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%accounts%'
		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=927553.56..927554.06 rows=200 width=8) (actual time=64344.770..64344.775 rows=45 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=290595 read=993
   ->  HashAggregate  (cost=927543.91..927545.91 rows=200 width=8) (actual time=64344.614..64344.621 rows=45 loops=1)
         Buffers: shared hit=290592 read=993
         ->  HashAggregate  (cost=890043.91..905043.91 rows=1500000 width=8) (actual time=63132.365..64009.753 rows=1500000 loops=1)
               Buffers: shared hit=290592 read=993
               ->  Hash Right Join  (cost=69028.00..815051.95 rows=14998393 width=8) (actual time=1388.727..45626.082 rows=15354056 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=290592 read=993
                     ->  Seq Scan on orders  (cost=0.00..446056.09 rows=14998393 width=8) (actual time=0.034..10933.444 rows=14854040 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%accounts%'::text)
                           Rows Removed by Filter: 160960
                           Buffers: shared hit=255319 read=988
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1386.505..1386.505 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=35273 read=5
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.018..769.023 rows=1500000 loops=1)
                                 Buffers: shared hit=35273 read=5
 Total runtime: 64378.693 ms
(21 rows)

COMMIT;
COMMIT