Can I change the SID of an Oracle database?

dba.stackexchange https://dba.stackexchange.com/questions/338

  •  16-10-2019
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Question

The Server is Oracle Database 11g Enterprise Edition Release 11.1.0.7.0 - 64bit

Is there an easy & quick way to change the SIDs of the test databases on the server?

Dropping & recreating of the database is an option for me. But I'm looking for something requiring less time.

The other option to assign names in the clients tnsnames.ora is prone to errors, because they are not administrated centrally.

Compared with the time to drop & create a database on SQL-Server, the amount of time required to create a new Oracle database is excessively greater. Further on SQL-Server you can rename SQL-Server instances. [ Usually you rename the server where SQL-Server is running and have some problems until you rename the server too ].

Was it helpful?

Solution

Since 9i dbnewid utility (nid) can be used to change database name (and DBID if required). If database name being changed only then resetlogs is not required:

  • 1 startup database in mount mode

    shutdown immediate
startup mount

  • 2 run nid to change database name:

    nid target=sys/syspassword@dbtns dbname=newname setname=YES

  • 3 shutdown and start database in mount mode:

    shutdown immediate
startup mount

  • 4 change db_name in spfile (or in pfile editing the file):

    alter system set db_name=newname scope=spfile;

  • 5 recreate password file:

    orapwd file=orapwnewname password=syspassword

  • 6 startup the database

    startup

  • 7 post rename steps:

    change SID in listener.ora
correct tnsnames.ora
remove old trace directories
change /etc/oratab (UNIX) or rename windows service using oradim

OTHER TIPS

You need to recreate the control file

This post by Kaunain Ahmed describes the necessary steps:

  1. do: alter database backup controlfile to trace;
  2. extract the "create controlfile" command from the background-dump-destination tracefile.
  3. shutdown the DB.
  4. Change the DB-Name in your init.ora and change the init.ora
  5. Change the SID in the /etc/oratab or /var/opt/oracle/oratab
  6. Change the SID in your environment and source it
  7. Startup the database to mount-status startup mount
  8. Re-Create the controlfile with the statement from position 2.
  9. Do a alter database rename global_name to 10.Change the TNS-Configuration accordingly $ORACLE_HOME/network/admin/*.ora Look for SID and GLOBAL_NAME

There are other tools referenced in the thread.

Here's a post by AskTom which references the process in more detail. While it's for 10g, it should still work.

Yes, you can and it is quite easy too.

In Oracle, the ORACLE_SID is just the name for the Oracle Instance and has not very much to do with the DBNAME. A database with the name PROD, can be served using Instances with any valid name. There is no direct connection between the SID and the DBNAME. This connection is made using the parameters.

The parameter file is identified as init${ORACLE_SID}.ora or spfile${ORACLE_SID}.ora In the parameter file is the parameter db_name. This is where the connection between the Oracle Instance and the database is made.

So, you don't need to re-create a controlfile, you don't need to use nid, just make sure that your parameterfile has the right name, bring down the old Oracle Instance and start the new Oracle Instance after having set ORACLE_SID to the new Oracle Instance name. The parameterfile and the password file are both found using the ${ORACLE_SID} as part of their name.

Re-creating the controlfile is only needed when the DBNAME has to change. nid is needed after a clone operation where you need to change the DBID to prevent accidents that could hurt the backups of the source database.

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