> Hi
>
> I have one big problem with own database from Firebird 1.5 to now
> (2.01) and (2.1 beta 1)
>
> i have one database with over 5GB size
>
> First. i strongly need frequently change metadata (add stored
> procedure update table definition and .....) when some user working
> with database

It was never supported

> some times after check DB validation see i some error in database.
> mend database does not help me and only need backup and restore to
> solve problem
>
> why ?

Until you show details we can't say

Regards,
Vlad