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From Kathey Marsden <kmarsdende...@sbcglobal.net>
Subject Re: Disussion surrounding holding off metadata changes until certain issues resolved
Date Sun, 09 Apr 2006 16:08:33 GMT
Dag H. Wanvik wrote:

>>Old client, new server scenario: In this case, the downgrade of the
>>result set happens on the client, so applications would not be able
>>to use SUR. Only the new client lifts the restriction.
>>Due to the bug in the 10.1 client code for
>>supportsResultSetConcurrency (DERBY-965), the client would still get
>>a "false" on this query, which is correct. Note that this is be
>>accident rather than by design! Derby has a weakness here in that
>>metadata queries are answered by the server without regard to the
>>client's version (capabilities).
Thank you so much for calling out this potential compatibility issue in
this thread.  DERBY-775 was not on my compatibility radar.

I tried  the repro for DERBY-965 with JCC and the trunk server and see
that JCC returns false these values for supportsResultSetConcurrency, so
I think that we are ok for JCC too.  Is that correct?

SupportsResultSetConcurrency: TYPE_FORWARD_ONLY,CONCUR_READ_ONLY: false
SupportsResultSetConcurrency: TYPE_FORWARD_ONLY,CONCUR_UPDATABLE: false
SupportsResultSetConcurrency: TYPE_SCROLL_SENSITIVE,CONCUR_READ_ONLY: false
Apache Derby Network Server - alpha shutdown at 2006-04-09
15:38:51.040 GMT

>Generally, it seems results of such metadata calls should potentially
>be "negotiated down" if the client is older and cannot support the new
>feature.. I am not sure of the machinery of NetDatabaseMetaData can be
>used as is for this purpose...(i.e. the serverSupport<FeatureX>
>methods). Or?
Right, I think there is still a hole here in terms of metadata handling
and how to negotiate down.  I am guessing that will become incumbent on
someone who finds that they need  that negotiation for some  new
feature.    It looks like you are "off the hook" this time  because of

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