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 '%unusual%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=929867.46..929867.96 rows=200 width=8) (actual time=87167.000..87167.003 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=285602 read=6239 written=1
   ->  HashAggregate  (cost=929857.81..929859.81 rows=200 width=8) (actual time=87166.886..87166.897 rows=46 loops=1)
         Buffers: shared hit=285599 read=6239 written=1
         ->  HashAggregate  (cost=892357.81..907357.81 rows=1500000 width=8) (actual time=85757.748..86787.489 rows=1500000 loops=1)
               Buffers: shared hit=285599 read=6239 written=1
               ->  Hash Right Join  (cost=69028.00..816991.13 rows=15073337 width=8) (actual time=2528.813..62265.984 rows=15352727 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=285599 read=6239 written=1
                     ->  Seq Scan on orders  (cost=0.00..446496.39 rows=15073337 width=8) (actual time=0.040..20718.803 rows=14852707 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%packages%'::text)
                           Rows Removed by Filter: 162293
                           Buffers: shared hit=250321 read=6239 written=1
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=2526.504..2526.504 rows=1500000 loops=1)
                           Buckets: 262144  Batches: 1  Memory Usage: 52735kB
                           Buffers: shared hit=35278
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.017..1810.197 rows=1500000 loops=1)
                                 Buffers: shared hit=35278
 Total runtime: 87201.018 ms
(21 rows)

COMMIT;
COMMIT