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From aaron morton <aa...@thelastpickle.com>
Subject Re: Cassandra read reapair
Date Thu, 23 May 2013 21:59:57 GMT
If you are reading and writing at CL QUOURM and getting inconsistent results that sounds like
a bug. If you are mixing the CL levels such that R + W <= N then it's expected behaviour.



Can you reproduce the issue outside of your app ? 

Cheers

-----------------
Aaron Morton
Freelance Cassandra Consultant
New Zealand

@aaronmorton
http://www.thelastpickle.com

On 21/05/2013, at 8:55 PM, Kais Ahmed <kais@neteck-fr.com> wrote:

> > Checking you do not mean the row key is corrupt and cannot be read. 
> Yes, i can read it but all read don't return the same result except for CL ALL
> 
> > By default in 1.X and beyond the default read repair chance is 0.1, so it's only
enabled on 10% of requests. 
> You are right read repair chance is set to 0.1, but i launched a read repair which did
not solved the problem. Any idea?
> 
> >What CL are you writing at ? 
> All write are in CL QUORUM
> 
> thank you aaron for your answer. 
> 
> 
> 2013/5/21 aaron morton <aaron@thelastpickle.com>
>> Only some keys of one CF are corrupt. 
> Checking you do not mean the row key is corrupt and cannot be read. 
> 
>> I thought using CF ALL, would correct the problem with READ REPAIR, but by returning
to CL QUORUM, the problem persists.
>> 
> 
> By default in 1.X and beyond the default read repair chance is 0.1, so it's only enabled
on 10% of requests. 
> 
> 
> In the absence of further writes all reads (at any CL) should return the same value.

> 
> What CL are you writing at ? 
> 
> Cheers
> 
> -----------------
> Aaron Morton
> Freelance Cassandra Consultant
> New Zealand
> 
> @aaronmorton
> http://www.thelastpickle.com
> 
> On 19/05/2013, at 1:28 AM, Kais Ahmed <kais@neteck-fr.com> wrote:
> 
>> Hi all,
>> 
>> I encountered a consistency problem one some keys using phpcassa and Cassandra 1.2.3
since a server crash 
>> 
>> Only some keys of one CF are corrupt. 
>> 
>> I lauched a nodetool repair that successfully completed but don't correct the issue.
>> 
>> 
>> 
>> When i try to get a corrupt Key with :
>> 
>> CL ONE, the result contains 7 or 8 or 9 columns
>> 
>> CL QUORUM, result contains 8 or 9 columns
>> 
>> CL ALL, the data is consistent and returns always 9 columns
>> 
>> 
>> 
>> I thought using CF ALL, would correct the problem with READ REPAIR, but by returning
to CL QUORUM, the problem persists.
>> 
>> 
>> Thank you for your help
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
> 
> 


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