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From Kathey Marsden <kmarsdende...@sbcglobal.net>
Subject Re: Soft Upgrade and Downgrade
Date Wed, 22 Mar 2006 23:36:32 GMT
Rick Hillegas wrote:

> Today, however, I was taught the following curious fact about
> DatabaseMetaData methods:
> o When the customer calls one of these methods, it causes the server
> to fault in some query text from the server jar files, to compile that
> query text, and to store the compiled form in the database. From that
> point onward, the compiled form is locked in place and determines the
> results of the DatabaseMetaData method for all subsequent callers.
> o The results from a DatabaseMetaData call therefore depend on whether
> the first user faulted in the text BEFORE or AFTER the Upgrade. It
> seems that this indeterminate behavior is induced by Soft Upgrade and
> maybe by Hard Upgrade as well.
>From what you describe it sounds like it might be DERBY-1107 which is a
general issue related to to any version change of  Derby not just soft
upgrade, DERBY-1107 https://issues.apache.org/jira/browse/DERBY-1107. 
There is also some history in that bug.

Historically the metadata queries have been trouble makers. I think the
metadata issue might  be worthy of a Wiki page of its own and perhaps
some architectural thought put into how to best handle metadata queries
on version change and in general.


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