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RE: Multiple queries is a single request

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Wed, 2 Jun 2004 17:47:32 +0100
Message-ID: <E864E95CB35C1C46B72FEA0626A2E808031A9CE0@0-mail-br1.hpl.hp.com>
To: Phil Dawes <pdawes@users.sourceforge.net>
Cc: Chris Bizer <chris@bizer.de>, www-rdf-interest@w3.org



-------- Original Message --------
> From: Phil Dawes <>
> Date: 2 June 2004 17:35
> 
> 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?).

Yes, I think they do support persistent connections.  Also, they are
multithreaded (should your queries take a long time to execute, longer than
the RTT.

	Andy

> 
>  > > 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 12:48:34 GMT

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