MySQL Bugs: #39757: Wrong RAM usage warning when more than 4GB memory is available

Bug #39757	Wrong RAM usage warning when more than 4GB memory is available
Submitted:	30 Sep 2008 14:35	Modified:	21 Jul 2009 9:49
Reporter:	Kay Roepke	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Enterprise Monitor: Agent	Severity:	S3 (Non-critical)
Version:	2.0.0.7092	OS:	MacOS (10.5)
Assigned to:	Kay Roepke	CPU Architecture:	Any
Tags:	kay_merlin_immediate, sigar

Description:
When a server has more than 4GB RAM available it still triggers the memory advisor, due to an overflowing value somewhere.

How to repeat:
Run the agent on a server that has just more than 4 GB of free memory. It should trigger the advisor giving you a wrong value for the available system memory.

Suggested fix:
Unsure where the actual problem is, the sigar code looks correct, as does the agent code.
Further investigation necessary.

QA: please reproduce on another system with > 4 GB RAM

the 2 rules that checks RAM show correct values on 'blade09', an Ubuntu 6.10 with 10G RAM:
- "RAM Usage Excessive" does not fire
- "Key Buffer Size May Not Be Optimal For System RAM" fires (OK, only 0.16 % used for the buffer ...)

Only problem at the moment is, that for the "Key buffer ..." one I do not receive any mails although the Notification log says the mails are sent. But that's a different problem ...

the RAM graph for this Ubuntu system shows "free" values around ~ 6GB, which fits to the value grabbed from the success check of the "RAM Usage Excessive" rule:

Evaluated Expression
(6427361280 / 1024 / 1024) < 300

I'm not sure whether we need to 'generate' a value just few above 4G to get this problem?

Can anyone reproduce this? As of 2008-11-11, we cannot...

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

This still shows up, but is a bit tricky to reproduce.

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

waiting for build

Patch installed in versions => 2.1.0.1056.

An entry was added to the 2.1.0 changelog:

On Mac OS X when a server had more than 4GB RAM available the memory advisor was still triggered. This appeared to be due to an overflowing value.