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HBase, mail # user - Isolation level


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Re: Isolation level
Michael Segel 2012-06-18, 11:46
Since you don't have OLTP,  the terms need to be better defined.
What is meant by an uncommitted_ write in HBase?

RLL in RDBMS is different than RLL in HBase. You don't have the concept of a transaction in HBase.

-Mike

On Jun 17, 2012, at 10:32 PM, Anoop Sam John wrote:

> Hi
>           You can check Scan#setIsolationLevel() API for changing the level. By default it is  read committed means read only committed writes.
>
> -Anoop-
> ________________________________________
> From: Jerry Lam [[EMAIL PROTECTED]]
> Sent: Friday, June 15, 2012 9:51 PM
> To: [EMAIL PROTECTED]
> Subject: Re: Isolation level
>
> Hi Cristina:
>
> My understanding of HBase is that the isolation level fro read ops is Read
> Committed. There is only write lock which could protect the data from
> modifying by other requests but there is no read-lock (it is there but it
> doesn't have any effect). Since put ops are atomic, it can succeed or fail
> but not in the middle so clients can only read the data if the write ops
> succeeds
>
> HTH,
>
> Jerry
>
>
> On Fri, Jun 15, 2012 at 7:59 AM, Cristina <[EMAIL PROTECTED]> wrote:
>
>> Hi,
>>
>> I have read that Hbase has read committed as isolation level, but I have
>> some
>> doubts.
>> Is it possible to chage this level, for instance to read uncommitted? How
>> could
>> I do this?
>> Another question, Is this isolation level based on locks? I have doubts
>> because
>> Hbase has multiversion concurrency control so it may implement read
>> committed
>> snapshot or snapshot isolation.
>>
>> Thanks,
>>   Cristina
>>
>>