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=928369.63..928370.13 rows=200 width=8) (actual time=65801.994..65801.999 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=244123 read=47718 written=337
   ->  HashAggregate  (cost=928359.99..928361.99 rows=200 width=8) (actual time=65801.866..65801.885 rows=46 loops=1)
         Buffers: shared hit=244120 read=47718 written=337
         ->  HashAggregate  (cost=890859.99..905859.99 rows=1500000 width=8) (actual time=64431.944..65431.740 rows=1500000 loops=1)
               Buffers: shared hit=244120 read=47718 written=337
               ->  Hash Right Join  (cost=69028.00..815792.87 rows=15013424 width=8) (actual time=1914.113..47251.243 rows=15353267 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=244120 read=47718 written=337
                     ->  Seq Scan on orders  (cost=0.00..446496.39 rows=15013424 width=8) (actual time=0.048..11262.258 rows=14853250 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%packages%'::text)
                           Rows Removed by Filter: 161750
                           Buffers: shared hit=244118 read=12442 written=337
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1912.011..1912.011 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=2 read=35276
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.016..1177.545 rows=1500000 loops=1)
                                 Buffers: shared hit=2 read=35276
 Total runtime: 65836.038 ms
(21 rows)

COMMIT;
COMMIT