Re: [Jrtg-users] insert() error - NullPointerException

[Laurent G. <lg...@gm...>]

Jonathan,

Alright, that makes sense. Now I'm just having some difficulties accessing
those methods through JMX.

lgeyer@xxx:/usr/local/jrtg$ java -jar
/usr/local/bin/cmdline-jmxclient-0.10.3.jar - localhost:8089
com.virtela.poller:type=RTGDBDriver pauseDBInserts
12/05/2008 18:42:40 -0500 org.archive.jmx.Client
com.virtela.poller:type=RTGDBDriver is not a registered bean

lgeyer@xxx:/usr/local/jrtg$ java -jar
/usr/local/bin/cmdline-jmxclient-0.10.3.jar - localhost:8089
com.virtela.poller:type=DBDriver pauseDBInserts
12/05/2008 18:42:47 -0500 org.archive.jmx.Client
com.virtela.poller:type=DBDriver is not a registered bean

What am I missing here?

Thanks for your help,

Laurent

On Fri, Dec 5, 2008 at 5:46 PM, Leech, Jonathan <jl...@vi...> wrote:

>  Laurent,
>
> Very good question. The RTGDBDriver has the commitAllTransactions(), and
> reconnectAll() methods exposed through JMX to do extactly that externally.
> This would help in scenarios of a planned maintenance, or an outage that is
> detected quickly. Also you should call pauseDBInserts() on the DBBuffer
> first. So the steps would be
> 1) pauseDBInserts()
> 2) commitAllTransactions()
> 3) perform database maintenance
> 4) reconnectAll()
> 5) resumeDBInserts().
>
> JRTG has not yet been instrumented to automatically reconnect to the
> database after certain fatal errors. The place to do this would be either
> the DBDriver class or in the ConnectionWrapper class. I intended to do so in
> the ConnectionWrapper class, there is even a comment at the top: // TODO:
> attempt to reconnect to the database after certain SQL errors. This
> recquires some knowledge of which errors should result in a reconnection and
> which shouldn't. A good place to find this kind of information might be
> JBoss connection pool logic, or a similar connection pooling library.
>
> The NPE is a bug. Line 193 of JRTGDBDriver should be modified to read: if
> (ps != null) ps.close(); It is masking the real SQLExceptions caused by the
> database restart.
>
> Also, if you have a firewall or some other evil device in between your
> poller and database, you should probably also add a call to
> setQueryTimeout() on the PreparedStatement prior to ps.execute() on line
> 178. I don't know specifically how the mySQL JDBC driver would react to a
> connection dropped by a firewall, or if it implements setQueryTimeout(), but
> I can attest to the fact that the Oracle JDBC driver will hang indefinitely
> on the execute() method if the connection is dropped, unless a timeout is
> provided.
>
> -Jonathan
>
>  ------------------------------
> *From:* Laurent Geyer [mailto:lg...@gm...]
> *Sent:* Friday, December 05, 2008 1:52 PM
> *To:* jrt...@li...
> *Subject:* [Jrtg-users] insert() error - NullPointerException
>
> Hi,
>
> So far so good. Have had jrtg running little over a month now and it's been
> solid.
>
> Unfortunately today I noticed I lost about two days worth of data. The date
> it stopped collecting coincided with a MySQL server restart following a
> MySQL upgrade.
>
> Dec 5, 2008 3:44:34 PM com.virtela.poller.DBDriver insert
> WARNING: insert() error.
> java.lang.NullPointerException
>         at com.virtela.poller.RTGDBDriver.insert(RTGDBDriver.java:193)
>         at com.virtela.poller.DBDriver.insert(DBDriver.java:220)
>         at com.virtela.poller.DBDriver.insert(DBDriver.java:200)
>         at com.virtela.poller.DBBuffer$3.call(DBBuffer.java:253)
>         at com.virtela.poller.DBBuffer$3.call(DBBuffer.java:250)
>         at
> java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
>         at java.util.concurrent.FutureTask.run(FutureTask.java:138)
>         at
> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:885)
>         at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
>         at java.lang.Thread.run(Thread.java:619)
>
> Is there any way I can reconnect the MySQL session and commit the inserts
> following a restart or loss of connectivity?
>
> Thanks,
>
> Laurent
>
>
>