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%packages%'
		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=920125.07..920125.57 rows=200 width=8) (actual time=37518.731..37518.733 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=279655 read=9148
   ->  HashAggregate  (cost=920115.43..920117.43 rows=200 width=8) (actual time=37518.535..37518.544 rows=46 loops=1)
         Buffers: shared hit=279652 read=9148
         ->  HashAggregate  (cost=882615.43..897615.43 rows=1500000 width=8) (actual time=36279.294..37218.555 rows=1500000 loops=1)
               Buffers: shared hit=279652 read=9148
               ->  Hash Right Join  (cost=69028.00..808139.80 rows=14895125 width=8) (actual time=803.840..27293.645 rows=15354119 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=279652 read=9148
                     ->  Seq Scan on orders  (cost=0.00..441209.30 rows=14895125 width=8) (actual time=0.031..8523.092 rows=14854097 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%packages%'::text)
                           Rows Removed by Filter: 160903
                           Buffers: shared hit=251856 read=1666
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=802.201..802.201 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=27796 read=7482
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.020..447.963 rows=1500000 loops=1)
                                 Buffers: shared hit=27796 read=7482
 Total runtime: 37569.511 ms
(21 rows)

COMMIT;
COMMIT