SubLevel index : is it useful ?

[Emmanuel Lecharny <el...@gmail.com>]

Hi guys,

I may be a bit rusty, but AFAICT, we got rid of the oneLevel index, as 
we can use the Rdn index to do the same job.

I question the need of the subLevel index now : can't we use the RDN 
index for the very same purpose ? IMO, but I may be wrong, it would be 
just a matter of adding some extra information in the RDN index (ie, the 
number of descendant for each entry) and to define a cursor that do a 
recursive descent into the RDN index.

thoughts ?

Note : i'm asking, bcause it may have a huge impact in the way Selcuk 
will implement the MVCC layer...

-- 
Regards,
Cordialement,
Emmanuel Lécharny
www.iktek.com

Re: SubLevel index : is it useful ?

[Emmanuel Lécharny <el...@apache.org>]

On 10/5/11 9:35 PM, Stefan Seelmann wrote:
> Hi Emmanuel,
>
> On Wed, Oct 5, 2011 at 1:44 PM, Emmanuel Lecharny<el...@gmail.com>  wrote:
>> I may be a bit rusty, but AFAICT, we got rid of the oneLevel index, as we
>> can use the Rdn index to do the same job.
> No, not yet, see below.
>
>> I question the need of the subLevel index now : can't we use the RDN index
>> for the very same purpose ? IMO, but I may be wrong, it would be just a
>> matter of adding some extra information in the RDN index (ie, the number of
>> descendant for each entry) and to define a cursor that do a recursive
>> descent into the RDN index.
> Yes, I'm sure that is possible and that is what I did for the HBase
> partition. But its not done yet. I started a branch [1] to experiment
> with it but don't have time to continue. Feel free to pick up the
> changes there or start a new refactoring.

Okie, thanks !

I will pursue the experiment.

-- 
Regards,
Cordialement,
Emmanuel Lécharny
www.iktek.com

Re: SubLevel index : is it useful ?

[Stefan Seelmann <se...@apache.org>]

Hi Emmanuel,

On Wed, Oct 5, 2011 at 1:44 PM, Emmanuel Lecharny <el...@gmail.com> wrote:
> I may be a bit rusty, but AFAICT, we got rid of the oneLevel index, as we
> can use the Rdn index to do the same job.

No, not yet, see below.

> I question the need of the subLevel index now : can't we use the RDN index
> for the very same purpose ? IMO, but I may be wrong, it would be just a
> matter of adding some extra information in the RDN index (ie, the number of
> descendant for each entry) and to define a cursor that do a recursive
> descent into the RDN index.

Yes, I'm sure that is possible and that is what I did for the HBase
partition. But its not done yet. I started a branch [1] to experiment
with it but don't have time to continue. Feel free to pick up the
changes there or start a new refactoring.

Kind Regards,
Stefan

[1] http://svn.apache.org/repos/asf/directory/apacheds/branches/one-sub-level-index-removal/