[OpenLayers-Dev] Bug #622 testing and performance issues

Stephen Woodbridge woodbri at swoodbridge.com
Wed Apr 4 00:11:51 EDT 2007

Christopher Schmidt wrote:
> On Tue, Apr 03, 2007 at 11:16:03PM -0400, Stephen Woodbridge wrote:
>> Christopher,
>> Here is some profiling output on on the various requests that were 
>> giving me severe performance problems. I ran these against tonight's SVN 
>> revision 2997. It looks like you added the code to delete the existing 
>> features on each new request but I'm still seeing really bad performance 
>> and I thought having these profiles might help see the problem that I am 
>> having. I'm running FF on Window 2000 box.
>> Thanks again and I hope this helps,
>>    -Steve
>> Steps:
>> 3) Turn on Profiling
>>     click Zoom + (again)
>> Profile results:
>>> destroy	1	98.73%	178718.75ms	178718.75ms	178718.75ms	178718.75ms	178718.75ms	OpenLayers.js (line 526)
> This is bad. This is the renderer... but why is it stuck in this
> function? there is nothing done here. (It's all done in subclasses.) I
> can't imagine why this would happen.  
> Everything else looks fine.
> Even more worrisome is that your renderer is getting destroyed here at
> all... it should only get destroyed when the vector layer is
> destroyed... I'm not seeing the same issues here...
> All in all, this seems rather insane. 
> Can anyone else reproduce this? Stephen, can you reproduce this in any
> other browser?

I tried IE6 and Opera 9 and it seems to work for these without the huge 
delays. The display of the zoom tool get weirded out in Opera, but that 
is probably not related to this problem.

I tried the Click to Algers and zoom out on my Win XP laptop and it 
seems to have the same performance problem. with 78.6% in destroy and 
16.6% in nodeTypeCompare. Oh, and this system is running FF

The only thing common about these two systems is that they both have 
512MB of Memory. I notice that the memory usage in the task manager has 
a very strange usage pattern like a saw-tooth that repeats over and over 
while it is stuck in this state. The pattern follow this:

                - ~328 MB
/ |
   |         /
   |---\     |  - ~100 MB
        \    |
         \  /
          \/    - ~46 MB

And this pattern just keeps repeating about 1-2 secs per interval if I 
recall correctly.


> Regards,

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