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 '%special%accounts%'
		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=926743.13..926743.63 rows=200 width=8) (actual time=63635.133..63635.136 rows=45 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=237750 read=53585 dirtied=90 written=12
   ->  HashAggregate  (cost=926733.49..926735.49 rows=200 width=8) (actual time=63635.004..63635.016 rows=45 loops=1)
         Buffers: shared hit=237747 read=53585 dirtied=90 written=12
         ->  HashAggregate  (cost=889233.49..904233.49 rows=1500000 width=8) (actual time=62461.602..63291.337 rows=1500000 loops=1)
               Buffers: shared hit=237747 read=53585 dirtied=90 written=12
               ->  Hash Right Join  (cost=69028.00..814315.55 rows=14983588 width=8) (actual time=1885.638..45566.942 rows=15354058 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=237747 read=53585 dirtied=90 written=12
                     ->  Seq Scan on orders  (cost=0.00..445615.79 rows=14983588 width=8) (actual time=0.038..11268.118 rows=14854042 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%accounts%'::text)
                           Rows Removed by Filter: 160958
                           Buffers: shared hit=237744 read=18310 dirtied=90 written=12
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1883.202..1883.202 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=3 read=35275
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.013..1170.923 rows=1500000 loops=1)
                                 Buffers: shared hit=3 read=35275
 Total runtime: 63667.339 ms
(21 rows)

COMMIT;
COMMIT