Trying to connect internally to Oracle, getting an idle instance?

Question

So I have an Oracle instance, and I know it's running on this system, I've su'd to the oracle user, and I'm trying to connect using "/ as sysdba". However, when I do connect, it says the instance is idle. I know the database is up and opened, because my application's talking to it. My paths (ORACLE_HOME, etc.) might be incorrect: any idea which incorrect setting might result in this?

% sqlplus "/ as sysdba"

SQL*Plus: Release 10.2.0.3.0 - Production on Mon Dec 8 09:23:22 2008

Copyright (c) 1982, 2006, Oracle. All Rights Reserved.

Connected to an idle instance.

09:23:22 SQL> Disconnected

% ps -ef | grep smon oracle 6961 1 0 Nov 05 ? 1:24 ora_smon_ORA003 %

Answer 1

that means that the database instance is not mounted nor open. Execute the startup command and see if any errors appear.

Answer 2

The database cannot be idle and in use by your application at the same time. It seems like the sqlplus session must be connected to a different instance than the application. Try specifying the connect identifier in the connect statement as follows:

sqlplus "/@ConnectIdentifier as sysdba"

Answer 3

make sure you have your ORACLE_HOME setup exactly the same as when the server was started, I've seen this problem with oracle 9.2.0.5.0 on solaris,

ORACLE_HOME=/opt/oracle
ORACLE_HOME=/opt/oracle/

is two different things, and will result in issues connecting locally.

Answer 4

Case is significant on *nix systems, so make sure your ORACLE_SID exactly matches the instance name. In this case, ORA003 is NOT the same as ora003.

Answer 5

try from the machine console

export ORACLE_SID=your sid here
sqlplus /nolog
startup

I know on windows there is a command to create a service to start up an instance for you, oradmin -new -sid %ORACLE_SID% -intpwd %oracle_pwd% -startmode A