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=846226.02..846226.52 rows=200 width=8) (actual time=26861.827..26861.829 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=54186 read=235123
   ->  HashAggregate  (cost=846216.38..846218.38 rows=200 width=8) (actual time=26861.730..26861.739 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=54183 read=235123
         ->  HashAggregate  (cost=808716.38..823716.38 rows=1500000 width=8) (actual time=26130.686..26564.297 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=54183 read=235123
               ->  Hash Right Join  (cost=69028.00..734316.76 rows=14879924 width=8) (actual time=975.794..17885.632 rows=15339272 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=54183 read=235123
                     ->  Seq Scan on orders  (cost=0.00..442089.90 rows=14879924 width=8) (actual time=0.039..8538.602 rows=14839252 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%packages%'::text)
                           Rows Removed by Filter: 160748
                           Buffers: shared hit=54181 read=199847
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=965.528..965.528 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=2 read=35276
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.011..578.789 rows=1500000 loops=1)
                                 Buffers: shared hit=2 read=35276
 Planning time: 5.237 ms
 Execution time: 26888.150 ms
(24 rows)

COMMIT;
COMMIT