IBM Data Management magazine Issue 2, 2009

Let’s prove that they’re gone:

SELECT FROM CLIENTS;

You will get zero rows displayed.

f wait for the outcome of pending writes. DB2 9. 7 now uses the default-locking state so that readers will not wait for the outcome of a pending write. Instead they will read the currently committed version of the row. Hence, readers don’t block writers and writers don’t block readers.

I am very impressed by these new SQL compatibility eatures. I have only been able to scratch the surface in this article, So I encourage you to take DB2 9. 7 for a spin. You won’t be disappointed!

Object and concurrency enhancements I’d like to wrap up by mentioning two important improvements to DB2 9. 7 that can save you time and increase performance: first-use validation, and a new default locking state.

First-use validation

Whenever underlying database objects (tables, views, procedures, functions, and so on) are altered, the next time an object is retrieved with its dependent objects, it will be automatically revalidated. This is definitely a time-saver for application developers. The automatic dependency check is done whenever an object is altered.

Anil Mahadev is an IBM Data Champion and a member of the Board of Directors for the IDUG India Forum. He is currently working as an independent consultant in Bengaluru, India, and exploring database implementation, Windows clustering, high availability, and strategies for multi-database platforms and applications.

Read currently committed (default in DB2) In previous releases of DB2, it was not possible to have one user trying to read and one trying to write to the same row at the same time. This is based on the principle that readers

General information on IBM DB2: ibm.com/db2/9

DB2 product documentation: ibm.com/ support/ docview.wss?rs=71&uid=swg27009474

IBM developer Works: DB2 for Linux, UNIX, and Windows: ibm.com/developerworks/data/products/db2luw

Upcoming DB2 technologies:

ibm.com/db2/technology-sandbox RESOURCES

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