Oracle for Unix - I


Found usually in /etc or /var/opt/oracle.

oratab is used by ORACLE utilities. It is created by the root.sh script (a part of Oracle installer), and is updated by the Database Configuration Assistant when creating a database.

Entries in this file have the following format:

A colon, ':', is used as the field terminator. A new line terminates the entry. Lines beginning with a pound sign, '#', are comments.

The first and second fields are the system identifier and home directory of the database respectively. The third filed indicates to the dbstart utility that the database should , "Y", or should not, "N", be brought up at system boot time.

List all installed Oracle products

For Oracle 8i and above:
cd $ORACLE_HOME/install
cat unix.rgs

Verify Oracle installation

select host_name, instance_name, version, status from v$instance;

TNS-12542: TNS:address already in use

Check if the TNS port is not already in use by another Oracle instance.
  1. Check if the host name specified in listener.ora is correct.
  2. Do a netstat - a to check if any other application is using the port specified in listener.ora
  3. If the listener.ora has been copied from somewhere (samples or elsewhere), check the ORACLE_HOME

Set the Listener Process for Automatic Startup

Edit /var/opt/oracle/lsnrtab, and change/add a line containing the name of your listener (as specified in listener.ora and change the start-up value to "Y")