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%deposits%'
		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=923436.14..923436.64 rows=200 width=8) (actual time=67124.059..67124.061 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=283688 read=6380 written=336
   ->  HashAggregate  (cost=923426.50..923428.50 rows=200 width=8) (actual time=67123.947..67123.953 rows=46 loops=1)
         Buffers: shared hit=283685 read=6380 written=336
         ->  HashAggregate  (cost=885926.50..900926.50 rows=1500000 width=8) (actual time=65963.281..66789.788 rows=1500000 loops=1)
               Buffers: shared hit=283685 read=6380 written=336
               ->  Hash Right Join  (cost=69028.00..811228.96 rows=14939508 width=8) (actual time=1514.548..47396.503 rows=15352895 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=283685 read=6380 written=336
                     ->  Seq Scan on orders  (cost=0.00..443410.80 rows=14939508 width=8) (actual time=0.042..11706.345 rows=14852877 loops=1)
                           Filter: ((o_comment)::text !~~ '%special%deposits%'::text)
                           Rows Removed by Filter: 162123
                           Buffers: shared hit=248407 read=6380 written=336
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1512.449..1512.449 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=0.022..844.259 rows=1500000 loops=1)
                                 Buffers: shared hit=35278
 Total runtime: 67165.065 ms
(21 rows)

COMMIT;
COMMIT