Moscone West L2, Rm 2005
This presentation looks at various tips, tricks, and traps regarding the use and implementation of Oracle indexes. Topics include indexes and constraint management; how different types of indexes are needed for different constraint options; and how constraints, in turn, influence the cost-based optimizer (CBO). Next the session discusses subtle differences between unique and nonunique indexes and why these differences matter. It looks at tricks that make B-tree indexes extremely useful even if columns have few distinct values, as few as just one value. It also looks at how NULLs can actually be indexed effectively in B-tree indexes. Finally, it considers various problems with index monitoring and why the results can't be trusted.