MySQL Bugs: #30969: Advisort for Query Cache is alerting whole the time

Bug #30969	Advisort for Query Cache is alerting whole the time
Submitted:	12 Sep 2007 9:43	Modified:	1 Aug 2008 15:16
Reporter:	Oli Sennhauser	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Enterprise Monitor: Advisors/Rules	Severity:	S3 (Non-critical)
Version:	1.1.1	OS:	Any
Assigned to:	Andy Bang	CPU Architecture:	Any

Description:
advisor for query_cache...
threshold ist set to alert for 75%
query cache makes a query about 15% slower
as soon as I have a ratio bigger than 1 : 1 (hits to insert) it should be fine
which is 50%
last customer we had often short below 75% and it was alerting whole the time.
so I think the threasholds are not too god!

How to repeat:
dito

Suggested fix:
info: >> 1 : 1 is fine
warning around 1 : 1 can be not fine (+/- 10%?)
alert  << 1 : 1 can be bad.

Based on Oli's input and in consultation with Support (Mark Leith), we're changing the thresholds from:

    info: 95, warn: 85, crit: 75

to:

    info: 60, warn: 50, crit: 40

Committed revision 9122.

Verified new thresholds in advisor build 1.3.0.9137.

Moved to 'Documenting' so MC can make the appropriate notes in the 1.3 docs (if any), reminding him that he should move them back to 'Verified' with a target of 2.0.

Setting to "verified" and "target" 2.0 as requested.

Also added an entry to the 1.3 changelog:

The alert thresholds for the Query Cache Advisor were changed: 

     Information  Warning  Critical  
From      95        85        75  
To        60        50        40

This was fixed in 2.0 at the same time it was fixed in 1.3, so please re-test with the latest 2.0 stuff.

Verified new thresholds in advisor build 2.0.0.7017.

Changelog updated to include note that #30969 is now fixed in 2.0.