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How to Resolve "Connected to an idle instance"

Connected to an idle instance

Actually, Connected to an idle instance is a message rather than an error, it indicates that the database you entered is idle, stopped or shutdown. It's pretty normal if your database instance is not started up, you can just start the Oracle database instance up and check the open status.

However, if the message surprised you, then you should know what happened. In this post, I will talk about Connected to an idle instance on Linux and Windows respectively below.

On Linux

Let's see the symptom.

[oracle@test ~]$ sqlplus / as sysdba

SQL*Plus: Release - Production on Wed Oct 30 00:38:10 2019

Copyright (c) 1982, 2019, Oracle.  All rights reserved.

Connected to an idle instance.

The message has the same meaning as ORA-01034: ORACLE not available.

Solution: Export Correct ORACLE_SID

If you think the instance should be up and running, but you saw Connected to an idle instance, may be you should check $ORACLE_SID first.

[oracle@test ~]$ echo $ORACLE_SID

Oh, the running instance should be ERPACC, I went for the wrong one. To correct this, I exported the environment variable like this.

[oracle@test ~]$ export ORACLE_SID=ERPACC

If you have confirmed that both $ORACLE_SID and $ORACLE_HOME are correct, maybe you should know why the running instance decided to shutdown itself due to some severe incidents.

One more guess, one of your colleagues turned the database off and didn't tell you.

On Windows

Let's check oracle database services on Windows server. First of all, open windows service console directly.

Oracle Services are Running on Windows
Oracle Services are Running on Windows

It appeared that all oracle services are running well on this Windows server.

Let's try to connect to the database locally:

C:\Users\Administrator>sqlplus / as sysdba

SQL*Plus: Release Production on Wed Oct 30 00:55:22 2019

Copyright (c) 1982, 2016, Oracle.  All rights reserved.

Connected to an idle instance.

"Connected to an idle instance"? It's confusing. The statuses between above two are inconsistent. What happened?

The reasons to the inconsistency could be:

By the way, if you tried to connect to the stopped database from an outside client, the listener could refuse to establish the connection. In such moment, you have to know how to connect to an idle database remotely.

16 thoughts on “How to Resolve "Connected to an idle instance"”

  1. I have the same problem, days ago I tried to download some files for my projects. I faced that problem, it may a virus appeared in my OS.

    1. For normal users, asking DBA for starting up the database can be a workaround. But I would recommend you to startup the database through Windows services, not by SQL command.

  2. Hello,
    After trying > startup
    I got this error :
    ORA-01078: failure in processing system parameters
    LRM-00109: could not open parameter file ‘C:\APP\EHABMOHAMED\VIRTUAL\PRODUCT\12.2.0\DBHOME_1\DATABASE\INITORCL.ORA’

      1. Thanks for your replay!
        but when trying to startup with the file
        (SQL> startup PFILE=”C:\app\EhabMohamed\virtual\product\12.2.0\dbhome_1\dbs\init.ora”;)
        I faced these issues :
        ORA-01261: Parameter db_recovery_file_dest destination string cannot be translated
        ORA-01263: Name given for file destination directory is invalid
        OSD-04018: Unable to access the specified directory or device.
        O/S-Error: (OS 123) The filename, directory name, or volume label syntax is incorrect.

  3. press the windows logo button + R on the keyboard and type ”services.msc” without the quotation marks into the box that pops up on the screen.
    hit ENTER
    It will open the services box
    scroll down to where you see Oracle, then stop all Oracle services and restart them again one by one
    when you are done restarting
    Open CMD command prompt and type “sqlplus / as sysdba” without the quote. It will connect now

  4. “Connected to an idle instance”
    Following thing I have done:
    1. Listener and all oracle services stopped and restarted
    2. It is logging on “sqlplus / as sysdba” using cmd and I am able to restart instance, showing database-
    – Database mounted, but database is not opening after restarting the instance.

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