Re: haystack + jena

Hi David,

I've just gotten a new box that is capable of running Haystack on my 
desk, and made the mistake of telling it where my IMAP server is 
located; I have little over 3000 messages in my Inbox ;).  Oops, looks 
like the system died.

There are a couple of very high level issues that I suspect need to be 
resolved for Haystack/Jena integration.  Based on the requirements 
research I did earlier this year, if Jena is to replace 
Cholesterol/Adenine then Jena will need to support event triggers and 
probably incorporate the S, P, O and O, P, S indices used by Haystack, 
and Haystack would have to translate the Adenine inferences into one of 
the inferencing languages that Jena supports.  However, as I understand 
it, Haystack is normally configured to query its models in memory with 
currently unused graphs swapped out to disk.  If integrated at the pager 
level then Haystack could continue using Cholesterol and Adenine, and 
use e.g Josecki simply as a file transfer utility for paged subgraphs.

Although the second approach has the effect of sharing information 
between Haystack and Jena, it is really more like import/export than 
actual integration.  The huge number of triples created by Adenine will 
probably overwhelm Jena's storage capabilities, and doesn't make good 
use of Jena's built in inferencing.  Arguably this would mean that Jena 
should only be used to export DSpace data to Haystack through this 
interface, and not for storage of Haystack triples as a whole.

I can copy out the relevant parts of our requirements doc if you are 
interested.

Cheers,
-kls

Seaborne, Andy wrote:

>David,
>
>In the first instance, that would be me.
>
>There are two possible scenarios: using a Joseki server and remotely
>connecting Haystack to that Joseki server (for example, the new history
>store) or connecting Haystack to a external but local Jena model (for
>example, one held in a database).  
>
>Both these are interesting; both can be done with the same query approach
>although the tighter local binding may also be capable of finer grain
>access.  I can help with either.
>
>There is also the open mailing list mailto:jena-dev@goups.yahoo.com for
>developers using Jena which everyone should feel free to use.  This is the
>place for Jena and Joseki questions.
>
>  
>
>>I think this should be relatively straightforward once the
>>information starts to flow.
>>    
>>
>
>I hope so as well.
>
>	Andy
> 
>-----Original Message-----
>From: David R. Karger [mailto:karger@theory.lcs.mit.edu] 
>Sent: 10 September 2003 15:46
>To: www-rdf-dspace@w3.org
>Subject: haystack + jena
>
>
>
>
>Something we've been discussing for a while (and an important step for
>simile) is to get haystack working as front end against a jena back
>end.  I've identified a haystacker to work on this from our end.  Is
>there an HPer who can similarly accept responsiblity for the jena side
>of things?  I think this should be relatively straightforward once the
>information starts to flow.
>
>thanks
>David
>  
>


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Received on Wednesday, 10 September 2003 12:35:44 UTC