[Pdns-users] SLAVE refresh performance

Klaus Darilion klaus.mailinglists at pernau.at
Tue Sep 13 05:58:58 UTC 2011

Am 12.09.2011 22:22, schrieb Peter van Dijk:
> 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.

How does PowerDNS architecture work? It seems that lookups performed by
the "ueberbackend" are cached whereas lookups which are done by the
gsql-backend are not cached. Is this correct?


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