[Pdns-users] Error when querying a domain on PDNS authoritative for first time

[Thomas]

Hello.

In effect the pdns was idle all night, as we test only during office 
time ;-)
MySQL is local on the machine were pdns resides. MySQL 'wait_timeout' is 
28800 seconds, 8 hours, so it is very likely it timed out during the night.

Once it will be in service I think it has work enough to do to not go in 
timeout.

Thanks,
Thomas

Am 29.09.2021 um 11:08 schrieb Pieter Lexis via Pdns-users:
> Hi Thomas,
>
> On 9/29/21 10:46, Thomas via Pdns-users wrote:
>> Hello.
>>
>> We are testing pdns and would like to migrate to it in few days. Now I
>> have seen errors showing up in the pdns logs when I first query a domain
>> and (I presume) this domain is not in cache of pdns.
>>
>> Error ist the following:
>>
>> Backend reported permanent error which prevented lookup (GSQLBackend
>> unable to lookup 'limitis.com|ANY':Could not prepare statement: SELECT
>> content,ttl,prio,type,domain_id,disabled,name,auth FROM records WHERE
>> disabled=0 and name=? and domain_id=?: MySQL server has gone away),
>> aborting
> "MySQL server has gone away" means that the connection to the database
> was interrupted or closed. PowerDNS uses separate connections for TCP
> and UDP queries that come in. It might be that your server gets so few
> queries that MySQL terminates the idle connection(s).
>
> You could try increasing the wait_timeout and maybe connect_timeout as well.
>
> If the database is running on another machine or VM, I suggest you check
> the network-path is this keeps happening.
>
>> I activated general_log in MariaDB but do no see any error when this
>> statements are executed or in the error_log:
>>
>> 210929 10:25:57     14 Connect  pdns at localhost as anonymous on pdns
>>                      14 Query    SET SESSION TRANSACTION ISOLATION LEVEL
>> READ COMMITTED
>>                      14 Prepare  SELECT
>> content,ttl,prio,type,domain_id,disabled,name,auth FROM records WHERE
>> disabled=0 and name=? and domain_id=?
>>                      14 Execute  SELECT
>> content,ttl,prio,type,domain_id,disabled,name,auth FROM records WHERE
>> disabled=0 and name='testdomain.eu' and domain_id=18787
>>                      14 Reset stmt
>>                      14 Prepare  select kind,content from domains,
>> domainmetadata where domainmetadata.domain_id=domains.id and name=?
>>                      14 Execute  select kind,content from domains,
>> domainmetadata where domainmetadata.domain_id=domains.id and
>> name='testdomain.eu'
>>                      14 Reset stmt
> This looks good!
>
>> After restaring pdns the errors have gone away, but seems strange to me.
>> Where could this errors come from? MySQL connection timeouts maybe? But
>> timeouts would result in the logs of mysql I'd asume.
> I know too little of MySQL to know if it logs when it terminates a
> connection due to inactivity.
>
> Cheers,
>
> Pieter