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=846087.82..846088.32 rows=200 width=8) (actual time=36276.025..36276.026 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=254999 read=34057 written=5
   ->  HashAggregate  (cost=846078.18..846080.18 rows=200 width=8) (actual time=36275.910..36275.921 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=254996 read=34057 written=5
         ->  HashAggregate  (cost=808578.18..823578.18 rows=1500000 width=8) (actual time=35028.703..35954.814 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=254996 read=34057 written=5
               ->  Hash Right Join  (cost=69028.00..734103.04 rows=14895029 width=8) (actual time=941.752..20106.809 rows=15354101 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=254996 read=34057 written=5
                     ->  Seq Scan on orders  (cost=0.00..441649.60 rows=14895029 width=8) (actual time=0.026..8769.942 rows=14854081 loops=1)
                           Filter: ((o_comment)::text !~~ '%express%packages%'::text)
                           Rows Removed by Filter: 160919
                           Buffers: shared hit=219718 read=34057 written=5
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=930.835..930.835 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=35278
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.016..508.464 rows=1500000 loops=1)
                                 Buffers: shared hit=35278
 Planning time: 2.784 ms
 Execution time: 36312.856 ms
(24 rows)

COMMIT;
COMMIT