[ka-Map-users] Re: kaMap - resource hogger?

[ramesh karra]

Thanks for the quick and detailed reply paul!

I suspected memory leak/garbage collection as the
issue but I was not sure if this the case with kaMap
or AJAX in general. 

Are there any tools(like DOM Inspector) available to
see what objects are currently (allocated) in the
memory? 

I am using firefox and not IE. Next time, I will keep
an eye on the amount of memory in use by firefox.

My map data is relatively small and is static. So, I
do not expect the mapserver/kaMap to create tiles
again and again.

Thanks again,
Ramesh



--- Paul Spencer <pspencer at dmsolutions.ca> wrote:

> Ramesh,
> 
> there is a general problem with ajax applications
> that involves how  
> browsers garbage collection memory.  It is possible,
> and in fact very  
> easy, to set up situations where the browser is
> unable to release  
> memory of objects that have no references to them. 
> This is generally  
> called a memory leak.  It is highly likely that
> ka-Map has such  
> memory leaks because I don't really understand how
> to avoid them.   
> AJAX-related leaks are much worse in IE than
> firefox, so if you are  
> running IE and ka-Map then when your system becomes
> slow, check your  
> task manager to see how much memory the IE process
> is using.
> 
> There is no way that I know of to detect/eliminate
> leaks other than  
> to manually inspect the code and try to figure out
> where the leaks  
> are happening.  Due to the nature of how leaks
> happen (closures etc),  
> this is a very difficult task.  While I do try to
> resolve leaks as  
> best as possible, it is quite likely that they are
> still in there.
> 
> The second issue that I will bring up is that
> MapServer doesn't  
> perform that well on my laptop, mostly because
> laptops have  
> harddrives with low RPMs compared to desktop/server
> systems and  
> rendering maps (at least for mapserver) is a
> disk-intensive process  
> (reading spatial data for a large image, writing the
> resulting image  
> to the disk, then reading it again to produce
> tiles), and even when  
> tiles are generated, they have to be read off disk.
> 
> The third issue is that running the client and
> server on the same  
> machine tends to produce resource competition.  Your
> machine is a  
> single processor and it can only do one thing at a
> time.
> 
> But mostly I suspect memory leaks if it is impacting
> other  
> applications :)
> 
> Cheers
> 
> Paul
> 
> On 27-Apr-06, at 1:53 AM, ramesh karra wrote:
> 
> > Hi,
> >
> > I have installed mapserver and kaMap on my
> laptop(IBM
> > T42 with Intel pentium 1.7GHz and 512MB RAM) after
> > loading my map and using it for some time, the
> system
> > becomes very slow(especially Microsoft Outlook).
> When
> > I closed my browser, system recovered and the
> Outlook
> > was back to normal.
> >
> > I am assuming this is related to kaMap and not
> > mapserver because mapserver is running all the
> time,
> > even when the browser is closed. Ofcourse, it
> still
> > possible that the mapserver is hogging resources
> when
> > kaMap is active and not when it is gone.
> >
> > Are there any known resource hogging issues with
> kaMap
> > or  mapserver?
> >
> > Thanks
> > Ramesh
> >
> > __________________________________________________
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>
+-----------------------------------------------------------------+
> |Paul Spencer                          
> pspencer at dmsolutions.ca   |
>
+-----------------------------------------------------------------+
> |Applications & Software Development                
>              |
> |DM Solutions Group Inc                
> http://www.dmsolutions.ca/|
>
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> 
> 
> 
> 
> 


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