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 '1993-06-01'
	and o_orderdate < cast(date '1993-06-01' + 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=1153492.79..1153492.84 rows=20 width=175) (actual time=28803.218..28803.225 rows=20 loops=1)
   Buffers: shared hit=885908 read=536338 dirtied=1700 written=9146
   ->  Sort  (cost=1153492.79..1154903.56 rows=564308 width=175) (actual time=28803.214..28803.215 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=885908 read=536338 dirtied=1700 written=9146
         ->  HashAggregate  (cost=1132833.68..1138476.76 rows=564308 width=175) (actual time=28245.505..28641.891 rows=381255 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=885905 read=536338 dirtied=1700 written=9146
               ->  Hash Join  (cost=352126.51..1118725.98 rows=564308 width=175) (actual time=4816.323..25880.242 rows=1146483 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=885905 read=536338 dirtied=1700 written=9146
                     ->  Hash Join  (cost=352124.95..1110965.18 rows=564308 width=153) (actual time=4816.266..25448.193 rows=1146483 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=885904 read=536338 dirtied=1700 written=9146
                           ->  Hash Join  (cost=283096.95..1033472.56 rows=564308 width=12) (actual time=2555.223..22011.106 rows=1146483 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=885902 read=501062 dirtied=1700 written=9128
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..688866.87 rows=14897625 width=12) (actual time=0.083..14297.683 rows=14808293 loops=1)
                                       Buffers: shared hit=716135 read=439648 dirtied=1700 written=9073
                                 ->  Hash  (cost=275944.50..275944.50 rows=572161 width=8) (actual time=2549.492..2549.492 rows=573702 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30603kB
                                       Buffers: shared hit=169767 read=61414 written=55
                                       ->  Bitmap Heap Scan on orders  (cost=12321.09..275944.50 rows=572161 width=8) (actual time=302.672..2301.205 rows=573702 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-06-01'::date) AND (o_orderdate < '1993-09-01'::date))
                                             Heap Blocks: exact=229558
                                             Buffers: shared hit=169767 read=61414 written=55
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12178.05 rows=572161 width=0) (actual time=216.695..216.695 rows=577673 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-06-01'::date) AND (o_orderdate < '1993-09-01'::date))
                                                   Buffers: shared hit=551 read=1072
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=2247.084..2247.084 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276 written=18
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.020..1117.339 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276 written=18
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.031..0.031 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=0.009..0.014 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 7.218 ms
 Execution time: 28831.370 ms
(42 rows)

COMMIT;
COMMIT