FreeTDS Development Group

[Stan Liberman <stan AT vailsys.com>]

On Wed, 2002-06-26 at 21:07, Brian Bruns wrote:
> On 26 Jun 2002, Stan Liberman wrote:
> 
> > 
> > 574400 - Several patches for thread safety in tds. Our apps consistently
> > core dumped at attempt to login from several threads. Pretty much just
> > replaced non thread-safe functions with their safe equivalents.
> 
> This gets into a sticky situation, older unices will not have the _r 
> versions of the calls, so we should be checking via autoconf for their 
> existence and using only then.  So, something like 
> 
> #if HAVE_LOCALTIME_R
>       tm = localtime_r(&t, &res);
> #else
>       tm = localtime(&t);
> #endif
> 
> and in configure.in adding:
> 
> AC_CHECK_FUNCS(localtime_r)
> 
> Otherwise, I'm all for this one going in.

Actually, I've just realized that I forgot one more patch for configure
- in order for these functions for work properly _REENTRANT must be
defined in the DEFS.

> 
> > 574402 - If connection was dropped ( we created it by simply killing the
> > database, and once disconnected the network cable ) the application
> > using dblib was going into tight loop consuming 99% of CPU.
> > There are two fixes: one for tds/token.c checking of the marker is 0 in
> > tds_process_cancel, other one for dblib/dblib.c dbsqlok() to make sure
> > that tds_process_default_tokens() returns success.
> > I'm not sure if this is the proper way of fixing this particular
> > problem, but we've been running with this patch for several weeks now
> > without any problems.
> 
> Looks like you are returning TDS_ERROR from the dblib routines?  This is 
> not a valid return, we should be using SUCCEED or FAIL always.

Ok. For some reason I was under impression that this return value of the
dbsqlok was checked against TDS_ERROR - it looks like I was wrong.

> Otherwise, 
> the patch looks ok, was it intended only to deal with tds_process_cancel?

Yes. At least that was the only place we have discovered a consistent
problem. 

> 
> It's definitely better what we have now, but I'm wondering how 
> comprehensive it is?
> > 
> > I hope these patches will make it into release, or I'll have to create
> > our own branch again (which is no fun). Just a note :)
> > 
> 
> 
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Regards,
Stan