Re: question marks ('?') in snmptable output
One problem we have with this bug is it is very difficult to reproduce;
I am trying to create some samples which will simulate the failure.
The indexes are accessible.
Thanks for the clarification on what a 'gap' or '?' might be; it will
help me in creating the samples :)
The current hypothesis is we have a buffer overrun, and its messing with
the secondary index.
Dave Shield wrote:[color=blue]
> On 31/08/06, Mike Varley <email@example.com> wrote:
>> Don't you hate it when people withhold information? :)[/color]
> a) You might say that - I couldn't possibly comment
> b) You get used to it after two or three years on the list :-(
>> So here is a more accurate sample of the output:
>> id(index1) num(index2) ipaddress someotherinfo
>> 095 2 192.168.24.253 klm
>> DE8 ? 192.168.21.34 ?[/color]
> Hmmm.... so the '?' appears in one of the index columns as well.
> Are these indexes accessible or not?
> If they are, then the original analysis probably still stands.
> If not, then I'd need to have another look at the code (which is
> unlikely to be before the weekend, I'm afraid).
>> So, as you can see, our secondary index is one of those 'gaps' -- we did
>> a test to see what happens if you perform a GETNEXT and provide
>> (a) just the 1st index (index1), or
>> (b) a secondary index (index1.index2) that is valid but non-existant,[/color]
> No - that's not quite what I meant. Sorry, I wasn't clear enough.
> Try a single GETNEXT request, containing two (valid) OIDs from the
> previous row of the table - one referring to the instance immediately
> above one of the '?'s and one referring to the instance immediately
> above a valid value in that row.
> What do the results of that GETNEXT look like? In particular, do
> the instance subidentifiers of the two OIDs returned match each other?
> Normally, a GETNEXT of two instances should walk through the table in
> step with each other - returning matching instance subidentifiers each
> time. The '?'-style output would normally arise if these two got out
> of sync.
>> By 'gaps' do you mean the MIB code is replying with NULL? Or just an
>> incosistant value?[/color]
> No - they'd be perfectly reasonable values returned. Just not
> referring to the same row.
> For example:
> GETNEXT myCol myLoc
> RESPONSE myCol.1 myLoc.1
> GETNEXT myCol.1 myLoc.1
> RESPONSE myCol.2 myLoc.2
> GETNEXT myCol.2 myLoc.2
> RESPONSE myCol.3 myLoc.5
> That last response would result in a '?' being displayed for the
> "myLoc" column in row #3. OK?
> PS: I may not respond for a couple of days - away visiting friends.
> I'll pick up on any unfinished business when I get back.
Mike Varley -= SOMA Networks =-
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