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 '1993-02-01'
	and o_orderdate < cast(date '1993-02-01' + 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=1157305.82..1157305.87 rows=20 width=175) (actual time=29025.872..29025.878 rows=20 loops=1)
   Buffers: shared hit=867749 read=558520 dirtied=108 written=6739
   ->  Sort  (cost=1157305.82..1158710.03 rows=561682 width=175) (actual time=29025.868..29025.871 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=867749 read=558520 dirtied=108 written=6739
         ->  HashAggregate  (cost=1136742.85..1142359.67 rows=561682 width=175) (actual time=28526.494..28873.724 rows=372615 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=867746 read=558520 dirtied=108 written=6739
               ->  Hash Join  (cost=353107.06..1122700.80 rows=561682 width=175) (actual time=4176.663..25145.894 rows=1112900 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=867746 read=558520 dirtied=108 written=6739
                     ->  Hash Join  (cost=353105.49..1114976.11 rows=561682 width=153) (actual time=4176.622..24691.443 rows=1112900 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=867745 read=558520 dirtied=108 written=6739
                           ->  Hash Join  (cost=284077.49..1037522.88 rows=561682 width=12) (actual time=2470.880..22049.609 rows=1112900 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=832467 read=558520 dirtied=108 written=6739
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..691730.67 rows=14959556 width=12) (actual time=0.055..14997.560 rows=14807792 loops=1)
                                       Buffers: shared hit=651567 read=509071 dirtied=108 written=3124
                                 ->  Hash  (cost=276959.63..276959.63 rows=569394 width=8) (actual time=2465.081..2465.081 rows=555204 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 29880kB
                                       Buffers: shared hit=180900 read=49449 written=3615
                                       ->  Bitmap Heap Scan on orders  (cost=12364.72..276959.63 rows=569394 width=8) (actual time=304.925..2270.853 rows=555204 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-02-01'::date) AND (o_orderdate < '1993-05-01'::date))
                                             Heap Blocks: exact=228741
                                             Buffers: shared hit=180900 read=49449 written=3615
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12222.38 rows=569394 width=0) (actual time=219.440..219.440 rows=561224 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-02-01'::date) AND (o_orderdate < '1993-05-01'::date))
                                                   Buffers: shared read=1608 written=114
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1697.898..1697.898 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=35278
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.015..770.946 rows=1500000 loops=1)
                                       Buffers: shared hit=35278
                     ->  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..0.009 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 5.020 ms
 Execution time: 29052.312 ms
(42 rows)

COMMIT;
COMMIT