Results 1 to 2 of 2
  1. #1
    Join Date
    Nov 2007
    Posts
    62

    Unanswered: Why we need minimum PIT ?

    Hello,

    I'm trying to understand how rollforward works.
    my guestion is - Why we need minimum PIT ?

    Lets say I have restored db from online backup, and it is now in rollforward pending state - that means db contains some unfinished transactions. So if I have transaction logs - why not to undo all unfinished transactions - the database will be consistent ?
    But no we still need to do roll forward at least till minimum PIT.
    Why ?

    thanks
    Vilius

  2. #2
    Join Date
    Aug 2001
    Location
    UK
    Posts
    4,650
    So if I have transaction logs - why not to undo all unfinished transactions - the database will be consistent ?
    Only the logs have info on what the value was before the start of a transaction - specifically, for updates and deletes.

    Also, the data in the backup image may be inconsistent, say, T1 in Tbspace1 was backedup at 10.15 with txn was in progress, and T2 in Tbspace2 was backed up at 10.17 when the same txn has been committed. So, how do you rollback ?
    Visit the new-look IDUG Website , register to gain access to the excellent content.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •