With each new release, DB2 is getting smarter and smarter. However, DB2 is not yet clairvoyant enough to understand the intentions of all queries and turn them into optimal forms. What’s the bottom line? Do you need to worry about how you code? The answer is yes, but not as much as in the past.
In this comprehensive overview of DB2 10, for z/OS Lori Ann Galluzzo goes through the features of DB2 10 in great detail. Each feature is discussed, along with how and when to take advantage of the feature, as well as some pitfalls and things to watch out for.
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.
There are often multiple ways to code a query, some of which perform better than others. It is not just a matter of effectively utilizing the indexes, but also the SQL constructs. This week, Tony Andrews of Themis, and a popular speaker, author, consultant and trainer is writing on this topic.