[Pdns-users] SLAVE refresh performance

Peter van Dijk peter.van.dijk at netherlabs.nl
Mon Sep 12 20:22:52 UTC 2011

On Sep 12, 2011, at 4:17 PM, Klaus Darilion wrote:

> Am 12.09.2011 15:37, schrieb Peter van Dijk:
>> All queries to the 'records' table (for SOA and for other resource
>> types) are eligible for the query cache.
> Obviously not all. For example if I trigger NOTIFYs from the master, I
> see multiple SOA lookups in the DB, although DNS-SOA queries to the
> slave will be answered without DB-queries directly from cache.

You are correct. I missed one code path when checking. My apologies. Indeed, SOA queries for checking slave freshness do not use any cache inside PowerDNS.

>>> I have set query-cache-ttl=100 and slave-cycle-interval=60. When the
> "slave-admin" queries would be cached as well, then I should see queries
> only every 2 minutes. But I still see the 10 000 SOA DB-queries every
> minute. Thus, it seems that "management" DB-queries are not affected by
> the query-cache.

Thank you for testing. This confirms that the SOA queries you are seeing are from within the database backend.

Kind regards,
Peter van Dijk

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