Hello Markus!

We are ready to help you with issues you mentioned.

Here are our questions:
1) When do you plan to finish this work? Here by ‘finish’ we mean beta-version, not totally stable but acceptable for research topics.
2) Where it is possible to see the current progress of triple store support, in which svn-branch all the development is doing?

3) What do you think about future support of bi-directional interaction between SMW and triple storage?
Here we are primarily interested in third-party updates of SMW data.  For example, one can add a new wikipage with certain properties. The inference engine that runs on a triple store will classify it and add the classification result in a store. It would be great if wiki could act accordingly: for example the new category would be added on a wikipage.
The question is: do you plan such things at least in a future? Or is it an extension developers work to do the described connection?

And several question about the current work:

===1 ===
> "Could we use FILTER on URI strings to find URIs that begin with a certain prefix, or is this too slow?"
Have I understood this correctly: you need to measure performance of the SPARQL query with regex clause in FILTER section [1]? Such queries will be in approximately following form:
SELECT ?a
WHERE
{ ?a rdf:type <some-URI-for-wikipage>
FILTER regex( ?a, “foaf”, i )
}

===2===
> Which parts of SPARQL UPDATE are currently (not) supported reliably?
Do we need do find/invent the test suite for this part of the working draft [2] and report about how many features of this draft is currently supported in 4Store?

===3===
> Is it generally best to do SPARQL DELETE INSERT for updates, or does the store require us to decompose this into multiple queries? Are there performance differences?
Here if we understand correctly you ask us to compare DELETE/INSERT[3] query with first DELETE and then INSERT by measuring their performance on some set of test samples.



[1] http://www.w3.org/TR/rdf-sparql-query/#funcex-regex
[2] http://www.w3.org/TR/sparql11-update/#t41
[3] http://www.w3.org/TR/sparql11-update/#t413

On Mon, Mar 28, 2011 at 10:05 AM, Markus Krötzsch <markus@semantic-mediawiki.org> wrote:
>
> On 27/03/11 20:52, Laurent Alquier wrote:
>>
>> Hi Markus
>>
>> Does this mean it will be possible to consider declaring triples outside
>> of a subject page ?
>
> No, this is not part of the initial design. But the changes will make it easier (and more natural) to add this capability later on (maybe using named graphs).
>
> The initial goal of the RDF store project is to improve query performance by taking advantage of optimised SPARQL implementations of RDF stores.
>
> Markus
>
>
>> On Sun, Mar 27, 2011 at 2:22 PM, Markus Krötzsch
>> <markus@semantic-mediawiki.org <mailto:markus@semantic-mediawiki.org>>
>> wrote:
>>
>>    Hi Yuri,
>>
>>    thank you for your interest. Contributions are very welcome! We plan to
>>    use an RDF store as a backend for storing and querying data. This will
>>    not completely abolish the use of MySQL tables, but at least all queries
>>    should be answered by the triple store (no more SQL-based #ask). We will
>>    use SPARQL and SPARQL Update for all communication. SPARQL queries to
>>    external endpoints are not planned for the initial phase but adding them
>>    will be much easier after all the SPARQL communication methods are
>>    in SMW.
>>
>>    I am currently changing the SMW code in various places to make it
>>    compatible with such a setup. The first RDF store I will consider is
>>    4Store.
>>
>>
>>    How could you contribute to speed this up/make the features more
>>    complete?
>>
>>    Right now, I could mainly use support with figuring out the best way of
>>    formulating queries for achieving certain effects, both with 4Store and
>>    with Virtuoso (and any other store people want to use). Example
>>    questions of this type (to be answered for each store that we care
>>    about):
>>
>>    * "Could we use FILTER on URI strings to find URIs that begin with a
>>    certain prefix, or is this too slow?"
>>    * "Which parts of SPARQL UPDATE are currently (not) supported reliably?"
>>    * "Is it generally best to do SPARQL DELETE INSERT for updates, or does
>>    the store require us to decompose this into multiple queries? Are there
>>    performance differences?"
>>    * "What is the best way to implement counting queries on a given store?"
>>    (SPARQL 1.1 aggregates are still very preliminary and some stores have
>>    custom solutions)
>>
>>    I have more of these questions, and they generally need some testing on
>>    the real store, so this would be a place where contributors could help
>>    (also since there are many different stores people might care about).
>>
>>    There will be some more tasks that can be done as soon as I completed
>>    some more work on the SMW base architecture:
>>
>>    * We would like to support Virtuoso and maybe other stores as well.
>>    After 4store works, this should be a rather independent task to try and
>>    get it to run with other stores (each store will need some amount of
>>    special handling or optimisation, this can be prepared by answering the
>>    above SPARQL support questions).
>>
>>    * Testing. The more early testers we get, the better for the stability
>>    of the code.
>>
>>
>>    Regards,
>>
>>    Markus
>>
>>
>>    On 26/03/11 13:06, Yury Katkov wrote:
>>     > Hello everyone!
>>     >
>>     > We have compared the current solutions for the triple store
>>     > integration [1] and found that all those solutions are either
>>     > incomplete or use very hard patches of the SMW core.
>>     > Recently Markus mentioned that the next version of SMW will be better
>>     > integrated with RDF store. Is it possible to get some details about
>>     > these planned integration features? We want to contribute to  this
>>     > work by solving as many related tasks as possible. Such features
>>    would
>>     > be very useful for our installation of SMW and I believe for the
>>    whole
>>     > SMW project.
>>     >
>>     > Sincerely yours,
>>     > Yury Katkov
>>     >
>>     > [1]
>>    http://www.semantic-mediawiki.org/wiki/SPARQL_and_RDF_stores_for_SMW
>>     >
>>     >
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>>
>>
>>
>> --
>> - Laurent Alquier
>> http://www.linfa.net
>



--
Yury V. Katkov
Laboratory of intelligent systems
of the Saint-Petersburg National University of Information Technologies, Mechanics and Optics, Russia
http://ailab.ifmo.ru