OutOfMemory on weblogic server 2005-01-07 - By Kevin Gaasch
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Well, if it's being kicked off by the scheduler and not an actual
client, then the response time isn't really an issue, so neither is
asynchronous processing.
My guess is that you're still having memory problems. Even though you
may not be maxing out the heap with the new parameters, you could be
thrashing the box. I would watch the memory on the server while the
process is running. If it's Windows, watch the task manager, if it's
linux, use top. If the server is using too much virtual memory, it's
going to be spending too much time swapping pages in and out of the
virtual memory block and not allocating any CPU cycles to actually
processing the data. Plus, the server itself needs a good cushion of
memory just to handle it's own housekeeping.
If it does turn out to still be a memory problem, you should look at
ways to optimize that particular segment of code. Process the data in
small, managable chunks. For example, if the file is in some sort of
record format, process one record at a time. Read one record of data
from the database (or however you're getting it), format it, and write
it to the stream.
Also, re-use your objects as much as possible, so that the garabage
collector is not spending a lot of time and CPU reclaiming memory. And
bump your timeout to some insane value like 30 minutes. That will give
you time to monitor the process and the server to really get an idea of
what's going on. Plus, if you break the processing into chunks, you can
record the time each piece of data takes to process and use that to plan
for future files sizes. If the size of the file gets bigger, you need
to know, so you can predict how long your processing time is. That will
help you indentify a runaway thread.
Kevin E. Gaasch
Panhandle Plains Student Loan Center
Software Craftsman
Senior Programmer/Analyst
Sun Certified Java Programmer
Work: 806.324.4108
Cell: 806.674.1523
>>> sanjeevkoppal@(protected) 1/6/2005 10:55:53 PM >>>
Hi,
Our application is huge and the client side is Swing UI,
We are using JWS to launch the application.
And the backend in sybase.
This is happening in all platforms,
Developement and as well as in Production....
We are using Connection pool
as "David " had pointed out it is infact 'ms' for the first argument in
JAVA_OPTIONS
"-server -ms512m -mx1024m"
How do i monitor how long its taking to write?
We have set the transaction time-out to 240 seconds,after which the
server doesn't repond,
it just throws and exception saying "No response after "240" seconds".
Please let me know how can i run it in a different thread.
We also use Quartz scheduler which is different process,
do you think this would work if we do it on quartz sceduler..
let me know your suggestions and opinions...
regards
Sanjeev
Kevin Gaasch <keving@(protected)> wrote:
I would agree with David on this one. A client request should return
in
a timely manner. Hence, you would want that kind of processing done on
a separate thread.
One other suggestion I have is to set you minimum heap (ms) equal to
your maximum heap. That way the server doesn't have to burn CPU cycles
trying to allocate memory.
You should also consider refactoring the way you're building the file.
I would bet that your memory problems are not caused by the size of
the
file, but how you're creating it. For example, if you build the entire
file as a string in memory, that would eat a significantly larger
amount
of memory than writing the file to the stream in chunks. Remember that
if you're running in a multi-user environment, there will be other
clients trying to use the system. You don't want to "nail the server
to
the wall" for just one process.
As for your timeout problem, you can adjust the timeout length in the
JTA settings on the weblogic console.
Kevin E. Gaasch
Panhandle Plains Student Loan Center
Software Craftsman
Senior Programmer/Analyst
Sun Certified Java Programmer
Work: 806.324.4108
Cell: 806.674.1523
>>> david.karr@(protected) 1/6/2005 11:07:26 AM >>>
Are those the exact arguments you're sending on the command line? I'm
not sure what that would do, as you're specifying "-mx" twice. You
probably meant the first one to be "-ms". In any case, I imagine that
would still set "-mx" to 1024, but that's just a guess.
Are you monitoring how long it really takes to write the data to the
file? Is it really taking on the order of >240 seconds? If so, then
you should probably do that on a separate thread, asynchronously from
the original client request.
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