Nikolai Grigoriev created CASSANDRA-6423:
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Summary: Some histogram metrics of long[] type are unusable with
Graphite
Key: CASSANDRA-6423
URL: https://issues.apache.org/jira/browse/CASSANDRA-6423
Project: Cassandra
Issue Type: Bug
Components: Core
Environment: Cassandra 2.0.3, Oracle Linux 6.3, graphite
Reporter: Nikolai Grigoriev
Priority: Minor
I am not entirely sure if this is a Cassandra issue or the limitation of the
graphite reporter agent. But since the metrics in question are created by
Cassandra itself I have decided that it may be appropriate to report it here.
I am using Graphite with Cassandra 2.0.x and I have recently noticed frequent
'invalid line' messages in Graphite log. Unfortunately Graphite did not provide
enough details so I hacked it a bit to get more verbose error message with the
metric name. And here is what I have found:
{code}
29/11/2013 16:07:16 :: invalid line
".org.apache.cassandra.metrics.ColumnFamily.mykeyspace.some_cf.EstimatedRowSizeHistogram.value
[J@17c26ba5 1385741236"received from client 192.168.20.157:55553, ignoring
29/11/2013 16:07:16 :: invalid line
".org.apache.cassandra.metrics.ColumnFamily.mykeyspace.some_cf.EstimatedColumnCountHistogram.value
[J@5d2929d2 1385741236"received from client 192.168.20.157:55553, ignoring
29/11/2013 16:07:16 :: invalid line
".org.apache.cassandra.metrics.ColumnFamily.mykeyspace.some_cf.EstimatedRowSizeHistogram.value
[J@3978c9c6 1385741236"received from client 192.168.20.157:55553, ignoring
29/11/2013 16:07:16 :: invalid line
".org.apache.cassandra.metrics.ColumnFamily.mykeyspace.some_cf.EstimatedColumnCountHistogram.value
[J@290703a4 1385741236"received from client 192.168.20.157:55553, ignoring
29/11/2013 16:07:16 :: invalid line
".org.apache.cassandra.metrics.ColumnFamily.mykeyspace.some_cf.EstimatedRowSizeHistogram.value
[J@b801907 1385741236"received from client 192.168.20.157:55553, ignoring
{code}
Then a quick search through Cassandre code confirmed that there is a number of
histograms created as Gauge with long[] data. So, when they are serialized by
GraphiteReporter they are just printed as long[].toString(), making these
metrics useless.
I am not sure what would be the best solution to it. I do see some histograms
(LiveScannedHistogram etc) that are implemented differently and they are
properly sent to Graphite.
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