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Re: On disk index structure support?

On Wed, 18 Apr 2001, David Li wrote:
> Hi,
> 
> 
> We are into the stage of tuning the performance of our RDF DB for large
> volume RDF data at the range of 100K triples. I found it's necessary to
> assist this with some on disk index structure to perform better search.

Today ozone is very good handling highly structured data. 'Highly structured'
means that collections that a typically used to model object relations have up
to a few hundreds of members.

For bigger collections a generic index package is needed. I perfectly agree on
this. The query kernel (see other thread in this list) should provide exactly
these generic indexing and querying. On top of this kernel we could build OQL,
SODA or other front-ends like the fast searchable BigCollection for internal use
that you are asking for, David.

> 
> I look arround the API and found:
> 
> DxDiskHashMap 
> 
> Is it OK to use this in the server side object codes? 

It is more or less exactly what you are looking for (but no searching) but it's
not integrated in the StoreManager of ozone. it will probably not work as
expected inside a database object (or it would require lot of work to make it
work as expected).

> Is there better
> selection of disk based index structure to use?
no, see above

> 
> Moreover, there is a tool set called XXL available from the following
> URL,
> 
> http://www.mathematik.uni-marburg.de/DBS/xxl
> 
> I am wondering if it may be possible to integrate it into Ozone to
> provide indexing support for server side object programming.

I had a brief look. Seems to be a great starting point for the query kernel.

Besides a backing implementation we need a API for the query kernel first.
Since it has to support different kind of front-ends, this seems to be a tricky
part of the entire query kernel effort.


Falko
-- 
______________________________________________________________________
Falko Braeutigam                              mailto:falko@smb-tec.com
SMB GmbH                                        http://www.smb-tec.com