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From Knut Anders Hatlen <Knut.Hat...@Sun.COM>
Subject Re: [jira] Updated: (DERBY-3347) ERROR XSDB3: Container information cannot change once written
Date Mon, 14 Apr 2008 10:16:06 GMT
Bryan Pendleton <bpendleton@amberpoint.com> writes:

> Mike Matrigali (JIRA) wrote:
>> affects  page 0, which happens to be accessed a lot and thus is in
>> cache a lot.   
> Perhaps it would be helpful to add a special internal testing API
> which enables test programs to discard the cache at interesting moments?
> I know special testing hooks are gross, but sometimes they can also be
> really helpful for enabling better testing.

It shouldn't be too difficult to implement, I think. The CacheManager
interface already has the needed functionality through these methods:

  - ageOut() - removes all clean objects that are not held

  - discard() - same as ageOut(), but also removes dirty objects
    (without cleaning them)

For the statement cache, ageOut() is exposed to the users via the stored
procedure SYSCS_UTIL.SYSCS_EMPTY_STATEMENT_CACHE(). We could probably do
something similar for the page cache and the container cache.

Knut Anders

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