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From Ishan Chhabra <ichha...@rocketfuel.com>
Subject Re: Interaction of SequenceID and timestamps
Date Wed, 15 Jan 2014 00:17:09 GMT
Thanks for pointing out the code. My understanding is correct.

Thanks!


On Tue, Jan 14, 2014 at 3:40 PM, Ted Yu <yuzhihong@gmail.com> wrote:

> Please take a look at the following method in
> KeyValueHeap#KVScannerComparator
> :
>
>     public int compare(KeyValueScanner left, KeyValueScanner right) {
>
> Cheers
>
>
> On Tue, Jan 14, 2014 at 3:26 PM, Ishan Chhabra <ichhabra@rocketfuel.com
> >wrote:
>
> > I am trying to understand the interaction of sequenceId and timestamps
> for
> > KVs, and what was the real issue behind
> > https://issues.apache.org/jira/browse/HBASE-6590 which says that
> bulkload
> > can be used only to update only historical data and not current data.
> >
> > Taking an example:
> >
> > Lets say I have a KV (r, c, val1, 10), where 10 is the timestamp already
> in
> > HBase.
> > Now, if I bulkload a KV (r, c, val2, 20) without the patch, will that be
> > sorted behind the previous KV since the file created has a sequenceID 0,
> or
> > will it be correctly be the new returned value during a scan for the
> (r,c).
> >
> > I conducted some experiments myself and concluded that timestamp has a
> > priority over sequenceId and sequenceId is used to break a tie only when
> > the timestamp is the same, but I need to make sure that my understanding
> is
> > correct.
> >
> > Thanks!
> >
> > --
> > *Ishan Chhabra *| Rocket Scientist | RocketFuel Inc.
> >
>



-- 
*Ishan Chhabra *| Rocket Scientist | RocketFuel Inc.

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