OEM Database Control Exceptions
There are quite a few errors which you perphase meet when you begin to use EM in Windows. Such as:
"Agent process exited abnormally during initialization" in system event log,
"java.lang.Exception: Exception in sending Request :: null" in OEM Database Control Database Instance home page
"status pending" in OEM Database Control Database Instance home page
"Io exception: Unknown host specified" in OEM Database Control Database Login
One root cause was an incorrect time zone autoconfigured by the Database Control service.
Below info from http://forums.oracle.com/forums/thread.jspa?messageID=1374397
On Windows 2000 / XP, for the OEM single instance control, (with no grid agent) the service OracleDBConsole<SID> runs both a control service and an agent. After creation of the database using the Database Configuration Assistant 10.2.0.2, the <ORACLE_HOME/><hostname_SID>/sysman/config/emd.properties file was created with no agentTZRegion parameter. At the first startup of the agent, it recognised this and added a line "agentTZRegion=GMT" (the correct time zone would have been Australia/Melbourne). This action is reported in <ORACLE_HOME>/<hostname _SID>/emdb.nohup: ----- Fri Apr 28 17:57:51 2006::Console Launched with PID 3348 at time Fri Apr 28 17:57:51 2006 ----- ----- Fri Apr 28 17:59:26 2006::Property 'agentTZRegion' is missing from C:\oracle\product\10.2.0\db_1\ AMAZON.RUBICON.COM.AU_DAP1/sysman/config/emd.properties. This is normal when the agent is started for the very first time.Updating it... ----- ----- Fri Apr 28 17:59:26 2006::C:\oracle\product\10.2.0\db_1\AMAZON.RUBICON.COM.AU_DAP1/sysman/config/emd.properties copied to C:\oracle\product\10.2.0\db_1\AMAZON.RUBICON.COM.AU_DAP1/sysman/config/emd.properties.2006-04-28-17-59-26 while updating the property 'agentTZRegion' ----- ----- Fri Apr 28 17:59:35 2006::An agentTZregion of 'GMT' is installed in C:\oracle\product\10.2.0\db_1\AMAZON.RUBICON.COM.AU_DAP1/sysman/config/emd.properties. ----- ----- Fri Apr 28 17:59:36 2006::The agentTZRegion value in C:\oracle\product\10.2.0\db_1\AMAZON.RUBICON.COM.AU_DAP1/sysman/config/emd.properties is not in agreement with what agent thinks it should be.Please verify your environment to make sure that TZ setting has not changed since the last start of the agent.If you modified the timezone setting in the environment, please stop the agent and exectute 'emctl resetTZ agent' and also execute the script 'mgmt_target.set_agent_tzrgn' to get the value propagated to repository ----- As you can see, the agent adds the agentTZRegion parameter and immediately recognises that it has set the wrong value. (Possibly this could be avoided by setting a system TZ environment variable before creating the database.) The agent fails, and the service ends up with a java process running, but the service not properly started, so you can't restart it via the services console. "emctl status dbconsole" says it is not running. Once this has happened,future startups of the OracleDBConsole<SID> report the last of the errors (the one starting "::The agentTZRegion value in") and again the agent fails. The solution is 1. Kill the java process which is the console portion of OracleDBConsole<SID> 2. Edit the emd.properties file to have the correct timezone 3. Reboot or restart the OracleDBConsole<SID> Note that deleting and recreating the service via "emca -deconfig dbcontrol db -repos drop" and "emca -config dbcontrol db -repos create" does not cure the problem - it again creates an emd.properties file with no agentTZRegion value.
The timezone supported can be found at: %ORACLE_HOME%\sysman\admin\supportedtmz.lst
Another note when installing Oracle in Linux is that /etc/hosts must be checked carefully, or else the emca will be failed, left the problem confused. It should be like below.
1: 127.0.0.1 localhost.localdomain localhost
2: <IP> <hostname>
and then the emca will recognize the hostname as <hostname>, not localhost.localdomain etc, which cause the OEM can’t display correctly.