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 '1994-10-01'
	and o_orderdate < cast(date '1994-10-01' + 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=1191312.02..1191312.07 rows=20 width=175) (actual time=77721.391..77721.400 rows=20 loops=1)
   Buffers: shared hit=1060106 read=372353 dirtied=155 written=9477
   ->  Sort  (cost=1191312.02..1192728.78 rows=566705 width=175) (actual time=77721.388..77721.392 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=1060106 read=372353 dirtied=155 written=9477
         ->  HashAggregate  (cost=1170565.15..1176232.20 rows=566705 width=175) (actual time=77167.425..77553.594 rows=381828 loops=1)
               Buffers: shared hit=1060103 read=372353 dirtied=155 written=9477
               ->  Hash Join  (cost=399607.31..1156397.53 rows=566705 width=175) (actual time=11965.314..72925.654 rows=1150432 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1060103 read=372353 dirtied=155 written=9477
                     ->  Hash Join  (cost=399605.74..1148603.77 rows=566705 width=153) (actual time=11965.271..71971.669 rows=1150432 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1060102 read=372353 dirtied=155 written=9477
                           ->  Merge Join  (cost=330577.74..1068241.67 rows=566705 width=12) (actual time=7887.528..65236.973 rows=1150432 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=1044014 read=353163 dirtied=155 written=8603
                                 ->  Sort  (cost=330577.74..332006.65 rows=571566 width=8) (actual time=7887.174..8109.399 rows=574424 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51503kB
                                       Buffers: shared hit=212095 read=19475 dirtied=38 written=1319
                                       ->  Bitmap Heap Scan on orders  (cost=12308.51..275923.00 rows=571566 width=8) (actual time=643.451..7570.126 rows=574424 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-10-01'::date) AND (o_orderdate < '1995-01-01'::date))
                                             Buffers: shared hit=212095 read=19475 dirtied=38 written=1319
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12165.61 rows=571566 width=0) (actual time=528.295..528.295 rows=578433 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-10-01'::date) AND (o_orderdate < '1995-01-01'::date))
                                                   Buffers: shared read=1632 written=92
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..691699.52 rows=14976493 width=12) (actual time=0.152..53296.075 rows=14808277 loops=1)
                                       Buffers: shared hit=831919 read=333688 dirtied=117 written=7284
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=4076.029..4076.029 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=16088 read=19190 written=874
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.037..2660.115 rows=1500000 loops=1)
                                       Buffers: shared hit=16088 read=19190 written=874
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.021..0.021 rows=25 loops=1)
                           Buckets: 1024  Batches: 1  Memory Usage: 2kB
                           Buffers: shared hit=1
                           ->  Seq Scan on nation  (cost=0.00..1.25 rows=25 width=30) (actual time=0.007..0.015 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 77771.364 ms
(40 rows)

COMMIT;
COMMIT