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 '1994-03-01'
	and o_orderdate < cast(date '1994-03-01' + 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=1159028.31..1159028.36 rows=20 width=175) (actual time=31176.327..31176.334 rows=20 loops=1)
   Buffers: shared hit=813638 read=610528 dirtied=175 written=653
   ->  Sort  (cost=1159028.31..1160463.32 rows=574005 width=175) (actual time=31176.325..31176.328 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=813638 read=610528 dirtied=175 written=653
         ->  HashAggregate  (cost=1138014.19..1143754.24 rows=574005 width=175) (actual time=30512.834..30996.474 rows=381472 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=813635 read=610528 dirtied=175 written=653
               ->  Hash Join  (cost=353726.63..1123664.07 rows=574005 width=175) (actual time=4973.197..27155.623 rows=1148919 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=813635 read=610528 dirtied=175 written=653
                     ->  Hash Join  (cost=353725.07..1115769.94 rows=574005 width=153) (actual time=4973.139..26728.514 rows=1148919 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=813634 read=610528 dirtied=175 written=653
                           ->  Hash Join  (cost=284697.07..1038131.86 rows=574005 width=12) (actual time=2860.599..23149.044 rows=1148919 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=796385 read=592499 dirtied=175 written=632
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..691607.05 rows=14956835 width=12) (actual time=0.078..14212.709 rows=14822651 loops=1)
                                       Buffers: shared hit=640504 read=516077 written=504
                                 ->  Hash  (cost=277421.73..277421.73 rows=581992 width=8) (actual time=2854.334..2854.334 rows=573731 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30604kB
                                       Buffers: shared hit=155881 read=76422 dirtied=175 written=128
                                       ->  Bitmap Heap Scan on orders  (cost=12637.85..277421.73 rows=581992 width=8) (actual time=328.199..2636.860 rows=573731 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-03-01'::date) AND (o_orderdate < '1994-06-01'::date))
                                             Heap Blocks: exact=230645
                                             Buffers: shared hit=155881 read=76422 dirtied=175 written=128
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12492.35 rows=581992 width=0) (actual time=239.082..239.082 rows=579410 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-03-01'::date) AND (o_orderdate < '1994-06-01'::date))
                                                   Buffers: shared read=1658 written=5
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=2096.862..2096.862 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=17249 read=18029 written=21
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.012..1010.424 rows=1500000 loops=1)
                                       Buffers: shared hit=17249 read=18029 written=21
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.035..0.035 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=0.013..0.021 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 7.976 ms
 Execution time: 31213.126 ms
(42 rows)

COMMIT;
COMMIT