[dnsdist] dnsdist latency bucket metric still broken in 1.8.0?

[Otto Moerbeek]

On Thu, Apr 13, 2023 at 10:00:25PM +0200, Christoph via dnsdist wrote:

> Remi Gacogne via dnsdist:
> > The fix not being backported is an oversight, I added the "backport to
> > 1.7.x" flag so we include it in an upcoming 1.7.x release.
> 
> Great to hear that this was unexptected.
> 
> > > Recently we upgraded our dnsdist instances to 1.8.0
> > > but the upgrade did not improve the values in dnsdist_latency_bucket.
> > > Now after the upgrade, the graph show basically a flat line.
> > > This only affects our FreeBSD servers, not our Debian based dnsdist
> > > instances.
> > 
> > That's weird. Would you be able to share the prometheus output, or the
> > dumpStats() one, so we know if this is the same bug or a related one?
> 
> I added it here because I wanted to add the graph as well but github upload
> is failing me, so just prometheus:
> https://github.com/PowerDNS/pdns/issues/11239#issuecomment-1507536007

Did you compile dnsdist yourself? If I try to install dnsdist on
13.1-RELEASE-p6 I only get 1.7.3:

# pkg install dnsdist
New packages to be INSTALLED:
	dnsdist: 1.7.3

# pkg install dnsdist-1.8.0

pkg: No packages available to install matching 'dnsdist-1.8.0' have
been found in the repositories

A quick test with a self-compiled 1.8.0 dnsdist shows a non-zero sum
for me, so I'm confused what's goiong on.

prometheus  output after a few queries to a UDP upstream:

# HELP dnsdist_latency Histogram of responses by latency (in milliseconds)
# TYPE dnsdist_latency histogram
dnsdist_latency_bucket{le="1"} 0
dnsdist_latency_bucket{le="10"} 4
dnsdist_latency_bucket{le="50"} 6
dnsdist_latency_bucket{le="100"} 6
dnsdist_latency_bucket{le="1000"} 6
dnsdist_latency_bucket{le="+Inf"} 6
dnsdist_latency_sum 74
dnsdist_latency_count 6

	-Otto