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 '%special%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=849479.89..849480.39 rows=200 width=8) (actual time=29502.124..29502.126 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=259521 read=30801 written=18
   ->  HashAggregate  (cost=849470.25..849472.25 rows=200 width=8) (actual time=29502.024..29502.033 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=259518 read=30801 written=18
         ->  HashAggregate  (cost=811970.25..826970.25 rows=1500000 width=8) (actual time=28364.363..29184.477 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=259518 read=30801 written=18
               ->  Hash Right Join  (cost=69028.00..737197.90 rows=14954470 width=8) (actual time=918.322..18627.390 rows=15353306 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=259518 read=30801 written=18
                     ->  Seq Scan on orders  (cost=0.00..443852.85 rows=14954470 width=8) (actual time=0.028..8313.626 rows=14853289 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%packages%'::text)
                           Rows Removed by Filter: 161711
                           Buffers: shared hit=224240 read=30801 written=18
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=910.647..910.647 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=0.018..506.691 rows=1500000 loops=1)
                                 Buffers: shared hit=35278
 Planning time: 2.856 ms
 Execution time: 29528.207 ms
(24 rows)

COMMIT;
COMMIT