Contention/Locking Problem on Network

[Chris]

Hi All

I have supplied a Runtime version of an application to a client which is
split into a FE/BE configuration. I am using Access 2003 and deploying onto
Windows XP

Each machine has a copy of the Front End and the backend was placed in its
own folder and setup so that it was visible and accessable on the nextwork.
At load time (i.e. when the user invokes the application) , the system
re-connects to the backend, updating all the table links in the front end. So
in this case, it is going across the LAN to the backend DB.

The problem I have is if Person A logs on, then Person B cannot - the system
waits until the first person has exited the system (and Vice-versa). I have
tried accessing the BE via the UNC and as a drive letter on both machines,
but still the same problem.

I haven't had this problem before, and can't think why it should occur -
Access is after all a multi user system, so has anyone out there got any
ideas as to what I should be checking? The only "lock" that I would expect
would be on the LDB, but the folder has been set up with write permissions,
and both machines can (independantly) access the drive and use the DB - so it
is not a persmissions problem.


Many Thanks
Chris

 

[Klatuu]

How are your default locking options set in both the Fe and Be?

 

[Chris]

Hi Klatuu

The FE and BE have the following set:

DDE Refresh - enabled
Default File format - Access 2000
Default Open Mode - Shared
Default Record Locking - No locks
Open Databases using record-level locking checked

The strange thing is, that the previous installation worked "one-way" - i.e.
if Person B logged on first, then Person A could as well, but not the other
way round (altough in this case Person B was mapping onto Person A's machine
via the network, and Person A was just linking to the BE locally)

 

[Klatuu]

That should do it. Strange behaviour there. The only other thing I can
think of would be if there is something in the code somewhere that is setting
locking.
I guess I am lost now, you might try posting your question in the multiuser
room. You may get a more intelligent answer.

 

[Chris]

Klatuu

No worries. Thanks for your input anyway, it is always useful to get a fresh
pair of eyes on a problem - sometimes you don't see the wood for the trees.

When I get to the bottom of this, I'll reply to this post so that you'll
know what the problem was. It's bound to be something really silly knowing me

 

[Paul Shapiro]

Do all users have permission to create files in the BE folder? The first
person to open the db needs to create the .ldb file or the db can't be
shared. Try opening the db with the machine that seems to open the db
exclusively and see if the .ldb exists.
Paul Shapiro

 

[Chris]

Paul

Good question, I thought that they did, as in the first scenario, if Person
A (the "owner" as it were on whose machine the folder was created) logs on
first, then Person B hangs until Person A logs off. However, if it is done
the other way round then Person A can get on, so I didn't think it was a
folder permissions problem, but I will check to see if an LDB get created in
both scenarios, as that sounds like a good pointer to see where the problem
lies.
I am back in with the client later this week, so will report back then

Thanks for your help

Regards
Chris

 

[Chris]

Klatuu

Well an update at long last. It would appear that I do not have a locking
problem after all (after numerous displays in the code!!), but rather that
the open of the first form was taking a very long time to run (around 3
minutes).

What happens at logon, is that the system reads the INI file to see where
the backend database is and re-creates all the table links and this is taking
a long time. Once the user is into the system, single record reads appear
fine with acceptable response times.

The Backend is on a PC (which is doubling as a server) which is Pentium
2.0Gz with 256 MB of RAM and I suspect that once this starts trying to handle
the Access network info the system slows down, so I guess it begs the
question as to what the recommended spec is for a machine running Access 2003
via the Runtime environment.

I'll have a look around this site to see if I can find any info on this

Regards
Chris