Changing the database name without rebuilding
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Thread: Changing the database name without rebuilding

  1. #1
    Join Date
    Nov 2001
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    Ontario
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    Question

    Hello,

    Can anybody tell me how you can change the database name without rebuilding the database?
    I was told it can be done by a simple command but can't find the answer anywhere?

    Help Spinner

  2. #2
    Join Date
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    Location
    Helsinki. Finland
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    The "simple command" (s)he meant is probably "CREATE CONTROLFILE REUSE set DATABASE "newdbname" RESETLOGS;" But it's not that simple :-)

    You cannot do it with just that single command. You will have to force a checkpoint first, then alter database backup controlfile to trace resetlogs; Then shutdown. And then recreate the controlfile... Check 15390.1.


  3. #3
    Join Date
    Nov 2001
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    Turkey
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    This Document include all about to change DBNAME.

    Regards.


    Doc ID: Note:15390.1
    Subject: How to Determine and Change DB_NAME or ORACLE_SID
    Type: BULLETIN
    Status: PUBLISHED
    Content Type: TEXT/PLAIN
    Creation Date: 22-SEP-1994
    Last Revision Date: 25-APR-2001


    PURPOSE
    This entry describes how to find and change the "db_name" for a database, or
    the ORACLE_SID for an instance, without recreating the database.

    SCOPE & APPLICATION
    For DBAs requiring to either find or change the db_name or ORACLE_SID.

    RELATED DOCUMENTS
    [NOTE:1018634.102] AFTER RENAMING THE DATABASE SELECT FROM DUAL RETURNS
    OLD DATABASE NAME
    [NOTE:9560.1] ALTER TABLESPACE/DATABASE TO RENAME FILES


    To find the current DB_NAME and ORACLE_SID:
    ===========================================

    Query the views v$database and v$thread.

    V$DATABASE gives DB_NAME
    V$THREAD gives ORACLE_SID

    If ORACLE_SID = DB_SID and db_name = DBNAME:

    To find the current value of ORACLE_SID:

    SVRMGR> select instance from v$thread;

    INSTANCE
    ----------------
    DB_SID

    To find the current value of DB_NAME:

    SVRMGR> select name from v$database;

    NAME
    ---------
    DBNAME


    Modifying a database to run under a new ORACLE_SID:
    ===================================================

    1. Shutdown the instance

    The database must be shutdown with SHUTDOWN NORMAL or SHUTDOWN IMMEDIATE.
    It must not be shutdown abnormally using SHUTDOWN ABORT.

    2. Backup all control, redo, and data files.

    3. Go through the .profile, .cshrc, .login, oratab, tnsnames.ora,
    (for SQL*Net version 2), and redefine the ORACLE_SID environment
    variable to a new value.

    For example, search through disks and do a grep ORACLE_SID *

    4. Change locations to the "dbs" directory

    % cd $ORACLE_HOME/dbs

    and rename the following files:

    o init.ora (or use pfile to point to the init file.)
    o control file(s). This is optional if you do not rename any
    of the controlfiles, and the control_files parameter is used.
    The "control_files" parameter is set in the "init.ora" file
    or in a file it references with the ifile parameter. Make
    sure that the control_file parameter does not point to old
    file names, if they have been renamed.
    o "crdb.sql" & "crdb2.sql", This is optional. These are
    only used at database creation.

    5. To rename the database files and redo log files, follow the
    instructions in [NOTE:9560.1].

    6. Change the ORACLE_SID environment variable to the new value.

    7. Check in the "$ORACLE_HOME/dbs" directory to see if the password
    file has been enabled. If enabled, the file "orapw" will
    exist and a new password file for the new SID must be created
    (renaming the old file will not work). If "orapw" does not
    exist, skip to step 8. To create a new password file, issue
    the following command as oracle owner:

    orapwd file=orapw password=?? entries= granted permission to start the database instance>

    8. Start up the database and verify that it works. Once this is done,
    shutdown the database and take a final backup of all control, redo,
    and data files.

    The database must be shutdown with SHUTDOWN NORMAL or SHUTDOWN IMMEDIATE.
    It must not be shutdown abnormally using SHUTDOWN ABORT.

    9. When the instance is started, the control file is updated with the
    current ORACLE_SID.


    Changing the "db_name" for a Database:
    ======================================

    1. Login to Server Manager

    % svrmgrl
    SVRMGR> connect internal

    2. Type

    SVRMGR> alter system switch logfile;

    to force a checkpoint.

