Installation Error - Java and performance question

g Greg

on October 26, 2010

Hi,

I have installed to a Windoes Server 2003 SP2 32bit. When executing client.bat, I get the message "Could not create Java virtual machine". I have reviewed other posts and replies. I ran the check_java.bat file and got the following

java version "1.6.0_20"
Java(TM) SE Runtime Environment (build 1.6.0_20-b02)
Java HotSpot(TM) Client VM (build 16.3-b01, mixed mode, sharing)

If you see java version "1.5" or above then your Java
version is compatible with the OpenCDISC Validator.

If not, you will need to upgrade your Java Runtime Environment (JRE).
For instructions, please visit http://www.opencdisc.org/download

I ran the debug_client and got the following.

Error occurred during initialization of VM
Could not reserve enough space for object heap
Could not create the Java virtual machine.

I can get the application to launch if I modify the client.bat

From this

START /B javaw -XX:+HeapDumpOnOutOfMemoryError -Xms256m -Xmx1024m -jar lib/validator-gui-1.1.jar

to this

START /B javaw -XX:+HeapDumpOnOutOfMemoryError -Xms128m -Xmx512m -jar lib/validator-gui-1.1.jar

Just reducing the -Xms and -Xmx parameters

My questions:

How does reducing these parameters affect validator performance?

On a server with 12GB ram and Java version of 1.6, should I expect the default client .bat with -Xms256m -Xmx1024m to work.

Forums: Troubleshooting and Problems

t Tim

on December 20, 2010

RE: Installation Error - Java and performance question

Hi,

Given that those parameters control the amount of memory available to the Validator, it's possible for them to negatively impact performance in instances where the data being processed requires a lot to be retained in-memory.

For small studies this is generally a non-issue, but in the case of large studies where datasets that are looked up against as part of cross-dataset validations are quite big, there can be problems. Typically the Validator will just give up, and throw an OutOfMemoryException to tell you that the program cannot continue without more memory available to it. However, in other cases it's possible for the Validator to enter a sort of "snails pace" state, where it will continue validating, but the exchange required to free up memory after each new record is processed makes the whole session take many, many hours.

We're working on finding a way to automatically address that second issue, though if you're monitoring the process using the desktop client you can typically tell when it's entered this state by judging how fast the progress meter is going.

In any case, those parameters should work fine when running on a server of that size, as at most the Validator will use 1/12 of your available RAM. If the server has a lot of other processes running on it, however, it's possible that they use up your memory to the point where it's not possible to allocate the default amount to the Validator.

Regards,
Tim