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

Re: JMX CF Beans

[Tyler Hobbs]

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 

RE: JMX CF Beans

[Viktor Jevdokimov]

src/java/org/apache/цassandra/db/DataTracker.java:
public double getBloomFilterFalseRatio()
{
…
return (double) falseCount / (trueCount + falseCount);
…
}


ReadCount/WriteCount on CF is for this CF on this node only, so it’s 
local/internal only reads/writes for the node’s range.


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Viktor Jevdokimov
Senior Developer

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From: Nicolas Lalevée [mailto:nicolas.lale...@hibnet.org]
Sent: Friday, January 25, 2013 16:08
To: user@cassandra.apache.org
Subject: JMX CF Beans

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 ?

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 ?

Nicolas

[1] http://wiki.apache.org/cassandra/JmxInterface

<><>

JMX CF Beans

[Nicolas Lalevée]

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 ?

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 ?

Nicolas

[1] http://wiki.apache.org/cassandra/JmxInterface