Hi!
On Mon, Dec 22, 2014 at 08:46:39PM +0000, Andy Seaborne wrote:
> If there a a few connections (<=2) and large numbers of small
> queries issued over each connection. Assuming there are no sorts and
> no timeouts set, then the execution of the query should be all on
> the thread that it came in on. And you 8 (shame it's not 8*8!)
> cores. Do you have couple of example queries you can share?
Sure! It is typically something like
PREFIX dc: <http://purl.org/dc/elements/1.1/> PREFIX :
<http://dbpedia.org/resource/> PREFIX rdfs:
<http://www.w3.org/2000/01/rdf-schema#> PREFIX dbpedia2:
<http://dbpedia.org/property/> PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX dbo: <http://dbpedia.org/ontology/> PREFIX owl:
<http://www.w3.org/2002/07/owl#> PREFIX xsd:
<http://www.w3.org/2001/XMLSchema#> PREFIX dbpedia: <http://dbpedia.org/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX skos:
<http://www.w3.org/2004/02/skos/core#> SELECT ?t WHERE { { ?res
rdfs:label "California"@en } UNION { ?redir dbo:wikiPageRedirects
?res . ?redir rdfs:label "California"@en } ?res rdf:type ?t
FILTER ( ! regex(str(?res), "^http://dbpedia.org/resource/[^_]*:";, "i") ) }
or variations for different labels.
> Does the CPU load increase to start with, then drops off?
> Fuseki/TDB is typically CPU-busy when the OS warms up and the
> working set index files is memory.
I see no obvious CPU load variations. A lot of the queries are
repeated (so quickly warmed cache) and the server runs the user software
itself too.
> Maybe the first thing to try is to point jvisualvm (in the JDK) or
> some other monitoring tool at the Fuseki process and see if there is
> any evidence. The thread dump would be useful. (jconsole even has a
> "Detect Deadlock" which I have never used but the button label is
> suggestive)
Hmm, seems like that requires a GUI. I can give that a whirl at the
end of the week as I have only remote access to the machine until then.
--
Petr Baudis
If you do not work on an important problem, it's unlikely
you'll do important work. -- R. Hamming
http://www.cs.virginia.edu/~robins/YouAndYourResearch.html
