Re: piggy-bank installation in two pieces

From: Leo Sauermann <>
Date: Mon, 19 Dec 2005 13:07:58 +0100

16.12.2005 15:44, Stefano Mazzocchi:

> Leo Sauermann wrote:
>> So, I would be happy to seperate the sesame database from the XPI
>> plugin, but how to do this with good performance?
> Well, the only way to have good performance is to attach the rendering
> system with the triple store, so that they can communicate in-process
> instead of having to communicate thru a socket.
> ...
> What do you think?
I would say that we are on the right track. Simile has the intention to
seperate storage threads because of the Memory leak problem. Gnowsis has
the problem of Jena storage and wants to move to Sesame2 (for aperture).
When we both are finished, we can think better about this issue -
looking back at our experience.
 From our side, this looks like march 2006.

A problem in gnowsis are data updates: we have SKOS-like APIs where you
can add/remove SKOS:Concept instances and link them to each other, with
some background work todo. So parts of the gnowsis API need something
like the flickr API, a HTTP based simple API.
With updates we have the same problem as piggy-bank, regarding listeners
and RSS-like SPARQL.

> What I expect is some sort of RSS-like subscription service, where
> your piggy bank can "subscribe" to a particular sparql query and the
> system can understand, thru HTTP headers, if the content of the triple
> store has changed since the last time that query was issued.

So this issue is maybe interesting to others, too.
 From my point of view, "listening" and callbacks are always bad hacks
in http, so we will see which bad hack will be useful for it. Callbacks
in CORBA or SOAP are also painful, we can expect similar complexity - OR
use the RSS paradigm of continous polling. Probably the RSS approach
will succeed, it is simple and robust. (and takes bandwidth and CPU
time, but who cares).

So Stefano: please keep us updated about your ongoing progress of
seperating piggy-bank!

DI Leo Sauermann
P.O. Box 2080          Fon:   +49 631 205-3503
67608 Kaiserslautern    
Germany                Mail:
Received on Mon Dec 19 2005 - 12:01:07 EST

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