Wavefront query using an OR operator fails to complete when one of the point tags does not exist

Products

• Wavefront by VMware

Issue/Introduction

Symptoms:

• You see an error similar to the following when running a time series query using an OR condition on two point tags where one point tag does not exist:

Tag: [xxx=xxx] does not exist

For example:

ts(disk.free, source=jenkins and fstype=ext* and (device="sda1" or device="sda3") and mode=rw)

Tag: [device=sda3] does not exist|

Where device="sda1" is an existing reported point tag but device="sda3" is not.

Resolution

Use the operator ?= for the point tags that may or may not exist.
For example :
ts(disk.free, source=jenkins, fstype=ext*,mode=rw, device="sda1" or device?="sda3")

Additional Information

The Tag: [xxx=xxx]does not exist message only displays if one point tag does not exist and has never existed. It is not displayed if the point tag existed at one time but is no longer being reported.