network connectivity split database question

message from Tim Zych on 18 May 2004

If I use data binding, that is FE controls linked to BE data where the BE is
on a shared drive, what precautions if any must I take w/respect to the
"disconnected" state that the network lapses into after a period of
inactivity?

Has anyone ever noticed this? A simpler example is Explorer. If I open an
instance of Explorer and navigate to shared drives, then walk away for a
couple of hours, come back then try to open a shared drive, it sometimes
takes several seconds for the drives to become available, as if my machine
is reconnecting to the directory structure.

I'm wondering what side effects this can have for a split linked database.
Are there any corruption issues to be aware of? Or is this a non issue?

Thanks.

Allen Browne replied to Tim Zych on 18 May 2004

Non-issue, Tim.

You can force Windows to hold the connection open by leaving a recordset
open. You may get a tiny performance boost after a long period of
inactivity, but you also increase the risk of something corrupting.

There are some procedures that do benefit from holding a connection open.
For example, if the back end is moved and you need to loop through your
TableDefs and reassign the Connect property for each, the code runs several
times faster if you OpenDatabase on the back end file first You don't
actually use that Database variable, and you close it as soon as the
relinking completes, but it really makes a difference to hold the file open
for the operation.

Fred Boer replied to Allen Browne on 19 May 2004

How does this relate to the LBD locking issue as described here:
http://www.granite.ab.ca/access/performanceldblocking.htm

I have implemented this for my application, but, Allen, your answer seems to
suggest that this increases the risk of corruption? Or am I confused?

Thanks!
Fred Boer

"Allen Browne" <AllenBrowne@SeeSig.Invalid> wrote in message
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Tony Toews replied to Fred Boer on 23 May 2004

Now here I disagree with Allen. If the connection was doing updates
then yes it would raise the risk of corruption. But if it's just
sitting there doing nothing then I don't see how the risk of
corruptions can increase.

With the possible exception of bad data being injected into the
network by unstable hardware or such.

Tony

Allen Browne replied to Fred Boer on 20 May 2004

If the network or PC goes down while the file is being held open, there is a
risk of corruption. In a stable environment, this may be a small enough
factor that you choose to ignore it, but my preference is not to hold things
open any longer than necessary.

Depends on your values: which is more important: data integrity above
performance?

Tony Toews replied to Tim Zych on 19 May 2004

What I've noticed is that Access 97/Jet 3.5 transmits about 2.5 kb of
data every 30 seconds or so across the network when using a network
monitor. Thus I suspect this is sufficient to keep this network
connection from timing out as happens with Explorer. I don't know if
A2000 does the same.

Corruption issues seem to happen only when doing updates and only
during that brief moment when the update is actually happening. Which
is not the same as updating a record on a form with the pencil in
place. One client has had five or ten power failures where all 10 or
20 users were affected without any corruption issues.

Tony

Archived message: network connectivity split database question (MS Access Forms)