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Posted to user@cassandra.apache.org by Nicolas Lalevée <ni...@hibnet.org> on 2013/01/25 15:07:50 UTC
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
Re: JMX CF Beans
Posted by Nicolas Lalevée <ni...@hibnet.org>.
thanks. both of you.
Nicolas
Le 25 janv. 2013 à 19:05, Tyler Hobbs <ty...@datastax.com> a écrit :
>
> On Fri, Jan 25, 2013 at 8:07 AM, Nicolas Lalevée <ni...@hibnet.org> 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
Posted by Tyler Hobbs <ty...@datastax.com>.
On Fri, Jan 25, 2013 at 8:07 AM, Nicolas Lalevée <nicolas.lalevee@hibnet.org
> 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 <http://datastax.com/>
RE: JMX CF Beans
Posted by Viktor Jevdokimov <Vi...@adform.com>.
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.
Best regards / Pagarbiai
Viktor Jevdokimov
Senior Developer
Email: Viktor.Jevdokimov@adform.com<ma...@adform.com>
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From: Nicolas Lalevée [mailto:nicolas.lalevee@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