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 '1993-09-01'
	and o_orderdate < cast(date '1993-09-01' + 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=1148360.16..1148360.21 rows=20 width=176) (actual time=31424.517..31424.534 rows=20 loops=1)
   Buffers: shared hit=644829 read=768759 dirtied=876 written=9842
   ->  Sort  (cost=1148360.16..1149765.99 rows=562331 width=176) (actual time=31424.512..31424.527 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=644829 read=768759 dirtied=876 written=9842
         ->  HashAggregate  (cost=1127773.42..1133396.73 rows=562331 width=176) (actual time=30832.020..31263.515 rows=378496 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=644826 read=768759 dirtied=876 written=9842
               ->  Hash Join  (cost=350851.98..1113715.15 rows=562331 width=176) (actual time=5568.956..26793.885 rows=1135288 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=644826 read=768759 dirtied=876 written=9842
                     ->  Hash Join  (cost=350850.42..1105981.53 rows=562331 width=154) (actual time=5568.904..26378.192 rows=1135288 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=644825 read=768759 dirtied=876 written=9842
                           ->  Hash Join  (cost=281822.42..1028518.57 rows=562331 width=12) (actual time=3500.044..23018.927 rows=1135288 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=644823 read=733483 dirtied=876 written=9842
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..685496.54 rows=14820463 width=12) (actual time=0.077..14628.363 rows=14808453 loops=1)
                                       Buffers: shared hit=484976 read=663691 dirtied=839 written=9842
                                 ->  Hash  (cost=274686.37..274686.37 rows=570849 width=8) (actual time=2858.673..2858.673 rows=567359 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30355kB
                                       Buffers: shared hit=159847 read=69792 dirtied=37
                                       ->  Bitmap Heap Scan on orders  (cost=12095.64..274686.37 rows=570849 width=8) (actual time=540.487..2598.750 rows=567359 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-09-01'::date) AND (o_orderdate < '1993-12-01'::date))
                                             Heap Blocks: exact=228086
                                             Buffers: shared hit=159847 read=69792 dirtied=37
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..11952.92 rows=570849 width=0) (actual time=402.814..402.814 rows=568961 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-09-01'::date) AND (o_orderdate < '1993-12-01'::date))
                                                   Buffers: shared read=1553
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=2047.960..2047.960 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=146) (actual time=0.027..970.236 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..0.012 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 5.575 ms
 Execution time: 31461.324 ms
(42 rows)

COMMIT;
COMMIT