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 '1993-04-01'
	and o_orderdate < cast(date '1993-04-01' + 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=1158032.33..1158032.38 rows=20 width=175) (actual time=24438.151..24438.157 rows=20 loops=1)
   Buffers: shared hit=810521 read=617322 dirtied=691 written=1314
   ->  Sort  (cost=1158032.33..1159440.68 rows=563340 width=175) (actual time=24438.148..24438.151 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=810521 read=617322 dirtied=691 written=1314
         ->  HashAggregate  (cost=1137408.66..1143042.06 rows=563340 width=175) (actual time=24087.253..24300.633 rows=378816 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=810518 read=617322 dirtied=691 written=1314
               ->  Hash Join  (cost=353466.28..1123325.16 rows=563340 width=175) (actual time=3815.619..21287.461 rows=1136682 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=810518 read=617322 dirtied=691 written=1314
                     ->  Hash Join  (cost=353464.71..1115577.67 rows=563340 width=153) (actual time=3815.585..20904.988 rows=1136682 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=810517 read=617322 dirtied=691 written=1314
                           ->  Hash Join  (cost=284436.71..1038099.57 rows=563340 width=12) (actual time=2065.006..18429.954 rows=1136682 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=810513 read=582048 dirtied=691 written=1064
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..691925.05 rows=14961292 width=12) (actual time=0.052..12964.471 rows=14822519 loops=1)
                                       Buffers: shared hit=605190 read=555727 dirtied=617 written=679
                                 ->  Hash  (cost=277291.63..277291.63 rows=571572 width=8) (actual time=2059.339..2059.339 rows=568298 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30392kB
                                       Buffers: shared hit=205323 read=26321 dirtied=74 written=385
                                       ->  Bitmap Heap Scan on orders  (cost=12411.05..277291.63 rows=571572 width=8) (actual time=285.145..1876.050 rows=568298 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-04-01'::date) AND (o_orderdate < '1993-07-01'::date))
                                             Heap Blocks: exact=230000
                                             Buffers: shared hit=205323 read=26321 dirtied=74 written=385
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12268.16 rows=571572 width=0) (actual time=204.926..204.926 rows=574616 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-04-01'::date) AND (o_orderdate < '1993-07-01'::date))
                                                   Buffers: shared hit=83 read=1561 written=4
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1738.972..1738.972 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=4 read=35274 written=250
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.026..898.698 rows=1500000 loops=1)
                                       Buffers: shared hit=4 read=35274 written=250
                     ->  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=0.006..0.010 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.428 ms
 Execution time: 24461.335 ms
(42 rows)

COMMIT;
COMMIT