    3. Type

    SVRMGR> alter database backup controlfile to trace resetlogs;

    This will create a trace file containing the "CREATE CONTROLFILE"
    command to recreate the controlfile in its current form.

    4. Shutdown the database and exit SVRMGR

    SVRMGR> shutdown

    SVRMGR> exit

    The database must be shutdown with SHUTDOWN NORMAL or SHUTDOWN IMMEDIATE.
    It must not be shutdown abnormally using SHUTDOWN ABORT.

    5. Change locations to the directory where the trace files are located.
    They are usually in the "$ORACLE_HOME/rdbms/log" directory. If
    "user_dump_dest" is set in the "init.ora" file, then go to the
    directory listed in the "user_dump_dest" variable. The trace file will
    have the form "ora_NNNN.trc with NNNN being a number.

    6. Copy the contents of the trace file starting from the line with
    STARTUP NOMOUNT down to the end of the trace file and put it in
    a new file called something like "ccf.sql".

    7. Edit the "ccf.sql" file

    FROM: CREATE CONTROLFILE REUSE DATABASE "olddbname" RESETLOGS ...
    TO: CREATE CONTROLFILE set DATABASE "newdbname" RESETLOGS ...

    Change the word 'REUSE' to 'set' and the 'olddbname' to 'newdbname'.

    It is possible to recreate the controlfile using the syntax:
    CREATE CONTROLFILE REUSE set DATABASE "newdbname" RESETLOGS ...

    But this syntax will allow the existing controlfiles to be overwritten
    without giving an error.

    FROM:
    # Recovery is required if any of the datafiles are restored backups,
    # or if the last shutdown was not normal or immediate.
    RECOVER DATABASE USING BACKUP CONTROLFILE
    TO:
    # Recovery is required if any of the datafiles are restored backups,
    # or if the last shutdown was not normal or immediate.
    # RECOVER DATABASE USING BACKUP CONTROLFILE

    The last command in ccf.sql should be:
    alter database open resetlogs

    8. Save and exit the "ccf.sql" file

    9. Rename the old control files for backup purposes and so that they do
    not exist when creating the new ones.

    10. Edit the "init.ora" file so that db_name="newdb_name" .

    11. Login to Server Manager

    % svrmgrl
    SVRMGR> connect internal

    12. Run the "ccf.sql" script

    SVRMGR> @ccf

    This will issue a startup nomount, and then recreate the controlfile.

    If, at this point, an error stating that a file needs media recovery
    is reported, then the database was not shutdown normally as specified
    in step 4. Try recovering the database using the redo in the current
    logfile, by issuing:

    SVRMGRL> recover database using backup controlfile until cancel;

    This will prompt for an archived redologfile. It may be possible to
    open the database after applying the current logfile. BUT this is not
    guaranteed.

    To apply the necessary redo, check the online logfiles and apply the
    one with the same sequence number as reported in the message. This
    usually is the logfile with status=CURRENT. If not apply, the logfiles
    in turn until the logfile with status=CURRENT has been applied. If,
    after applying the current logfile, the database will not open then it
    is highly likely that the operation must be restarted having shutdown
    the database normally.

    To find a list of the online logfiles:

    SVRMGR> select group#, seq#, status from v$log;
    GROUP# SEQUENCE# STATUS
    ---------- --------- ----------------
    1 123 CURRENT <== this redo needs to be applied
    2 124 INACTIVE
    3 125 INACTIVE
    4 126 INACTIVE
    5 127 INACTIVE
    6 128 INACTIVE
    7 129 INACTIVE

    7 rows selected.

    SVRMGR> select member
    from v$logfile
    where GROUP# = 1;

    Member
    ------------------------------------
    /u02/oradata/V815/redoV81501.log

    After applying the current online log file the following prompt should
    be displayed:

    Log Applied
    Media Recovery Complete

    At this point the database can be opened with:

    SVRMGR> alter database open resetlogs;

    13. The global database name may also need to be changed:

    alter database rename global_name to .

    See [NOTE:1018634.102] for further detail.

    14. Make sure the database is working.

    15. Shutdown and backup the database.

    The database must be shutdown with SHUTDOWN NORMAL or SHUTDOWN IMMEDIATE.
    It must not be shutdown abnormally using SHUTDOWN ABORT.







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