Hotsos Symposium Speaker – Henry Poras

Mr. Poras is a returning Hotsos Symposium presenter.


Henry Poras has been an Oracle DBA for over ten years, working with custom applications as well as off-the-shelf products. He is currently developing an airline reservation system, which has strict HA and performance demands. Innovative techniques are being brought to bear in order to test this system prior to completion of development.

He has also developed and taught college courses for five years.

Presentation Title

Queueing Theory Analysis of Statspack Reports
Obtained from Database Load Tests — Part 2


Statspack reports obtained during load testing will be analyzed through the eyes of Queueing Theory. Applying these techniques to data obtained over varying loads allows us to determine the optimal load on the system. In a continuation of last year's talk, real world results will be examined from the perspective of queueing theory. We have found a number of benefits to this approach (besides just satisfying our curiosity). We will be able to confirm the source of resource bottlenecks, behavior of response time with load, and behavior of throughput with load. This analysis is applied to a multi-tiered RAC system.

Some of the topics to be covered include:

  • Mapping queueing theory parameters to Oracle/Statspack metrics. Much of the interesting analysis can be accomplished using just three statspack metrics.

  • Quickly differentiating whether saturation is occurring in the database or elsewhere in a multi-level system.

  • Detailed analysis and drilldown of bottlenecks and resource utilization

  • Validation of experimental setup. This includes an example where we found unforeseen loading of our stressing tool, which was skewing our results

  • Comparing throughput and residence time behavior as a function of load in RAC and non-RAC systems.

  • Seeing if the entire database can be modeled as a queueing center. How is this different from breaking down the database into CPU and IO components?

We will also start to explore more complex scenarios, including examining multiple sessions which are running multiple workloads.

Previous knowledge of queueing theory is not necessary.

Presentation Materials

Presentation materials are available online to attendees only. Henry's white paper may be found on the Hotsos portal. Please use portal id rather than email address to log in.


The speaker schedules can be found at the following links: