Re: frustrating memory anomaly

On Apr 9, 2005, at 7:24 am, Anthony Brian Arthur wrote:

> Hi,
>
> Configuration:
>
> OS - OS X server 10.3.8
> CPU - dual 1.8
> RAM - 3 gig
> WO - 5.2 or greater
>
> I have an app that fails in deployment (becoming unavailable in the 
> middle of a transaction) that does not fail while testing the same 
> scenario in development.  This happens while downloading a rather 
> large data set to a file.  The deployed memory settings are -Xms256m 
> -Xmx1800m.  Now, even though this is a large data set, it is virtually 
> impossible for it to be greater than 1.8 gig.  This is a raw row fetch 
> from 1 table, no joins.  Meanwhile the whole database in an oracle 
> dump is only 2.16 gig.
>
Hi Brian,

Does the app crash in the middle of the transaction or does the 
connection fail?  If you're running out of memory, I would expect to 
see a OOM exception in the logs.  Are you seeing that?  I ask because 
it sounds like you might be timing out in deployment (because the 
machine is not local to you, the download takes longer).

Try tweaking the connection timeout param in JavaMon.


>   So my question is, how do I know for sure that Monitor is really 
> claiming the specified java heap settings?  I can see it in the 
> 'current settings' block on the configuration page, but I am skeptical 
> for the reason I already outlined.  Any suggestions?

I'm not aware of any way to test the maximum heap size from within Java 
(or from outside Java, for that matter...).  I personally have used the 
-Xmx setting (though not with a 1800 MB maximum!  :-) with success.


sacha


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