Are you sure that named graphs have better performance?
I'm not a specialist, and I'd like to know other users' opinion about that
question. I thinks it depends both on the structure of your data and the
queries you run.
My use case consisted in using a dataset with +/- 168 M triples, including +/- 10 M
titles (triples like ?s dcterms:title "some words"), and running queries with
FILTER(REGEX()) :
-- a query like this took a long time (1 min or more) :
SELECT * WHERE {
?edition dcterms:title ?title .
FILTER(REGEX(?title, $word, 'i')) .
?edition rdarelationships:expressionManifested ?expr .
?expression bnf-roles:r70 ?author .
?author foaf:familyName $name
}
-------------
-- whereas a query like this one takes about 1 sec :
SELECT * WHERE {
GRAPH <:titles> {
?edition dcterms:title ?title .
FILTER(REGEX(?title, $word, 'i'))
}
?edition rdarelationships:expressionManifested ?expr .
?expression bnf-roles:r70 ?author .
?author foaf:familyName $name
}
----------------
So, depending on your data, it might be more efficient to use named graphs, e. g. :
SELECT ?rel (count (?rel) as ?co)
where {
GRAPH <:names> { ?object MKG:English_name 'Pyrilamine' } # <-- HERE : named
graph for names
?RelAttr owl:annotatedTarget ?object ;
owl:annotatedSource ?subject ;
owl:annotatedProperty ?rel ;
MKG:pyear '1967' .
}
group by ?rel
limit 10
-------------------------------
Then how to build named graphs?
There are several ways, here are 3 methods :
#1) when uploading files in Fuseki web interface, specify the graph URI for the
file
#2) use tdbloader : java -Xms4096m -Xmx4096m -cp ./fuseki-server.jar
tdb.tdbloader --graph=$namedGraph --tdb=$configFile $f
#3) use SPARQL INSERT + DELETE
#1 & #2 are fast, but all the triples of the file go into the same graph, so
maybe you have to have to modify your files first.
#3 is slower, but you don't have to modify your files. see my question on
StackOverflow :
https://stackoverflow.com/questions/48500404/sparql-offset-whithout-order-by-to-get-all-results-of-a-query
Le 07/12/2018 à 18:16, HYP a écrit :
OK. I explain my project in the following
The KG schema is composed of a set of semantic types like disease or drugs, and
a set of relations like treated_by(disease, drug).
Then each instance relation, like treated_by(disease_1, drug_1) has an
annotation property 'year' which means this triple occur in the 'year'.
My query has two steps. Firstly, query the related triples about some drug,
like Pyrilamine, and group them according to the relation types and give a
count. Secondly, query the related nodes in one relation type.
The first step query, like:
SELECT ?rel (count (?rel) as ?co)
where {
?object MKG:English_name 'Pyrilamine' .
?RelAttr owl:annotatedTarget ?object ;
owl:annotatedSource ?subject ;
owl:annotatedProperty ?rel ;
MKG:pyear '1967' .
}
group by ?rel
limit 10
On 12/8/2018 01:00，ajs6f<aj...@apache.org> wrote：
Let's slow down here a bit.
We can't give you any reasonable advice until you tell us _much_ more about
your work. What is the data like? What kinds of queries are you doing? How are
you running them? What do you expect to happen?
Please give us a great deal more context.
ajs6f
On Dec 7, 2018, at 11:45 AM, HYP <hyphy...@163.com> wrote:
I store the 1.4B triples in two steps. Firstly, I made 886 rdf files, each of
which contains 1615837 triples. Then, I upload them into TDB using Fuseki.
This is a huge job. Are you sure that named graphs have better performance?
Then how to build named graphs?
On 12/7/2018 23:48，Vincent Ventresque<vincent.ventres...@ens-lyon.fr> wrote：
Do you mean -Xms = 64G ?
N.B. : with 1.4 B triples, you should have better performance using
named graphs.
Le 07/12/2018 à 16:37, 胡云苹 a écrit :
My memory is 64G and my setting is no upper limit.
On 12/7/2018 23:34，Vincent Ventresque<vincent.ventres...@ens-lyon.fr>
<mailto:vincent.ventres...@ens-lyon.fr> wrote：
Hello
How do you run fuseki? you can increase java memory limit with
java options :
java -jar -Xms4096m -Xmx4096m fuseki-server.jar
(where 4096m = 4 Go, but could be 8192m or more)
N.B. : I'm not a specialist, don't know if -Xms and -Xmx must be
the same
If I remember correctly the memory limit is 1.2 Go when you run
'./fuseki start' or './fuseki-server'
Vincent
Le 07/12/2018 à 16:23, 胡云苹 a écrit :
Dear jena,
I have built a graph with 1.4 billion triples and store it as a
data set in TDB through Fuseki upload system. Now, I try to make
some sparql search, the speed is very slow.
For example, when I make the sqarql in Fuseki in the following,
it takes 50 seconds. How can I improve the speed?
-
