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 '1993-09-01'
	and o_orderdate < cast(date '1993-09-01' + 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=1193872.34..1193872.39 rows=20 width=175) (actual time=33579.201..33579.209 rows=20 loops=1)
   Buffers: shared hit=614018 read=813973 dirtied=1109 written=141
   ->  Sort  (cost=1193872.34..1195278.97 rows=562653 width=175) (actual time=33579.196..33579.201 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=614018 read=813973 dirtied=1109 written=141
         ->  HashAggregate  (cost=1173273.81..1178900.34 rows=562653 width=175) (actual time=33070.890..33422.943 rows=378879 loops=1)
               Buffers: shared hit=614015 read=813973 dirtied=1109 written=141
               ->  Hash Join  (cost=400630.35..1159207.49 rows=562653 width=175) (actual time=6066.099..30163.612 rows=1136398 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=614015 read=813973 dirtied=1109 written=141
                     ->  Hash Join  (cost=400628.79..1151469.45 rows=562653 width=153) (actual time=6066.063..29579.343 rows=1136398 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=614014 read=813973 dirtied=1109 written=141
                           ->  Merge Join  (cost=331600.79..1071188.39 rows=562653 width=12) (actual time=2910.921..23742.561 rows=1136398 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=578829 read=813880 dirtied=1109 written=139
                                 ->  Sort  (cost=331600.75..333023.44 rows=569075 width=8) (actual time=2910.793..3065.149 rows=568003 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51202kB
                                       Buffers: shared hit=210396 read=21394 dirtied=239
                                       ->  Bitmap Heap Scan on orders  (cost=12359.01..277202.13 rows=569075 width=8) (actual time=407.709..2655.898 rows=568003 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-09-01'::date) AND (o_orderdate < '1993-12-01'::date))
                                             Buffers: shared hit=210396 read=21394 dirtied=239
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12216.74 rows=569075 width=0) (actual time=315.925..315.925 rows=574112 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-09-01'::date) AND (o_orderdate < '1993-12-01'::date))
                                                   Buffers: shared read=1644
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..693595.74 rows=15008619 width=12) (actual time=0.115..17874.924 rows=14822519 loops=1)
                                       Buffers: shared hit=368433 read=792486 dirtied=870 written=139
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=3153.567..3153.567 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=35185 read=93 written=2
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.016..843.141 rows=1500000 loops=1)
                                       Buffers: shared hit=35185 read=93 written=2
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.017..0.017 rows=25 loops=1)
                           Buckets: 1024  Batches: 1  Memory Usage: 2kB
                           Buffers: shared hit=1
                           ->  Seq Scan on nation  (cost=0.00..1.25 rows=25 width=30) (actual time=0.005..0.008 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 33647.635 ms
(40 rows)

COMMIT;
COMMIT