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HBase >> mail # user >> Atomicity questions


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Re: Atomicity questions
Thanks. I'll try and take a look, but I haven't worked with zookeeper
before. Does it use zookeeper for any of ACID functionality?

On Thu, Dec 1, 2011 at 2:55 PM, lars hofhansl <[EMAIL PROTECTED]> wrote:
> Hi Mohit,
>
> the best way to study this is to look at MultiVersionConsistencyControl.java (since you are asking how this handled internally).
>
> In a nutshell this ensures that read operations don't see writes that are not completed, by (1) defining a thread read point that is rolled forward only after a completed operations and (2) assigning a special timestamp (not the timestamp that you set from the client API) to all KeyValues.
>
> -- Lars
>
>
> ----- Original Message -----
> From: Mohit Anchlia <[EMAIL PROTECTED]>
> To: [EMAIL PROTECTED]
> Cc:
> Sent: Thursday, December 1, 2011 2:22 PM
> Subject: Atomicity questions
>
> I have some questions about ACID after reading this page,
> http://hbase.apache.org/acid-semantics.html
>
> - Atomicity point 5 : row must either be "a=1,b=1,c=1" or
> "a=2,b=2,c=2" and must not be something like "a=1,b=2,c=1".
>
> How is this internally handled in hbase such that above is possible?
>
>
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB