Kbase P7065: What is the cost of adding a new index?
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
12/03/2003 |
|
Status: Unverified
GOAL:
What is the cost of adding a new index?
FIX:
Although indexes usually provide performance gains in the retrieval of specific row or set of rows, there is a cost in adding indexes to a table:
Slower create and delete operations on rows. This is because index entries will be added or deleted when rows are added or deleted. The more indexes you have, the more index entries will have to be added or deleted.
Slower updates of index columns. This is because the index entries must be updated whenever a column that is a component of an index is updated with a new value.
Additional storage space. This is because the index entries will occupy additional disk space.
Additional administration and maintenance. This is because the increase in number of indexes will increase the time to rebuild indexes. In addition, the increase in size of the database will result in more time to manage the functions such as backup and restore.