Just thinking aloud....
High water mark (HWM)is the boundary between ever used and never used space in a segment. Oracle always reads up to the HWM during full table scan, no matter if the space is empty.
Why CBO doesn't know this fact?
It should just be a matter of adding yet another statistic in the arsenal of CBO and should be gathered up during stat gathering job?
Or am I missing something here....
High water mark (HWM)is the boundary between ever used and never used space in a segment. Oracle always reads up to the HWM during full table scan, no matter if the space is empty.
Why CBO doesn't know this fact?
It should just be a matter of adding yet another statistic in the arsenal of CBO and should be gathered up during stat gathering job?
Or am I missing something here....