why set replica placement strategy at keyspace level ?

[Manu Zhang]

Although I've got to know Cassandra for quite a while, this question 
only has occurred to me recently:


Why are the replica placement strategy and replica factors set at the 
keyspace level?


Would setting them at the column family level offers more flexibility?

Is this because it's easier for user to manage an application? Or 
related to internal implementation? Or it's just that I've overlooked 
something?

Re: Issue when deleting Cassandra rowKeys.

[Edward Capriolo]

Make sure the timestamp on your delete is > then timestamp of the data.

On Sat, Jan 26, 2013 at 1:33 PM, Kasun Weranga  wrote:

> Hi all,
>
> When I delete some rowkeys programmatically I can see two rowkeys remains
> in the column family. I think it is due to tombstones. Is there a way to
> remove it when deleting rowkeys. Can I run compaction programmatically
> after deletion? will it remove all these remaining rowkeys.
>
> Thanks,
> Kasun.
>
>

Re: Issue when deleting Cassandra rowKeys.

[Michael Kjellman]

What is your gc_grace set to?

Are your findings before or after this time after the deletion?

From: Kasun Weranga mailto:kas...@wso2.com>>
Reply-To: "user@cassandra.apache.org" 
mailto:user@cassandra.apache.org>>
Date: Saturday, January 26, 2013 10:33 AM
To: "user@cassandra.apache.org" 
mailto:user@cassandra.apache.org>>, 
"d...@cassandra.apache.org" 
mailto:d...@cassandra.apache.org>>
Subject: Issue when deleting Cassandra rowKeys.

Hi all,

When I delete some rowkeys programmatically I can see two rowkeys remains in 
the column family. I think it is due to tombstones. Is there a way to remove it 
when deleting rowkeys. Can I run compaction programmatically after deletion? 
will it remove all these remaining rowkeys.

Thanks,
Kasun.

Issue when deleting Cassandra rowKeys.

[Kasun Weranga]

Hi all,

When I delete some rowkeys programmatically I can see two rowkeys remains
in the column family. I think it is due to tombstones. Is there a way to
remove it when deleting rowkeys. Can I run compaction programmatically
after deletion? will it remove all these remaining rowkeys.

Thanks,
Kasun.

Re: JMX CF Beans

[Nicolas Lalevée]

thanks. both of you.

Nicolas

Le 25 janv. 2013 à 19:05, Tyler Hobbs  a écrit :

> 
> On Fri, Jan 25, 2013 at 8:07 AM, Nicolas Lalevée  
> wrote:
> Just a quick question about the attributes exposed via JMX. I have some doc 
> [1] but it doesn't help about CF beans.
> 
> The "BloomFilterFalseRatio", is that the ratio of found vs missed, or the 
> ratio of false positive vs the number of tests, or something else ?
> 
> False positives.
> 
> You should be aware of this bug, though: 
> https://issues.apache.org/jira/browse/CASSANDRA-4043
>  
> 
> The "ReadCount" and "WriteCount", how do they count regarding the replication 
> factor ? As far as I understand, the read and write on the StorageProxy is 
> the actual number of requests coming from clients. So judging that the sum on 
> all cf of the read and write is near equal to the replication factor multiply 
> by the number of read and write on the StorageProxy, I am guessing that the 
> read and write per cf are the replicas one. Am I right ?
> 
> 
> StorageProxy read/write counts should equal the number of client requests.
> ColumnFamily read/write counts correspond to actual, local data reads, so the 
> sum of this number across all nodes will be approximately RF * the 
> StorageProxy counts.
> 
> 
> -- 
> Tyler Hobbs
> DataStax