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=920258.97..920259.47 rows=200 width=8) (actual time=71271.953..71271.957 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=248998 read=40311 written=32
   ->  HashAggregate  (cost=920249.32..920251.32 rows=200 width=8) (actual time=71271.859..71271.870 rows=46 loops=1)
         Buffers: shared hit=248995 read=40311 written=32
         ->  HashAggregate  (cost=882749.32..897749.32 rows=1500000 width=8) (actual time=70175.402..70931.374 rows=1500000 loops=1)
               Buffers: shared hit=248995 read=40311 written=32
               ->  Hash Right Join  (cost=69028.00..808423.04 rows=14865257 width=8) (actual time=2232.847..51478.667 rows=15353275 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=248995 read=40311 written=32
                     ->  Seq Scan on orders  (cost=0.00..442089.90 rows=14865257 width=8) (actual time=0.045..11741.096 rows=14853258 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%packages%'::text)
                           Rows Removed by Filter: 161742
                           Buffers: shared hit=243927 read=10101 written=32
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=2230.943..2230.943 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=5068 read=30210
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.006..1375.010 rows=1500000 loops=1)
                                 Buffers: shared hit=5068 read=30210
 Total runtime: 71324.568 ms
(21 rows)

COMMIT;
COMMIT