Is there a way to manipulate the jdbc_response probe's memory usage

Products

• DX Unified Infrastructure Management (Nimsoft / UIM)

Issue/Introduction

It seems that the jdbc_response probe is using a lot of virtual memory. Is there a way that I can control the amount of memory that is used by the probe?

Environment

Release : 20.4
Component : UIM JDBC RESPONSE

Resolution

The probe, by default, allocates virtual memory in Linux based on the JVM default settings, which can result in a large amount of VIRT space being used.

Strictly speaking, this does not mean the probe is actually using this much memory - it can be thought of as memory the probe has indicated that it "might" or "wants to" use.   It is allocated only in virtual address space; it does not actually use disk space or memory space on the system.

The probe generally uses memory based on the number of profiles that are currently in use, so care should be taken with these setting, but you can partially control the memory usage with the following settings:

1. Raw configure the probe in IM or AC.
2. Create a new section called 'startup' at the root
3. Create a new section called 'opt' under startup
4. Create a new key/value pair under opt like:

name = java_mem_max 
value = -Xmx4g

name = java_mem_init 
value = -Xms2g

5. Save the options

Note:  This will reduce the amount of VIRT memory used by the probe, but it will not be a 1:1 correlation, for example if you set the java_mem_max to 512mb you may still see 2G of VIRT space used.   Again, this is not actually something to be concerned about and the above settings are given only as a guide -- in the vast majority of cases we would recommend to leave this alone.

Additional Information

https://www.linuxquestions.org/questions/linux-kernel-70/virt-memory-jumps-by-64m-900398/

https://stackoverflow.com/questions/561245/virtual-memory-usage-from-java-under-linux-too-much-memory-used