Re: Perfomance bug in v10

>
> Teodor, could you check if this patch fixes your real-world problem?

It works fine with original query, thank you. But some other query slowdowns for 
~10% (9 secs vs 10 secs). Look at following part of plans of huge query:

without patch:
->  Nested Loop  (cost=34.82..50.91 rows=1 width=20)
                  (actual time=0.017..0.061 rows=5 loops=24121)
   ->  ...
   ->  Materialize  (cost=0.56..15.69 rows=1 width=5)
                    (actual time=0.003..0.004 rows=2 loops=109061)
     ->  Index Scan using ... (cost=0.56..15.68 rows=1 width=5)
                              (actual time=0.013..0.014 rows=2 loops=24121)

with patch:
->  Nested Loop  (cost=34.82..50.91 rows=1 width=20)
                  (actual time=0.018..0.063 rows=5 loops=24121)
   -> ...
   ->  Index Scan using ...  (cost=0.56..15.68 rows=1 width=5)
                             (actual time=0.012..0.013 rows=2 loops=109061)

(dots hidden the same parts)

As you said, it removes Materialize node, although it's useful here.

If you wish, I can do a test suite, its size will be around 10MB and send it by 
private  email.

-- 
Teodor Sigaev                                   E-mail: teodor@sigaev.ru
                                                    WWW: http://www.sigaev.ru/