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Posted to user@cassandra.apache.org by Reik Schatz <re...@gmail.com> on 2015/01/08 16:57:42 UTC
Updated JMX metrics overview
I am adding some jmx metrics to our monitoring tool. Is there a good
overview of all existing jmx metrics and their description?
http://wiki.apache.org/cassandra/Metrics has only a few metrics.
In particular I have questions about these now:
org.apache.cassandra.db type=StorageProxy TotalHints - is this the
number of hints since the node was started or a lifetime value
org.apache.cassandra.db type=StorageProxy ReadRepairRepairedBackground
- is this the total number of background read repair requests that the
node received since
restart?
org.apache.cassandra.db type=StorageProxy ReadRepairRepairedBlocking -
same as above, I assume thats the number of read repairs that have
blocked a query (when does that even happen - aren't read repairs run
in the background)
org.apache.cassandra.metrics type=Storage name=Exceptions Count - is
this the total number of unhandled exceptions since node restart?
Re: Updated JMX metrics overview
Posted by Tyler Hobbs <ty...@datastax.com>.
On Thu, Jan 8, 2015 at 9:57 AM, Reik Schatz <re...@gmail.com> wrote:
>
>
> org.apache.cassandra.db type=StorageProxy TotalHints - is this the
> number of hints since the node was started or a lifetime value
>
Since the node was started.
>
> org.apache.cassandra.db type=StorageProxy ReadRepairRepairedBackground
> - is this the total number of background read repair requests that the
> node received since
> restart?
>
It's the number of background read repairs that the node coordinated since
restart
>
> org.apache.cassandra.db type=StorageProxy ReadRepairRepairedBlocking -
> same as above, I assume thats the number of read repairs that have
> blocked a query (when does that even happen - aren't read repairs run
> in the background)
>
For reads, the coordinator typically sends a request for data to one
replica and a request for a digest to the other replicas. If the digests
don't match (or don't match the data), a full data request is made (to make
sure the correct results are returned) and the replicas with stale data are
repaired.
>
> org.apache.cassandra.metrics type=Storage name=Exceptions Count - is
> this the total number of unhandled exceptions since node restart?
Yes.
--
Tyler Hobbs
DataStax <http://datastax.com/>