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From "Kristian Waagan (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-4084) Determine the subSubProtocol name for the in-memory back end
Date Mon, 09 Mar 2009 21:23:50 GMT

    [ https://issues.apache.org/jira/browse/DERBY-4084?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12680283#action_12680283

Kristian Waagan commented on DERBY-4084:

Rick wrote:
Bryan raises the issue of how we distinguish the transient in-memory database (implemented
by Kristian's patch) from Cheng's implementation, which snapshots the database to disk on
To clarify, I'm hoping to incorporate Cheng's features into the Derby code line, possibly
with help from Cheng himself. Note that the database won't be saved to disk on exit by default,
you have to set a property to do that (I think in Cheng's patch it was a system property).
Regardless of whether such a feature is added or not, the database must be considered transient.
A crash or abnormal VM shutdown will cause [all] data to be lost.

Also note that even without the specific feature mentioned, the user can explicitly "snapshot"
the database by invoking Derby's existing backup routine(s), and then restore the database
on boot/creation (for instance by using the createFrom URL attribute). The difference between
the save on exit feature and the backup mechanism, is that the former is automatic on shutdown.
I don't think the existing backup routines can be easily invoked from the in-memory storage

Thanks for the comments so far, and keep'em coming ;)

> Determine the subSubProtocol name for the in-memory back end
> ------------------------------------------------------------
>                 Key: DERBY-4084
>                 URL: https://issues.apache.org/jira/browse/DERBY-4084
>             Project: Derby
>          Issue Type: Sub-task
>    Affects Versions:
>            Reporter: Kristian Waagan
> The community should agree on a name for the subSubProtocol for the in-memory back end.
The name will be used in the connection URL, and it is the mechanism used to tell Derby to
use the in-memory back end:
> jdbc:derby:subSubProtocol:dbName
> Two hot candidates are:
>  o mem
>  o memory
> The former is shorter, the latter is slightly more descriptive. If you have opinions
on this, please post a comment.
> We should decide on this before we cut the branch for 10.5.

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