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From Víctor Hugo Oliveira Molinar <vhmoli...@gmail.com>
Subject Re: Deletion consistency
Date Fri, 15 Feb 2013 19:03:49 GMT
*Mike*, for now I can't upgrade my cluster. I'm going to check the servers
time sync. Thanks;

*Bryan*, so u think it's not a distributed deleted problem. Thanks for
bringing it up.
Btw, hector should not be hiding any exception from me.
Although there's a mutator reuse in my application. I'm gonna check if it
may be the problem too.


Guys, one more doubt:
Is there any limitation on how many columns should I delete per delete
operation? I'm currently sending 100 deletions each time.

On Fri, Feb 15, 2013 at 4:46 PM, Bryan Talbot <btalbot@aeriagames.com>wrote:

> With a RF and CL of one, there is no replication so there can be no issue
> with distributed deletes.  Writes (and reads) can only go to the one host
> that has the data and will be refused if that node is down.  I'd guess that
> your app isn't deleting records when you think that it is, or that the
> delete is failing but not being detected as failed.
>
> -Bryan
>
>
>
> On Fri, Feb 15, 2013 at 10:21 AM, Mike <mtheroux2@yahoo.com> wrote:
>
>> If you increase the number of nodes to 3, with an RF of 3, then you
>> should be able to read/delete utilizing a quorum consistency level, which I
>> believe will help here.  Also, make sure the time of your servers are in
>> sync, utilizing NTP, as drifting time between you client and server could
>> cause updates to be mistakenly dropped for being old.
>>
>> Also, make sure you are running with a gc_grace period that is high
>> enough.  The default is 10 days.
>>
>> Hope this helps,
>> -Mike
>>
>>
>> On 2/15/2013 1:13 PM, Víctor Hugo Oliveira Molinar wrote:
>>
>>> hello everyone!
>>>
>>> I have a column family filled with event objects which need to be
>>> processed by query threads.
>>> Once each thread query for those objects(spread among columns bellow a
>>> row), it performs a delete operation for each object in cassandra.
>>> It's done in order to ensure that these events wont be processed again.
>>> Some tests has showed me that it works, but sometimes i'm not getting
>>> those events deleted. I checked it through cassandra-cli,etc.
>>>
>>> So, reading it (http://wiki.apache.org/**cassandra/DistributedDeletes<http://wiki.apache.org/cassandra/DistributedDeletes>)
>>> I came to a conclusion that I may be reading old data.
>>> My cluster is currently configured as: 2 nodes, RF1, CL 1.
>>> In that case, what should I do?
>>>
>>> - Increase the consistency level for the write operations( in that case,
>>> the deletions ). In order to ensure that those deletions are stored in all
>>> nodes.
>>> or
>>> - Increase the consistency level for the read operations. In order to
>>> ensure that I'm reading only those yet processed events(deleted).
>>>
>>> ?
>>>
>>> -
>>> Thanks in advance
>>>
>>>
>>>
>>
>

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