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From ruslan usifov <ruslan.usi...@gmail.com>
Subject Re: Nodes frozen in GC
Date Tue, 08 Mar 2011 13:49:40 GMT
2011/3/8 Peter Schuller <peter.schuller@infidyne.com>

>
> (1) I cannot stress this one enough: Run with -XX:+PrintGC
> -XX:+PrintGCDetails -XX:+PrintGCTimeStamps and collect the output.
> (2) Attach to your process with jconsole or some similar tool.
> (3) Observe the behavior of the heap over time. Preferably post
> screenshots so others can look at them.
>
>
> I'm not sure that up to the end you has understood, sorry

I launch cassandra with follow gc login options (but doesn't mention about
this before, because of this document
http://www.datastax.com/docs/0.7/troubleshooting/index#nodes-seem-to-freeze-after-some-period-of-time,
there is no any mention about gc.log ):

JVM_OPTS="$JVM_OPTS -XX:+PrintGCApplicationStoppedTime"
JVM_OPTS="$JVM_OPTS -Xloggc:/var/log/cassandra/gc.log"


And detect that nodes frozen with follow log entires

Total time for which application threads were stopped: 30.0000957 seconds

And so on. Also when i think that nodes are frozen i got
UnavailableException and TimeOutException, about 20-30 times (i make few
Attempts (300 with 1 sec sleep) before final fail), follow fragment of code
illustrate what i do

        for(; $l_i < 300; ++$l_i)
        {
            try
            {
                $client->batch_mutate($mutations,
cassandra_ConsistencyLevel::QUORUM);
                $retval = true;

                break;
            }
            catch(cassandra_UnavailableException $e)
            {
                array_push($l_exceptions, get_class($e));
                sleep(1);
            }
            catch(cassandra_TimedOutException $e)
            {
                array_push($l_exceptions, get_class($e));
                sleep(1);
            }
            catch(Exception $e)
            {
                $loger->err(get_class($e).': '.$e->getMessage());
                $loger->err($mutations);

                break;
            };
        };

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