Removing Database Control (dbconsole) from a database
Oracle Database 10g introduced Database Control (dbconsole) to aid in day to day administration tasks and monitoring. When building a database for use as a repository for Oracle Enterprise Manager Grid Control or the recently released Oracle Enterprise Manager Cloud Control 12c, you will need to remove Database Control and its associated repository from the database.
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Quick Manual Database Creation
Using Oracle Managed Files you can quickly create a database manually with very little upfront effort. Oracle Managed Files greatly simplifies the database creation process because all that is needed is the location in which to write the database files.
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Read–Only Tables in Oracle Database 11g
Prior to Oracle Database 11gR1 in order to create a read only table you had to employ clever uses of triggers, constraints or other methods to prevent the data from being changed. In many of those cases only INSERT, UPDATE, and DELETE operations were prevented while many DDL operations were not. Oracle Database 11gR1 provides the ability to create read only tables with a simple ALTER TABLE statement.
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Automating Database Startup/Shutdown on Oracle Enterprise Linux
Oracle provides the ORACLE_HOME/bin/dbstart and ORACLE_HOME/bin/dbshut scripts that can be used to start the the databases when the Operating System boots and to stop the databases when shutting down the Operating System.
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Creating a Database using Database Configuration Assistant
Database Configuration Assistant (DBCA) provides a graphical interface for database creation and database configuration. This document will detail the creation of a database using the Database Configuration Assistant. The screen shots in this document were taken from an Oracle 11gR2 install on Oracle Enterprise Linux.
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Clone a Database to Another Host using Enterprise Manager 11gR1 Grid Control
This document will detail the steps to clone a database to another host using Oracle Enterprise Manager 11gR1 Grid Control.
Deferred Segment Creation
Starting with Oracle Database 11gR2 when you create an empty heap organized table in locally managed tablespace segment creation is deferred until the time in which the first row is inserted. Segment creation is also deferred on indexes created implicitly when the table is created and indexes explicitly created after the table was created. If the table contains any LOB columns, the segment creation is also deferred.
Multiplexing Control Files
This document will detail multiplexing of control files. Having multiple control files reduces the risk of control file loss due to corruption or accidental removal. In the case of corruption or loss recovery is no more difficult than copying the control file from another location.
The first step in multiplexing the control files is to see where the exiting control files are located.
SQL> show parameter control_files
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
control_files string /u02/app/oracle/oradata/orcl/c
tl/control01.ctl, /u01/app/ora
cle/flash_recovery_area/orcl/c
ontrol02.ctl
SQL>
We want to verify were the current control files are because we want to ensure that we do no put the multiplexed control files on the same location/disk. This way we ensure that we have a copy of the control in the case of disk loss.
We can see that currently there are two control files. In order to add a control we need to update the CONTROL_FILES parameter with the new location using the ALTER SYSTEM SET CONTROL_FILES command.
SQL> alter system 2 set control_files='/u02/app/oracle/oradata/orcl/ctl/control01.ctl', 3 '/u01/app/oracle/flash_recovery_area/orcl/control02.ctl', 4 '/u03/app/oracle/oradata/orcl/ctl/control03.ctl' 5 scope=spfile; System altered. SQL>
In the command above I added the location /u03/app/oracle/oradata/orcl/ctl/. Also note that the scope was set to SPFILE and not BOTH or MEMORY this is to prevent the database from attempting to look for the new file at this time.
Next we shutdown the database and copy one of the existing control files to the new location.
SQL> shutdown immediate Database closed. Database dismounted. ORACLE instance shut down. SQL> host [oracle@ora1 ~]$ cp /u02/app/oracle/oradata/orcl/ctl/control01.ctl /u03/app/oracle/oradata/orcl/ctl/control03.ctl [oracle@ora1 ~]$ ls -alh /u03/app/oracle/oradata/orcl/ctl/ total 9.4M drwxr-xr-x 2 oracle oinstall 4.0K Apr 26 09:07 . drwxr-xr-x 5 oracle oinstall 4.0K Apr 26 08:21 .. -rw-r----- 1 oracle oinstall 9.3M Apr 26 09:07 control03.ctl [oracle@ora1 ~]$
Now all that is left is to bring the database back up.
SQL> startup
ORACLE instance started.
Total System Global Area 849530880 bytes
Fixed Size 1339824 bytes
Variable Size 528485968 bytes
Database Buffers 314572800 bytes
Redo Buffers 5132288 bytes
Database mounted.
Database opened.
SQL> show parameter control_files;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
control_files string /u02/app/oracle/oradata/orcl/c
tl/control01.ctl, /u01/app/ora
cle/flash_recovery_area/orcl/c
ontrol02.ctl, /u03/app/oracle/
oradata/orcl/ctl/control03.ctl
SQL>
Multiplexing the control files is a simple process that provides great benefits in the case of control file corruption and loss.
Multiplexing the Redo Log Files
To protect against failure of the redo logs, Oracle allows redo logs to be multiplexed. With multiplexed redo logs two or more identical copies can be placed in separate locations. The log writer process (LGWR) writes the same redo information to each multiplexed log.
Moving/Renaming Redo Log Files
It is possible to move/rename the online redo logs should the need arise. This document will detail the steps required to move/rename the online redo logs in an 11gR2 environment on Linux. These steps also apply to a 10g environment.
Moving/Renaming Datafiles While the Database is Online
It is possible to move and or rename datafiles while the database is online provided the tablespace in which the files belong is a non SYSTEM tablespace and does not contain any active ROLLBACK or TEMPORARY segments.
This document will detail the steps to move/rename a datafile using Oracle 11g R2 on Linux. These steps also apply with 10g.
Moving/Renaming Control Files
It is possible to move/rename the database’s control files should the need arise. This document will detail the steps required to move/rename the control files in an 11gR2 environment on Linux. These steps also apply to a 10g environment.
Setting up RMAN for backup and recovery using Database Control
Using Database Control you can configure RMAN to back up you database to disk or tape with relative ease. This document will detail how to configure RMAN for disk based backups and perform a backup.
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Database Control (dbconsole) will not start
The configuration files and repository used by Database Control contains information about the database, the listener and the hostname in which it is installed. Changes in either of those three items after the installation of Database Control will cause problems in the operations of Database Control.
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