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Re: optimizing container pages serialization to enable streaming

From: Ashok Malhotra <ashok.malhotra@oracle.com>
Date: Tue, 12 Nov 2013 08:54:43 -0500
Message-ID: <52823323.9090308@oracle.com>
To: public-ldp-wg@w3.org
The XML Query and XSLT folks have long used streaming as a fundamental usecase.
Do you want me to ask them for implementations that support streaming?
All the best, Ashok
On 11/11/2013 9:32 PM, Wilde, Erik wrote:
> hello eric.
>
> On 2013-11-11, 15:25 , "Eric Prud'hommeaux" <eric@w3.org> wrote:
>> Yup. C's code works both on S1 and S2. It just works better on S2. A
>> non-streaming client works identically well with S1 and S2.
> after thinking about this a little more, i am wondering how relevant the
> optimization is to begin with. do we have any data that would tell us that
> this might be a problem? for example, while the inherently ordered XML of
> feeds would easily allow streaming parsing, i am not aware of any
> implementation that actually does that (using SAX). instead, what usually
> happens is that implementations use DOM, which first reads the whole
> resource, builds the internal XML tree, and then the code starts working
> with that complete tree.
>
> in DOM/XML, the very fuzzy rule of thumb is that a DOM tree needs 10x as
> much memory as the source file. i would assume for RDF there's a similar
> rough guesstimate relating serializations and in-memory models? the thing
> is that neither feeds nor LDP are made for sharing/exchanging massive
> amounts of data. they are loosely coupled protocols to allow easy resource
> access. given today's machines, it may be safe to assume that 100mb of
> runtime memory consumption seems tolerable. in XML-land, that would
> translate to a resource size of 10mb. i haven't seen many feeds exceeding
> that size: you can control by page size, and you can also control by not
> randomly embedding everything in a feed (for example, podcasts are really
> small, because the large video files are linked and not embedded).
>
> just wondering: do we have any guesstimates of RDF memory requirements,
> and do we really plan for scenarios where LDP resources are exceeding the
> resulting maximum resource sizes we might want to see?
>
> thanks and cheers,
>
> dret.
>
>
Received on Tuesday, 12 November 2013 13:55:14 UTC

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