Hi,
The solution I have posted at this stage was not intended to be mature
enough to merge into the main line (not a patch yet). I was just "asking for
questions" like "do you have better solution?" since I'm not quite
understanding the main code line yet. You may treat it as an example of
solution (at least it satisfied our need for high availability).
I may spend more time later on c-ares and wish I can contribute to it in a
way that it requires.
BTW, the keep alive option (and keepcnt, keepintvl) only applies to the
specific tcp connection, won't affect other sockets in local linux host or
remote host. The keep alive message will only be sent when there is no
application message exchange. You may specify longer keepidle to reduce
traffic (and the keepalive is a very small packet).
Thanks,
Anlin.
On 8/12/07, c-ares-request_at_cool.haxx.se <c-ares-request_at_cool.haxx.se> wrote:
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> 1. Re: Two questions: 1. Callback function not called; 2. TCP
> connecting to un-existing server prevents from using existing
> server. (Daniel Stenberg)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 11 Aug 2007 17:28:40 +0200 (CEST)
> From: Daniel Stenberg <daniel_at_haxx.se>
> Subject: Re: Two questions: 1. Callback function not called; 2. TCP
> connecting to un-existing server prevents from using existing
> server.
> To: c-ares hacking <c-ares_at_cool.haxx.se>
> Message-ID: <Pine.LNX.4.64.0708111659080.15897_at_yvahk3.pbagnpgbe.fr>
> Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
>
> On Thu, 9 Aug 2007, Anlin Zhang wrote:
>
> > Attached is a diff -u out put to show my fix of the tcp connection
> problem.
> > I also insert here since it's not big:
>
> Three problems with this patch:
>
> 1. it doesn't follow the current source code style (indent levels)
>
> 2. it isn't written to build only for the systems that support these
> options
>
> 3. it contains printf() calls
>
> > The tcp keepalive option I added on the soket will take care of any
> > non-responding machine.
>
> First, not all systems support these so I would rather have a more
> universally
> available approach. Possibly in addition to this.
>
> Then, you set the values pretty extreme, imho... I haven't really
> investigated
> this, but is this TCP connection kept alive between the resolves? I kind
> of
> assume so, and then this 2-second keep-alive will create quite some
> traffic
> for lots of applications.
> BTW, how do I directly answer your posting on the web? so that it looks
> like
> > a cascade follow-up?
>
> On the web? This is a mailing list so if you just reply to the mail it'll
> show
> up threaded in all subscribers' mail clients and in the web archives
> showing
> this mailing list.
>
> --
> c-ares -- my preferred DNS asynch resolver library
>
>
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> End of c-ares Digest, Vol 20, Issue 4
> *************************************
>
Received on 2007-08-13