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=845628.44..845628.94 rows=200 width=8) (actual time=31135.155..31135.160 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=191979 read=97330 written=15
   ->  HashAggregate  (cost=845618.80..845620.80 rows=200 width=8) (actual time=31135.018..31135.031 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=191976 read=97330 written=15
         ->  HashAggregate  (cost=808118.80..823118.80 rows=1500000 width=8) (actual time=29922.123..30549.799 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=191976 read=97330 written=15
               ->  Hash Right Join  (cost=69028.00..733868.57 rows=14850045 width=8) (actual time=1350.924..20097.720 rows=15353275 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=191976 read=97330 written=15
                     ->  Seq Scan on orders  (cost=0.00..442089.90 rows=14850045 width=8) (actual time=0.036..9165.450 rows=14853258 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%packages%'::text)
                           Rows Removed by Filter: 161742
                           Buffers: shared hit=191974 read=62054 written=2
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1338.013..1338.013 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=2 read=35276 written=13
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.021..862.236 rows=1500000 loops=1)
                                 Buffers: shared hit=2 read=35276 written=13
 Planning time: 5.007 ms
 Execution time: 31165.755 ms
(24 rows)

COMMIT;
COMMIT