BEGIN;
BEGIN
EXPLAIN (ANALYZE, BUFFERS)
select
	c_count,
	count(*) as custdist
from
	(
		select
			c_custkey,
			count(o_orderkey)
		from
			customer left outer join orders on
				c_custkey = o_custkey
				and o_comment not like '%express%packages%'
		group by
			c_custkey
	) as c_orders (c_custkey, c_count)
group by
	c_count
order by
	custdist desc,
	c_count desc;
                                                                    QUERY PLAN                                                                     
---------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=925439.88..925440.38 rows=200 width=8) (actual time=82422.873..82422.876 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=250718 read=39858 written=19
   ->  HashAggregate  (cost=925430.24..925432.24 rows=200 width=8) (actual time=82422.763..82422.778 rows=46 loops=1)
         Buffers: shared hit=250715 read=39858 written=19
         ->  HashAggregate  (cost=887930.24..902930.24 rows=1500000 width=8) (actual time=81344.136..82096.897 rows=1500000 loops=1)
               Buffers: shared hit=250715 read=39858 written=19
               ->  Hash Right Join  (cost=69028.00..813008.77 rows=14984294 width=8) (actual time=4267.797..60373.721 rows=15354088 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=250715 read=39858 written=19
                     ->  Seq Scan on orders  (cost=0.00..444294.89 rows=14984294 width=8) (actual time=0.056..14598.957 rows=14854067 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%packages%'::text)
                           Rows Removed by Filter: 160933
                           Buffers: shared hit=250713 read=4582
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=4264.733..4264.733 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=2 read=35276 written=19
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.012..3227.943 rows=1500000 loops=1)
                                 Buffers: shared hit=2 read=35276 written=19
 Total runtime: 82482.607 ms
(21 rows)

COMMIT;
COMMIT