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

Paul Spencer pspencer at dmsolutions.ca
Thu Apr 27 06:36:26 EDT 2006


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 :)



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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