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=929877.46..929877.96 rows=200 width=8) (actual time=72113.141..72113.144 rows=45 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=189155 read=102686 dirtied=164 written=3883
   ->  HashAggregate  (cost=929867.81..929869.81 rows=200 width=8) (actual time=72112.974..72112.986 rows=45 loops=1)
         Buffers: shared hit=189152 read=102686 dirtied=164 written=3883
         ->  HashAggregate  (cost=892367.81..907367.81 rows=1500000 width=8) (actual time=70956.619..71764.203 rows=1500000 loops=1)
               Buffers: shared hit=189152 read=102686 dirtied=164 written=3883
               ->  Hash Right Join  (cost=69028.00..816999.13 rows=15073737 width=8) (actual time=2516.267..52415.577 rows=15339289 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=189152 read=102686 dirtied=164 written=3883
                     ->  Seq Scan on orders  (cost=0.00..446496.39 rows=15073737 width=8) (actual time=0.050..14698.479 rows=14839269 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%packages%'::text)
                           Rows Removed by Filter: 160731
                           Buffers: shared hit=189150 read=67410 dirtied=164 written=1423
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=2514.039..2514.039 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=2 read=35276 written=2460
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.022..1748.531 rows=1500000 loops=1)
                                 Buffers: shared hit=2 read=35276 written=2460
 Total runtime: 72152.554 ms
(21 rows)

COMMIT;
COMMIT