Samur Araujo wrote:
Dear Sherman, note that no matter what query tool or browser you are
using, it is necessary to tune the underline database to achieve your
performance requirements. Enabling all Explorator's repositories mean
that you want to query several databases and sparql enpoint at the
same time. When you do so, Explorator queries a federation of
endpoints, groups all results and retrieves an unique set of triples.
Of course, you should keep in mind that we have not tune our sesame or
virtuoso instances to achieve the best performance, also we have not
created FTS for sesame or virtuoso yet. Again, such performance
problem will be encountered no matter what system you use.
About sesame, we are using it just as a proof of concept, however you
can extend Explorator adapters to connect to others rdf repositories.
At the moment, Explorator is able to connect to whatever sparql
endpoint (we have tested it for Virtuoso and Sesame endpoints.) you
want. Keep in mind that we can not guarantee performance for external
endpoints. Most of them retrieve timeout when you do a complex query
that takes longer that a few milleseconds.
Samur,
Are you exploiting the "Retry" feature of Virtuoso's Anytime Query function?
Look at: http://lod.openlinksw.com/sparql (note the options at the
bottom of the page which are part of our sparql protocol extensions).
You have to think in terms of location aware cost-optimization if you
want to venture into the federated query realm (SPARQL or SQL). We've
done this work long time ago re. SQL (the Virtual DBMS aspect of
Virtuoso), and similar work will be delivered re. SPARQL in due course
(the SPARQL-BI extentions and the Anytime Query functionality are
critical infrastructure components for this endeavor).
Kingsley
Regards,
Samur Araujo
TECWEB
On Tue, Jun 2, 2009 at 11:45 AM, Samur Araujo <[email protected]
<mailto:[email protected]>> wrote:
Dear Sherman, Notes that doesn
On Tue, Jun 2, 2009 at 11:43 AM, Sherman Monroe
<[email protected] <mailto:[email protected]>> wrote:
Daniel,
I see some interesting concepts worth exploring here, e.g.
using windows (with paging inside the window). But as I refine
my query, there isn't any apparent context that orients me in
the data. E.g. how does one box/set relate to the others.
I notice you're using Sesame, do you think it can scale? I
tried selecting several repositories at once, but the system
seems to hang awhile (couple of minutes) before returning
results.
-sherman
On Tue, Jun 2, 2009 at 8:26 AM, Daniel Schwabe
<[email protected] <mailto:[email protected]>> wrote:
Kingsley Idehen wrote:
Daniel Schwabe wrote:
Sherman,
as another alternative, I urge you to take a look
at Explorator [1] (there is a short movie
explaining the basic idea, you can also play with
the live interface), which can do all of what you
said, and more.
It provides a more general exploration paradigm,
of which the example you give below is only one of
the possibilities...
Best
Daniel
[1] http://www.tecweb.inf.puc-rio.br/explorator.
Daniel,
When you speak to the <http://lod.openlinksw.com>
instance, do you use SPARQL Protocol or the Faceted
Browsing REST API or either depending on task ?
I suspect SPARQL protocol, but please confirm.
We use the SPARQL protocol, because the code is geared to
deal with any SPARQL endpoint. The only thing we have
customize, precisely because of lack of standardization,
is the FTS function. There is special code to detect when
the server is Virtuoso, to use bif:contains. Other than
that, is uses standard constructs.
If I understand it correctly, the Faceted Browsing REST
API would not allow us to issue the kinds of queries we
need; as I mentioned in earlier messages, Explorator is
much more than pure faceted browsing.
Did you have anything specific in mind in this regard?
Cheers
D.
--
Thanks,
-sherman
I pray that you may prosper in all things and be healthy, even
as your soul prospers
(3 John 1:2)
--
Regards,
Kingsley Idehen Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO
OpenLink Software Web: http://www.openlinksw.com
