Oracle Idle instance case

Typically, there is a problem with the environment variable, either Oracle performs file permissions issues, either with the root user or Oracle_sid Export Settings error, or the database itself is not started, etc.

The scenario described in this article is an issue that tells an environment variable:

Su-oracle
Export Oracle_sid
Sqlplus/as SYSDBA

The above steps are completely correct, check the environment variable oracle_home is also normal. However you check at this time. Bash_profile may have been corrected later, and the environment variable that started running Pmon may not be at this time
The parameters set in the. Bash_profile.

Solution:

PS-EF |grep Pmon---find process ID

Cat/proc/pmon_id/environ

Look at the environment variables run by the Pmon and match the check for errors. Modify based on error parameters (restart instance takes effect)

Oracle Idle instance case