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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... 

-Mike

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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