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=918005.07..918005.57 rows=200 width=8) (actual time=66603.207..66603.211 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=223971 read=65338 written=105
   ->  HashAggregate  (cost=917995.43..917997.43 rows=200 width=8) (actual time=66603.076..66603.089 rows=46 loops=1)
         Buffers: shared hit=223968 read=65338 written=105
         ->  HashAggregate  (cost=880495.43..895495.43 rows=1500000 width=8) (actual time=65242.627..66234.926 rows=1500000 loops=1)
               Buffers: shared hit=223968 read=65338 written=105
               ->  Hash Right Join  (cost=69028.00..806619.92 rows=14775101 width=8) (actual time=1317.733..46932.303 rows=15354087 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=223968 read=65338 written=105
                     ->  Seq Scan on orders  (cost=0.00..442089.90 rows=14775101 width=8) (actual time=0.035..10520.517 rows=14854067 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%packages%'::text)
                           Rows Removed by Filter: 160933
                           Buffers: shared hit=220075 read=33953 written=105
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1315.316..1315.316 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=3893 read=31385
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.016..760.386 rows=1500000 loops=1)
                                 Buffers: shared hit=3893 read=31385
 Total runtime: 66649.986 ms
(21 rows)

COMMIT;
COMMIT