On 24/11/17 09:30, Mohammad Noorani Bakerally wrote:
Just checked something, I've used the SPARQL Client YASGUI and the sparql
query is answered properly, can we deduce that the issue is with the client
?
That would seem most likely, something on the network path from client
to server - it is so hard to be definite about these low level errors.
Andy
On Fri, Nov 24, 2017 at 10:22 AM, Mohammad Noorani Bakerally <
[email protected]> wrote:
Yes, I'm going to check the logs, but so far, a query like SELECT * WHERE
{ ?s ?p ?o .} LIMIT 10 is properly handled and results is returned, I can
share the sparql endpoint, it is http://opensensingcity.
emse.fr/sparql/bistro, it's just for some testing purposes, so if I
understand, if a query is answered, Fuseki must be properly configured with
apache, the resets happens immediately and there is no delay, i've not
checked the log but it seems the request doesn't even go to the server
On Fri, Nov 24, 2017 at 10:03 AM, Andy Seaborne <[email protected]> wrote:
HttpException: -1 Unexpected error making the query:
java.net.SocketException: Connection reset
This is a problem at a low level in the networking stack (fake status
code -1 from Jena also says it's not an HTTP error). The other end
responded with a TCP RST (the connection reset bit) which is attempt to use
a connection the other end thinks is closed or does not exist.
There are many reasons that can cause this - some kind of network
environmental issue between client and server.
Having a reverse proxy (RP) in front of the Fuseki server is one possible
cause e.g. when Fuseki isn't there but the reverse proxy is, there can be a
rejection at the TCP level. Or the RP has rebooted reboot.
There are many reasons (StackOverflow has many questions about this).
Check the Fuseki server log - did the query even reach the server? Resets
usually happen at the start (e.g after a long period of no use and the RP
has timed the connection out (Fuseki, standalone, hasn't configured to
Jetty to do this)..
If it did reach the server, then some intermediate may have forcefully
closed the connection.
Andy
On 23/11/17 22:38, Mohammad Noorani Bakerally wrote:
I am getting an exception when executing the following a valid construct
query on Fuseki via jena. Any idea about this problem ?
The query:
==============
PREFIX dcat: <http://www.w3.org/ns/dcat#>
PREFIX data: <http://opensensingcity.emse.fr/LDPDesign/data/>
PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
PREFIX : <http://opensensingcity.emse.fr/LDPDesignVocabulary/>
CONSTRUCT { <
https://bistrotdepays.opendatasoft.com/id/theme/Sport%2C%20Loisirs> ?p
?o .
} WHERE { <
https://bistrotdepays.opendatasoft.com/id/theme/Sport%2C%20Loisirs> ?p
?o .
}
The exception:
============
HttpException: -1 Unexpected error making the query:
java.net.SocketException: Connection reset
at org.apache.jena.sparql.engine.http.HttpQuery.rewrap(HttpQuer
y.java:374)
at org.apache.jena.sparql.engine.http.HttpQuery.execGet(HttpQue
ry.java:337)
at org.apache.jena.sparql.engine.http.HttpQuery.exec(HttpQuery.java:288)
at
org.apache.jena.sparql.engine.http.QueryEngineHTTP.execConst
ructWorker(QueryEngineHTTP.java:465)
at
org.apache.jena.sparql.engine.http.QueryEngineHTTP.execModel
(QueryEngineHTTP.java:428)
at
org.apache.jena.sparql.engine.http.QueryEngineHTTP.execConst
ruct(QueryEngineHTTP.java:389)
at
org.apache.jena.sparql.engine.http.QueryEngineHTTP.execConst
ruct(QueryEngineHTTP.java:384)
at
loader.configuration.SPARQLDataSource.executeGraphQuery(SPAR
QLDataSource.java:43)
at genPLDPD.Evaluation.evalRM(Evaluation.java:136)
