RE: DB2 Symmetric Multiprocessing (option 26 of 5770SS1) Was: Performance tuning

He tells you why no autotune.
Again and again and again.

To reiterate: When you use SQL every time it runs a statement it checks
to see if the environment has changed before running the statement and may
decide a different way to run it.
For example, at memory size X a full table scan may be better than at
memory size Y where it may use a different technique.
Therefore if you have auto tune set on and it's constantly changing memory
sizes then it has to constantly re-evaluate how to run an sql statement.
If the tuning is done manually and not quite so frequently, then you don't
have this issue.


Rob Berendt