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 '1994-02-01'
	and o_orderdate < cast(date '1994-02-01' + 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=1193504.27..1193504.32 rows=20 width=175) (actual time=36113.301..36113.310 rows=20 loops=1)
   Buffers: shared hit=753577 read=674220 dirtied=219 written=61
   ->  Sort  (cost=1193504.27..1194889.04 rows=553908 width=175) (actual time=36113.295..36113.301 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=753577 read=674220 dirtied=219 written=61
         ->  HashAggregate  (cost=1173225.90..1178764.98 rows=553908 width=175) (actual time=35616.367..35948.348 rows=372127 loops=1)
               Buffers: shared hit=753574 read=674220 dirtied=219 written=61
               ->  Hash Join  (cost=399925.44..1159378.20 rows=553908 width=175) (actual time=8295.782..32268.236 rows=1110494 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=753574 read=674220 dirtied=219 written=61
                     ->  Hash Join  (cost=399923.88..1151760.40 rows=553908 width=153) (actual time=8295.718..31625.050 rows=1110494 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=753573 read=674220 dirtied=219 written=61
                           ->  Merge Join  (cost=330895.88..1071654.24 rows=553908 width=12) (actual time=5052.463..26131.407 rows=1110494 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=746498 read=646017 dirtied=219 written=54
                                 ->  Sort  (cost=330895.88..332296.79 rows=560365 width=8) (actual time=5052.237..5224.422 rows=554756 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 50581kB
                                       Buffers: shared hit=135698 read=94922 dirtied=219 written=17
                                       ->  Bitmap Heap Scan on orders  (cost=12173.73..277392.21 rows=560365 width=8) (actual time=697.282..4743.942 rows=554756 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-02-01'::date) AND (o_orderdate < '1994-05-01'::date))
                                             Buffers: shared hit=135698 read=94922 dirtied=219 written=17
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12033.64 rows=560365 width=0) (actual time=576.298..576.298 rows=562004 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-02-01'::date) AND (o_orderdate < '1994-05-01'::date))
                                                   Buffers: shared read=1609
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..694833.10 rows=15034639 width=12) (actual time=0.112..17961.715 rows=14822442 loops=1)
                                       Buffers: shared hit=610800 read=551095 written=37
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=3241.050..3241.050 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=7075 read=28203 written=7
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.027..1693.314 rows=1500000 loops=1)
                                       Buffers: shared hit=7075 read=28203 written=7
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.034..0.034 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=0.010..0.017 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 36173.260 ms
(40 rows)

COMMIT;
COMMIT