Kbase P55317: Avoiding unneeded indexes
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
11/20/2003 |
|
Status: Unverified
GOAL:
Avoiding unneeded indexes
FIX:
Another danger is simply defining too many indexes on a table. You should define an index for a table when you have most or all of these requirements.
- The index greatly reduces the amount of data to search to locate needed records. This is why you should avoid indexes on small numbers of distinct values.
- The index is needed frequently. If only one occasionally used procedure needs some unusual selection, it is probably not worth defining an index just for that case.
- Fast performance is essential for the procedure that uses the index.
If you have a batch report that runs once a month that needs some special selection criteria, it probably isn·t worth defining an index just for that purpose.
Maintaining an index every time you create or update a record is relatively expensive. Maintaining many indexes on the same table can be very expensive. Avoid defining indexes you don·t really need.