Each new DB2 release brings enhancements to the SQL optimizer, which is designed to speed response times by improving the access path used to return qualified data to the application. However, these improvements can only be realized by first REBINDing the program package.
Posted: June 07, 2016 |
Recently I was sitting in on a customer review and the topic of maximum number of open data sets came up. In DB2 11, the maximum number of open datasets is increased from 10,000 to 200,000.
Posted: May 31, 2016 |
Back in August 2011, I wrote about the use of roles and trusted context in auditing DBA activity. Just recently two separate customers have asked me about how and when to use this. Given that -- not to mention the increased attention on enterprise security, the growing demand for remote access through mobile devices, and the ongoing need to audit all management activities -- this topic is well worth revisiting.
Posted: May 24, 2016 |
Back in 2011, I wrote a series of posts about the evolution of optimization hints and the new DB2 10 statement-level optimization hints.
Now with DB2 11, the statement-level optimization hint can override the selectivity of predicates for matching statements. This is needed because DB2 cannot estimate filter factors for certain types of predicates. It must rely on inaccurate estimates or even default filter factors to select access paths for statements that use such predicates.
Posted: May 17, 2016 |
I recently worked with a customer who hadn't been using the PARALLEL parameter for REORG TABLESPACE. They'd set the LISTDEF parameter at the database level, which qualifies a large number of table spaces with hundreds of partitions per table space. Because the customer lacked the disk space to process hundreds of partitions simultaneously, they set the REORG_LIST_PROCESSING system parameter to SERIAL, which defaults the value of PARALLEL to (NO).
Posted: May 10, 2016 |
With the adoption of software development methodologies such as Agile, consumers have come to expect new solutions and product updates to come at a much faster pace. This same expectation now exists for business applications that rely upon mobile computing, cloud storage, real-time analytics and other emerging technologies.
Posted: May 03, 2016 |
I'm very excited about the upcoming IDUG DB2 Tech Conference for North America. Though DB2 for z/OS 12 doesn't have an official release date, it will be prominent of discussion at the conference.
Posted: April 26, 2016 |
I’ve written a lot about Data Server Manager (DSM) since its release in October and the announcement of DB2 for z/OS support in January.
Posted: April 19, 2016 |
Last week I briefly went through the history of block fetch. Today I look at the block fetch enhancements delivered in DB2 11 for z/OS, known as package-based continuous block fetch, or blasting.
Posted: April 12, 2016 |
When DB2 was first released, a distributed application would open a cursor and fetch a single row of data. This fetch request would go to DB2, then DB2 would return one row to the application. If the application requested 20 rows to be displayed on the screen, then 20 cross-network requests had to be made. This would greatly reduce the response time for the given application.
Posted: April 05, 2016 |