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

[Thomas]

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

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

If I execute the query "SELECT 
content,ttl,prio,type,domain_id,disabled,name,auth FROM records WHERE 
disabled=0 and name='testdomain.eu' and domain_id=18787" there are no 
errors.

PDNS is pdns-4.5.1-1pdns.el8.x86_64
MariaDB is MariaDB-server-10.4.21-1.el8.x86_64
Rocky Linux release 8.4 (Green Obsidian)

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.

Greetings,
Thomas