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From DuyHai Doan <>
Subject Re: Does NTP affects LWT's ballot UUID?
Date Tue, 10 Oct 2017 07:13:42 GMT
The ballot UUID is obtained using QUORUM agreement between replicas for a
given partition key and we use this TimeUUID ballot as write-time for the

The only scenario where I can see a problem is that NTP goes backward in
time on a QUORUM of replicas, which would break the contract of
monotonicity. I don't know how likely this event is ...

On Tue, Oct 10, 2017 at 9:07 AM, Daniel Woo <> wrote:

> Hi guys,
> The ballot UUID should be monotonically increasing on each coordinator,
> but the UUID in cassandra is version 1 (timestamp based), what happens if
> the NTP service adjusts system clock while a two phase paxos prepare/commit
> is in progress?
> --
> Thanks & Regards,
> Daniel

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