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 '1994-02-01'
	and o_orderdate < cast(date '1994-02-01' + 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=1151125.19..1151125.24 rows=20 width=175) (actual time=19552.480..19552.489 rows=20 loops=1)
   Buffers: shared hit=1353211 read=63365 written=3509
   ->  Sort  (cost=1151125.19..1152468.32 rows=537252 width=175) (actual time=19552.477..19552.481 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=1353211 read=63365 written=3509
         ->  HashAggregate  (cost=1131456.58..1136829.10 rows=537252 width=175) (actual time=19094.942..19407.600 rows=371940 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=1353208 read=63365 written=3509
               ->  Hash Join  (cost=351404.45..1118025.28 rows=537252 width=175) (actual time=3319.080..17359.630 rows=1109444 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1353208 read=63365 written=3509
                     ->  Hash Join  (cost=351402.89..1110636.51 rows=537252 width=153) (actual time=3319.047..17002.101 rows=1109444 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1353207 read=63365 written=3509
                           ->  Hash Join  (cost=282374.89..1033549.73 rows=537252 width=12) (actual time=1703.336..14631.161 rows=1109444 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=1317929 read=63365 written=3509
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..689865.05 rows=14916721 width=12) (actual time=0.098..9595.115 rows=14807964 loops=1)
                                       Buffers: shared hit=1093853 read=57959 written=3504
                                 ->  Hash  (cost=275560.54..275560.54 rows=545113 width=8) (actual time=1697.192..1697.192 rows=554270 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 29844kB
                                       Buffers: shared hit=224076 read=5406 written=5
                                       ->  Bitmap Heap Scan on orders  (cost=11835.84..275560.54 rows=545113 width=8) (actual time=259.282..1527.062 rows=554270 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-02-01'::date) AND (o_orderdate < '1994-05-01'::date))
                                             Heap Blocks: exact=227887
                                             Buffers: shared hit=224076 read=5406 written=5
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..11699.57 rows=545113 width=0) (actual time=183.844..183.844 rows=559266 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-02-01'::date) AND (o_orderdate < '1994-05-01'::date))
                                                   Buffers: shared hit=1 read=1594
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1604.680..1604.680 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=0.014..699.169 rows=1500000 loops=1)
                                       Buffers: shared hit=35278
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.019..0.019 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=0.006..0.011 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.140 ms
 Execution time: 19575.683 ms
(42 rows)

COMMIT;
COMMIT