1 year ago, management of the company I am working for decided to switch
all development projects to J2EE architecture (OC4J).
Within the year, we have running in many technical problems connected to
OC4J (stability hanging, java deadlocks, performance problems etc). We
have logged many (~10) long (100KB of text, 2-4 mount) TARs to Oracle
support. Generally there no many help from Oracle side. I have filling
there no strong competence from Oracle analyst�s side;(
We have learned a lot about OC4J architecture, parameters etc. during this
time (see information below). But at the moment I still have filling that
we are working in the dark, using black box method.
I will try to explain that I mean, by comparing Oracle Database & Oracle
There excellent documentation regarding Oracle Database architecture
(Oracle Concepts). There is good description about each Database process
PMON, SMON, etc, there is one process per connection (in dedicated
configuration), there is many diagnostic possibilities etc. If I have
performance issue with Oracle Database, first of all I will take a look on
TOP CPU consumers from OS respective, then I�ll go forward to Oracle
statistics or switching 10046 event etc.
As opposite, take a look on OC4J. There is no any information like
mentioned above regarding OC4J, not in Oracle documentation, not in the
Web;(. There is just one process, which represent OC4J from OS. If there
is performance issue with OC4J, we can�t say a lot regarding which
process/activity/piece of code takes CPU etc.
My question is:
- Do you know any good information source about OC4J architecture; there
will be described internals (processes, communications flows etc);
- Do you know good courses regarding this theme?
- Information about any related book is welcomed?
- Can you share you experience working on OC4J problems?
Thank you in advance,
I would like to share information that we have regarding OC4J architecture
As I mentioned above OC4J from OS looks like one process, which consume HW
resources. OC4J use threads architecture for endow concurrency. You can
see threads dump in the Java output (in $OH opmn/logs/.default_island.1 log file by default) by running
command (this is any java process behavior, I believe).
From dump we can see main threads list, as well as information about javadeadlocks if any.
b) Below is thread types list you can see in the java output by running
kill �3 command:
RMIServer [0.0.0.0/0.0.0.0:3101] count:2
Suspend Checker Thread
VM Periodic Task Thread
Unfortunately I don�t have information about algorithms of work and what
is responsibility of each type of thread, at the moment.
c) In addition there is garbage collector process.
There is many information in the Web regarding this type of process.
-verbose:gc parameter usage is helpful in diagnostic process.
II. The TOP parameters you need to look on is:
If you use BC4J.
Hope this information will help you.
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