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DB2 Self-Tuning Memory Manager gives DB2 9.7 the edge over Oracle Database 11g

Carol Davis-Mann

Carol Davis-Mann

December 7, 2010

The fifth task in our study comparing complexity in Oracle Database 11g and DB2 9.7 is Automatic Memory Tuning.  As with previous tasks we found DB2 9.7 to be significantly less complex than Oracle Database. 

DB2 has a Self Tuning Memory Manager (STMM) component, which can be enabled online and is relatively simple to configure (using a two-step process if the default parameters are used).  In comparison, undertaking memory tuning in an Oracle Database environment involves multiple operating system checks and several memory parameters that require a full database restart.  During our testing we also encountered issues with Oracle Database configuration parameters being reset after tuning. 

Overall the restrictive nature of the Oracle Database memory management compared to DB2 9.7 STMM is the result of Oracle Database’s inability to be fully automated, with restrictions in both automatic sizing and in buffer cache management. This inevitably leads to manual intervention on the DBA’s part.  Interestingly, Oracle Database is only able to increase memory up to its configured setting, but is unable to lower memory settings based on the workloads. In contrast, DB2 memory is adjusted by DB2 9.7 STMM as workload requirements change (either an increase or a decrease).

The complexity metric for DB2 is nearly 90% less complex than for Oracle Database. 

“This difference in complexity can have a significant impact in various aspects of total cost of ownership. Our projections show that the Oracle Database automatic memory management task for the specified environment could take over 100 minutes of DBA interaction time to complete. In contrast, the same automatic memory management task for DB2 would take a little over 10 minutes.”  Iqbal Goralwalla, Head of DB2 Midrange, Triton Consulting.

DB2 9.7 Vs Oracle Database 11g

The white paper with a breakdown for each task can be downloaded here – https://www14.software.ibm.com/webapp/iwm/web/signup.do?lang=en_US&source=sw-infomgt&S_PKG=analyst-db2_oracle_triton

Complexity analysis is a new approach to evaluating and communicating the usability of software and is based on established research as described in this document https://www-01.ibm.com/software/ucd/Resources/ComplexityAnalysisDGarticle.pdf.