stack created HBASE-16142:
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Summary: Trigger JFR session when under duress -- e.g. backed-up
request queue count -- and dump the recording to log dir
Key: HBASE-16142
URL: https://issues.apache.org/jira/browse/HBASE-16142
Project: HBase
Issue Type: Task
Components: Operability
Reporter: stack
Priority: Minor
Chatting today w/ a mighty hbase operator on how to figure what is happening
during transitory latency spike or any other transitory 'weirdness' in a
server, the idea came up that a java flight recording during a spike would
include a pretty good picture of what is going on during the time of duress
(more ideal would be a trace of the explicit slow queries showing call stack
with timings dumped to a sink for later review; i.e. trigger an htrace when a
query is slow...).
Taking a look, programmatically triggering a JFR recording seems doable, if
awkward (MBean invocations). There is even a means of specifying 'triggers'
based off any published mbean emission -- e.g. a query queue count threshold --
which looks nice. See
https://community.oracle.com/thread/3676275?start=0&tstart=0 and
https://docs.oracle.com/javacomponents/jmc-5-4/jfr-runtime-guide/run.htm#JFRUH184
This feature could start out as a blog post describing how to do it for one
server. A plugin on Canary that looks at mbean values and if over a configured
threshold, triggers a recording remotely could be next. Finally could integrate
a couple of triggers that fire when issue via the trigger mechanism.
Marking as beginner feature.
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