We develop on a small model 170. The JDBC calls -- from a PC back to the iSeries -- are terribly slow. Similar calls to a Windows backend or Linux are extremely fast. Are there any optimizations we need to make sure are done to run SQL/JDBC on an iSeries?
In addition, a few Java programs on the iSeries take almost two and a half minutes just to start the JVM. Can this be improved?
First, have you compared the processor power of your iSeries server with that of the PC & Linux servers to see if this a valid performance comparison?
Another common mistake is not tuning your application and database for DB2 UDB for iSeries. Every database server is different in terms of how it optimizes & implements JDBC request. Here a couple of URLs with good DB2 performance information: DB2 education (see SQL Performance Basics & Coding for SQL Performance) and DB2 UDB education/white papers (see Indexing & Statistics Strategy)
You may want to look at using JDBC Connection Pooling & Extended Dynamic performance to improve JDBC performance. This website, Technical resources -- The Java programming language, has some good information, including a link to a Redbook on iSeries Java performance titled: "Java & WebSphere Performance on IBM eServer iSeries Server"
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