Hi Vanessa,
Please confirm the Virtuoso version you are using (virtuoso-t -?) and version
of the JDBC Driver (java virtuoso.jdbc3.Driver).
When you say the Virtuoso server totally stops, is it still running but just
not responding to SQL or HTTP request or has the server actually shutdown ?
If you can still connect via SQL with the Virtuoso "isql" command line tool can
you run the "status('')" command to determine the status of the database and
provide this also.
A copy of the "virtuoso.log" would also be useful to see to check for any
errors that might account for this behaviour.
I would also direct you to the Virtuoso performance and tuning guide:
http://docs.openlinksw.com/virtuoso/databaseadmsrv.html#ptune
Section 6.1.7.5.4. JDBC, which details the new to set the appropriate
transaction isolation level , which is read committed to minimise the
possibility of locks/deadlocks.
Best Regards
Hugh Williams
Professional Services
OpenLink Software
Web: http://www.openlinksw.com
Support: http://support.openlinksw.com
Forums: http://boards.openlinksw.com/support
Twitter: http://twitter.com/OpenLink
On 18 Feb 2011, at 12:52, Vanessa Lopez wrote:
> Hi all!
>
> I seem to have problems when I have two clients of my program
> accessing the same instance of virtuoso (even when the clients are
> independent), eventually one fails and virtuoso totally stops running.
>
> Virtuoso.jdbc3.VirtuosoException: Activity on a closed connection
> at virtuoso.jdbc3.VirtuosoConnection.getFuture(Unknown Source)
> at virtuoso.jdbc3.VirtuosoFuture.sendCancelFuture(Unknown Source)
> at virtuoso.jdbc3.VirtuosoFuture.nextResult(Unknown Source)
> at virtuoso.jdbc3.VirtuosoResultSet.process_result(Unknown Source)
> at virtuoso.jdbc3.VirtuosoResultSet.next(Unknown Source)
>
> Or:
> virtuoso.jdbc3.VirtuosoException: Connection failed: Connection refused
> at virtuoso.jdbc3.VirtuosoConnection.connect(Unknown Source)
> at virtuoso.jdbc3.VirtuosoConnection.connect(Unknown Source)
> at virtuoso.jdbc3.VirtuosoConnection.<init>(Unknown Source)
> at virtuoso.jdbc3.Driver.connect(Unknown Source)
> at java.sql.DriverManager.getConnection(DriverManager.java:582)
> at java.sql.DriverManager.getConnection(DriverManager.java:207)
>
> Each client opens and closes its own connection every time it wants to
> execute a query, I don't see how they can interfere with each other
> ( there are not static variables):
>
> Connection con = null;
> private ResultSet result;
>
> try{
> Class.forName(DRIVER);
> if(this.con != null)
> this.con.close(); // to close a previous connection
> con = null;
>
> con = DriverManager.getConnection(PROTOCOL+
> repository.getServerURL() + "/UID=" + repository.getLogin() + "/PWD="
> + repository.getPassword());
> Statement stmt = con.createStatement();
> stmt.setQueryTimeout (query_timeout);
> result = stmt.executeQuery("SPARQL " + sparql);
>
> }catch(Exception e){
> result = null;
> System.out.println("Fail to execute: " + sparql);
> e.printStackTrace();
> }
>
> // Do whatever with the results .. the connection will be closed next
> time we want to get a connection
>
> Thanks!! :-)
> Vanessa.
>
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