Re: Performance inside and outside view ( WAS Re: Select the max on a field ) - Mailing list pgsql-sql

"Tom Lane" <tgl@sss.pgh.pa.us> wrote in message
news:7350.1031842223@sss.pgh.pa.us...
> "Gaetano Mendola" <mendola@bigfoot.com> writes:
> > Yes that's right it's help me,
> > but here the optimizer have some problems:
>
> What's the datatype of id_user, and why are you quoting the compared
> constant in some cases but not others?  I don't think the difference
> has anything to do with the view here ...

id_user is an INTEGER type.

Well what about this two selects:

a) SELECT DISTINCT ON (id_user) *   FROM user_logs  WHERE id_user = 5430  ORDER BY id_user, id_user_log DESC;

b) CREATE VIEW last_user_logs AS    SELECT DISTINCT ON (id_user) *    FROM user_logs    ORDER BY id_user, id_user_log
DESC;
    SELECT *    FROM last_user_logs    WHERE id_user = 5430


I think that in the second case the filter is not pushed inside the view.

Ciao
Gaetano