8 Replies Latest reply on Jul 4, 2016 8:31 PM by Bashar.

    ORA-01555

    Beauty_and_dBest

      Hi ALL,

       

      11gR1

       

       

      We have lots of frequently occurring ora-01555 in out alert logs.

       

      I search google and some of the recommended solutions are:

       

      1. Increase size of rollback segment which will reduce the likelihood of overwriting

      rollback information that is needed.

       

      2. Add additional rollback segments. This will allow the updates to be spread

      across more rollback segments thereby reducing the chances of overwriting required

      rollback information.


      1.
      Is item #1 can be addressed by setting its datafile to "auto-extend on"?
      or do I need to add more datafiles and auto extend each of them?

      alter tablespace

         undotbs1

      add datafile

         '/u01/prod/data/UNDOTBS01A.DBF'

      size 2000m

      autoextend on;


      2.

      Is item #2 can be handled by automatic undo retention management?
      How do you add rollback segments in 11g? Is it deprecated already?

      As verified with our DBA, our current allocation for the redo log is 32GB. Current utilization is only 28GB. If it has not reached its current allocation, do we need to increase this?



      Your assistance will be highly appreciated.



      Kind regards,
      jc