Thanks for your help Harsha.
So using Thrift would just poll the metrics from the supervisors upon
each request?
Ahmed
On 07/31/2014 04:40 PM, Harsha wrote:
Hi Ahmed,
It uses "topology.builtin.metrics.bucket.size.secs"
as a time bucket and calls registerMetric on all the metrics with the
specified time bucket above.
https://storm.incubator.apache.org/apidocs/backtype/storm/task/TopologyContext.html#registerMetric%28java.lang.String,%20backtype.storm.metric.api.ICombiner,%20int%29.
Storm will then call getValueAndReset on the metric every
timeBucketSizeInSecs and the returned value is sent to all metrics
consumers.
I am not sure about using thrift api to fetch metrics ( probably
ok) but they will get you the latest metrics and as you notice they
might be changing before duration you mentioned in
"topology.builtin.metrics.bucket.size.secs".
Recommended way is to implement MetricsConsumer . Storm has
LoggingMetricsConsumer
https://github.com/apache/incubator-storm/blob/master/storm-core/src/jvm/backtype/storm/metric/LoggingMetricsConsumer.java.
Check this link on how to use that class
http://www.bigdata-cookbook.com/post/72320512609/storm-metrics-how-to.
-Harsha
On Thu, Jul 31, 2014, at 06:38 AM, Ahmed El Rheddane wrote:
Hello,
I have been using Storm for a while now. I retrieve the builtin metrics
via a Thrift connection (I don't know if there is a better way to do
so). I regularly fetch the metrics and I can still see changes in the
values within durations inferior to the default 60 seconds for the
metrics bucket size. Can anybody help me understand how does Storm use
the value of topology.builtin.metrics.bucket.size.secs and how
frequently does it report the stats to Nimbus?
Thanks in advance.
Ahmed
