Improve performance by adding or removing indexes

You can often improve the performance of a query by adding or, in some cases, removing indexes. You can also enable the optimizer to automatically fetch a set of keys from an index buffer.

To improve the performance of a query, consider using some of the methods that the following topics describe.

In addition:

• Consider using the CREATE INDEX ONLINE and DROP INDEX ONLINE statements to create and drop an index in an online environment, when the database and its associated tables are continuously available. These SQL statements enable you to create and drop indexes without having an access lock placed over the table during the duration of the index builds or drops. For more information, see Creating and dropping an index in an online environment.
• Set the BATCHEDREAD_INDEX configuration parameter to enable the optimizer to automatically fetch a set of keys from an index buffer. This reduces the number of times a buffer is read.