[Pdns-users] powerdns authoritative 4.0.0 alpha stops working from time to time

[Radosław Piliszek]

Hello,

I am having the same problem using PowerDNS Authoritative Server
4.0.0-alpha2 from CentOS 7 repository and the MySQL backend.

I enabled the highest level of logging (9).

And here are the results...

First failed queries (e.g. three times for three connections to the backend):

Remote 127.0.0.1 wants '...', do = 0, bufsize = 512: packetcache MISS
Query: SELECT content,ttl,prio,type,domain_id,disabled,name,auth FROM
records WHERE disabled=0 and type=? and name=?
Backend reported condition which prevented lookup (GSQLBackend lookup
query: Could not execute mysql statement: SELECT
content,ttl,prio,type,domain_id,disabled,name,auth FROM records WHERE
disabled=0 and type=? and name=?: Lost connection to MySQL server
during query) sending out servfail

All following queries:

Remote 127.0.0.1 wants '...', do = 0, bufsize = 512: packetcache MISS
Backend reported condition which prevented lookup (GSQLBackend lookup
query: Attempt to bind more parameters than query has: SELECT
content,ttl,prio,type,domain_id,disabled,name,auth FROM records WHERE
disabled=0 and type=? and name=?) sending out servfail

There are no other log messages in between these.

After the connection is lost, the "Attempt to bind more parameters
than query has" (as already mentioned here) appears until the PowerDNS
server is restarted...

Also, in my setup the connection is lost due to timeout because in
this test environment queries appear very rarely. I think PowerDNS
should handle timeouted sessions more gracefully like trying to
restart the connection instead of failing the DNS request...

In summary, two problems:
1) Connection to backend lost = queries stuck on error.
2) Session timeouts are not handled gracefully.

Kind regards,
Radosław Piliszek

> On 26 Feb 2016, at 15:18, Pieter Lexis <pieter.lexis at powerdns.com> wrote:
>
> Hi Peter,
>
> On Fri, 26 Feb 2016 14:49:16 +0200
> Keresztes Péter-Zoltán <zozo at z0z0.tk> wrote:
>
>> I have installed the new 4.0 version of the pdns. It works great however from time to time it suddenly stops working. In the logs I see lots of these:
>
> By "stops working", do you mean that the process dies or it just stops responding or it only sends out SERVFAILs?
>
>> Feb 26 07:42:34 dns1 pdns[6514]: Backend reported condition which prevented lookup (GSQLBackend lookup query: Attempt to bind more parameters than query has: SELECT content,ttl,prio,type,domain_id,disabled,name,auth FROM records WHERE disabled=0 and type=? and name=?) sending out servfail
>
> This is the `basic-query`, interesting that it gives this error, as we never bind more than 2 elements in the code.
>
> If your server is not stressed for resources could you set `query-logging=yes` in the pdns.conf (with possibly `loglevel=7` as well if no queries show up in syslog) to identify the query that causes this and share the results with us?
>
> Secondly, could you share your pdns.conf (without passwords)?
>
> Best regards,
>
> Pieter
>
> --
> Pieter Lexis
> PowerDNS.COM BV -- https://www.powerdns.com
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