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=852423.81..852424.31 rows=200 width=8) (actual time=37351.576..37351.580 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=209642 read=81693 written=1097
   ->  HashAggregate  (cost=852414.17..852416.17 rows=200 width=8) (actual time=37351.391..37351.401 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=209639 read=81693 written=1097
         ->  HashAggregate  (cost=814914.17..829914.17 rows=1500000 width=8) (actual time=36115.584..37011.474 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=209639 read=81693 written=1097
               ->  Hash Right Join  (cost=69028.00..739846.57 rows=15013519 width=8) (actual time=1466.869..22934.379 rows=15337869 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=209639 read=81693 written=1097
                     ->  Seq Scan on orders  (cost=0.00..445615.79 rows=15013519 width=8) (actual time=0.037..9189.585 rows=14837848 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%packages%'::text)
                           Rows Removed by Filter: 162152
                           Buffers: shared hit=174361 read=81693 written=1097
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1457.521..1457.521 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=0.025..866.155 rows=1500000 loops=1)
                                 Buffers: shared hit=35278
 Planning time: 4.426 ms
 Execution time: 37380.990 ms
(24 rows)

COMMIT;
COMMIT