[Pdns-users] PowerDNS authoritative server random timeouts
Netsons - Federico Chiacchiaretta
f.chiacchiaretta at netsons.com
Wed Oct 2 23:15:41 UTC 2019
I excluded network issues for a while, so I focused my analysis
Simply running a 'show processlist' during one of the random timeouts
brought me to the solution: I found a lot of queries in state 'Waiting
for query cache lock', so I completely disabled query_cache in MySQL
I made the change on Sep 19th, and never had a timeout since then.
I hope this can be useful for anyone experiencing the same issue.
Netsons S.r.l. - https://www.netsons.com
On Thu, 2019-09-26 at 07:23 +0200, Klaus Darilion wrote:
> I think, first you should find out if there is a problem with
> or the network - or inbetween.
> If this happens regularly, just use tcpdump to caputre all DNS
> to a file (rotate files, keep only X files and choose X to not fill
> complete hard disk).
> Or even simpler - just capture with tcpdump the loopback traffic
> own check script) with -i lo.
> Make sure you really see the requests to PDNS, but no answers. Of
> there are answers, but much too late.
> The problem may be that PDNS reads fromt he socket to sloow. Then
> socket fills up and you have packet loss (tools like netstat can
> Also monitor the PDNS statistics. Ie read:
> Then watch the number of outstanding queries, maybe send them every
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