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=1157395.39..1157395.44 rows=20 width=175) (actual time=20780.027..20780.032 rows=20 loops=1)
   Buffers: shared hit=1202271 read=220105 dirtied=1373 written=11797
   ->  Sort  (cost=1157395.39..1158842.84 rows=578981 width=175) (actual time=20780.024..20780.027 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=1202271 read=220105 dirtied=1373 written=11797
         ->  HashAggregate  (cost=1136199.11..1141988.92 rows=578981 width=175) (actual time=20322.032..20629.860 rows=381613 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=1202268 read=220105 dirtied=1373 written=11797
               ->  Hash Join  (cost=353486.75..1121724.58 rows=578981 width=175) (actual time=3320.498..18133.686 rows=1146507 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1202268 read=220105 dirtied=1373 written=11797
                     ->  Hash Join  (cost=353485.18..1113762.03 rows=578981 width=153) (actual time=3320.465..17746.050 rows=1146507 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1202267 read=220105 dirtied=1373 written=11797
                           ->  Hash Join  (cost=284457.18..1036049.31 rows=578981 width=12) (actual time=1855.112..15539.766 rows=1146507 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=1166989 read=220105 dirtied=1373 written=11797
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..689865.05 rows=14916721 width=12) (actual time=0.154..10250.654 rows=14807964 loops=1)
                                       Buffers: shared hit=959022 read=196468 dirtied=1373 written=11797
                                 ->  Hash  (cost=277113.60..277113.60 rows=587452 width=8) (actual time=1848.264..1848.264 rows=573843 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30608kB
                                       Buffers: shared hit=207967 read=23637
                                       ->  Bitmap Heap Scan on orders  (cost=12753.82..277113.60 rows=587452 width=8) (actual time=303.080..1666.556 rows=573843 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-08-01'::date) AND (o_orderdate < '1993-11-01'::date))
                                             Heap Blocks: exact=229950
                                             Buffers: shared hit=207967 read=23637
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12606.95 rows=587452 width=0) (actual time=223.309..223.309 rows=578805 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-08-01'::date) AND (o_orderdate < '1993-11-01'::date))
                                                   Buffers: shared read=1654
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1453.108..1453.108 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=35278
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.015..615.892 rows=1500000 loops=1)
                                       Buffers: shared hit=35278
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.020..0.020 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..0.011 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.200 ms
 Execution time: 20802.660 ms
(42 rows)

COMMIT;
COMMIT