The number of index levels in the index
tree.
The index level and index density indicate
whether or not an index needs to be reorganized. The number of
levels in the index tree determines the number of input and output
operations needed to access a row using the index.
Indexes with fewer levels are more efficient
than indexes with greater numbers of levels. The density is a
fraction between 0 and 1 providing an indication of how full each
index page is on average.
An Index Level value of 1 is ideal. An index
with an Index Level value of 4 or above or with a level value of 2
or 3 with an Index Density greater than 0.5 is a good candidate for
reorganization.
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