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From Kathey Marsden <kmarsdende...@sbcglobal.net>
Subject Re: [PATCH](DERBY-573) Provide support for optimizer overrides in Derby
Date Fri, 09 Dec 2005 05:35:26 GMT
Mamta Satoor wrote:

>Hi Satheesh,
>Thanks for reviewing the patch.
>I think your concern is well founded. A new column in a system table
>referenced by metadata.properties would cause a problem in soft upgrade
>mode. I am not sure if we have run into this in the past and how we handled
With an older version of Cloudscape a few years ago we had a similar
issue where a metadata query referenced a new stored procedure which
didn't exist on an older version and to this day we still struggle with
that unfortunate event because there are errors recompiling stored
prepared statements when reverting   to the previous version.  After
that we changed the Cloudscape code to drop the metadata stored prepared
statements whenever the version changed up or down and let them get
recreated with the new version.  That does not occur with Derby however.

My feeling is that it would be safest in the long run to always drop the
metadata statements whenever the version changes up or down and let them
be recreated  with the current version.   Too late for  existing
versions but a safe  long term strategy.

Just my 2 cents.


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