Ora-27107 Error when the Services are Running Properly and connecting earlier this week was fine.

the fix is that  you are missing ORACLE_SID

make sure you have database listener and database up and running.

to verify these, at the command prompt:

"lnsrctl services"

you should see a long message saying

<database sid> has 1 service handler


"tnsping <oracle_sid>"

you should see a short message saying

connect to .....<oracle_sid> <host=..><port=...>
ok


then

in windows,
do "SET ORACLE_SID=<oracle_databae_you_connnect>",

in unix

do "export ORACLE_SID=<oracle_databae_you_connnect>"



last , try to connect again.

Didn't work.  I tried that hours ago.  Same result.

have you done these already?

make sure you have database listener and database up and running.

to verify these, at the command prompt:

"lnsrctl services"

you should see a long message saying

<database sid> has 1 service handler


"tnsping <oracle_sid>"

you should see a short message saying

connect to .....<oracle_sid> <host=..><port=...>
ok

This error "Shared Memory Realm does not exist" generally means the database is not up.

also try these  steps:

1. Verify the service is running (This does not mean the DB is up).
2. Check the alert log for errors about why the database didn't come up.
3. From a command prompt:
sqlplus /nolog
connect / as sysdba
startup pfile=c:/path_to_pfile/initMYDB.ora

Yes, I've done that.  The listener is up and the db service is up.  I can stop and start them
easily without error.

ok, then do this:

 From a command prompt:
sqlplus /nolog
connect / as sysdba
startup pfile=c:/path_to_pfile/initMYDB.ora

sorry, you have not mentioned what OS you are running.

the above method is for UNIX

if you are in Windows:

From a command prompt:
sqlplus /nolog
connect sys/password@<sid> as sysdba
startup pfile=c:/path_to_pfile/initMYDB.ora

When I use EM, the password for sys works.
When I try your solution, it says invalid username/password.

There's a case of beer in it for you if you can get me back in business.

Ok, deal! ;-)

provide the following info:

1. where are you connecting from , a separate client machine or server machine itself?
2. how many oracle instances are there in the server machine?
3. what OS are you running? (my guess is windows, because you mentioned services)
4. Do you recall any work has been done on the server machine or database since the last good time?

Connecting from my desk, via Terminal Services to the server.  I have limited
success working in the Server room, the mouse does not work well on that terminal.

Only 1 instance of Oracle running

Windows 2000 Server

Nothing extraordinary has been done on the server between it working and it suddenly
not working.

OK, typo in the sys password.
I can log in, I can start the database, I can mount the database, I just can't Open the database.

better, post the shown error message then or it's the same error message?

so what did oracle say when you tried opening the database?

I need to repair the UNDO tablesspace.  Can I do that without the database Open?

Errors in file c:\oracle\admin\BWB\udump\ORA01636.TRC:
ORA-00376: file 2 cannot be read at this time
ORA-01110: data file 2: 'C:\ORACLE\ORADATA\BWB\UNDOTBS01.DBF'

Sat Nov 22 10:32:24 2003
Error 376 happened during db open, shutting down database
USER: terminating instance due to error 376
Instance terminated by USER, pid = 1636
ORA-1092 signalled during: ALTER DATABASE OPEN...

Between you and 2 guys from Oracle (Matt/Martin) I've finally gotten the
instance back up.  I appreciate you sticking with me all morning.  It's been
a trying 2 days.  You have earned my respect (not to mention a case)
and at least 1 gold start.  Many thanks,
-chris

The ultimate problem was that we had used Windows compression on the
drive and it took 3 days for it to be a problem for Oracle.  Oracle states
that they do not support Windows compression (or any other for that matter).
But we needed the disk space.