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From Michael Segel <michael_se...@hotmail.com>
Subject Re: Concurrency control
Date Wed, 18 Jul 2012 19:40:40 GMT
It goes beyond the atomic writes... 
There isn't the concept of transactions in HBase. 

He could also be talking about Hive, which would be appropriate for this mailing list... 


On Jul 18, 2012, at 11:49 AM, Harsh J wrote:

> Hi,
> Do note that there are many users who haven't used Teradata out there
> and they may not directly pick up what you meant to say here.
> Since you're speaking of Tables, I am going to assume you mean HBase.
> If what you're looking for is atomicity, HBase does offer it already.
> If you want to order requests differently, depending on a condition,
> the HBase coprocessors (new from Apache HBase 0.92 onwards) provide
> you an ability to do that too. If your question is indeed specific to
> HBase, please ask it in a more clarified form on the
> user@hbase.apache.org lists.
> If not HBase, do you mean read/write concurrency over HDFS files?
> Cause HDFS files do not allow concurrent writers (one active lease per
> file), AFAICT.
> On Wed, Jul 18, 2012 at 9:09 PM, saubhagya dey <saubhagya.dey@gmail.com> wrote:
>> how do i manage concurrency in hadoop like we do in teradata.
>> We need to have a read and write lock when simultaneous the same table is
>> being hit with a read query and write query
> -- 
> Harsh J

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