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From Kathey Marsden <kmarsdende...@sbcglobal.net>
Subject Disussion surrounding holding off metadata changes until certain issues resolved (was: Re: [jira] Updated: (DERBY-1107) For existing databases JDBC metadata queries do not get updated properly between maintenance versions.)
Date Mon, 03 Apr 2006 22:00:14 GMT
Satheesh Bandaram wrote:

>Kathey Marsden wrote:
>>Satheesh Bandaram wrote:
>>I think on this one,  we just need to get the DERBY-1076 patch
>not sure if adding of new tests should stop development
>that passes current Derby checkin criteria of clean derbyAll.

I think if an area has regressions, significant quality issues,  poor
test coverage or is  a significant risk area it is appropriate for
anyone in the community to raise objections to new functionality  being
added to that area  until the core quality issues  are addressed. 
Upgrade is particularly sensitive because if not working, the resolution
may require time travel to resolve. Since there was no infrastructure in
place to handle upgrade changes of metadata,  it had outstanding
regressions, and it has traditionally been an area of serious issue I
asked Knut to wait and he agreed., probably because he agrees with the
six core principals of the "Apache Way"  especially the one about
"consistently high quality software".


>>The blockage was based on the fact that we once had an irreconcilable
>>downgrade bug and seemed to be set up for that again.  
>What was the code change that caused this problem in 5.1? You have
>provided symptoms of the problem. It would be good to understand the
>code change that cause this symptom.
The code change was that in  5.1.60 there were new classes and methods
that were added and referred to in  the metadata SQL  queries.  Going
back to the previous version,  the metadata queries were still there but
the classes and methods were not,  so it caused this failure.   In the
10.1 codeline, this means  that no new functions  or syntax not
compatible with older versions can be added to the queries.   Adding the
drop on version change  except for read only databases seems the safest
thing here to me.  It seems like it will be a long time before we have a
10.2 release, who knows what will go in the 10.1 codeline.

>Again, I am not sure if DERBY-1107 should stop metadata developments.
>Wasn't this "issue" present from the beginning?
It is a serious outstanding issue with the handling of metadata
changes.  It would be good to see it resolved soon, because it is again
one possibly needing time travel to resolve, but isn't stopping  any
metadata changes from going in  now.


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