Hotsos Symposium Speaker – Bryn LLewellyn

Mr. Llewellyn is a new Hotsos Symposium presenter.


Bryn LlewellynBryn has worked in the software field for 30 years. He joined Oracle UK in 1990, at the European Development Center, to work in the Oracle Designer team. He transferred to the Oracle Text team and then into Consulting as the Text specialist for Europe. He relocated to Redwood Shores in 1996 to join the Oracle Text Technical Marketing Group. He has been the Product Manager for PL/SQL since 2001.

It's hard for Bryn to remember his life before Oracle. He started off doing image analysis and pattern recognition at Oxford University (programming in FORTRAN!) and then worked in Oslo, first at the Norwegian Computing Center and then and in a startup. In Norway, Bryn programmed in Simula (its inventors were his close colleagues). This language is recognized the first object-oriented programming language and was the inspiration for Smalltalk and C++.

Presentation Title

Using the PL/SQL Hierarchical Performance Profiler


Oracle Database 11g brings a new hierarchical performance profiler for database PL/SQL. In very broad terms, you use it like you use SQL Trace: turn on data collection, run the code, turn off data collection, and format the raw data for human analysis. However, because of the richness of the information gathered, the formatter stores its output in database tables or generates a set of hyperlinked HTML pages. You can then answer questions like these: show me the list of subprograms and SQL statements that were executed during the run, ordered by the elapsed time; for a particular subprogram, show me the time spent in itself and the time spent in each of the subprograms it calls; for a particular subprogram, show me the list of subprograms that call it ordered by the total time for those calls. This information guides you efficiently to the code whose optimization will have the greatest effect.

This presentation explains how to use the profiler and how to interpret its output. It illustrates this with a practical case study.

Presentation Materials

Presentation materials are available online to attendees only. Mr. Llewellyn's presentation is now available on the Hotsos portal. Attendees may use their portal ids to log in to retrieve the materials.


The speaker schedules can be found at the following links: