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=920628.97..920629.47 rows=200 width=8) (actual time=77873.046..77873.051 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=258838 read=30471 written=167
   ->  HashAggregate  (cost=920619.32..920621.32 rows=200 width=8) (actual time=77872.921..77872.931 rows=46 loops=1)
         Buffers: shared hit=258835 read=30471 written=167
         ->  HashAggregate  (cost=883119.32..898119.32 rows=1500000 width=8) (actual time=76747.258..77528.355 rows=1500000 loops=1)
               Buffers: shared hit=258835 read=30471 written=167
               ->  Hash Right Join  (cost=69028.00..808719.04 rows=14880057 width=8) (actual time=2339.364..54162.866 rows=15353984 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=258835 read=30471 written=167
                     ->  Seq Scan on orders  (cost=0.00..442089.90 rows=14880057 width=8) (actual time=0.048..12719.289 rows=14853968 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%accounts%'::text)
                           Rows Removed by Filter: 161032
                           Buffers: shared hit=238490 read=15538
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=2337.264..2337.264 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=20345 read=14933 written=167
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.019..1484.781 rows=1500000 loops=1)
                                 Buffers: shared hit=20345 read=14933 written=167
 Total runtime: 78864.580 ms
(21 rows)

COMMIT;
COMMIT