tools for analyzing logs in extended format?

Does anyone know about *any* existing existing tools which can process
logs in the extended format?  I would like to generate simple statistics such

- the average time to process each request
- the average request time for each hour of the day, day of the week
- the fraction of requests which are handled by a certain higher-level cache
- etc.

Obviously, I can write this myself - I was just wondering if anyone had something
I might use as a starting point.