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From Pavel Bortnovskiy <PBortnovs...@Jefferies.com>
Subject Re: Table exists in same JVM after Derby is shutdown
Date Fri, 05 Aug 2011 22:05:42 GMT
Dag: thank you for your prompt response.

The database is entirely in the memory, so there are no files do delete.

However, the behavior is consistent and my attached example clearly 
demonstrates it (has the attachment come through?):

1) I create an in-memory database and then a table in it.
Then the database is shut down.

2) The second test tries to create an in-memory db with the same name,
and the tables still remain in it, despite that it was explicitly shutdown 
in the previous test.
I would expect that the shutdown effectively cleans everything up.
Is it not so?

Thanks,
Pavel.



From:
dag.wanvik@oracle.com (Dag H. Wanvik)
To:
"Derby Discussion" <derby-user@db.apache.org>
Date:
08/05/2011 05:57 PM
Subject:
Re: Table exists in same JVM after Derby is shutdown



Pavel Bortnovskiy <PBortnovskiy@Jefferies.com> writes:

> Hello, all:
>
> While executing a bunch of JUnit tests within the same JVM (all executed 

> by IntelliJ IDEA) I started seeing strange and unexpected errors 
occurring
> .
> Upon closer inspection, I noticed that in many of those tests tables 
with 
> the same names are attempted to be created.
> Then I realized that although Derby is shutdown and then re-created, the 

> tables remain, thus causing collisions.

The "create=true" connection attribute is ignored (with a warning) if
the database with the same name alrady exists.

>
> I've created a digest (attached) which is executed as one JUnit test to 
> illustrate what I'm seeing.
> The behavior I would expect is that once Derby is shutdown, no tables 
> would remain in the JVM, and if a database (with the same name) is 
> re-created, it would be a tabula rasa.

The tables are no longer in memory (or should not be unless you found a
bug), but they are not erased from the disk image of the database.  As
per the above, one would need to explicitly delete it using OS file
system tools for the data to be cleared. Some JUnit tests delete tables
in TestCase#tearDown, others use singleUseDatabaseDecorator to isolate
itself from the rest of the tests. The tests not necessarily very
consistent in their patterns for this..

Dag

>
> Can you please let me know whether my expectations are erroneous and 
> whether I should find workarounds (albeit trivial to implement).
> However, what would concern me in that case is that the tables and the 
> data remain in the JVM, thus consuming memory
> (and, if unused, creating memory leaks).
>
> Thank you,
>
> Pavel.
>
>
>
>
>
>
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Jefferies archives and monitors outgoing and incoming e-mail. The contents of this email,
including any attachments, are confidential to the ordinary user of the email address to which
it was addressed. If you are not the addressee of this email you may not copy, forward, disclose
or otherwise use it or any part of it in any form whatsoever. This email may be produced at
the request of regulators or in connection with civil litigation. Jefferies accepts no liability
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recipients is prohibited.  In the United Kingdom, Jefferies operates as Jefferies International
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Street, London EC4V 3BJ.  Jefferies International Limited is authorised and regulated by the
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