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=919442.92..919443.42 rows=200 width=8) (actual time=64909.778..64909.781 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=271043 read=18013 written=45
   ->  HashAggregate  (cost=919433.28..919435.28 rows=200 width=8) (actual time=64909.677..64909.685 rows=46 loops=1)
         Buffers: shared hit=271040 read=18013 written=45
         ->  HashAggregate  (cost=881933.28..896933.28 rows=1500000 width=8) (actual time=63898.774..64589.285 rows=1500000 loops=1)
               Buffers: shared hit=271040 read=18013 written=45
               ->  Hash Right Join  (cost=69028.00..807682.14 rows=14850227 width=8) (actual time=1471.491..44938.641 rows=15353957 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=271040 read=18013 written=45
                     ->  Seq Scan on orders  (cost=0.00..441649.60 rows=14850227 width=8) (actual time=0.037..9654.996 rows=14853941 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%accounts%'::text)
                           Rows Removed by Filter: 161059
                           Buffers: shared hit=241800 read=11975
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1469.644..1469.644 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=29240 read=6038 written=45
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.010..758.232 rows=1500000 loops=1)
                                 Buffers: shared hit=29240 read=6038 written=45
 Total runtime: 64948.071 ms
(21 rows)

COMMIT;
COMMIT