Re: Oracle and SQL Tuning

I would respond that optimal means different thing to different people. Optimal with respect to:

transaction time,
indexes used ( if any),
# of IO's,
records returned per block per IO event whihc is a function of the db_block_buffer_size
whether the SQL statement has already been run once before, still present in the SQL shared pool and does not have to be parsed again ....
I could go on and on...

 The column selection of "*" returns null values so maybe that SQL is not as "optimal" because the columns with null data would also be returned; Assuming nulls are allowed in the column constraints. I'm not sure what the interviewer was looking for.

Cliff Received on Sun Aug 30 1998 - 13:28:33 CDT