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From Paulo Motta <pauloricard...@gmail.com>
Subject Re: Query Consistency Issues...
Date Tue, 15 Dec 2015 20:40:59 GMT
> We are using 2.1.7.1

Then you should be able to use the java driver timestamp generators.

> So, we need to look for clock sync issues between nodes in our ring?  How
close do they need to be?

millisecond precision since that is the server precision for timestamps, so
probably NTP should do the job. if your application have submillisecond
updates in the same partitions, you'd probably need to use client-side
timestamps anyway, since they allow setting timestamps with sub-ms
precision.

> Very cool!  If we have multiple nodes in our application, I suppose
*their* clocks will have to be sync'ed for this to work, right?

correct, you may also use ntp to synchronize clocks between clients.

2015-12-15 12:19 GMT-08:00 James Carman <james@carmanconsulting.com>:

>
>
> On Tue, Dec 15, 2015 at 2:57 PM Paulo Motta <pauloricardomg@gmail.com>
> wrote:
>
>> What cassandra and driver versions are you running?
>>
>>
> We are using 2.1.7.1
>
>
>> It may be that the second update is getting the same timestamp as the
>> first, or even a lower timestamp if it's being processed by another server
>> with unsynced clock, so that update may be getting lost.
>>
>>
> So, we need to look for clock sync issues between nodes in our ring?  How
> close do they need to be?
>
>
>> If you have high frequency updates in the same partition from the same
>> client you should probably use client-side timestamps with a configured
>> timestamp generator on the driver, available in Cassandra 2.1 and Java
>> driver 2.1.2, and default in java driver 3.0.
>>
>>
> Very cool!  If we have multiple nodes in our application, I suppose
> *their* clocks will have to be sync'ed for this to work, right?
>

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