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=1159862.58..1159862.63 rows=20 width=175) (actual time=25387.992..25388.001 rows=20 loops=1)
   Buffers: shared hit=811182 read=615952 dirtied=313 written=662
   ->  Sort  (cost=1159862.58..1161296.70 rows=573647 width=175) (actual time=25387.989..25387.992 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=811182 read=615952 dirtied=313 written=662
         ->  HashAggregate  (cost=1138861.57..1144598.04 rows=573647 width=175) (actual time=24737.116..25214.349 rows=378806 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=811179 read=615952 dirtied=313 written=662
               ->  Hash Join  (cost=353665.90..1124520.40 rows=573647 width=175) (actual time=4834.592..21943.954 rows=1136585 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=811179 read=615952 dirtied=313 written=662
                     ->  Hash Join  (cost=353664.33..1116631.19 rows=573647 width=153) (actual time=4834.549..21550.191 rows=1136585 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=811178 read=615952 dirtied=313 written=662
                           ->  Hash Join  (cost=284636.33..1038998.49 rows=573647 width=12) (actual time=2462.445..18284.745 rows=1136585 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=811176 read=580676 dirtied=313 written=627
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..692448.35 rows=14980738 width=12) (actual time=0.065..12318.694 rows=14822651 loops=1)
                                       Buffers: shared hit=646176 read=514265 dirtied=114 written=529
                                 ->  Hash  (cost=277377.14..277377.14 rows=580701 width=8) (actual time=2455.868..2455.868 rows=568264 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30390kB
                                       Buffers: shared hit=165000 read=66411 dirtied=199 written=98
                                       ->  Bitmap Heap Scan on orders  (cost=12612.62..277377.14 rows=580701 width=8) (actual time=299.172..2260.003 rows=568264 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-04-01'::date) AND (o_orderdate < '1993-07-01'::date))
                                             Heap Blocks: exact=229769
                                             Buffers: shared hit=165000 read=66411 dirtied=199 written=98
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12467.44 rows=580701 width=0) (actual time=216.125..216.125 rows=574034 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-04-01'::date) AND (o_orderdate < '1993-07-01'::date))
                                                   Buffers: shared read=1642 written=5
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1905.517..1905.517 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276 written=35
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.022..911.113 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276 written=35
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.021..0.021 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: 5.510 ms
 Execution time: 25461.718 ms
(42 rows)

COMMIT;
COMMIT