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=924740.21..924740.71 rows=200 width=8) (actual time=93080.625..93080.627 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=245674 read=45155 dirtied=52 written=2437
   ->  HashAggregate  (cost=924730.56..924732.56 rows=200 width=8) (actual time=93080.516..93080.527 rows=46 loops=1)
         Buffers: shared hit=245671 read=45155 dirtied=52 written=2437
         ->  HashAggregate  (cost=887230.56..902230.56 rows=1500000 width=8) (actual time=91736.021..92658.576 rows=1500000 loops=1)
               Buffers: shared hit=245671 read=45155 dirtied=52 written=2437
               ->  Hash Right Join  (cost=69028.00..812537.09 rows=14938695 width=8) (actual time=4933.366..69239.901 rows=15339250 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=245671 read=45155 dirtied=52 written=2437
                     ->  Seq Scan on orders  (cost=0.00..444735.19 rows=14938695 width=8) (actual time=0.053..21557.838 rows=14839229 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%packages%'::text)
                           Rows Removed by Filter: 160771
                           Buffers: shared hit=245668 read=9880 dirtied=52 written=383
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=4931.399..4931.399 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=3 read=35275 written=2054
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.013..3603.410 rows=1500000 loops=1)
                                 Buffers: shared hit=3 read=35275 written=2054
 Total runtime: 93129.359 ms
(21 rows)

COMMIT;
COMMIT