While building another stored procedure that I execute by check_mssql in Nagios, I noticed a little hiccup.  My stored procedure was returning a value like "85.67".  When I executed the check_sql on the command line to run the procedure, I got a strange error...

# ./check_mssql -H mssqlclus1 -U username -P password -p 1433 -D database -w 20 -c 35 \
> -q "exec database.dbo.sp_GetDatabaseFileMetrics database,Used,Log,1" -W 90.00 -C 95.00 -s
CHECK_MSSQL CRITICAL - Result is not numeric with result threshold defined (0.089992 seconds) \
| time=0.089992s;20;35

Now that does not make sense at all.  I removed the -W and -C constraints and got:

CHECK_MSSQL OK - SQL Server result: 98.10 (0.122316 seconds) | time=0.122316s;20;35

I do not know about you, but "98.10" looks like a numeric to me.  So I opened up the perl for the check_mssql and looked for the conditions that triggered the error.  This was the regular expression it was evaluating to determine if the value returned was a numeric instead of a string.

$result =~ /^[-+]?\d+$/

Well, that does not do the trick if I have a value like "98.10".  A value of "98" would have been fine.  I freely admit I am no "code guru" by any means, but I figured I shoudl be able to come up with a fix for this.  I copied the stored procedure to 'check_mssql2' and went to work.  I created an OR condition to look for the integer regular expression or a decimal regular expression.  There may be a better way, but this worked for me.  I changed this:

!($result =~ /^[-+]?\d+$/)) {

to this:

!(($result =~ /^[-+]?\d+$/) || ($result =~ /^[-+]?\d+\.\d+$/))) {

I ran my tests and it worked great!  A really useful link I found was this Regular Expression Validator at http://www.sweeting.org/mark/html/revalid.php.  It also has some very handy reference info on the bottom which I found useful since I do not have the pleasure of writing them on a daily basis.