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 '1994-10-01'
	and o_orderdate < cast(date '1994-10-01' + 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=1156922.33..1156922.38 rows=20 width=175) (actual time=24030.168..24030.177 rows=20 loops=1)
   Buffers: shared hit=869036 read=553091 dirtied=879 written=6073
   ->  Sort  (cost=1156922.33..1158357.75 rows=574166 width=175) (actual time=24030.165..24030.170 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=869036 read=553091 dirtied=879 written=6073
         ->  HashAggregate  (cost=1135902.32..1141643.98 rows=574166 width=175) (actual time=23580.919..23883.179 rows=382122 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=869033 read=553091 dirtied=879 written=6073
               ->  Hash Join  (cost=352902.90..1121548.17 rows=574166 width=175) (actual time=3974.033..21445.598 rows=1151516 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=869033 read=553091 dirtied=879 written=6073
                     ->  Hash Join  (cost=352901.34..1113651.83 rows=574166 width=153) (actual time=3974.000..21044.134 rows=1151516 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=869032 read=553091 dirtied=879 written=6073
                           ->  Hash Join  (cost=283873.34..1036011.34 rows=574166 width=12) (actual time=2494.297..18785.931 rows=1151516 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=835359 read=551486 dirtied=879 written=6073
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..690386.01 rows=14936204 width=12) (actual time=0.071..12446.024 rows=14823054 loops=1)
                                       Buffers: shared hit=679466 read=475554 dirtied=879 written=6048
                                 ->  Hash  (cost=276607.52..276607.52 rows=581231 width=8) (actual time=2488.047..2488.047 rows=574982 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30653kB
                                       Buffers: shared hit=155893 read=75932 written=25
                                       ->  Bitmap Heap Scan on orders  (cost=12594.05..276607.52 rows=581231 width=8) (actual time=308.579..2284.851 rows=574982 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-10-01'::date) AND (o_orderdate < '1995-01-01'::date))
                                             Heap Blocks: exact=230170
                                             Buffers: shared hit=155893 read=75932 written=25
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12448.75 rows=581231 width=0) (actual time=223.903..223.903 rows=578991 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-10-01'::date) AND (o_orderdate < '1995-01-01'::date))
                                                   Buffers: shared read=1655
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1467.454..1467.454 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=33673 read=1605
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.014..622.939 rows=1500000 loops=1)
                                       Buffers: shared hit=33673 read=1605
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.019..0.019 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: 4.378 ms
 Execution time: 24056.696 ms
(42 rows)

COMMIT;
COMMIT