On 2014-05-07 12:52, Kingsley Idehen wrote:
> On 5/7/14 4:37 AM, Bart Vandewoestyne wrote:
>> Hello list,
>>
>> I'm confused. I have a SPARQL-query of the following form (slightly
>> obfuscated because of NDA-restrictions):
>>
>> SELECT ?val (COUNT(?id) as ?vc)
>> WHERE
>> {
>> ?id<http://foo.bar/description> ?val.
>> ?id<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
>> <http://foo.bar/SomeType>.
>> }
>> GROUP BY ?val
>> ORDER BY DESC(?vc)
>> LIMIT 15
>>
>> When running this query multiple times, it returns different values for
>> the ?vc counts... so it seems not deterministic. I don't see why. Is
>> this query really not deterministic???
>>
>> I'm running this on Virtuoso Version 7.1.1-dev.3208-pthreads as of Apr
>> 17 2014.
>>
>> If this is not the right mailinglist to pose this question, please let
>> me know the appropriate channel for this type of question.
>>
>> Kind regards,
>> Bart
>
> Please check the query timeout settings. This could be in the /sparql UI
> or in the INI (see the [SPARQL] section).
>
> Basically, Virtuoso has an "Anytime Query" feature whereby query
> solutions are produced relative to query timeouts. Thus, you can
> increase the timeout to ensure the SPARQL solution isn't comprised of
> what would appear to be partial results.
>
> Remember, unlike SQL, SPARQL is about propositions in an Open World etc..
Hello Kingsley,
In the [SPARQL] section of my virtuoso.ini, I have the
MaxQueryCostEstimationTime commented out, and the MaxQueryExecutionTime
is set to 600 (seconds, according to the docs). For as far as I know, I
am not using a command like
set result_timeout == <expression>;
as described in the documentation in section "Anytime queries". The
database I'm working with is 142 GB large and stored locally on my disk.
I am not changing or updating any data, just doing select queries. My
full config file is online at
https://www.dropbox.com/sh/hm0nj8q0j6pnx1k/AABaXTFHDy5JrZUTenJuGqqva/virtuoso_ini.txt
The query that I'm talking about, takes about 14 to 18 seconds, way
below the 600 seconds MaxQueryExecutionTime, so I don't think that's the
problem.
I am now testing with the latest development branch, being Version
07.10.3208-pthreads (commit bea4a6da40258afeebf4be3e18f299ec8f11967c).
Furthermore if I test with an older version (07.00.3203-pthreads for
Linux as of Mar 26 2014, commit
48f0ef879b913c5d3b306c1f83390079c5416fe6) then different runs of the
same query *do* return the same ?vc counts.
Any suggestion?
Kind regards,
Bart
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