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 '1993-06-01'
	and o_orderdate < cast(date '1993-06-01' + 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=1149522.44..1149522.49 rows=20 width=175) (actual time=24542.879..24542.885 rows=20 loops=1)
   Buffers: shared hit=447437 read=961349
   ->  Sort  (cost=1149522.44..1150954.66 rows=572890 width=175) (actual time=24542.876..24542.879 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=447437 read=961349
         ->  HashAggregate  (cost=1128549.14..1134278.04 rows=572890 width=175) (actual time=24236.645..24417.510 rows=381497 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=447434 read=961349
               ->  Hash Join  (cost=350800.83..1114226.89 rows=572890 width=175) (actual time=4713.052..22527.449 rows=1147321 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=447434 read=961349
                     ->  Hash Join  (cost=350799.27..1106348.09 rows=572890 width=153) (actual time=4713.011..22169.345 rows=1147321 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=447433 read=961349
                           ->  Hash Join  (cost=281771.27..1028726.74 rows=572890 width=12) (actual time=3142.570..19955.591 rows=1147321 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=447431 read=926073
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..685604.44 rows=14832686 width=12) (actual time=0.070..13820.440 rows=14822992 loops=1)
                                       Buffers: shared hit=373167 read=770581
                                 ->  Hash  (cost=274521.69..274521.69 rows=579931 width=8) (actual time=3138.850..3138.850 rows=574251 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30624kB
                                       Buffers: shared hit=74264 read=155492
                                       ->  Bitmap Heap Scan on orders  (cost=12300.73..274521.69 rows=579931 width=8) (actual time=193.051..2941.451 rows=574251 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-06-01'::date) AND (o_orderdate < '1993-09-01'::date))
                                             Heap Blocks: exact=228186
                                             Buffers: shared hit=74264 read=155492
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12155.75 rows=579931 width=0) (actual time=131.289..131.289 rows=574251 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-06-01'::date) AND (o_orderdate < '1993-09-01'::date))
                                                   Buffers: shared read=1570
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1563.193..1563.193 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=0.007..767.506 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.028..0.028 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..0.013 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 7.862 ms
 Execution time: 24556.908 ms
(42 rows)

COMMIT;
COMMIT