Occasional Emails reporting Database Connection Problem

[JohnS]

I am running SMF 2.0.6 with the Crushing Theme.
Occasionally SMF will send me a message saying it is having problems connecting to the database. By occasionally I mean no more than twice a day, some days once and other days not at all for quite long periods. There is no time pattern to the reports they have been generated at all sorts of different times.
I have never had any problem using the site or administering the site. I have had no complaints from any users and all the main users say they have never noticed anything.
We have been checking the server logs to see if there are any matching error reports in the logs and there is nothing in the MySQL or other server logs that we can find that matches this problem.
There should be no problems with access as the MySQL system allows more than twice the number of simultaneous connections as have ever been logged, the server has 16 processors and is not heavily loaded, disk space is more than adequate.
It has both me and the server admin baffled.
Has there ever been anything like this, could it be the SMF code sending out false reports? Or something other than database failure causing the sending out these reports.
Can you point me to where these reports are generated and is there anyway of logging what is happening when they are generated. There is certainly nothing in the logs I have looked at and I have looked at all of the ones I could find.
Any help to solve the mystery would be greatly appreciated.

[Kindred]

No, they are not false reports. There are conditions in which the software tries to connect to the database and can't... At which point, it sends the message.
If you're getting it twice a day, i would not worry too much... Just be aware that something is causing a condition which results in a failed connection (even if the connection completes in the very next query)

[JohnS]

Thanks. I will have to keep looking and see if I can find out why.

[kat]

Might be best to have a word with your host, with this one.

[JohnS]

I have been talking to them and they have been very helpful in trying to resolve this, but there is nothing to go on. The only thing we have managed to tie down is that on one occasion when the warning e-mail was issued there was a connection made to the database which was timed out because there was no transaction.
Feb 23 17:59:42 Killed MySQL Query ID: 651844, Query user: cumbxxxx_smf1, Query time: 18, Query cmd: Sleep
In all other cases there was nothing in the MySQL logs that corresponded with the issue of the warning email.
There is nothing in any log in SMF that gives any indication of anything untoward at the same time.
At first it was happening in the night around the same time as the databases were being backed up and we put it down to the database being locked for backup, but recently it has been occurring during the day when no backups are taking place.
If I knew which module issues the warning maybe I could put in some logging code to give me some more information as to what caused it as the mail sent is just generic.
As it stands the host has the database on monitor to try and track down what happens, if and when it happens again, but with something that can go away for several days this is tricky.

[kat]

Unless it happens a lot, I wouldn't worry about it, much. I'm sure most of us get those mails, occasionally.