Vstudio do not recognize db created by other user

[Ruslan Zasukhin]

On 5/31/08 10:04 PM, "william humphrey" <shoreagent at gmail.com> wrote:

Hi William,

> I have a similar issue. If you are running Valentina with a local database
> and you are accessing it with RunRev and then you open the same database in
> Valentina Studio you get multiple crashes (it brings both RunRev down and
> Valentina Studio down). I will report this easily repeatable error on Mantis
> but I'm confused. I remember asking about this once before because it is not
> behavior I expect. When you access a SQLite database locally using RunRev
> and then access it at the same time using SQLiteManager everything runs
> together nicely even though SQLite is not a multi-user database and is not
> on a server.

You can only READ in the second user? I doubt you can WRITE from both.

Sounds like they have implement SHARED ACCESS to database. MS Access have
this also. 

In fact shared access are implementing such dbs that do not have
client/server solutions.

We do not want shared-access because it is not so optimal as client/server.
And we do not want even implement it to be alternative for VServer. This is
then kind of cannibalism of own products.

Problem you describe have come in OS X because it do not provide exclusive
access to file. Yes we going for months implement linux-kind exclusiveness
of this using additional hidden lock file when db is opened.

But even when we implement it, this will mean that second user just will not
be able to open it, like this happens on Windows.

> Rather than answering my question with: "Put your valentina database on a
> server and then you will have no problem" what I want to hear is that there
> is a way to make this ok locally. Lots of people don't want the overhead of
> a server.
 
> As Valentina Studio keeps improving you are going to see more and more users
> wanting to have both their copy of RunRev and their custom database solution
> open and Valentina Studio open doing reports and stuff. Also many users will
> still not want to operate a server.

Okay, ask me -- if you can implement SHARED ACESS for Valentina ?

And I think I will answer -- practically not.
    main reason is that shared access way cannot live with db cache.
    this slow down things in tens times.

Valentina already using cache. Future Valentina transactions will work
thanks to cache pages. So we cannot live without cache.

SqlLite have DB LEVEL lock to implement own "transaction". SqlLite, yes, is
a single user db, this is why they can use such algorithms and solutions.


-- 
Best regards,

Ruslan Zasukhin
VP Engineering and New Technology
Paradigma Software, Inc

Valentina - Joining Worlds of Information
http://www.paradigmasoft.com

[I feel the need: the need for speed]