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From Jiang Chen <>
Subject Re: Updates lost
Date Tue, 30 Aug 2011 17:31:02 GMT
Looks like the theory is correct for the java case at least.

The default timestamp precision of Pelops is millisecond. Hence the
problem as explained by Peter. Once I supplied timestamps precise to
microsecond (using System.nanoTime()), the problem went away.

I previously stated that sleeping for a few milliseconds didn't help.
It was actually because of the precision of Java Thread.sleep().
Sleeping for less than 15ms often doesn't sleep at all.

Haven't checked the Python side to see if it's similar situation.



On Tue, Aug 30, 2011 at 9:57 AM, Jiang Chen <> wrote:
> It's a single node. Thanks for the theory. I suspect part of it may
> still be right. Will dig more.
> On Tue, Aug 30, 2011 at 9:50 AM, Peter Schuller
> <> wrote:
>>> The problem still happens with very high probability even when it
>>> pauses for 5 milliseconds at every loop. If Pycassa uses microseconds
>>> it can't be the cause. Also I have the same problem with a Java client
>>> using Pelops.
>> You connect to localhost, but is that a single node or part of a
>> cluster with RF > 1? If the latter, you need to use QUORUM consistency
>> level to ensure that a read sees your write.
>> If it's a single node and not a pycassa / client issue, I don't know off hand.
>> --
>> / Peter Schuller (@scode on twitter)

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