From: Remi Gacogne Date: Tue, 25 Oct 2022 12:23:04 +0000 (+0200) Subject: auth: Document that `consistent-backends` should not be used with scoped records X-Git-Tag: dnsdist-1.8.0-rc1~260^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=refs%2Fpull%2F12131%2Fhead;p=thirdparty%2Fpdns.git auth: Document that `consistent-backends` should not be used with scoped records --- diff --git a/docs/settings.rst b/docs/settings.rst index b02952d83f..7fb2db3919 100644 --- a/docs/settings.rst +++ b/docs/settings.rst @@ -325,10 +325,15 @@ Name of this virtual configuration - will rename the binary image. See .. versionadded:: 4.4.0 When this is set, PowerDNS assumes that any single zone lives in only one backend. -This allows PowerDNS to send ANY lookups to its backends, instead of sometimes requesting the exact needed type. +This allows PowerDNS to send ``ANY`` lookups to its backends, instead of sometimes requesting the exact needed type. This reduces the load on backends by retrieving all the types for a given name at once, adding all of them to the cache. It improves performance significantly for latency-sensitive backends, like SQL ones, where a round-trip takes serious time. +.. warning:: + This behaviour is only a meaningful optimization if the returned response to the ``ANY`` query can actually be cached, + which is not the case if it contains at least one record with a non-zero scope. For this reason ``consistent-backends`` + should be disabled when at least one of the backends in use returns location-based records, like the GeoIP backend. + .. note:: Pre 4.5.0 the default was no.