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From Ted Yu <yuzhih...@gmail.com>
Subject Re: Interaction of SequenceID and timestamps
Date Tue, 14 Jan 2014 23:40:44 GMT
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.
>

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