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Posted to users@jena.apache.org by Diogo FC Patrao <dj...@gmail.com> on 2012/04/24 19:43:59 UTC
SERVICE / ARQ
Hello
I wrote a SPARQL query with two Service clauses, to get information from
two different endpoints. Will ARQ query both endpoints simultaneously? Or
will it serialize the calls?
I'm almost certain it won't paralelize, but you never know...
Thanks!
--
diogo patrão
Re: SERVICE / ARQ
Posted by Rob Vesse <ra...@ecs.soton.ac.uk>.
On 4/24/12 12:34 PM, "Diogo FC Patrao" <dj...@gmail.com> wrote:
>> From personal experience sometimes it is much more fun to play around
>>with
>
> open source software than do your PhD - sometimes you just need a break
>;-)
>>
>
>Well, part of my experiments involved D2R and ARQ, so that was fun. Now
>I'm
>on the "writing stuff" stage, the hard and difficult one =)
I can sympathize with that, took me 4 months slog to write the bulk of
mine up and then another 4 months to finish the final chapter (though I
did move countries and start a new job in that period!)
Good luck with it
Rob
>
>dfcp
>
>
>Not saying you shouldn't try and finish your PhD though!
>>
>> Rob
>>
>> >
>> >Thanks,
>> >
>> >--
>> >diogo patrão
>> >
>> >
>> >
>> >
>> >
>> >On Tue, Apr 24, 2012 at 3:39 PM, Andy Seaborne <an...@apache.org> wrote:
>> >
>> >> On 24/04/12 18:43, Diogo FC Patrao wrote:
>> >>
>> >>> Hello
>> >>>
>> >>> I wrote a SPARQL query with two Service clauses, to get information
>> >>>from
>> >>> two different endpoints. Will ARQ query both endpoints
>>simultaneously?
>> >>>Or
>> >>> will it serialize the calls?
>> >>>
>> >>> I'm almost certain it won't paralelize, but you never know...
>> >>>
>> >>
>> >> It doesn't.
>> >>
>> >> (feel free to submit a patch!)
>> >>
>> >> Andy
>> >>
>> >>
>> >>> Thanks!
>> >>>
>> >>> --
>> >>> diogo patrão
>> >>>
>> >>>
>> >>
>>
>>
Re: SERVICE / ARQ
Posted by Diogo FC Patrao <dj...@gmail.com>.
> From personal experience sometimes it is much more fun to play around with
open source software than do your PhD - sometimes you just need a break ;-)
>
Well, part of my experiments involved D2R and ARQ, so that was fun. Now I'm
on the "writing stuff" stage, the hard and difficult one =)
dfcp
Not saying you shouldn't try and finish your PhD though!
>
> Rob
>
> >
> >Thanks,
> >
> >--
> >diogo patrão
> >
> >
> >
> >
> >
> >On Tue, Apr 24, 2012 at 3:39 PM, Andy Seaborne <an...@apache.org> wrote:
> >
> >> On 24/04/12 18:43, Diogo FC Patrao wrote:
> >>
> >>> Hello
> >>>
> >>> I wrote a SPARQL query with two Service clauses, to get information
> >>>from
> >>> two different endpoints. Will ARQ query both endpoints simultaneously?
> >>>Or
> >>> will it serialize the calls?
> >>>
> >>> I'm almost certain it won't paralelize, but you never know...
> >>>
> >>
> >> It doesn't.
> >>
> >> (feel free to submit a patch!)
> >>
> >> Andy
> >>
> >>
> >>> Thanks!
> >>>
> >>> --
> >>> diogo patrão
> >>>
> >>>
> >>
>
>
Re: SERVICE / ARQ
Posted by Robert Vesse <rv...@yarcdata.com>.
On 4/24/12 11:47 AM, "Diogo FC Patrao" <dj...@gmail.com> wrote:
>Hi Andy
>
>Thanks for the confirmation. As for a patch, let me finish my phd and then
>I can think of something else in my life =)
>
>Rob: this is some very important insight you brought here! It made me
>wonder whether there's a similar thing such as EXPLAIN in ARQ.
