Conor O'Mahony's Database Diary

Your source of IBM database software news (DB2, Informix, Hadoop, & more)

Archive for December 2009

IBM Data Management Partner Bootcamps now Online

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If you are an IBM partner who works with DB2, I recommend that you check out the recent additions to the IBM Learner Portal. Each year, the IBM Data Management team travel the world to host their popular bootcamps in classrooms near you. These bootcamps consist of both educational presentations and hands-on training. There are bootcamps for a variety of products, including DB2, Informix, and Optim. Now, IBM are making it even easier for you to access this high-quality technical content by adding the bootcamps to the IBM Learner Portal. That’s right, you can access these bootcamps from the comfort of your own desk. Not only that, but the topics in each bootcamp are accessible in a modular format, allowing quick access to individual topics.


Written by Conor O'Mahony

December 28, 2009 at 3:12 pm

Posted in Uncategorized

Clarifying Some Recent Oracle Benchmark Claims

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Earlier this month, Oracle issued a press release regarding their latest results for the SAP® Business Intelligence-Data Mart (BI-D) Standard Application Benchmark. In the press release, Oracle claim that the new Oracle Database result surpasses the best IBM DB2 result by more than six times. While this statement is true, it is a little misleading. You see IBM does not perform the SAP BI-D benchmark tests for DB2 on the Linux, Unix, Windows, or z platforms. IBM performs these benchmarks only for DB2 on the i platform. So, when Oracle says that its result surpasses the best IBM DB2 result by more than six times, it is comparing a 4-node Oracle RAC cluster with a single DB2 for i system. Oracle is also comparing a recent benchmark result against an IBM result that is more than a year old. So, while these comparisons seem spectacular at first glance, once you look at the details you realize that they are not entirely fair.

Also, please note that the BI-D benchmark is a read-only benchmark. We have increasingly heard from clients that this benchmark is not realistic for their environments. IBM clients tell us that their systems typically have mixed workloads. For instance, demands for more current data typically result in trickle feeding, and they often need to rebuild cubes while queries are running. For these reasons, IBM is increasingly unlikely to perform the BI-D benchmark tests. Instead, clients are interested in the more realistic SAP BI-MXL which includes inserts, updates, and deletes with the queries.

The other thing to be aware of is that these benchmark results further illustrate the gap in levels of support for SAP applications provided by these database software products. With IBM DB2, you simply set one variable (DB2_WORKLOAD=SAP) and all the required settings are configured automatically for you. However, if you look at the benchmark submission package, you will see that these new benchmark results from Oracle use some interesting configuration settings. Undocumented and unsupported configuration parameters in Oracle Database begin with an underscore. Well, Oracle uses six of these undocumented and unsupported configuration parameters in these benchmark results. I’m sure its not reassuring for Oracle Database users to learn that Oracle needs to use undocumented and unsupported parameters to get optimal performance. The parameters in question are:

  • _optimizer_cost_based_transformation= off
  • _query_rewrite_fudge = 1
  • _improved_row_length_enabled= FALSE
  • _optim_peek_user_binds = FALSE
  • _optimizer_autostats_job = FALSE
  • _optimizer_save_stats = FALSE

There are some interesting settings in here. Apparently, they don’t trust their cost-based optimizer because they disable it. And they appear to be setting some sort of query rewrite fudge factor. I wonder what fudge factor you should choose for optimal performance in your environment. And, if they are disabling it, perhaps the row length setting does not improve things as its name suggests it might 🙂

PS. Many thanks to Chris Eaton for his expertise and help with this blog post.

Written by Conor O'Mahony

December 23, 2009 at 8:31 pm

Integrated Systems mean Easier Deployment and Faster Performance

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If you attended the 2009 IBM Information on Demand conference, you may have seen the following video. It focuses on how two IBM clients benefit from workload-optimized solutions from IBM. A workload-optimized solution is essentially a single system where all components (hardware, database software, reporting software, analytics software, etc.) come pre-configured and pre-integrated for optimized operation. IBM offers pre-configured and pre-integrated solutions for both OLTP and OLAP environments, with DB2 pureScale and IBM Smart Analytics System respectively.

Because these integrated systems come pre-configured for optimal performance, you don’t have to worry about integrating, balancing, and tuning the systems during deployment. This saves a lot of time, and ensures a faster time to value for the new system. Farmers Insurance estimate that they saved months of deployment time. Rooms To Go went from nothing to an entire system (extracting, transforming, loading, warehousing, and analyzing data) with dashboards in just two months.

Another benefit of these systems is improved performance. IBM tests and certifies the integrations, ensuring they are configured for optimal operation. IBM also uses established best practices to pre-tune the systems. When Farmers Insurance put their system in place, they immediately saw performance gains of 42%.

Written by Conor O'Mahony

December 21, 2009 at 11:00 am

Help for Oracle DBAs Who are Moving to DB2

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Many Oracle DBAs and programmers are discovering that DB2 has a lot of features that are quite familiar to them. From data types to SQL, from built-in packages to PL/SQL, many of the features that are most familiar to Oracle Database users are now supported in DB2. This support has generated some interest from notable members of the Oracle community like Steven Feuerstein and Lewis Cunningham.

If you are an Oracle DBA or programmer, and you want to learn more, there are a couple of good resources:

  1. First, a resource that’s free. IBM published a Redbook that describes these new features. You can download the Redbook from Oracle to DB2 Conversion Guide: Compatibility Made Easy
  2. Second, a resource that costs money. IBM Education has created a new 2-day training course for database administrators, database application designers, and database application programmers who want to learn about moving from an Oracle Database environment to DB2. You can learn more about this course at Oracle to DB2 Enablement Workshop.

Written by Conor O'Mahony

December 10, 2009 at 6:12 pm

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