More Jonathan Lewis 13422386 1019544571447648 7687716130941590224 o1

More Jonathan Lewis

A little while ago, Jonathan Lewis presented a three day seminar in The Netherlands. You may have read other blogs on this site about this seminar. AMIS had sent six people to attend. And yes, I was one of the lucky ones too.
Although the seminar should be for developers and DBA’s, most of its content was aimed at DBA’s. As a developer I don’t think undo, redo and latches are very interesting. But there were enough nice things to make the seminar very useful. For instance

  • A nice example of how the way/order which records are inserted into a table can have impact on the performance of retrieving the data, due to differences in the clustering factor of the data/indexes.
  • An other example of querying simular datasets (in the same way), but with huge performance differences, if you are unlucky with some internal hash functions of Oracle.
  • A working example of the "go_faster" hint
  • A nice trick to get the DBA-role, see
  • and much more