[Pdns-users] SLAVE refresh performance

[Peter van Dijk]

Hello Klaus,

On Sep 12, 2011, at 12:40 PM, Klaus Darilion wrote:

> Am 09.09.2011 19:40, schrieb bert hubert:
>> 
>> Can you try 'query-cache-ttl=200' and see if this improves things? If it
>> does, it would help us solve the issue.
> 
> Which DB-queries will be cached by PDNS? Only DNS-query related
> DB-queries, or all DB-queries (e.g. slave-cycle-interval triggered queries)?

All queries to the 'records' table (for SOA and for other resource types) are eligible for the query cache.

> And what happens if the SLAVE updates the DB due to an incoming AXFR.
> Will it also expire relevant cache entries?

As far as I know, the TTL (which Bert suggests to set to 200) is the only thing managing expiry. So, no, there would be no automatic expiry on a slave domain update. However, we're not suggesting query-cache-ttl as a fix; we are wondering whether changing it like that would make a difference in your observed performance, just as a debugging aid.

Kind regards,
Peter van Dijk