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RE: Multiple queries is a single request

From: Phil Dawes <pdawes@users.sf.net>
Date: Wed, 2 Jun 2004 17:34:03 +0100
Message-ID: <16574.379.295415.588779@gargle.gargle.HOWL>
To: "Seaborne, Andy" <andy.seaborne@hp.com>
Cc: Chris Bizer <chris@bizer.de>, www-rdf-interest@w3.org

Hi Andy,

Seaborne, Andy writes:
 > Phil,
 > 
 > I have considered it and multiple queries per request can be useful.
 > However, the need for it is lessened because HTTP request can be issued one
 > after another on the same connection without first getting a reply.  This is
 > not the same as merging at the server but does mean many queries can be
 > issued at a time and independent queries don't an accumulate the
 > round-trip-time (RTT).  The language APIs to HTTP I have used don't make
 > this easy but HTTP does allow it.
 > 

Cool - I didn't know that. 
Have found http://asynchttp.sourceforge.net/ so will give this a go.

BTW, do you know if the common servers support this (e.g. apache, tomcat,
jetty, IIS?).

 > > 1) a query to retrieve the resource information
 > >     'select ?p, ?o where (foo:bah, ?p, ?o)'
 > > 2) a query to retrieve the labels for the properties
 > >     'select ?p, ?o ?l where (foo:bah, ?p, ?o) (?p rdfs:label ?l)'
 > > 3) a query to retrieve the labels for the objects
 > >     'select ?p, ?o ?l where (foo:bah, ?p, ?o) (?o rdfs:label ?l)'
 > 
 > I would do this as a "fetch" with a custom handler for the fetch operation.
 > If you think of "fetch" as "describe" then you are defining one such
 > operation that gets (foo:bah, ?p, ?o) and any labels for ?p and ?o.  "fetch"
 > isn't supposed to be a fixed operation, it is defined by the server.
 > 

I'm afraid that is the reason I'm not using it - veudas is designed to
be a generic browser/editor for rdf stores, so requiring the client to
implement/install a special fetch handler wont really work. (esp. as
the person using veudas isn't necessarily the same person maintaining
the store).

Thanks again - I'll let you know how I get on with the async http
stuff.

Cheers,

Phil
Received on Wednesday, 2 June 2004 12:34:59 GMT

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