[Dnsmasq-discuss] [PATCH] Retry queries only after giving the upstream server some time to respond

Dominik Derigs dl6er at dl6er.de
Mon Apr 5 20:16:43 UTC 2021


Hey Simon,

On Mon, 2021-04-05 at 20:38 +0100, Simon Kelley wrote:
> Post 2.83, a the second query would be combined with the first, which
> can only reduce upstream traffic. The change in 2.85 is that the second
> query triggers a retry, so closer to the original situation. BUT the
> retry is sent to all servers.

Yeah, sorry for not being precise enough, my comparison was 2.84 to
2.85(rc2) not to the pre-2.83 era. I much appreciated the reduction in
upstream traffic in 2.83 + 2.84 and hoped we can keep this up.

In my situation your proposed change wouldn't make any difference as
there is only one upstream server that is a local unbound recursive
resolver.

On Mon, 2021-04-05 at 20:38 +0100, Simon Kelley wrote:
> Only forward to
> all servers when the same query arrives twice from the same source.

This is the issue I'm concerned about. Some clients send the same query
multiple times (they don't seem to have a local cache). In addition,
other clients happen to send a query at the same time. This all
triggers a re-forwarding. As I get your idea, they would still all
produce forwarded queries. This is what I wanted to prevent with my
patch. Basically a v2.84-like behavior but with reduced likeliness of
failing because we eventually allow retrying if the first query died.
Just not immediately.

Hope that makes my idea clearer.

Best,
Dominik




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