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 '1994-09-01'
	and o_orderdate < cast(date '1994-09-01' + 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=1153504.28..1153504.33 rows=20 width=175) (actual time=24339.143..24339.150 rows=20 loops=1)
   Buffers: shared hit=1291060 read=131201 dirtied=92 written=536
   ->  Sort  (cost=1153504.28..1154880.64 rows=550543 width=175) (actual time=24339.138..24339.141 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=1291060 read=131201 dirtied=92 written=536
         ->  HashAggregate  (cost=1133349.10..1138854.53 rows=550543 width=175) (actual time=23845.543..24184.064 rows=378814 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=1291057 read=131201 dirtied=92 written=536
               ->  Hash Join  (cost=352046.90..1119585.53 rows=550543 width=175) (actual time=4532.013..21697.327 rows=1136992 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1291057 read=131201 dirtied=92 written=536
                     ->  Hash Join  (cost=352045.34..1112014.00 rows=550543 width=153) (actual time=4531.959..21282.678 rows=1136992 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1291056 read=131201 dirtied=92 written=536
                           ->  Hash Join  (cost=283017.34..1034727.85 rows=550543 width=12) (actual time=2407.371..18023.765 rows=1136992 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=1262411 read=124568 dirtied=92 written=529
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..690229.04 rows=14927063 width=12) (actual time=0.065..10557.590 rows=14822845 loops=1)
                                       Buffers: shared hit=1092655 read=62836 dirtied=92 written=482
                                 ->  Hash  (cost=276039.26..276039.26 rows=558211 width=8) (actual time=2401.243..2401.243 rows=568363 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30394kB
                                       Buffers: shared hit=169756 read=61732 written=47
                                       ->  Bitmap Heap Scan on orders  (cost=12118.10..276039.26 rows=558211 width=8) (actual time=301.466..2211.959 rows=568363 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-09-01'::date) AND (o_orderdate < '1994-12-01'::date))
                                             Heap Blocks: exact=229848
                                             Buffers: shared hit=169756 read=61732 written=47
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..11978.55 rows=558211 width=0) (actual time=219.036..219.036 rows=572910 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-09-01'::date) AND (o_orderdate < '1994-12-01'::date))
                                                   Buffers: shared read=1640
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=2104.250..2104.250 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=28645 read=6633 written=7
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.018..921.503 rows=1500000 loops=1)
                                       Buffers: shared hit=28645 read=6633 written=7
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.031..0.031 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: 7.884 ms
 Execution time: 24363.921 ms
(42 rows)

COMMIT;
COMMIT