How to Clean Up Duplicate Objects Owned by SYS and SYSTEM Schema (Doc ID 1030426.6)

Purpose

Problem Description:

If the same data dictionary object has been created under both user SYS and SYSTEM schema then errors will often occur when trying to use the database features associated with these objects.


Problem Explanation:

During the installation of Oracle many scripts are run which create the underlying data dictionary objects. Most of these scripts are run at database creation time, but others are only run if specific database features (such as replication or shared pool management) are needed. These scripts are usually run manually after the database has been created.

Running SQL scripts manually increases the chance of error greatly. One such common problem is running the SQL script as the wrong Oracle user.

Most SQL scripts located in the $ORACLE_HOME/rdbms/admin directory should be run as SYS (or internal) and not SYSTEM.

If you happen to run a SQL as the wrong user it is very hard to clean up from this situation as the number of objects that a script creates can be very large as well as there are no delivered scripts to drop the incorrect objects.

Details

In order to clean up the duplicate objects you need to issue a SQL script to find out the names of the duplicate objects.
You can then manually drop the objects or use a 'SQL generating SQL' script to generate a list of drop commands. 

Below is a SQL*Plus script that will list all objects that have been created in both the SYS and SYSTEM schema:

column object_name format a30
select object_name, object_type
from dba_objects
where object_name||object_type in
   (select object_name||object_type
    from dba_objects
    where owner = 'SYS')
and owner = 'SYSTEM';


The output from this script will either be 'zero rows selected' or will look something like the following:
OBJECT_NAME                OBJECT_TYPE
------------------------------         -------------
ALL_DAYS                           VIEW
CHAINED_ROWS               TABLE
COLLECTION                       TABLE
COLLECTION_ID                 SEQUENCE
DBA_LOCKS                       SYNONYM
DBMS_DDL                        PACKAGE
DBMS_SESSION                PACKAGE
DBMS_SPACE                   PACKAGE
DBMS_SYSTEM                PACKAGE
DBMS_TRANSACTION  PACKAGE
DBMS_UTILITY                PACKAGE


If the select statement returns any rows then this is an indication that at least 1 script has been run as both SYS and SYSTEM.

Since most data dictionary objects should be owned by SYS (see exceptions below) you will want to drop the objects that are owned by SYSTEM in order to clear up this situation.


EXCEPTION TO THE RULE

THE REPLICATION SCRIPTS (XXX) CORRECTLY CREATES OBJECTS WITH THE SAME NAME IN THE SYS AND SYSTEM ACCOUNTS. LISTED BELOW ARE THE OBJECTS USED BY REPLICATION THAT SHOULD BE CREATED IN BOTH ACCOUNTS. DO NOT DROP THESE OBJECTS FROM THE SYSTEM ACCOUNT IF YOU ARE USING REPLICATION. DOING SO WILL CAUSE REPLICATION TO FAIL!

The following objects are duplicates that will show up (and should not be removed) when running this script in 8.1.x and higher.

Without replication installed:
INDEX           AQ$_SCHEDULES_PRIMARY
TABLE           AQ$_SCHEDULES

If replication is installed by running catrep.sql:
INDEX           AQ$_SCHEDULES_PRIMARY
PACKAGE         DBMS_REPCAT_AUTH
PACKAGE BODY    DBMS_REPCAT_AUTH
TABLE           AQ$_SCHEDULES

When database is upgraded to 11g using DBUA, following duplicate objects are also created
OBJECT_NAME                OBJECT_TYPE
------------------------------ -------------
Help                          TABLE
Help_Topic_Seq                  Index

The objects created by sqlplus/admin/help/hlpbld.sql must be owned by SYSTEM because when sqlplus retrieves the help information, it refers to the SYSTEM schema only. DBCA runs this script as SYSTEM user when it creates the database but DBUA runs this script as SYS user when upgrading the database (reported as an unpublished BUG 10022360).  You can drop the ones in SYS schema.

Now that you have a list of duplicate objects you will simply issue the appropriate DROP command to get rid of the object that is owned by the SYSTEM user.


If the list of objects is large then you may want to use the following SQL*Plus script to automatically generate an SQL script that contains the appropriate DROP commands:

set pause off
set heading off
set pagesize 0
set feedback off
set verify off
spool dropsys.sql
select 'DROP ' || object_type || ' SYSTEM.' || object_name || ';'
from dba_objects
where object_name||object_type in
   (select object_name||object_type
    from dba_objects
    where owner = 'SYS')
and owner = 'SYSTEM';
spool off
exit


You will now have a file in the current directory named dropsys.sql that contains all of the DROP commands. You will need to run this script as a normal SQL script as follows:

$ sqlplus
SQL*Plus: Release 3.3.2.0.0 - Production on Thu May  1 14:54:20 1997
Copyright (c) Oracle Corporation 1979, 1994.  All rights reserved.
Enter user-name: system
Enter password: manager
SQL> @dropsys

Note: You may receive one or more of the following errors:
ORA-2266 (unique/primary keys in table referenced by enabled foreign keys):
If you encounter this error then some of the tables you are dropping have constrints that prevent the table from being dropped. To fix this problem you will have to manually drop the objects in a different order than the script does.
    
ORA-2429 (cannot drop index used for enforcement of unique/primary key):
 This is similar to the ORA-2266 error except that it points to an index. You will have to manually disable the constraint associated with the index and then drop the index.

ORA-1418 (specified index does not exist):
 This occurs because the table that the index was created on  has already been dropped which also drops the index. When the script tries to drop the index it is no longer there and thus the ORA-1418 error. You can safely ignore this error.