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%accounts%'
		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=847369.07..847369.57 rows=200 width=8) (actual time=26172.446..26172.448 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=247885 read=42437 written=180
   ->  HashAggregate  (cost=847359.43..847361.43 rows=200 width=8) (actual time=26172.368..26172.378 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=247882 read=42437 written=180
         ->  HashAggregate  (cost=809859.43..824859.43 rows=1500000 width=8) (actual time=25401.566..25839.177 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=247882 read=42437 written=180
               ->  Hash Right Join  (cost=69028.00..735614.79 rows=14848929 width=8) (actual time=806.608..17000.529 rows=15338965 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=247882 read=42437 written=180
                     ->  Seq Scan on orders  (cost=0.00..443852.85 rows=14848929 width=8) (actual time=0.018..7408.308 rows=14838943 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%accounts%'::text)
                           Rows Removed by Filter: 161057
                           Buffers: shared hit=212604 read=42437 written=180
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=800.388..800.388 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=0.010..415.969 rows=1500000 loops=1)
                                 Buffers: shared hit=35278
 Planning time: 2.455 ms
 Execution time: 26183.121 ms
(24 rows)

COMMIT;
COMMIT