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=849876.83..849877.33 rows=200 width=8) (actual time=34786.750..34786.754 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=212340 read=78742 written=157
   ->  HashAggregate  (cost=849867.19..849869.19 rows=200 width=8) (actual time=34786.648..34786.661 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=212337 read=78742 written=157
         ->  HashAggregate  (cost=812367.19..827367.19 rows=1500000 width=8) (actual time=33966.193..34470.914 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=212337 read=78742 written=157
               ->  Hash Right Join  (cost=69028.00..737826.26 rows=14908185 width=8) (actual time=990.446..21276.294 rows=15353775 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=212337 read=78742 written=157
                     ->  Seq Scan on orders  (cost=0.00..445175.49 rows=14908185 width=8) (actual time=0.025..8524.222 rows=14853753 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%accounts%'::text)
                           Rows Removed by Filter: 161247
                           Buffers: shared hit=177059 read=78742 written=157
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=977.131..977.131 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=0.015..533.265 rows=1500000 loops=1)
                                 Buffers: shared hit=35278
 Planning time: 3.112 ms
 Execution time: 34822.687 ms
(24 rows)

COMMIT;
COMMIT