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=1155157.00..1155157.05 rows=20 width=175) (actual time=22381.822..22381.829 rows=20 loops=1)
   Buffers: shared hit=968274 read=451571 dirtied=1081 written=348
   ->  Sort  (cost=1155157.00..1156599.28 rows=576912 width=175) (actual time=22381.818..22381.820 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=968274 read=451571 dirtied=1081 written=348
         ->  HashAggregate  (cost=1134036.46..1139805.58 rows=576912 width=175) (actual time=22009.193..22243.935 rows=382420 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=968271 read=451571 dirtied=1081 written=348
               ->  Hash Join  (cost=351947.85..1119613.66 rows=576912 width=175) (actual time=3908.292..19763.582 rows=1150400 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=968271 read=451571 dirtied=1081 written=348
                     ->  Hash Join  (cost=351946.29..1111679.56 rows=576912 width=153) (actual time=3908.249..19381.100 rows=1150400 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=968270 read=451571 dirtied=1081 written=348
                           ->  Hash Join  (cost=282918.29..1033997.88 rows=576912 width=12) (actual time=2380.929..16904.260 rows=1150400 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=933008 read=451555 dirtied=1081 written=348
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..689358.00 rows=14920775 width=12) (actual time=0.070..11123.717 rows=14823489 loops=1)
                                       Buffers: shared hit=777594 read=375956 dirtied=852 written=328
                                 ->  Hash  (cost=275631.95..275631.95 rows=582872 width=8) (actual time=2374.897..2374.897 rows=575701 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30681kB
                                       Buffers: shared hit=155414 read=75599 dirtied=229 written=20
                                       ->  Bitmap Heap Scan on orders  (cost=12354.87..275631.95 rows=582872 width=8) (actual time=271.009..2182.961 rows=575701 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-11-01'::date) AND (o_orderdate < '1995-02-01'::date))
                                             Heap Blocks: exact=229432
                                             Buffers: shared hit=155414 read=75599 dirtied=229 written=20
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12209.16 rows=582872 width=0) (actual time=194.262..194.262 rows=578060 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-11-01'::date) AND (o_orderdate < '1995-02-01'::date))
                                                   Buffers: shared read=1581
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1514.696..1514.696 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=35262 read=16
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.019..633.280 rows=1500000 loops=1)
                                       Buffers: shared hit=35262 read=16
                     ->  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=0.005..0.009 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.184 ms
 Execution time: 22413.105 ms
(42 rows)

COMMIT;
COMMIT