DB2 Performance Features in DB2 V9 for z/OS – Part 11

While talking with clients and friends at the recent conferences, I noticed that everyone seemed to like the blog entries I’ve done about the DB2 performance features of DB2 v9 for z/OS. Some have even implemented some of the features previously mentioned and have already reduced their costs and overall processing elapsed times. So, with DB2 Version 9 for z/OS having over 50+ great new DB2 performance features, we will continue highlighting these many great new features in the coming weeks.

One of the biggest improvements has come for application and SQL processing in the improvements in index lookaside. This application and SQL index lookaside improvement is built into DB2 Version 9 and leverages the access of the previous work within the current SQL process or other SQL processes.

Index lookaside is the improved process where DB2 keeps track of the index and data pages referenced and their associated index value ranges using system cache. This provides DB2 with the ability to bypass or ignore any subsequent duplicate requests for I/Os against these desired pages. Since these duplicate page requests happen quite frequently during insert activities, index lookaside provides tremendous I/O relief for insert activities. Index lookaside is a great index I/O performance improvement feature that came with DB2 Version 8 for insert activities only.

In DB2 Version 9, the index lookaside process has been leveraged for delete processing also. Since most insert and delete activities process via some order, the index key values and their associated index and data pages could be requesting duplicate I/Os. According to IBM, analysis has found that the new index lookaside feature can save tremendous amounts of I/O — sometime up to a 100 times reduction in I/O requests.

Given these index lookaside features that are built into DB2 Version 9 for z/OS it should be immediately available to all your SQL and applications. This should help improve the DB2 performance of existing applications that do a large portion of insert and delete processing with or index lookaside reducing overall elapsed time for your processing.

Leave a Reply

You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>