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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: Some questions about the write operation and hinted handoff
Date Thu, 08 Jul 2010 20:32:06 GMT
Right, if the nodes are marked up but do not confirm the writes, it
will result in a TimedOutException.  (It still won't generate hinted
writes).

To summarize: hinted writes are only generated when Cassandra (a)
knows a target is down ahead of time and (b) still has enough UP
targets to satisfy the requested CL.

On Thu, Jul 8, 2010 at 1:48 PM, Benjamin Black <b@b3k.us> wrote:
> To clarify, this requires the coordinator know nodes are down.  If the
> nodes are marked UP, but do not confirm the writes, this behavior does
> not seem possible.
>
> On Thu, Jul 8, 2010 at 11:31 AM, Jonathan Ellis <jbellis@gmail.com> wrote:
>> On Thu, Jul 8, 2010 at 1:19 PM, Benjamin Black <b@b3k.us> wrote:
>>> On Thu, Jul 8, 2010 at 9:02 AM, ChingShen <chingshenchen@gmail.com> wrote:
>>>> Hmm.. as you mentioned that it will write a hint and report success at
>>>> CL.ANY, does the hinted handoff only work at CL.ANY?
>>>>
>>>
>>> Still no.  Hints are written when nodes are down, regardless of CL,
>>> unless HH is disabled.  CL does not influence whether hints are
>>> written, it influences whether success is reported to the client.  For
>>> CL.ANY a hint is a success, for CL.ONE it is a failure.
>>
>> If the coordinator knows it can't achieve the requested CL it won't do
>> any writes, hinted or otherwise, and will immediately report
>> UnavailableException to the client.
>>
>> --
>> Jonathan Ellis
>> Project Chair, Apache Cassandra
>> co-founder of Riptano, the source for professional Cassandra support
>> http://riptano.com
>>
>



-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com

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