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=852890.57..852891.07 rows=200 width=8) (actual time=31513.151..31513.153 rows=46 loops=1)
   Sort Key: (count(*)), (count(orders.o_orderkey))
   Sort Method: quicksort  Memory: 27kB
   Buffers: shared hit=202343 read=88739 written=555
   ->  HashAggregate  (cost=852880.93..852882.93 rows=200 width=8) (actual time=31513.055..31513.064 rows=46 loops=1)
         Group Key: count(orders.o_orderkey)
         Buffers: shared hit=202340 read=88739 written=555
         ->  HashAggregate  (cost=815380.93..830380.93 rows=1500000 width=8) (actual time=30568.010..31156.494 rows=1500000 loops=1)
               Group Key: customer.c_custkey
               Buffers: shared hit=202340 read=88739 written=555
               ->  Hash Right Join  (cost=69028.00..740086.57 rows=15058872 width=8) (actual time=1047.756..19491.725 rows=15353775 loops=1)
                     Hash Cond: (orders.o_custkey = customer.c_custkey)
                     Buffers: shared hit=202340 read=88739 written=555
                     ->  Seq Scan on orders  (cost=0.00..445175.49 rows=15058872 width=8) (actual time=0.028..8420.949 rows=14853753 loops=1)
                           Filter: ((o_comment)::text !~~ '%unusual%accounts%'::text)
                           Rows Removed by Filter: 161247
                           Buffers: shared hit=179052 read=76749 written=549
                     ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=4) (actual time=1034.691..1034.691 rows=1500000 loops=1)
                           Buckets: 2097152  Batches: 1  Memory Usage: 69119kB
                           Buffers: shared hit=23288 read=11990 written=6
                           ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=4) (actual time=0.012..585.976 rows=1500000 loops=1)
                                 Buffers: shared hit=23288 read=11990 written=6
 Planning time: 3.322 ms
 Execution time: 31544.358 ms
(24 rows)

COMMIT;
COMMIT