Case study on some rowcache internals, cached non-existent objects and a describe bug

Tanel Poder


I got a question regarding Metalink note 296235.1 about a describe bug which causes objects to “disappear” when they are described when database is not open.

It was an interesting case involving a bug, so I wrote a quite long analysis with test cases today. However when posting the entry to wordpress, it managed to completely mess up the formatting. After wasting half an hour trying to get the formatting correct I gave up and saved the article into a PDF instead.

You can access it here: /files/oracle_rowcache.pdf

By the way, I welcome more questions about Oracle internals or performance tuning.

Often when starting to explain something, I realize that I don’t really know the answer well enough, which is a valuable experience as it makes me figure it out and learn!

So, if you have a question, write it into a comment here or drop me an email to