I love using user-defined functions (UDFs) in DB2 for i. They encapsulate business logic, provide for code modularity and improve code reusability. But they can also flush performance down the drain. So in this tip, I’d like to use a sample UDF to analyze how it can affect the performance of an SQL statement.

For this illustration, I’ve exported the Microsoft SQL Server Adventure Works sample data to DB2 for i. There are three main tables to consider in this query; SalesOrderHeader (31465 rows), SalesOrderDetail (121317 rows) and ProductCostHistory (22680 rows; I dumped in some extra randomized data into this

Troubleshooting communications problems is akin to dealing with teenagers. There’s plenty of room for blame and finger-pointing, and resolving a problem sometimes seems impossible. I don’t have anything to help you with teenagers, but I can recommend a free tool for communications problems. It’s called Wireshark, and here’s how to use it with IBM i communications traces.

First, visit www.wireshark.org to get Wireshark. It is a network protocol analyzer that runs under Microsoft Windows and several operating systems of the Unix flavor. Like the best things in life, Wireshark is free.

Next, install the QSPTLIB library. This is a library

On an IBM i partition, you may need to route IP traffic for a particular server over a specific IP address. You could be doing this to segment network traffic or because you can only reach a host server through a specific interface (say an interface that has access to a firewall). Here’s the drill for modifying your IBM i TCP/IP routing entries to set up host routing.

The Situation

The best way to demonstrate how to set up IBM i host routing is by showing you an example. So let’s start with a single IBM i partition with a