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=845353.96..845354.46 rows=200 width=8) (actual time=32410.178..32410.182 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=214016 read=74787 written=1176
   ->  HashAggregate  (cost=845344.32..845346.32 rows=200 width=8) (actual time=32410.074..32410.084 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=214013 read=74787 written=1176
         ->  HashAggregate  (cost=807844.32..822844.32 rows=1500000 width=8) (actual time=31135.549..32084.980 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=214013 read=74787 written=1176
               ->  Hash Right Join  (cost=69028.00..733442.57 rows=14880351 width=8) (actual time=1024.307..20463.586 rows=15339273 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=214013 read=74787 written=1176
                     ->  Seq Scan on orders  (cost=0.00..441209.30 rows=14880351 width=8) (actual time=0.027..8624.057 rows=14839251 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%packages%'::text)
                           Rows Removed by Filter: 160749
                           Buffers: shared hit=192449 read=61073 written=452
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1013.063..1013.063 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=21564 read=13714 written=724
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.012..601.296 rows=1500000 loops=1)
                                 Buffers: shared hit=21564 read=13714 written=724
 Planning time: 3.069 ms
 Execution time: 32433.850 ms
(24 rows)

COMMIT;
COMMIT