Oracle Midlands : Event #16 – Summary

Last night was Oracle Midlands Event #16 and we were lucky enough to get Jonathan Lewis for the third time. I think he now holds the record for the most presentations at Oracle Midlands. Both his sessions were on indexing.

The first session was really a general session about B-Tree and Bitmap indexes. What they are. Where they are not. Ways to reduce the number of indexes or avoid indexes entirely etc. It started with some basic information, almost like a primer, then worked on through to some more complicated stuff. Jonathan encouraged questions as he went along, and he got plenty.

I like the broad appeal of this type of format because it means there is something for everyone in the room. The newer people are going to get lost after a while, but they still get something out of the session. The more seasoned people get a refresher, then get challenged more as the session goes on. For me it takes time for some of the concepts to sink in, so each time I see a session like this I will get a little further along and things will click a little better. If I watched a session just full of the complicated stuff I would probably switch off. Just the simple stuff and I would be bored. This approach draws you along and allows you to work a little past your comfort zone. 🙂

Because of the number of questions, the first session was running long, so we had a short break, then Jonathan finished the first session and started on the second…

The second session focussed on the things that have happened over the years that affect how we approach indexing. This included features in a number of database versions that either directly or indirectly affect indexing. Jonathan also talked about the impact of technologies like partitioning, Exadata and InMemory that may give us situations where the best index is no index. 🙂

I got a lot out the these sessions. I asked a lot of questions and got to clear up a bunch of things in my head. I tend to mostly work on OLTP systems, so there is a lot of warehousing stuff where I don’t get a lot of practical experience. Knowing the theory and actively using it are two very different things, so it’s good to have an opportunity to get direct answers like this.

Thanks to Jonathan for coming to speak to us. Thanks as always to Red Stack Tech for sponsoring the event, allowing it to remain free, and to Mike for organising it!

See you all again soon!