I have these couple of Qs on DB2 LUW. Can anyone please give me the inner details -
1. What does NLEVELS actually mean to the physical design (indexes) of the database?
2. What role does NLEVELS play when the optimizer selects one access plan?

Thanks & Regards,
Pranab

You can do a google search on B-Tree indexes to understand what the tree looks like, and why there are levels. Obviously, a very large table may require an index tree to have more levels than a small table.

The number of levels usually does not affect the access path selection, since on additional level requires only one addition page I/O, which may be in bufferpool memory already.