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https://issues.apache.org/jira/browse/DERBY-5043?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13001131#comment-13001131
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Lily Wei commented on DERBY-5043:
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Thank you so much for looking at this issue, Kim. Please see my comments:
1) The description at the top of DERBY-2905 says that after shutdown, the
still-registered driver "does not support any future loading of connections,"
but the reply to Rick just now says that "When deregister=false, user can just
obtain a new connection without issue Class.forName()." I thought the point of
making true the default was that after a shutdown the driver could no longer be
used, so it really needed to be deregistered. I admit I did not read the entire
history of DERBY-2905, where this might be clarified.
>>
In the life of DERBY-2905, the nature of the fixed version change a little bit.
I can see maybe I need two DERBY issues to address issue accordingly.
It is true that when deregister=false, user can just obtain a new connection
without issue Class.forName().
However, when users shutdown Derby without specify deregister attribute, Derby
will adopt deregister=true and unload the auto loaded driver. For users to
obtain a new connection after that, they need to issue Class.forName() to avoid
memory leak issue causing by having the auto loaded driver hanging around. It
implies there will be no still-registered driver.
During the discussion of implementing DERBY-2905, I think that is the desire
behavior for Derby.
2) Is this attribute valid only when using JDBC 4.0 or 4.1? (Driver autoloading
is present with JDBC 4.0 but not with 3.0.)
Yes, the attribute is valid for JDBC 4.0 and 4.1
3) Does this attribute apply to the embedded driver only? Does it have any
meaning if you are shutting down the network driver?
The attribute is applied to embedded driver.
> Document the new url attribute deregister to keep the AutoloadedDriver
> registers in DriverManager
> -------------------------------------------------------------------------------------------------
>
> Key: DERBY-5043
> URL: https://issues.apache.org/jira/browse/DERBY-5043
> Project: Derby
> Issue Type: Improvement
> Components: Documentation
> Affects Versions: 10.7.1.1
> Reporter: Lily Wei
> Assignee: Kim Haase
> Labels: derby_triage10_8
> Fix For: 10.8.0.0
>
> Attachments: Repro2905.java
>
>
> With DERBY-2905, we have a new connection url attribute - deregister. After a
> shutdown of the embedded driver, the AutoloadedDriver is unregistered from
> the DriverManager. Users who wish to keep the AutoloadedDriver can set the
> deregister attribute on the connection url to false. It is only valid with
> shutdown=true. And, the default behavior with shutdown=true is
> deregister=true.
> For example:
> 'shutdown=true;deregister=true" (It is okay not to specify deregister=true)
> 'shutdown=true;deregister=false"
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