Oracle Open World Recap, Day Three
And we’re on to day three…
Keynotes
Intel spoke about their hardware and their vision for the interconnected future; Oracle spoke about their vertical apps. Both were quite dull and used far too many movie clips.
I have come to the conclusion that cinematics are the refuge of a bad speaker.
Interpreting Explain Plans
A very good and worthwhile session. An Oracle employee walked through every section of an explain plan, confirming what I already knew about how to read them as well as filling in additional details as to why the optimizer makes the choices it does.
Thinking Clearly About Performance
A good set of axioms for how to diagnose performance issues and prioritize repairs. Unfortunately, not a lot of technical details about how to improve performance.
User Experience Testing
I had the opportunity to work with some Oracle developers in testing UIs for future products. Fun and hopefully good for Oracle. Sorry I cannot say more about the experience, but that’s the rules.
Common Upgrade Mistakes And How To Avoid Them
As a result of UI testing, I was late to this session. By the time I got there, they were going over relatively obvious things, like using Flashback database as a way to rollback a database upgrade.
Managing Transactions With Disappearing Indexes
I was looking forwards to this talk with high hopes. I mean, disappearing indexes? What is this strange thing that might be very useful in many places.
First, the delivery. A general suggestion to speakers: If you’re going to start off by saying, “I’m not going to bore you with my resume,” don’t follow that up with “I’m not going to tell you about the time I deployed Oracle 4 on VMS writing Pro*C. Or the time I worked with the original team on VLDB. Or the time when I single handedly climbed Mount Olympus to personally wrestle Ares into submission while nursing a bum knee.” It’s a bit galling.
Even better, don’t present as if the world should fall down on its collective knees at your brilliance. Present as if you were telling a story, not a grouping of supposed feats.
The talk itself; disappearing indexes is basically tracking bulk transactions by converting a scratch column from some value into NULLs as the processing moves along. Since Oracle indexes generally ignore NULLs, the number of rows associated with the index decrease as the operation progresses. The fewer rows, the smaller the index. Hence, a disappearing index.
This seems like it may be a neat way to solve a specific problem; however, I think its applicability is going to be very limited across the general spectrum.
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