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From Alain RODRIGUEZ <arodr...@gmail.com>
Subject Re: Tuning cassandra (compactions overall)
Date Tue, 22 May 2012 12:42:54 GMT
"not sure what you mean by
And after restarting the second one I have lost all the consistency of
my data. All my statistics since September are totally false now in
production

Can you give some examples?"

After restarting my 2 nodes (one after the other), All my counters
have become wrong. The counters values were modified by the restart.
Let's say I had a counter column called 20120101#click that value was
569, after the restart the value has become 751. I think that all the
values have increased (I'm not sure) but all counters have increased
in differents way, some values have increased a lot other just a bit.

"Counter are not idempotent so if the client app retries TimedOut
requests you can get an over count. That should not result in lost
data."

Some of these counters haven't be written since September and have
still been modified by the restart.

"Have you been running repair ?"

Yes, Repair didn't helped. I have the feeling that repairing doesn't
work on counters.

I have restored the data now, but I am afraid of restarting any node.
I can remain in this position too long...

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