a)  Suppose we updated the catalog tables in real time, that is, after every update, insert, or delete SQL statement were executed-rather than only running RUNSTATS once every few days or longer.

Is this idea (real time updates), a good idea?   Provide arguments both for and against.

b)  Suppose the DBMS kept track of how long it took to execute each SQL statement:  i.e., for every single SELECT, INSERT, UPDATE, and DELETE statement.  Explain how the database system could use this information in some meaningful and practical ways to suggest to the DBA when it is time to reorganize the tables and indexes (or for the DBA to take other action). 

c)  When should a DBA consider dropping indexes from a table?  Give at least 3 good reasons.