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=853164.37..853164.87 rows=200 width=8) (actual time=28656.158..28656.160 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=211629 read=79959 written=1521
   ->  HashAggregate  (cost=853154.73..853156.73 rows=200 width=8) (actual time=28656.054..28656.059 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=211626 read=79959 written=1521
         ->  HashAggregate  (cost=815654.73..830654.73 rows=1500000 width=8) (actual time=27834.344..28341.026 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=211626 read=79959 written=1521
               ->  Hash Right Join  (cost=69028.00..740512.07 rows=15028532 width=8) (actual time=1208.873..18417.245 rows=15352887 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=211626 read=79959 written=1521
                     ->  Seq Scan on orders  (cost=0.00..446056.09 rows=15028532 width=8) (actual time=0.031..8056.499 rows=14852868 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%deposits%'::text)
                           Rows Removed by Filter: 162132
                           Buffers: shared hit=211624 read=44683 written=1466
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1197.441..1197.441 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=2 read=35276 written=55
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.010..750.356 rows=1500000 loops=1)
                                 Buffers: shared hit=2 read=35276 written=55
 Planning time: 3.366 ms
 Execution time: 28683.301 ms
(24 rows)

COMMIT;
COMMIT