Lesson Agenda

• Understand what these access paths are:

  • Full Table Scans
    • Impact of multi-block read count, high water mark
  • ROWID Scans
  • Index Scans
    • Several types…

• When a path typically useful

• Why CBO chooses

• Why CBO can make wrong choice

• What the CBO cost calculation is

  • Where documentation exists

Notes: