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 '%unusual%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=845644.90..845645.40 rows=200 width=8) (actual time=24002.525..24002.527 rows=47 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=261553 read=27250
   ->  HashAggregate  (cost=845635.26..845637.26 rows=200 width=8) (actual time=24002.409..24002.415 rows=47 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=261550 read=27250
         ->  HashAggregate  (cost=808135.26..823135.26 rows=1500000 width=8) (actual time=23303.809..23710.928 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=261550 read=27250
               ->  Hash Right Join  (cost=69028.00..733660.77 rows=14894898 width=8) (actual time=947.310..15704.529 rows=15353766 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=261550 read=27250
                     ->  Seq Scan on orders  (cost=0.00..441209.30 rows=14894898 width=8) (actual time=0.034..6867.828 rows=14853742 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%accounts%'::text)
                           Rows Removed by Filter: 161258
                           Buffers: shared hit=248439 read=5083
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=935.856..935.856 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=13111 read=22167
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.024..547.613 rows=1500000 loops=1)
                                 Buffers: shared hit=13111 read=22167
 Planning time: 4.803 ms
 Execution time: 24022.934 ms
(24 rows)

COMMIT;
COMMIT