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=928681.01..928681.51 rows=200 width=8) (actual time=66149.445..66149.448 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=285151 read=6437 written=1
   ->  HashAggregate  (cost=928671.36..928673.36 rows=200 width=8) (actual time=66149.351..66149.362 rows=46 loops=1)
         Buffers: shared hit=285148 read=6437 written=1
         ->  HashAggregate  (cost=891171.36..906171.36 rows=1500000 width=8) (actual time=64920.916..65819.138 rows=1500000 loops=1)
               Buffers: shared hit=285148 read=6437 written=1
               ->  Hash Right Join  (cost=69028.00..815953.91 rows=15043491 width=8) (actual time=1774.255..46735.097 rows=15338896 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=285148 read=6437 written=1
                     ->  Seq Scan on orders  (cost=0.00..446056.09 rows=15043491 width=8) (actual time=0.067..11258.508 rows=14838874 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%accounts%'::text)
                           Rows Removed by Filter: 161126
                           Buffers: shared hit=249870 read=6437 written=1
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1772.505..1772.505 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=0.015..977.052 rows=1500000 loops=1)
                                 Buffers: shared hit=35278
 Total runtime: 66178.028 ms
(21 rows)

COMMIT;
COMMIT