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From "Alex Popescu" <the.mindstorm.mailingl...@gmail.com>
Subject Re: Efficient way of loading multiple properties of a node?
Date Tue, 24 Oct 2006 09:27:07 GMT
On 10/24/06, Jukka Zitting <jukka.zitting@gmail.com> wrote:
> Hi,
>
> On 10/24/06, Alex Popescu <the.mindstorm.mailinglist@gmail.com> wrote:
> > You are right Julian, but the spec doesn't say anything about batch
> > propery fetching; so Steffan is right: it is an implementation detail.
> > And if the implementation proves itself to go over the wire to fetch
> > each property then this would be considered an important design bug in
> > that implementation.
>
> I'd call it a feature rather than a bug since there are cases where
> aggressive caching of property values is not a good idea, for example
> if you're just traversing the node tree, then prefetching the property
> values will just slow things down. In any case it's an important
> consideration that I certainly wouldn't discard as an implementation
> detail. In fact I'd call the property access performance a major
> non-functional feature, that we might want to specify some benchmarks
> for to guide application developers on what to expect.
>

You can look at it in both ways. And it is a delicate one. We cannot
ignore the fact that network round-trips are very expensive, nor the
points that you are raising :-).

> PS. There actually is one way to achieve batch property access in JCR,
> namely the XML export feature. Create a custom ContentHandler that
> simpy records the Attributes instance and ignores all other SAX event
> information. Note that the received XML attributes may be encoded as
> described in JSR 170, but for many use cases this is not a problem.
> It's a bit of a hack, but if you're limited by a network layer like
> JCR-RMI that needs to do a network roundtrip for each property access,
> it might be the best option there is...
>

Hmm... interesing. Never thought of this functionality in this way.

./alex
--
.w( the_mindstorm )p.

> BR,
>
> Jukka Zitting
>

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