MySQL Bugs: #6090: Invalid Floating Point operation

Bug #6090	Invalid Floating Point operation
Submitted:	14 Oct 2004 11:13	Modified:	10 Oct 2005 8:13
Reporter:	Andras Fabian	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Administrator	Severity:	S3 (Non-critical)
Version:	1.0.13	OS:	Windows (Windows 2000)
Assigned to:	Mike Lischke	CPU Architecture:	Any

Description:
Recently we had to switch off the query cache on our MySQL Server for some tests. The we wanted to see the behavior of our servers, but immediatly after switching to the "Health" view, the message "invalid floating point operation" popped up (and after closing, it allways comes back after a second or so). This has to do witch some invalid handling from a 0 value (or something like this) when the query_cache_type was set to 0 (i.e.: OFF). I'm sure, that this is the cause, because before this setting (and this was the only parameter we changed) everything worked fine.

How to repeat:
Set "query_cache_type = 0" for a database and the go to the "Health" View in the MySQL Administrator.

Suggested fix:
Well, no  "invalid floating point operation" should occure. Maybe it can be fixed by changing the formule of the "query cache hit" ? 
Please fix this ASAP because now the MySQL Administrator is unusable !!! (and we need it for monitoring)

Ok. A colleague just showed me, that his "MySQL Administrator" is working correctly. The we crosschecked out "Healt" graphs, and I found the culprit. I added a Graph which has as "value formula": Qcache_free_memory, "Max. formula" :query_cache_size and "value unit" : count. After removing this graph (I used another connection, where there was a Qcache set - so no floating point error) everything works fine again. Nevertheless, a better error handling would be good in this situatin, because the popping "invalid floating point opeartion" window is really annoying.

Hi,

Thank you for the report, but I wasn't able to repeat it.
Could you provide set of actions that cause this error?

OK. I just tried to reproduce it again, and it "worked".
1. You need a MySQL-DB which has the settin "query_cache_type=0" (i.e. : OFF)
2. Then connect to this DB via MySQL Administrator
3. Go to "Health" view.
4. Then (for example under "Memory Health") add a new Graph (right click, "add graph").
   a. set "Value Formula" = [Qcache_free_memory]
   b. set "Max. Formula" = [query_cache_size]
   c. set "Value Unit" = [Count]
   d. "Apply"
5. Now the error should pop up (at least me, it did immediatly).

I hope this helps.

Andras

Additional info:
To reproduce this error query_cache_size should be set to 0 or disabled.
If query_cache_size has value > 0  , it works fine whether query_cache_type value is 0 or not.

Thank you for your bug report. This issue has been committed to our
source repository of that product and will be incorporated into the
next release.

If necessary, you can access the source repository and build the latest
available version, including the bugfix, yourself. More information 
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