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  1. #1
    Join Date
    Dec 2004
    Posts
    25

    Unanswered: datafiles vs whole database

    whats the difference between point-in-time of "Datafiles" and point-in-time of "whole database"?

    By recovering a whole database point-in-time isn't it it recover back all the datafiles?

  2. #2
    Join Date
    Feb 2005
    Location
    Leesburg, VA
    Posts
    42
    Funny, I'm teaching DBA Fundamentals II this week which goes through all of this.

    If you do a: recover database;

    You are recovering ALL datafiles. The database must be in mount mode to do this since it involves SYSTEM and UNDO.

    However, if you are trying to recover a NON-SYSTEM or UNDO datafile, you can take it offline and just recover that one.

    So if you lose a file while the database is up, let's say it's file# 5, you do:

    alter database datafile 5 offline;
    recover automatic datafile 5;
    alter database datafile 5 online;

    without ever having to take down the DB.
    Steven Karam
    Oracle 10g Certified Master
    Web: OrclDBA.com
    Email: steve@orcldba.com

  3. #3
    Join Date
    Dec 2004
    Posts
    25
    Thanks for the info...noted that.
    But my question derived from the EM Console (10g). Under Recover type of "Whole Database", there is two options which I get a little confused. The recovery type is selected as "Whole Database". And ontop of that, we can choose to select "Restore to current time or previous point in time" OR "Restore all datafiles" (which is also available as current time or prior point in time).

    So back to my question earlier, what is the difference if i choose to "Restore to current time or previous point in time" OR "Restore all datafiles".
    Anyhow, it will also restore all datafiles isn't it... since this is a "Whole Database" recovery.

    Thanks

  4. #4
    Join Date
    Feb 2005
    Location
    Leesburg, VA
    Posts
    42
    You sure those are the words? I'm not near a 10g DB right now...it's RESTORE all datafiles, and RECOVER till a point in time. There are two different phases: restore and recover.

    Restore all datafiles puts them back into place. Recover till a point in time applies archive logs to recover.

    Sorry, I'll try to get to a 10g OEM to see what's up. I'm sure it's just vocab.
    Steven Karam
    Oracle 10g Certified Master
    Web: OrclDBA.com
    Email: steve@orcldba.com

  5. #5
    Join Date
    Dec 2003
    Posts
    1,074
    You can restore the entire database to a particular point in time, either in the past or through the most recent redo log. And you can restore a single datafile to the most recent point in time as illustrated above.

    If you want to restore a single datafile to a prior point in time, but you do not want to restore the rest of your database to that same point, then you'd have to use RMAN and TSPITR (Tablespace Point In Time Recovery).

    -Chuck

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