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 '1994-11-01'
	and o_orderdate < cast(date '1994-11-01' + 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=1154177.14..1154177.19 rows=20 width=175) (actual time=24932.829..24932.835 rows=20 loops=1)
   Buffers: shared hit=716329 read=712748 dirtied=1140 written=330
   ->  Sort  (cost=1154177.14..1155605.63 rows=571395 width=175) (actual time=24932.825..24932.828 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=716329 read=712748 dirtied=1140 written=330
         ->  HashAggregate  (cost=1133258.58..1138972.53 rows=571395 width=175) (actual time=24559.610..24793.238 rows=382386 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=716326 read=712748 dirtied=1140 written=330
               ->  Hash Join  (cost=352500.96..1118973.70 rows=571395 width=175) (actual time=5648.517..22472.535 rows=1150414 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=716326 read=712748 dirtied=1140 written=330
                     ->  Hash Join  (cost=352499.39..1111115.46 rows=571395 width=153) (actual time=5648.470..22073.730 rows=1150414 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=716325 read=712748 dirtied=1140 written=330
                           ->  Hash Join  (cost=283471.39..1033516.53 rows=571395 width=12) (actual time=2563.733..18230.378 rows=1150414 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=716323 read=677472 dirtied=1140 written=330
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..688504.24 rows=14887303 width=12) (actual time=0.062..12178.337 rows=14822937 loops=1)
                                       Buffers: shared hit=592008 read=570278 dirtied=1140 written=310
                                 ->  Hash  (cost=276224.10..276224.10 rows=579749 width=8) (actual time=2557.870..2557.870 rows=575732 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30682kB
                                       Buffers: shared hit=124315 read=107194 written=20
                                       ->  Bitmap Heap Scan on orders  (cost=12486.86..276224.10 rows=579749 width=8) (actual time=288.388..2353.849 rows=575732 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-11-01'::date) AND (o_orderdate < '1995-02-01'::date))
                                             Heap Blocks: exact=229876
                                             Buffers: shared hit=124315 read=107194 written=20
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12341.92 rows=579749 width=0) (actual time=207.197..207.197 rows=579192 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-11-01'::date) AND (o_orderdate < '1995-02-01'::date))
                                                   Buffers: shared read=1633
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1771.208..1771.208 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.032..876.865 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.025..0.025 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=0.010..0.015 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.420 ms
 Execution time: 25349.641 ms
(42 rows)

COMMIT;
COMMIT