Set the fetch size in the jasperreports.properties file to modify the number of rows to fetch
In the jasperreports.properties file you can set net.sf.jasperreports.jdbc.fetch.size=n, where n is the number of rows to fetch at a time - optimizing this can reduce the number of trips to the database.
For instance, if this value isn't set, Oracle uses a default value of 10 and DB2 uses 32 - by setting it to something higher, like 1000, you could conceivably reduce the round-trips to the database by more than two-thirds.
Other Performance Tips:
- Measure and Test
- Ad Hoc
- JasperReports Configuration Items