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 '1994-06-01'
	and o_orderdate < cast(date '1994-06-01' + 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=1148222.85..1148222.90 rows=20 width=175) (actual time=17312.652..17312.659 rows=20 loops=1)
   Buffers: shared hit=1258366 read=155150 dirtied=1189 written=11
   ->  Sort  (cost=1148222.85..1149647.41 rows=569823 width=175) (actual time=17312.649..17312.651 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=1258366 read=155150 dirtied=1189 written=11
         ->  HashAggregate  (cost=1127361.84..1133060.07 rows=569823 width=175) (actual time=16965.235..17183.319 rows=382138 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=1258363 read=155150 dirtied=1189 written=11
               ->  Hash Join  (cost=350989.17..1113116.26 rows=569823 width=175) (actual time=3183.313..15184.231 rows=1149830 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1258363 read=155150 dirtied=1189 written=11
                     ->  Hash Join  (cost=350987.61..1105279.63 rows=569823 width=153) (actual time=3183.274..14819.267 rows=1149830 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1258362 read=155150 dirtied=1189 written=11
                           ->  Hash Join  (cost=281959.61..1027704.29 rows=569823 width=12) (actual time=1698.822..12669.285 rows=1149830 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=1258360 read=119874 dirtied=1189 written=11
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..684553.69 rows=14798186 width=12) (actual time=0.063..7727.877 rows=14823288 loops=1)
                                       Buffers: shared hit=1060665 read=87476 dirtied=1162 written=11
                                 ->  Hash  (cost=274724.82..274724.82 rows=578748 width=8) (actual time=1693.498..1693.498 rows=574855 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30648kB
                                       Buffers: shared hit=197695 read=32398 dirtied=27
                                       ->  Bitmap Heap Scan on orders  (cost=12268.60..274724.82 rows=578748 width=8) (actual time=217.727..1520.537 rows=574855 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-06-01'::date) AND (o_orderdate < '1994-09-01'::date))
                                             Heap Blocks: exact=228521
                                             Buffers: shared hit=197695 read=32398 dirtied=27
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12123.91 rows=578748 width=0) (actual time=145.977..145.977 rows=575423 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-06-01'::date) AND (o_orderdate < '1994-09-01'::date))
                                                   Buffers: shared read=1572
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1478.019..1478.019 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=0.004..732.016 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.027..0.027 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..0.011 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 3.925 ms
 Execution time: 17328.754 ms
(42 rows)

COMMIT;
COMMIT