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=924317.51..924318.01 rows=200 width=8) (actual time=68180.518..68180.521 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=227011 read=63565 dirtied=154 written=3038
   ->  HashAggregate  (cost=924307.86..924309.86 rows=200 width=8) (actual time=68180.392..68180.404 rows=46 loops=1)
         Buffers: shared hit=227008 read=63565 dirtied=154 written=3038
         ->  HashAggregate  (cost=886807.86..901807.86 rows=1500000 width=8) (actual time=67004.111..67844.002 rows=1500000 loops=1)
               Buffers: shared hit=227008 read=63565 dirtied=154 written=3038
               ->  Hash Right Join  (cost=69028.00..812110.87 rows=14939399 width=8) (actual time=2353.572..47722.718 rows=15353299 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=227008 read=63565 dirtied=154 written=3038
                     ->  Seq Scan on orders  (cost=0.00..444294.89 rows=14939399 width=8) (actual time=0.077..11709.677 rows=14853282 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%packages%'::text)
                           Rows Removed by Filter: 161718
                           Buffers: shared hit=227006 read=28289 dirtied=154 written=263
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=2351.372..2351.372 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=2 read=35276 written=2775
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.021..1546.280 rows=1500000 loops=1)
                                 Buffers: shared hit=2 read=35276 written=2775
 Total runtime: 68218.686 ms
(21 rows)

COMMIT;
COMMIT