Dashboard Metric Expression Calculation Issue

[CommunityUser]

Hi folks

We have AppD running for some services we are monitoring, and I have noticed that on the metric expression calculation, if one of the values I am calculating against is "no data found" the calculation fails completely.

My question is this: Is there a way that we can configure the metric to show a zero where no data is found instead of "no data found"?

Thanks

James

[Nawaz_Ali_Moha1]

To overcome this issue, we need to set the com.appdynamics.metric.query.metricexpressions.tolerateNull flag to true in ControllerFlagServlet. If you are using a SaaS controller please reach out to AppDynamics support to enable this flag.

If you are using On-Prem Controller follow the below steps to enable the flag:

1. Login to <controllerURL>/controller/

2. Use root@system and controller root password for login

3. Look for metricexpressions.tolerateNull field and set it to ‘true’

4. Hit Submit button.

[CommunityUser]

Hi Rajesh,

I'm having a similar issue where a value is returning null and by using it as part of a metric expression, it nulls the whole metric expression.

I also tried to build a pie chart that uses {calls}-{slow}-{verySlow}-{stalls} to equate the successful BTs, if any of the values return "--" the pie chart does not display correctly.

Any help would be greatly appreciated.

Cheers,

Scott.

[Jeanie_Kedia1]

Hi @Anonymous, 

There doesn't seem to be a true and guaranteed solution/fix to this problem at the moment. Thanks for bringing it out our attention. 

Community members may make suggestions (similar to the one Rajesh made above) it's worth a try but not a solution as such. So, I hope other community members can share their experience and offer something of value to help you and others out with this issue.

[CommunityUser]

Hi there .. is there a fix to this issue at least in current versions? 

Thx

[chidex]

This fix doesn't work. I have applied it on 4.5.14 controller and it didn't work

[iamryan]

Hi @Chidi.uchegbu,

This post is from a while back. Our latest Saas Controller is now on 20.6.0 as of earlier this month. Are you able/willing to upgrade to that version and see if this helps fix the issue? 

[chidex]

Hi Ryan,

I am just testing this on   AppDynamics Controller build 20.6.0-2248 but the behaviour is erratic.

I saw it working when one metric value was null but on restarting the controller it stopped working.

[iamryan]

Hi @Chidi.uchegbu,

Thanks for giving that a try. If this seems like a bug, I would suggest reaching out to AppD Support by going to https://www.appdynamics.com/support

If you do contact support please do share any information that could help this thread out. 

[Rajesh_Putta]

Hi James,

Before i answer your question, i would like to give you some technical information and then that explains your question

We have an option to zero fill metric values when there is no data reported for that metric. As you mentioned that the metric which you are using in metric expression calculation  to plot on dashboard has some times no data reported and in those cases, you see calculation failures.

To avoid it, you could give a try of this option to fill the no data values with zero when that metric doesn't get any values reported.

Steps for making those changes

1) Take a backup of domain.xml file located under <controller-install-dir>/appserver/glassfish/domains/domain1/config/

2) Stop controller appserver as shown here

Navigate to <controller-install-dir>/bin

For windows

controller.bat stop-appserver

For Linux

./controller.sh stop-appserver

3) Please ensure that appserver is stopped using ps -ef |grep "java"

4) Once controller appserver is stopped, go to domain.xml file located under <controller-install-dir>/appserver/glassfish/domains/domain1/config/

add 

<jvm-options>-Ddisable.zero.fill=false</jvm-options>

along with other JVM options

5) Restart controller appserver as shown here

For windows

controller.bat start-appserver

For Linux

./controller.sh start-appserver

Wait for 10-15 mins for appserver to start and then check the behavior. You expect to see zero filled values for no data reported for metrics.

Thanks

Rajesh

[CommunityUser]

Hi Rajesh

Thank's so much for this information. We will carry out the steps you provided during an out of hours window and hopefully tomorrow I will be able to post with my results.

Thanks

James

[Rajesh_Putta]

Thanks James. Before you apply this change, could you please cross check whether that  particular metric is filled with zero values or not when there is no data reported. You could check those values of that metric from metric browser.

If this is not filled with zero when there is no data reported for that metric, please go ahead and apply the recommendations as mentioned earlier.

Thanks

Rajesh