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%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=929931.91..929932.41 rows=200 width=8) (actual time=74037.204..74037.204 rows=44 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=183937 read=108157 written=26
   ->  HashAggregate  (cost=929922.26..929924.26 rows=200 width=8) (actual time=74037.062..74037.071 rows=44 loops=1)
         Buffers: shared hit=183934 read=108157 written=26
         ->  HashAggregate  (cost=892422.26..907422.26 rows=1500000 width=8) (actual time=72838.780..73685.860 rows=1500000 loops=1)
               Buffers: shared hit=183934 read=108157 written=26
               ->  Hash Right Join  (cost=69028.00..817130.75 rows=15058303 width=8) (actual time=2104.266..51856.937 rows=15352859 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=183934 read=108157 written=26
                     ->  Seq Scan on orders  (cost=0.00..446936.69 rows=15058303 width=8) (actual time=0.047..13107.329 rows=14852841 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%deposits%'::text)
                           Rows Removed by Filter: 162159
                           Buffers: shared hit=178657 read=78156 written=26
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=2101.829..2101.829 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=5277 read=30001
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.023..1331.463 rows=1500000 loops=1)
                                 Buffers: shared hit=5277 read=30001
 Total runtime: 74073.825 ms
(21 rows)

COMMIT;
COMMIT