From the bestselling Oracle10g book, Oracle Database 10g New Features by Mike Ault, Madhu Tumma, and Daniel Liu, published by Rampant TechPress and can be purchased directly from Rampant TechPress for 10% off by clicking here.

Oracle provides two UNIX scripts that assist DBAs with starting and stopping the database: dbstart and dbshut. For Windows platforms, the oradim utility is provided for starting and stopping the Oracle instance.

The dbstart utility reads the oratab file, shown in the example below. The oratab file will reside in either /etc or /var/opt/oracle, depending on the UNIX version. It contains three data items separated by colons:

ASG920xr:/usr/oracle/9.2.0:Y
ASG817xr:/usr/oracle/8.1.7:Y
TEST920xr:/usr/oracle/9.2.0:N
PROD920xr:/usr/oracle/9.2.0:N

The first field is the Oracle SID. The second field is the home directory for that Oracle SID. The Y or N instructs Oracle whether to start or stop the particular database when either the dbstart or dbshut command is issued. The dbstart command simply parses the oratab file and starts those databases that have a Y in the third field. It also uses the ORACLE_HOME specified in the file to connect internally to the database and issue the startup command.

The dbstart command can be added to the UNIX servers’ initialization or run level scripts. This enables dbstart to be executed each time the machine is booted or when it changes run levels. The method for implementing this is platform-specific, as we see below.

Auto Start on HP-UX and Solaris

For HP-UX version 10 and above, the system initialization scripts are contained in /etc/rc<n>.d directories, where “n” is the operating system run-level. These directories contain scripts that begin with K or S, followed by a number, and then a file name (S75cron). All scripts that begin with “S” are executed at system startup in ascending order of their number. Scripts beginning with “K” (Kill) are called at system shutdown time.

As a general rule of thumb, the Oracle startup script should have a high sequence number (S99dbstart), which will ensure that other system processes have been started prior to Oracle. Likewise, the kill scripts should have a low sequence number in order to shut down Oracle early in the process (K01dbshut).

Auto Start on AIX

For AIX servers, the system initialization file is /etc/inittab and the initialization script is /etc/rc. A utility (/usr/sbin/mkitab) can be used to make an entry in the inittab file. The shutdown script for AIX is /usr/sbin/shutdown, although it should not be modified to support dbshut.

To add the dbstart utility to the AIX initialization process, the following steps can be performed:

      1. Create the script /etc/rc.oracle. The script should contain the following:

       su oracle <<EOF
       <$ORACLE_HOME>/bin/dbstart
       EOF 

• Add the script to the inittab using the mkitab utility.

       $ /usr/sbin/mkitab “rcoracle:2:wait:/etc.rc.oracle >/dev/console 2>&1”

All references to <$ORACLE_HOME> should be replaced with the actual Oracle Home directory. Now upon system startup, the dbstart utility is invoked at run level 2.

Starting and Stopping on Windows

The dbstart and dbstop shell scripts do not exist on Windows platforms. Consequently Oracle database startup and shutdown is implemented completely differently. The oradim utility is used on the Windows platform to perform these tasks.

C:\oracle9i\bin\oradim -startup -sid ORCL92 –usrpwd manager
-starttype SRVC,INST -pfile C:\oracle9i\admin\ORCL92\pfile\init.ora

• startup — Indicates that the specified instance should be started.
• sid — The SID of the database to start.
• usrpwd — The password for the database user.
• starttype — Specifies whether to start the instance, the service, or both (SRVC, INST).

The following command can be used to shutdown the instance with oradim:

C:\oracle9i\bin\oradim -shutdown -sid ORCL92 -shutttype SRVC,INST
–shutmode A

Notice that no password is needed to perform this task.

The shuttype parameter specifies what is to be stopped – the service (SRVC), the instance (INST), or both (SRVC, INST). The shutmode specifies the method that should perform the shutdown – (A)bort, (I)mmediate, or (N)ormal.

Each operation, regardless of success, is logged in the oradim log file (ORACLE_HOME\database\OraDim.Log). This file should be checked for errors after each oradim command is executed.

The oradim utility provides more than just the ability to start and stop Windows databases. oradim can create and edit databases. It also allows DBAs to configure script-based installation mechanisms, bypassing the Oracle Database Configuration Assistant’s graphical user interface (GUI).

For a reference of all oradim commands, use the oradim–help command.

oraenv and coraenv Utilities

The oraenv and coraenv utilities both aid in setting the Oracle environment on UNIX systems (other utilities exist on Windows platform that enable the Oracle Home to be set.) The coraenv utility is appropriate for the UNIX C Shell; oraenv should be used with either the Bourne or Korn shells.

Database operations require the ORACLE_HOME to be set before the user may access the database. If ORACLE_HOME is not set, commands such as sqlplus, exp, or any other utility for that matter, will not be found.

Both utilities are shell scripts that do the same thing in the different UNIX shells. They will prompt for a SID of the database unless ORAENV_ASK is set to N. The utility will also append the ORACLE_HOME value to the path, marking the location of the utility.

The oraenv command will prompt for the SID of the database that you wish $ORACLE_HOME to access.

      $ . oraenv
      ORACLE_SID = [] ? ASG920

The dbhome utility can now be used to verify that $ORACLE_HOME is correct.

      $ dbhome
      /usr/oracle/9.2.0

The “dot space” part of the command is required to make the environment change with the parent shell, as opposed to entering a command without it which would only affect the subshell running that process.

These commands can be used to avoid specifying the network service name when issuing commands. For instance, without using oraenv, an sqlplus command would look like:

    $ sqlplus system/manager@nameofservice as sysdba

whereas after oraenv has been executed, the following command would work:

    $ sqlplus system/manager as sysdba

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Mike Ault is one of the leading names in Oracle technology. The author of more than 20 Oracle books and hundreds of articles in national publications, Mike Ault has five Oracle Masters Certificates and was the first popular Oracle author with his book Oracle7 Administration and Management. Mike also wrote several of the “Exam Cram” books, and enjoys a reputation as a leading author and Oracle consultant.

Mike has released his complete collection of Oracle scripts, covering every possible area of Oracle administration and management. The collection is available at: http://www.rampant-books.com/download_adv_mon_tuning.htm.