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%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=927500.93..927501.43 rows=200 width=8) (actual time=79631.346..79631.349 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=273183 read=18152 written=292
   ->  HashAggregate  (cost=927491.29..927493.29 rows=200 width=8) (actual time=79631.216..79631.228 rows=46 loops=1)
         Buffers: shared hit=273180 read=18152 written=292
         ->  HashAggregate  (cost=889991.29..904991.29 rows=1500000 width=8) (actual time=78286.867..79263.882 rows=1500000 loops=1)
               Buffers: shared hit=273180 read=18152 written=292
               ->  Hash Right Join  (cost=69028.00..814921.79 rows=15013900 width=8) (actual time=2107.271..57776.739 rows=15353262 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=273180 read=18152 written=292
                     ->  Seq Scan on orders  (cost=0.00..445615.79 rows=15013900 width=8) (actual time=0.049..16814.561 rows=14853245 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%packages%'::text)
                           Rows Removed by Filter: 161755
                           Buffers: shared hit=238214 read=17840 written=292
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=2105.414..2105.414 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=34966 read=312
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.013..1266.507 rows=1500000 loops=1)
                                 Buffers: shared hit=34966 read=312
 Total runtime: 79665.737 ms
(21 rows)

COMMIT;
COMMIT