Performance catalogue

This is a list of articles that discuss design ideas that can have a big impact on performance. Each entry has a date stamp and a short note of the contents. The articles are generally listed most-recent first.

I am currently working backwards through my entire blog adding articles to catalogues as I go, so any individual catalogue may grow very slowly.

On the this blog

• Analytic Sorts (Nov 2022): Investigating a performance issue and finding a hole in a gap in an internal optimisation
• Hash Joins and functions (July 2022): how a trim() function in a hash join predicate used 1,800 seconds of CPU.
• Control File Waits (Jan 2022): Investigating where time can be lost on I/O with basicfile Lobs.
• Hacking with MVs (Dec 2021): reprint of a very old article on using materialized views to address performance issues with 3rd party systems
• Thoughts on “best practice”(Dec 2021): to join, use scalar subqueries, or other?
• Statistics_Level (Nov 2021): a quick check on what diagnostic statistics are active
• Sequence accelerator (Aug 2021): it’s important to think about the sequence cache size for most versions of Oracle, but an enhancement in 21c allows you to forget about it (almost).
• A little tweak in 19c (July 2021): the optimizer adding an “is not nulll” predicate that changes the cost of an execution path.
• Troubleshooting (August 2019): A generic strategy and specific example of how to re-engineer certain classes of query
• Unpivot mechanics (June 2017): what does Oracle do internally to handle an unpivot?

Other Authors

• An index of articles (dated between 2012 and 2015) about SAP and 12c by Stefan Koehler