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=1156682.91..1156682.96 rows=20 width=175) (actual time=28221.049..28221.057 rows=20 loops=1)
   Buffers: shared hit=1220715 read=196245 dirtied=30 written=1325
   ->  Sort  (cost=1156682.91..1158114.31 rows=572558 width=175) (actual time=28221.046..28221.050 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=1220715 read=196245 dirtied=30 written=1325
         ->  HashAggregate  (cost=1135721.77..1141447.35 rows=572558 width=175) (actual time=27676.322..28063.382 rows=378844 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=1220712 read=196245 dirtied=30 written=1325
               ->  Hash Join  (cost=352437.13..1121407.82 rows=572558 width=175) (actual time=3704.219..21564.464 rows=1137125 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1220712 read=196245 dirtied=30 written=1325
                     ->  Hash Join  (cost=352435.57..1113533.58 rows=572558 width=153) (actual time=3704.182..21177.779 rows=1137125 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1220711 read=196245 dirtied=30 written=1325
                           ->  Hash Join  (cost=283407.57..1035917.21 rows=572558 width=12) (actual time=2098.760..18583.592 rows=1137125 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=1185433 read=196245 dirtied=30 written=1325
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..690721.02 rows=14950262 width=12) (actual time=0.029..11946.289 rows=14822937 loops=1)
                                       Buffers: shared hit=959474 read=191187 written=1322
                                 ->  Hash  (cost=276176.11..276176.11 rows=578482 width=8) (actual time=2090.612..2090.612 rows=568411 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30396kB
                                       Buffers: shared hit=225959 read=5058 dirtied=30 written=3
                                       ->  Bitmap Heap Scan on orders  (cost=12457.88..276176.11 rows=578482 width=8) (actual time=383.819..1857.796 rows=568411 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-09-01'::date) AND (o_orderdate < '1994-12-01'::date))
                                             Heap Blocks: exact=229402
                                             Buffers: shared hit=225959 read=5058 dirtied=30 written=3
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12313.25 rows=578482 width=0) (actual time=275.032..275.032 rows=571812 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-09-01'::date) AND (o_orderdate < '1994-12-01'::date))
                                                   Buffers: shared hit=1 read=1614
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=1589.517..1589.517 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=0.017..667.888 rows=1500000 loops=1)
                                       Buffers: shared hit=35278
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.024..0.024 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..0.009 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 4.146 ms
 Execution time: 28252.763 ms
(42 rows)

COMMIT;
COMMIT