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%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=854379.07..854379.57 rows=200 width=8) (actual time=30110.487..30110.490 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=231680 read=59908 written=118
   ->  HashAggregate  (cost=854369.43..854371.43 rows=200 width=8) (actual time=30110.382..30110.388 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=231677 read=59908 written=118
         ->  HashAggregate  (cost=816869.43..831869.43 rows=1500000 width=8) (actual time=29292.132..29790.850 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=231677 read=59908 written=118
               ->  Hash Right Join  (cost=69028.00..741423.09 rows=15089267 width=8) (actual time=965.787..19330.102 rows=15353261 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=231677 read=59908 written=118
                     ->  Seq Scan on orders  (cost=0.00..446056.09 rows=15089267 width=8) (actual time=0.028..8581.109 rows=14853244 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%packages%'::text)
                           Rows Removed by Filter: 161756
                           Buffers: shared hit=196410 read=59897 written=118
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=953.866..953.866 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=35267 read=11
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.013..509.277 rows=1500000 loops=1)
                                 Buffers: shared hit=35267 read=11
 Planning time: 3.082 ms
 Execution time: 30148.482 ms
(24 rows)

COMMIT;
COMMIT