OC4J Process Architecture

From: <J.Velikanovs_at_alise.lv>
Date: Sun, 13 Jun 2004 20:05:04 +0300
Message-ID: <OF06F2092D.FD94744E-ONC2256EB2.00547FE8-C2256EB2.005E7C50@alise.lv>

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 OC4J.
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,
Jurijs

I would like to share information that we have regarding OC4J architecture (see below).

I.
Processes/Threads
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/<component name>.default_island.1 log file by default) by running a)
kill –3 <oc4j pid>
command (this is any java process behavior, I believe).
>From dump we can see main threads list, as well as information about java
deadlocks if any.
b) Below is thread types list you can see in the java output by running kill –3 command:
===
AJPConnectionListener [0.0.0.0/0.0.0.0:3001] ApplicationServerThread-0
Finalizer
JMSServer
OC4JMonitorThread
Reference Handler
RMIServer [0.0.0.0/0.0.0.0:3101] count:2 Signal Dispatcher
Suspend Checker Thread
TaskManager
Thread
VM Periodic Task Thread
VM 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. For example

http://java.sun.com/docs/hotspot/gc1.4.2
http://java.sun.com/docs/hotspot/gc1.4.2/faq.html
http://www.cons.org/cmucl/doc/gc-tuning.html

etc.
-verbose:gc parameter usage is helpful in diagnostic process.

II. The TOP parameters you need to look on is: a)
File $OH/opmn/conf/opmn.xml
numProcs="1"

<java-option value="-Xms1024M -Xmx1024M "/>
<log-file path="$OH//opmn/logs/ipm.log" level="3"/>
<log-file path="$OH/opmn/logs/ons.log" level="3"/>

b)
File $OH/j2ee/<component name>/config/server.xml <global-thread-pool min="100" max="200" queue="120" keepAlive="600000" cx-min="100" cx-max="200" cx-que ue="120" cx-keepAlive="600000" debug="true" />
taskmanager-granularity="9000000"
transaction-config timeout="500000"
c)
File $OH/j2ee/<component name>/config/oc4j.properties If you use BC4J.

jbo.pers.max.active.nodes=1000
jbo.pers.max.rows.per.node=1000
jbo.doconnectionpooling=true
jbo.initpoolsize=1
jbo.maxpoolsize=550
jbo.poolminavailablesize=0
jbo.poolmaxavailablesize=600
jbo.poolmonitorsleepinterval=600000
jbo.poolmaxinactiveage=600000
jbo.ampool.initpoolsize=1
jbo.ampool.maxpoolsize=550
jbo.ampool.minavailablesize=0
jbo.ampool.maxavailablesize=100
jbo.ampool.monitorsleepinterval=600000
jbo.ampool.maxinactiveage=600000

Hope this information will help you.

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Received on Sun Jun 13 2004 - 12:09:12 CDT