SQL tuning is not just looking at statements and their EXPLAIN plans, but it’s also about verifying whether or not a tuning change actually improves performance. Remember that SQL tuning is about saving elapsed time and/or CPU resources, and there is only one way to really do that: benchmarking!
We use Explain to find out the access path for a query. Jim Dee, from BMC shows you how you can compare the access path with previous versions of the query or package – comparing the estimated costs, and identifying those that have changed with a rebind.
We hope that you’ve enjoyed this month’s articles on DB2 performance on z/OS.
We talked about the new performance possibilities in DB2 11, about performance hints and tips for framework development, about explaining tuning to C-level and about efficient ways of replication.
The second entry of this month’s theme, DB2 for z/OS performance, is a video by Thomas Baumann covering “Tuning Explained to C-level”. Take the time to watch this great video by one of IDUG’s Hall of Famers. Because, as important as tuning your system, is explaining what you did to your management.