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%deposits%'
		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=853198.33..853198.83 rows=200 width=8) (actual time=31181.610..31181.612 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=219728 read=71354 written=670
   ->  HashAggregate  (cost=853188.69..853190.69 rows=200 width=8) (actual time=31181.517..31181.526 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=219725 read=71354 written=670
         ->  HashAggregate  (cost=815688.69..830688.69 rows=1500000 width=8) (actual time=30347.771..30866.436 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=219725 read=71354 written=670
               ->  Hash Right Join  (cost=69028.00..740317.39 rows=15074260 width=8) (actual time=1009.085..19894.905 rows=15354672 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=219725 read=71354 written=670
                     ->  Seq Scan on orders  (cost=0.00..445175.49 rows=15074260 width=8) (actual time=0.031..9259.236 rows=14854654 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%deposits%'::text)
                           Rows Removed by Filter: 160346
                           Buffers: shared hit=188021 read=67780 written=664
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=995.946..995.946 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=31704 read=3574 written=6
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.014..563.070 rows=1500000 loops=1)
                                 Buffers: shared hit=31704 read=3574 written=6
 Planning time: 2.972 ms
 Execution time: 31211.093 ms
(24 rows)

COMMIT;
COMMIT