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 '%express%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=928301.36..928301.86 rows=200 width=8) (actual time=70502.601..70502.605 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=244791 read=46797 written=477
   ->  HashAggregate  (cost=928291.71..928293.71 rows=200 width=8) (actual time=70502.489..70502.499 rows=46 loops=1)
         Buffers: shared hit=244788 read=46797 written=477
         ->  HashAggregate  (cost=890791.71..905791.71 rows=1500000 width=8) (actual time=69232.782..70143.293 rows=1500000 loops=1)
               Buffers: shared hit=244788 read=46797 written=477
               ->  Hash Right Join  (cost=69028.00..815650.19 rows=15028305 width=8) (actual time=2516.932..50831.858 rows=15353816 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=244788 read=46797 written=477
                     ->  Seq Scan on orders  (cost=0.00..446056.09 rows=15028305 width=8) (actual time=0.049..13287.298 rows=14853798 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%accounts%'::text)
                           Rows Removed by Filter: 161202
                           Buffers: shared hit=244785 read=11522 written=453
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=2514.936..2514.936 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=3 read=35275 written=24
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.013..1681.165 rows=1500000 loops=1)
                                 Buffers: shared hit=3 read=35275 written=24
 Total runtime: 70537.038 ms
(21 rows)

COMMIT;
COMMIT