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%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=845765.12..845765.62 rows=200 width=8) (actual time=26620.878..26620.880 rows=45 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=289479 read=83 written=1
   ->  HashAggregate  (cost=845755.48..845757.48 rows=200 width=8) (actual time=26620.809..26620.819 rows=45 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=289476 read=83 written=1
         ->  HashAggregate  (cost=808255.48..823255.48 rows=1500000 width=8) (actual time=25826.256..26289.365 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=289476 read=83 written=1
               ->  Hash Right Join  (cost=69028.00..734081.16 rows=14834864 width=8) (actual time=827.784..16726.379 rows=15352902 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=289476 read=83 written=1
                     ->  Seq Scan on orders  (cost=0.00..442530.20 rows=14834864 width=8) (actual time=0.023..6873.273 rows=14852883 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%deposits%'::text)
                           Rows Removed by Filter: 162117
                           Buffers: shared hit=254198 read=83 written=1
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=817.761..817.761 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=35278
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.011..416.792 rows=1500000 loops=1)
                                 Buffers: shared hit=35278
 Planning time: 2.369 ms
 Execution time: 26641.622 ms
(24 rows)

COMMIT;
COMMIT