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freetds - Re: [freetds] Sybase disconnect after idle

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  • From: Björn Lundin <b.f.lundin AT gmail.com>
  • To: FreeTDS Development Group <freetds AT lists.ibiblio.org>
  • Subject: Re: [freetds] Sybase disconnect after idle
  • Date: Thu, 23 Feb 2012 14:50:31 +0100

I've experienced firewalls cutting idle connections
After 1 hour.
Every 20 minutes, i did a dummy query as a workaround.
Worked nice.
Test by writing a program that connects, sleeps 3595 secs,
Queries db, sleeps 3605 seconds. If crash second time, you know the
timeframe.

--
Björn
Skickat från min iPhone

23 feb 2012 kl. 07:54 skrev Michael Peppler <mpeppler AT peppler.org>:

> On Feb 22, 2012, at 11:32 PM, Michelle Dupuis wrote:
>
>> I have a C program using freetds ver 0.91 (package on CentOS 5.7). All
>> seems to work well, but after some idle time (eg: 5 hours) the connection
>> seems to drop because attempts to issue a query result in error 20003
>> (disconnect). Is freetds disconnecting or is the Sybase server
>> disconnecting the session?
>> Is there any way to prevent this?
>
> Normally, Sybase will not disconnect an idle session. However, there are
> ways to enable this (e.g. checking on various MDA tables, and killing idle
> connections), so you check with your DBA that this is not in place on the
> database side.
> I'm not 100% up to date on the FreeTDS internals, but I don't think that it
> has any idle disconnect logic (I know for a fact that Sybase OpenClient
> does not).
> Another possibility is that there is a router or firewall between your
> program and the Sybase server, and it does idle disconnect - this is
> something that is fairly common - so maybe check with your network admins.
>
> If I remember correctly I think that Sybase OpenClient has an option to
> turn on a keep-alive probe - I don't know if FreeTDS has included anything
> similar. Enabling this should at least fool the network layer into thinking
> that there is activity and avoid any disconnects from routers/firewalls.
>
> Michael
> --
> Michael Peppler
> Sybase on Linux FAQ: http://www.peppler.org/FAQ/linux.html
>
> "A successful [software] tool is one that was used to do something
> undreamed of by its author." -- S. C. Johnson
>
>
>
>
>
>
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