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=924311.86..924312.36 rows=200 width=8) (actual time=64009.650..64009.654 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=281869 read=8707 written=21
   ->  HashAggregate  (cost=924302.21..924304.21 rows=200 width=8) (actual time=64009.517..64009.527 rows=46 loops=1)
         Buffers: shared hit=281866 read=8707 written=21
         ->  HashAggregate  (cost=886802.21..901802.21 rows=1500000 width=8) (actual time=62819.129..63681.508 rows=1500000 loops=1)
               Buffers: shared hit=281866 read=8707 written=21
               ->  Hash Right Join  (cost=69028.00..812106.35 rows=14939173 width=8) (actual time=1584.673..45985.659 rows=15354006 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=281866 read=8707 written=21
                     ->  Seq Scan on orders  (cost=0.00..444294.89 rows=14939173 width=8) (actual time=0.044..11074.526 rows=14853990 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%accounts%'::text)
                           Rows Removed by Filter: 161010
                           Buffers: shared hit=246614 read=8681 written=21
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1582.732..1582.732 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=35252 read=26
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.019..854.172 rows=1500000 loops=1)
                                 Buffers: shared hit=35252 read=26
 Total runtime: 64042.930 ms
(21 rows)

COMMIT;
COMMIT