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Posted to dev@accumulo.apache.org by "Dave Marion (JIRA)" <ji...@apache.org> on 2012/08/07 01:50:02 UTC

[jira] [Commented] (ACCUMULO-708) Modify ClassLoader to support different applications / multi-tenancy

    [ https://issues.apache.org/jira/browse/ACCUMULO-708?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13429587#comment-13429587 ] 

Dave Marion commented on ACCUMULO-708:
--------------------------------------

Documenting thoughts: Seems that there are only two contexts in which this applies: table operations (in which there is no user) and client operations (in which there is a user perform scan or update). The current classloader (be default) uses the boot classloader with a child classloader reading from $ACCUMULO_HOME/lib and a grandchild classloader reading from $ACCUMULO_HOME/lib/ext.

We would need a way for the classloader to discover either the table name or the current user when loadClass is called in the thread. This is currently the part that I am not sure of. Need input from others and to look at the code more.
                
> Modify ClassLoader to support different applications / multi-tenancy
> --------------------------------------------------------------------
>
>                 Key: ACCUMULO-708
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-708
>             Project: Accumulo
>          Issue Type: Improvement
>          Components: start
>    Affects Versions: 1.5.0
>            Reporter: Dave Marion
>            Assignee: Dave Marion
>              Labels: classloader
>   Original Estimate: 24h
>  Remaining Estimate: 24h
>
> I'd like to expand the current classloader to support loading classes from HDFS and different application contexts. I'll be modifying the ticket as the idea matures.

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Re: [jira] [Commented] (ACCUMULO-708) Modify ClassLoader to support different applications / multi-tenancy

Posted by Marc Parisi <ma...@accumulo.net>.
I think we should have a scan time class loader context that enables fully
hot swappable analysis and iteration. Security would need to be enforced,
but if we did that we could simply set the jar ala hadoop map/reduce and
have an iterator hot loaded in a different way for a different scan
session.

On Mon, Aug 6, 2012 at 7:50 PM, Dave Marion (JIRA) <ji...@apache.org> wrote:

>
>     [
> https://issues.apache.org/jira/browse/ACCUMULO-708?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13429587#comment-13429587]
>
> Dave Marion commented on ACCUMULO-708:
> --------------------------------------
>
> Documenting thoughts: Seems that there are only two contexts in which this
> applies: table operations (in which there is no user) and client operations
> (in which there is a user perform scan or update). The current classloader
> (be default) uses the boot classloader with a child classloader reading
> from $ACCUMULO_HOME/lib and a grandchild classloader reading from
> $ACCUMULO_HOME/lib/ext.
>
> We would need a way for the classloader to discover either the table name
> or the current user when loadClass is called in the thread. This is
> currently the part that I am not sure of. Need input from others and to
> look at the code more.
>
> > Modify ClassLoader to support different applications / multi-tenancy
> > --------------------------------------------------------------------
> >
> >                 Key: ACCUMULO-708
> >                 URL: https://issues.apache.org/jira/browse/ACCUMULO-708
> >             Project: Accumulo
> >          Issue Type: Improvement
> >          Components: start
> >    Affects Versions: 1.5.0
> >            Reporter: Dave Marion
> >            Assignee: Dave Marion
> >              Labels: classloader
> >   Original Estimate: 24h
> >  Remaining Estimate: 24h
> >
> > I'd like to expand the current classloader to support loading classes
> from HDFS and different application contexts. I'll be modifying the ticket
> as the idea matures.
>
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