Thank you Helen,

We are not the original developer of the application, but have now been given the task of maintaining/debugging this 750,000 + lines of Delphi 7 code. Does FireBird support isolation levels ? There are a number of transactions that are waiting for locks to be release, which can be solved by changing the isolation level to dirty/uncommitted reads. These are for read only transactions.

Regards,
Sean

--- In firebird-support@yahoogroups.com, Helen Borrie <helebor@...> wrote:
>
> At 06:29 p.m. 28/03/2013, sean_ohare@... wrote:
> >Hi Dmitry,
> >
> >That makes sense, I am not having server crashes. We have a 3rd party application that makes use of Firebird, when the Firebird server (Windows 7) has only a few clients (XP and Windows 7) then we have no issues, but as soon as we go start having 15 more clients we start to drop transactions. I suspect this is happening because of locked records/dead locks or something like that.
>
> Locking conflicts. You're correct, the problem is in the application's management of transactions and concurrency. The server has no way to know about problems in client work flow and thus to log them. However, the engine is quite verbose in the information it returns to the application when conflicts or errors occur, certainly returning more than enough information to enable the application to catch the problem and resolve it.
>
> > It think these types of things are happening but the application is not handling the errors correctly and that is why we their is data missing.
> > I don't think firebird is loosing the data, it is just not arriving because of a resource conflict.
>
> Forget "resource conflict", you're describing locking conflicts, which occur *intentionally* to ensure that data integrity is never compromised. Exactly what an application should do when lock conflicts occur is determined by the way the conflicting transactions are configured and ultimately by how the application handles the conflicts. What the application should never do is leave uncommitted transactions fluttering in the breeze, which will happen if locking conflicts are just ignored.
>
> >This is what I am trying to determine. Will 2.5 give me this ability to see the lock errors, etc.
>
> 2.5 has the ability to run traces on what the server is doing and log the activities to a file. That may help you to see the error of your ways if you are the developer of the application programs.
>
>
> Helen Borrie, Support Consultant, IBPhoenix (Pacific)
> Author of "The Firebird Book" and "The Firebird Book Second Edition"
> http://www.ibphoenix.com/products/books/firebird_book
> __________________________________________________________________
>