[dnsdist] Latency value under showServers()

[bert hubert]

On Mon, Mar 19, 2018 at 02:42:54PM +0000, Nigel H wrote:
>         dnsdist -e "grepq('.')"  | egrep -v '<internal domain>|<another
> internal domain>|arpa'

Best thing you can do is open a ticket asking us to expose grepq via the
API. This would get you this as JSON.

https://github.com/PowerDNS/pdns/issues/new

Thanks!

> 
> 
> Nigel.
> 
> On 19 March 2018 at 11:39, bert hubert <bert.hubert at powerdns.com> wrote:
> 
> > On Mon, Mar 19, 2018 at 11:30:08AM +0000, Nigel H wrote:
> > > I'm seeing a discrepancy when i run showServers() in dnsdist.  Our
> > internal
> > > pool of dns servers appears correct and monitoring shows the odd spike in
> > > latency but our external pool (opendns) seems to just keep increasing in
> > > value.  The documentation states its the latency for this servers in
> > > milliseconds but when I test using dig I'm seeing normal resolution times
> > > 1-8ms mostly but dnsdist reports latency like below (27ms).
> >
> > Hi Nigel,
> >
> > The likely reason for the increase is that opendns has only received 169
> > and
> > 148 queries so far.  This means the weighted average latency still includes
> > a lot of 0.
> >
> > Eventually, you should see the opendns latency plateau.
> >
> > With 'grepq()' you should be able to find the queries being sent to
> > opendns,
> > and how long dnsdist thought they were taking.
> >
> > You could then perhaps retry those queries with 'dig' to see how long they
> > take. 27ms is not unreasonable for mostly cache misses.
> >
> > > Can someone confirm its meaning?  Is it an average latency based an
> > amount
> > > of queries to this server or is it the highest latency seen?  Also does
> > > dnsdist incorporate the latency of the health check?
> >
> > The last part, no. First part, it is average.
> >
> >         Bert
> >