Tim


You never did answer my question. Can I assume you don't need anything from me.

Roy Lambert

Roy,

<< You never did answer my question. Can I assume you don't need anything
from me. >>

Sorry, I think OE refreshed on me and I missed it.

<< The main thread has a single session (2 databases, one for disk and one
for memory). so yes. >>

If you have the same physical tables hooked up to data-aware controls that
you are updating, then you may run into trouble when the progress update
causes messages to be processed due to the ShowMessage call.  IOW, the
data-aware controls are going to try to update themselves right in the
middle of a query executing, and that is going to cause a problem.

--
Tim Young
Elevate Software
www.elevatesoft.com

Tim


>Sorry, I think OE refreshed on me and I missed it.

Isn't it wonderful how it does that.

><< The main thread has a single session (2 databases, one for disk and one
>for memory). so yes. >>
>
>If you have the same physical tables hooked up to data-aware controls that
>you are updating, then you may run into trouble when the progress update
>causes messages to be processed due to the ShowMessage call. IOW, the
>data-aware controls are going to try to update themselves right in the
>middle of a query executing, and that is going to cause a problem.

That would be data aware controls linked to tables/queries other than the one for which the progress event is being called?

I recon the best solution is to put a warning in the manual. User intervention shouldn't really be required in an OnProgress event after all.

Roy Lambert

Roy,

<< That would be data aware controls linked to tables/queries other than the
one for which the progress event is being called? >>

Sure, if they are using the same session and/or same physical table(s).  It
could cause the engine to stop what it's doing and start doing something
else with the same internal objects that are, at that time, in an
inconsistent state.

<< I recon the best solution is to put a warning in the manual. User
intervention shouldn't really be required in an OnProgress event after all.
>>

I've thought about a warning, but like other topics like multi-threading
re-entrancy it is is very hard to condense the circumstances down to a
reasonable description that someone can understand.  You have to understand
how the message processing works in Windows combined with what re-entrancy
means combined with how EDB works internally with respect to state.

--
Tim Young
Elevate Software
www.elevatesoft.com

Tim


>I've thought about a warning, but like other topics like multi-threading
>re-entrancy it is is very hard to condense the circumstances down to a
>reasonable description that someone can understand.

I understand where you're coming from I've had it happen to me and I don't understand it

>You have to understand
>how the message processing works in Windows combined with what re-entrancy
>means combined with how EDB works internally with respect to state.

err ..... no chance.

Roy,

<< err ..... no chance. >>

Exactly.  Just describing the scenario confuses the issue to the point that
it doesn't matter.

--
Tim Young
Elevate Software
www.elevatesoft.com