FreeTDS Development Group

["Lowden, James K" <LowdenJK AT bernstein.com>]

> From: Paul Rensing [mailto:paul.rensing AT att.net]
> Sent: March 18, 2003 11:56 AM
> 
> The Python Sybase driver uses the CT interface. I turned on 
> debugging of
> the Python driver in the place where it usually fails. I have attached
> the output of the tracing.
> 
> The problem seems to be that, for the SQL query, occasionally it gets
> back from ct_results() a status of CS_STATUS_RESULT, instead of the
> usual CS_ROW_RESULT. After that it is very confused. If I immediately
> repeat the same query, it works just fine.
> 
> I am still wondering if this could be a timing issue on the 
> server end.

Microsoft servers issue spurious status result packets, far more than they
need to.  FreeTDS can't know which ones are real and which are noise, so it
passes them all up the stack.  I don't know that it's a timing issue,
exactly; I haven't found rhyme or reason.  

The Python folks wouldn't have bumped into this using Sybase's libraries
because they likely wouldn't have tried to connect to a Microsoft server
(and, even if they did, it would be TDS 4.2 and, as you say, the behavior is
sporadic).  

FreeTDS is violating the ct-lib specification IMO, because it's returning
CS_STATUS_RESULT for a query that's not a stored procedure.   The problem
is, we don't know it's not a stored procedure (because we don't parse the
outbound SQL), so we don't know the returned status packet should be
squelched from the ct-lib interface.  

If I'm right about all this, I'm afraid Python's just going to have to deal.
:/

Nice detective work, if I may say so.  

--jkl


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