Re: Querying and caching with large datasets

From: Jeen Broekstra <>
Date: Mon, 23 Jan 2006 15:09:37 +0100

David Huynh wrote:

> Jeen Broekstra wrote:
>> [snip]
>> Well, to be honest, we would of course encourage you to use Sesame
>> 2, since that is where your development can do the most good for us
>> and for other Sesame users. Then again, you are more familiar
>> probably with how Sesame 1 works, and we still do plan to do a few
>> Sesame 1.x releases. Also, keep in mind that Sesame 2 is Java 5
>> only, which may be a problem for you (I understand that for
>> Piggybank it is a problem as MacOSX still does not ship with Java 5
>> per default).
> I'm very tempted to upgrade to Sesame 2 for Piggy Bank, too... All
> the new features of Sesame 2 are quite irresistible.

"*gasp* David, come to the Dark Side... *rattle*"


>> As for stable releases: for Sesame 2, our plans are to be less
>> monolithic in our release strategy. There will be separate releases
>> of different components: a core Sesame module (containing APIs,
>> query engines, query models, and the main memory backend), and the
>> different persistent backends, web client and the parsers/writers
>> etc. will be distributed separately.
>> The way things currently are, we aim to have the Sesame 2 core
>> stable in about two months from now. The native store will be
>> available separately then as well (it is already released as part
>> of alpha-2 and as far as we have tested it is stable). The MySQL
>> backend and web client will probably be released a bit later, but
>> those are not really an issue for you, I guess.
> Jeen, do you foresee any change to the API before Sesame 2 core
> stable release?

We've just done our second alpha release, which is the first release
that contains a Java 5-specific API (returning typed collections and
such). I expect some minor modifications as a result of
early-adopter-feedback (and some additional testing of our own). Apart
from that, we expect the APIs to be stable now, with one major
exception: the query object model.

Sesame's query object model currently is 'self-evaluating'. We are
planning to separate the declarative part from the evaluation logic.
This allows us to make the object model more generic and to map
different query languages (such as SPARQL) to it easier. This will allow
tighter integration of Ryan Levering's SPARQL engine into Sesame and
thus: better performance.

For most users, this is not a problem as the query model is an internal
artifact that normal client code should not touch. But I can imagine
that for creating a query cache, this is an issue.

We are discussing the (re)design of the query model internally this
week. If necessary I will try and give some details of our plans when we
have our ideas straightened out (somewhere next week).

Received on Mon Jan 23 2006 - 14:07:51 EST

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