..239.774 rows=579534 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-10-01'::date) AND (o_orderdate < '1994-01-01'::date))
                                                   Buffers: shared read=1656
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1836.262..1836.262 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276 written=9
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.016..930.114 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276 written=9
                     ->  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=0.007..0.013 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 5.348 ms
 Execution time: 30451.853 ms
(42 rows)

COMMIT;
COMMIT