Oracle Scratchpad

Public Appearances



11th/12th June 2018 Vienna, Austria: I’ll be speaking at the 30th Anniversary Conference of the Austrian Oracle User Group on the topic “Just Don’t Do It” (Examples of how to avoid making the database do unnecessary work). My session will be on Tuesday 12th in the early afternoon.

In this presentation we work through several examples – taken from the OTN database forum, or from (camouflaged) client systems – of ways in which excess work can be eliminated. The options vary from basic configuration to simple code changes, from rephrasing the requirement to restating the logic, and being aware of the way that you may have missed features that are perfect matches for your requirement.

We consider array fetching, precision updates, side effects of analytic functions, trading SQL for PL/SQL, pros and cons of temporary tables and intermediate results, and the dangers of using scalar subqueries that might make queries easier to understand but could make them much slower to run. Along the way we tick off a couple of technical details about indexes, analytic functions, and the 12c match_recognize functionality.

21st June 2018 Edinburgh, Scotland: My presentation “Struggling with Statistics” (a shorter version of the presentation I’ve prepared for Trivadis in September) has been accepted for OUG Scotland 2018 and “Partitioning Enhancements in 12c Release 2” is on the reserve list.
19th/20th Sept 2018 Zurich, Switzerland: I’ll be speaking at the Trivadis Performance Days along with several of the mostly highly skilled and well-informed individuals in the Oracle arena. The topic I’ve suggested is: “Struggling with Statistics” (a longer version of the presentation I’ve offered to OUG Scotland):

When someone requests help on the Oracle forums to address the problem of a query picking a bad execution plan, one of the commonest (and most rapid) responses is the suggestion to make sure the statistics are up to date. Sometimes this will solve the problem, sometimes it won’t solve the problem but will produce a change that makes it easier to identify the problem, sometimes it just won’t help at all.

“Up to date” statistics, “accurate” statistics and histograms aren’t necessarily what you need to get Oracle to produce the execution plan you want, and in this presentation we look at some of the ways in which “good” statistics are not “good enough”, and come up with some strategies for recognising when we have to work around Oracle’s statistics and how we can work around them with the minimum of effort and risk.

3rd – 5th Dec 2018 Liverpool, UK: The UKOUG Annual Conference Tech 18 will be held in Liverpool this year. The call for papers isn’t open yet, but I can’t imagine not putting in a couple of abstracts: and I’ll probably be a bit upset if I fail to get a speaking slot. It is possible to register your interest at the UKOUG website

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