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Nicolas GASNIER wrote:
> Hi,
> 
> I want to improve my user interface reactivity by setting the 
> Load.ASYNCHRONOUS option on my QueryDataSet. On this dataset, I have a 
> "navigated" event I use to refresh two other datasets based on the the 
> current row ID (I don't want to use mastelinks, the detail dataset would be 
> too big). But this sometimes causes deadlocks between the event thread and 
> the thread of the provider. I think the first dataset I'm trying to refresh 
> wait for the QueryProvider to be released by the main dataset, but for a 
> reason I don't really understand, the main dataset is waiting for that too.
> 
> Does anyone experienced such problem, and how did you manage to solve it ?

I have not experienced this problem, nor do I remember anyone reporting 
it here..

Some questions:

1) You imply that both the detail and master datasets are using the 
"same" instance of QueryProvider.  Is that correct?

2) If so I would question the wisdom of this..  (DX if left to it's 
defaults creates a new instance of the default QueryProvider for each 
instance of QueryDataSet. (example out of DX QueryDataSet source**)

if (currentProvider == null) {
       setQueryProvider(new QueryProvider());
       currentProvider.setAccumulateResults(accumulateResults);
}

..where..

private void setQueryProvider(QueryProvider provider) /*-throws 
DataSetException-*/ {
     super.setProvider(provider);
     currentProvider = (QueryProvider)provider;
}

So.. I would guess you could be doing something else that is forcing the 
QueryDataSet to share a Provider.. (Maybe you should not be doing that..??)

Hope that helps..

John..




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> Some questions:
>
> 1) You imply that both the detail and master datasets are using the "same" 
> instance of QueryProvider.  Is that correct?

I tried the JBuilder deadlock monitor to find where the lock is, and it 
seems to happen between two threads that wait for the monitor on the 
provider.

>
> 2) If so I would question the wisdom of this..  (DX if left to it's 
> defaults creates a new instance of the default QueryProvider for each 
> instance of QueryDataSet. (example out of DX QueryDataSet source**)
>.....
> So.. I would guess you could be doing something else that is forcing the 
> QueryDataSet to share a Provider.. (Maybe you should not be doing 
> that..??)

I never change the provider, it is always left to default. May the lock be 
due to the fact that two dataset, event with different  providers, can't 
provide simultaneously ? When I launch my app main window, there is two 
components that will open their respective dataset, and sometimes they are 
in conflict to get a lock on something internal to data express...

>
> Hope that helps..
>
> John..
>
>
>
>
> -- 
> =============================================
> TeamB are volunteer helpers.  Please DO NOT REPLY VIA EMAIL!
> Post all questions and replies to this newsgroup ONLY
> For papers on DataExpress, Applets, JSP, and Web Development go to:
> http://www.microps.com/mps/paperFAQ.html
> ==================================================== 

Nicolas GASNIER wrote:

> 
> I never change the provider, it is always left to default. May the lock be 
> due to the fact that two dataset, event with different  providers, can't 
> provide simultaneously ? When I launch my app main window, there is two 
> components that will open their respective dataset, and sometimes they are 
> in conflict to get a lock on something internal to data express...

Since I've never encountered this before and have never heard of anyone 
else encountering that has reported here...

I don't have much to suggest..

I would look and see if maybe the driver is where the problem is occuring..

Sorry I could not be more help on this..

John..


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Post all questions and replies to this newsgroup ONLY
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