MySQL Bugs: #34188: Core advisors can be altered, but this prevents monitoring from working properly

Bug #34188	Core advisors can be altered, but this prevents monitoring from working properly
Submitted:	31 Jan 2008 8:03	Modified:	8 Dec 2008 21:12
Reporter:	Valeriy Kravchuk	Email Updates:
Status:	Not a Bug	Impact on me:	None
Category:	MySQL Enterprise Monitor: Advisors/Rules	Severity:	S3 (Non-critical)
Version:	1.x, 2.x	OS:	Any
Assigned to:	Sloan Childers	CPU Architecture:	Any

Description:
When one customizes "MySQL Agent Not Reachable" and "MySQL Server Not Reachable" advisors so that this rule is added:

"&& CURTIME() NOT BETWEEN '02:00:00' AND '05:30:00'" 

to the expression, all agents becomes "overwritten" on a Dashboard.

How to repeat:
Try to add

"&& CURTIME() NOT BETWEEN '02:00:00' AND '05:30:00'" 

to the "MySQL Agent Not Reachable" and "MySQL Server Not Reachable" advisors. Observe the misleading results on a dashboard.

Suggested fix:
We shouldn't allow users to modify "core" advisors if those are so important that they must be left alone.

Will consider preventing user from making a change like this that has unexpected, negative consequences.

I don't think we should deny editing these special rules.  The real problem is that unscheduling the agent_not_reachable (0f8ed31d-2655-4848-af39-9069a5076653) and/or the agent_not_communicating_with_mysqld (f6801cf3-a3f9-4eea-88b5-9639b0659e7c) rules and replacing them with customized rules breaks random status display indicators in the user interface.

We could either ask the RuleContainer at the JSP layer whether or not a rule is unschedulable and gray out the appropriate controls OR I suppose the server back end could deny the request and throw an exception for these two special rules.

This scenario works in 2.0 if you changing the expression as follows:

(CURTIME() NOT BETWEEN '02:00:00' AND '05:30:00' && %agent.reachable% = THRESHOLD)

You *must* also add a string "" for the warning threshold or the evaluation fails.

This scenario works in 1.3.3 if you changing the expression as follows:

(CURTIME() NOT BETWEEN '02:00:00' AND '05:30:00' && %agent.reachable% = THRESHOLD)

If we also see customer issues with these rules just being unscheduled, please open a bug/feature that is specific to that problem.