>From personal experience sometimes it is much more fun to play around with
open source software than do your PhD - sometimes you just need a break ;-)
Not saying you shouldn't try and finish your PhD though!
Rob
>
>Thanks,
>
>--
>diogo patrão
>
>
>
>
>
>On Tue, Apr 24, 2012 at 3:39 PM, Andy Seaborne <an...@apache.org> wrote:
>
>> On 24/04/12 18:43, Diogo FC Patrao wrote:
>>
>>> Hello
>>>
>>> I wrote a SPARQL query with two Service clauses, to get information
>>>from
>>> two different endpoints. Will ARQ query both endpoints simultaneously?
>>>Or
>>> will it serialize the calls?
>>>
>>> I'm almost certain it won't paralelize, but you never know...
>>>
>>
>> It doesn't.
>>
>> (feel free to submit a patch!)
>>
>> Andy
>>
>>
>>> Thanks!
>>>
>>> --
>>> diogo patrão
>>>
>>>
>>
Re: SERVICE / ARQ
Posted by Diogo FC Patrao <dj...@gmail.com>.
Hi Andy
Thanks for the confirmation. As for a patch, let me finish my phd and then
I can think of something else in my life =)
Rob: this is some very important insight you brought here! It made me
wonder whether there's a similar thing such as EXPLAIN in ARQ.
Thanks,
--
diogo patrão
On Tue, Apr 24, 2012 at 3:39 PM, Andy Seaborne <an...@apache.org> wrote:
> On 24/04/12 18:43, Diogo FC Patrao wrote:
>
>> Hello
>>
>> I wrote a SPARQL query with two Service clauses, to get information from
>> two different endpoints. Will ARQ query both endpoints simultaneously? Or
>> will it serialize the calls?
>>
>> I'm almost certain it won't paralelize, but you never know...
>>
>
> It doesn't.
>
> (feel free to submit a patch!)
>
> Andy
>
>
>> Thanks!
>>
>> --
>> diogo patrão
>>
>>
>
Re: SERVICE / ARQ
Posted by Andy Seaborne <an...@apache.org>.
On 24/04/12 18:43, Diogo FC Patrao wrote:
> Hello
>
> I wrote a SPARQL query with two Service clauses, to get information from
> two different endpoints. Will ARQ query both endpoints simultaneously? Or
> will it serialize the calls?
>
> I'm almost certain it won't paralelize, but you never know...
It doesn't.
(feel free to submit a patch!)
Andy
>
> Thanks!
>
> --
> diogo patrão
>
Re: SERVICE / ARQ
Posted by Rob Vesse <ra...@ecs.soton.ac.uk>.
ARQ will serialize the calls and may in fact make many calls for each
SERVICE clause depending on preceding bindings in the queries at that
point e.g.
SELECT *
WHERE
{
?s a <some-type>
SERVICE <some-endpoint> { ?s <some-predicate> ?value }
}
Since part of that query is on your local data and occurs first in the
query (both as written and as algebra because remember SPARQL is bottom up
evaluation and ARQ will evaluate the LHS of the join first) ARQ will first
gather things matching the ?s a <some-type> pattern and then use those
solutions to create multiple queries to the endpoint where ?s is
substituted for each possible value
This is often a better execution strategy than blindly sending the remote
query and hoping the results returned (which may be subject to endpoint
limits) actually match the local results.
Rob
On 4/24/12 10:43 AM, "Diogo FC Patrao" <dj...@gmail.com> wrote:
>Hello
>
>I wrote a SPARQL query with two Service clauses, to get information from
>two different endpoints. Will ARQ query both endpoints simultaneously? Or
>will it serialize the calls?
>
>I'm almost certain it won't paralelize, but you never know...
>
>Thanks!
>
>--
>diogo patrão