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Reset DMS Metrics
Oracle Application Server uses it's inbuilt DMS (dynamic monitoring
service) subsystem to collect and display runtime data for various
aspects of the product and applications that it is running.
The metrics are accessible in a number of places in an Oracle
Application Server installation -- the Application Server Console, the
command line utility dmstool, and the AggreSpy servlet.
For an OC4J standalone instance, the metrics are also available using
the Spy servlet. The Spy servlet is part of the DMS application which
is deployed by default into the default web application. The
documentation states that
"Spy
is a pre-packaged servlet that reports performance metrics for OC4J
standalone. Spy reports performance data for an OC4J process.
"
To access the Spy servlet, you use a URL of the form http://localhost:8888/dms/Spy -- where the the host:port combination here specify the OC4J instance you want to view the performance stats for.
The basic lifecycle of DMS is that the collection of the runtime data starts when the container is
started and stops when the container stops. The default view presented
by the Spy servlet is therefore of the data set that has been collected since the
OC4J process was first started.
What if you want to view the data on a daily basis for example? Can you reset the runtime data that has been collected?
Well the answer to that question is yes, if you are using OC4J 10g (9.0.4).
Thanks to one of our DMS developer's here's how you do it.
Resetting DMS Data
To reset the performance data, you send a URL to the Spy servlet to
inform it that it should do a reset. This basically
involves tacking on an "operation=reset" parameter onto a Spy URL.
The basic form of the URL to perform a reset looks likes:
"http://localhost:8888/dms/Spy?operation=reset&name=/name1&recurse=all"
Resetting Metric Names -- Conditions and Explanations
1.
The name is a metric name. An example of a metric name is
/JVM/freeMemory.value. The sensor this metric belongs to will be reset.
"recurse=all" or "recurse=children" in the query string have no effects
on metric names.
2. The name is a noun name. An example of a noun
name is /JVM or /OC4J/fooServlet, or the root noun /. You have to include
either "recurse=all" or "recurse=children" in the query string. "recurse=all"
resets all sensors contained by the noun and its descendant nouns.
"recurse=children" resets the sensors directly under the noun but not those
under its descendant nouns. DMS will not reset any sensors if you give none of
"recurse=all" or "recurse=children" in the query string.
3. You can not use sensor names.
4. You can not give both
"recurse=all" and "recurse=children" in the query string.
Resetting Metrics Tables -- Conditions and Explanations
In
addition to specify metrics by their names, you can also specify metrics by
table names and ask for a reset.
In this case, the query string becomes:
"http://localhost:8888/dms/Spy?operation=reset&table=table_name1&table=table_name2&recurse=children(recurse=all)"
1. You
can use table names as a specifier for a reset. You also have to include either "recurse=children" or
"recurse=all" in the query string. "recurse=children" will reset all the
metrics contained by the tables. "recurse=all" will reset all the metrics
contained by the tables as well as those contained by the tables that is under
the specified tables in the table hierarchy.
2. You
can use both "name=/noun/metric_name" and "table=table_name" at the same
time.
© Copyright 2004 buttso.
Last update: 4/5/2004; 2:32:20 PM.
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