Hotsos Symposium Speaker – Wolfgang Breitling

Wolfgang Breitling is a returning Hotsos Symposium presenter.

Biography

Wolfgang BreitlingWolfgang Breitling was born in Stuttgart, Germany, and studied mathematics, physics and computer sciences at the University of Stuttgart. Following several years as systems programmer for IMS and later DB2 databases on IBM mainframes, he made the transition to Oracle in 1993 on a project to implement Peoplesoft. In 1996, he became an independent consultant specializing in administering and tuning Peoplesoft on Oracle. The particular challenges in tuning Peoplesoft, with often no access to the SQL, motivated him to explore Oracle's cost-based optimizer in an effort to better understand how it works and to use that knowledge in tuning. He has shared the findings from this research in papers and presentations at Hotsos, UKOUG and other conferences and newsgroups dedicated to Oracle performance topics.

Presentation Title

Session #1: Anatomy of a SQL Tuning Session
and
Session #2: Seeding Statistics

Abstract

Session #1, Anatomy of a SQL Tuning Session: The presentation will lead through the progression of steps tuning a query. It is based on the actual process of tuning a SQL to be introduced to production, and highlights some of the techniques used to achieve a faster query, all based on the information available from dbms_xplan.display_cursor. No need for a 10046 or 10053 trace.

The steps include:

  • Modifying a view used in the query,
  • Altering the query itself and
  • Eventually some hints.

The query, which initially timed out at over 5 minutes, ultimately ran in a few seconds.

Session #2, Seeding Statistics: Everyone, hopefully, knows how to gather statistics for tables, columns and indexes.

Using two real examples, the presentation will explain reasons for explicitly setting instead of gathering statistics for a table, a column, and an index. It will show different ways to do that and describe the advantages and difficulties with the different options and give tips on how to use them.

Presentation Materials

Presentation materials are available online to attendees only.

Schedule

The speaker schedule is as follows: