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=850316.99..850317.49 rows=200 width=8) (actual time=29302.579..29302.581 rows=45 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=179398 read=111937 written=2397
   ->  HashAggregate  (cost=850307.35..850309.35 rows=200 width=8) (actual time=29302.477..29302.482 rows=45 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=179395 read=111937 written=2397
         ->  HashAggregate  (cost=812807.35..827807.35 rows=1500000 width=8) (actual time=28510.677..28980.844 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=179395 read=111937 written=2397
               ->  Hash Right Join  (cost=69028.00..738266.46 rows=14908178 width=8) (actual time=1250.803..19465.535 rows=15354096 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=179395 read=111937 written=2397
                     ->  Seq Scan on orders  (cost=0.00..445615.79 rows=14908178 width=8) (actual time=0.024..9105.910 rows=14854075 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%packages%'::text)
                           Rows Removed by Filter: 160925
                           Buffers: shared hit=179393 read=76661 written=2313
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1234.391..1234.391 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=2 read=35276 written=84
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.016..790.534 rows=1500000 loops=1)
                                 Buffers: shared hit=2 read=35276 written=84
 Planning time: 2.971 ms
 Execution time: 29333.874 ms
(24 rows)

COMMIT;
COMMIT