Many Ajax requests every second

We have Vaadin 6.8.9 with TabSheet.
Everything works fine except one thing - when I open certain tab I see that many AJAX requests are sent to server every couple of seconds.
Each request is “/UIDL?windowName=1” and each response like

for(;;);[{"changes":[] , "meta" : {}, "resources" : {}, "locales":[], "timings":[929206, 0] }] [i]

There are no request after I close this tab.

Now I need to determine the following:

  1. Why does this happens?
  2. It seems that some component tries to request repaint with changed data, but there is no changes. So how I can determine this component?
  3. I tried to debug Javascript to findout this component or source of request. But JS code for vaadin is minified and unreadable. Is there way to run vaadin with uncompressed JS?


You could try to compile the widgetset with “-style PRETTY” to get more readable (and much bigger) JavaScript.

On the other hand, debugging the client side with GWT development mode would probably let you get straight to the problematic code in Java once set up - you could put a Java breakpoint in ApplicationConnection where it sends the message and check the call stack to see what is triggering the update.

Thank you for your reply, Henry.
I’m just found the root cause - it was ProgressIndicator component.
According to documentation it polls results from every every

We are using “static” progress indicators - their values are setting on page creation and aren’t changed after that.
Is there a way to prevent polling for ProgressIndicator?
I can setup very big value for polling interval, but I believe that there is another way to do it :slight_smile:

In Vaadin 7.1 you have ProgressBar (which does not perform polling) in addition to the there deprecated ProgressIndicator (there is a better way to poll in 7.x).

With Vaadin 6, you need to use a suitable polling interval for the progress indicator unless the component is disabled, which would also change its appearance.