ROLLBACK CONTENTION NOTES:
  • Segment Name - Name of the rollback segment.
  • Seg# - Rollback segment number.
  • Gets - Number of header gets.
  • Waits - Number of header waits.
  • Hit Ratio - Ratio of gets to waits. This should be >= 99%.
  • Active Transactions - Number of active transactions.
  • Writes - Number of bytes written to rollback segment.

  • Hit Ratio should be >= 99% - if not, consider adding additional rollback segments.
  • Check the system undo header, system undo block, undo header, undo block statistics under "Wait Statistics" for additional information on rollback contention.