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=928692.36..928692.86 rows=200 width=8) (actual time=66785.291..66785.295 rows=45 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=291299 read=289 written=11
   ->  HashAggregate  (cost=928682.71..928684.71 rows=200 width=8) (actual time=66785.157..66785.171 rows=45 loops=1)
         Buffers: shared hit=291296 read=289 written=11
         ->  HashAggregate  (cost=891182.71..906182.71 rows=1500000 width=8) (actual time=65629.059..66452.309 rows=1500000 loops=1)
               Buffers: shared hit=291296 read=289 written=11
               ->  Hash Right Join  (cost=69028.00..815962.99 rows=15043945 width=8) (actual time=1517.637..47315.912 rows=15354056 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=291296 read=289 written=11
                     ->  Seq Scan on orders  (cost=0.00..446056.09 rows=15043945 width=8) (actual time=0.052..11527.935 rows=14854040 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%accounts%'::text)
                           Rows Removed by Filter: 160960
                           Buffers: shared hit=256109 read=198 written=1
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1515.272..1515.272 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=35187 read=91 written=10
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.017..848.285 rows=1500000 loops=1)
                                 Buffers: shared hit=35187 read=91 written=10
 Total runtime: 66826.879 ms
(21 rows)

COMMIT;
COMMIT