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From Wz1975 <wz1...@YAHOO.COM>
Subject Re: Read during digest mismatch
Date Wed, 14 Nov 2012 03:06:32 GMT
From my understanding,  if CL = 2, one read,  one digest are sent.  Only if it is    read
repair,  digest is sent to all replicates.


Thanks.
-Wei

Sent from my Samsung smartphone on AT&T

-------- Original message --------
Subject: Re: Read during digest mismatch 
From: Edward Capriolo <edlinuxguru@gmail.com> 
To: "user@cassandra.apache.org" <user@cassandra.apache.org> 
CC:  

I think the code base does not benefit from having too many different read code paths. Logically
what your suggesting is reasonable, but you have to consider the case of one being slow to
respond. 

Then what?

On Tuesday, November 13, 2012, Manu Zhang <owenzhang1990@gmail.com> wrote:
> If consistency is two, don't we just send data request to one and digest request to another?
>
> On Mon, Nov 12, 2012 at 2:49 AM, Jonathan Ellis <jbellis@gmail.com> wrote:
>>
>> Correct.  Which is one reason there is a separate setting for
>> cross-datacenter read repair, by the way.
>>
>> On Thu, Nov 8, 2012 at 4:43 PM, sankalp kohli <kohlisankalp@gmail.com> wrote:
>> > Hi,
>> >     Lets say I am reading with consistency TWO and my replication is 3. The
>> > read is eligible for global read repair. It will send a request to get data
>> > from one node and a digest request to two.
>> > If there is a digest mismatch, what I am reading from the code looks like it
>> > will get the data from all three nodes and do a resolve of the data before
>> > returning to the client.
>> >
>> > Is it correct or I am readind the code wrong?
>> >
>> > Also if this is correct, look like if the third node is in other DC, the
>> > read will slow down even when the consistency was TWO?
>> >
>> > Thanks,
>> > Sankalp
>> >
>> >
>>
>>
>>
>> --
>> Jonathan Ellis
>> Project Chair, Apache Cassandra
>> co-founder of DataStax, the source for professional Cassandra support
>> http://www.datastax.com
>
> 
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