Reinstalling OEM 11g

• When reinstalling OEM 11g from any reasons don’t forget to clean up your environment from previous installation attempts.
• Clean up ORACLE_HOME directories on OMS server
• Get rid of EM stuff from EM managed database
• 
  
• The first issue I faced is the existence of SYSMAN schema. I ran the following command to drop it:

[oracle@host ~]$  $<ORACLE_HOME>/bin/emca -deconfig dbcontrol db -repos drop -SYS_PWD / 
<sys pasword> -SYSMAN_PWD <sysman password>

• Also drop “sysman_mds” schema and recompile invalid objects (if applicable) in DBSNMP and MGMT_VIEWschemas. Re-compile invalid objects using:

SQL> @$ORACLE_HOME/sysman/admin/emdrep/sql/core/latest/admin/admin_recompile_invalid.sql SYSMAN

• After the above script was executed you must check invalid objects:

SQL> select count(*) from dba_objects where status<>'INVALID';

• 
  
• If invalid objects still exists you must re-compile them: see http://dbataj.blogspot.com/2007/08/how-to-compile-invalid-objects.html
• 
  
• During the first install the MDS Schema Configuration inserts 1 line into table SCHEMA_VERSION_REGISTRY. When reinstalling OEM "MDS Schema Configuration" will fail.

• Don’t forget to delete that entry from SCHEMA_VERSION_REGISTRY table:

SQL> delete from SCHEMA_VERSION_REGISTRY where COMP_NAME='Metadata Services';

• Then retry and the "MDS Schema Configuration" will be configured successfully.