What are the guidelines to decide which table s to index?- On rebuilding an Index, the existing index is dropped and a new one is built. This operation can consume a lot of time and resources.
- When an index is reorganized, the leaf level pages of the index are defragmented to match the logical order by physically reordering them.
- As rebuilding indexes is an expensive operation, following general guidelines should be taken into consideration:
Reorganise an index when the degree of fragmentation is between 5 and 30%
Rebuild an index when the degree of fragmentation is over 30%