Thanks Guozhang -- no this isn't quite it. The doc I read before contained the 
rationale for using physical offsets in the file, not logical offsets. I know 
the current version of Kafka now uses logical offsets again.  It's not a big 
deal though, I generally remember the contents of the page, and the important 
section about using the OS for caching is also contained the 0.8 docs. I was 
more curious about re-reading it.

I do have one question though. There are two ways (that I know of) of accessing 
a file -- the read() and write() system calls, or mmap'ing the file. Both go 
through the OS file cache, as far as I know. Which technique does Kafka 
actually use, when accessing log files? I always wondered. I started looking at 
the Scala source, but it's not immediately clear to me.

Thanks,
Philip
 -----------------------------------------
http://www.philipotoole.com 

     On Saturday, February 28, 2015 9:33 PM, Guozhang Wang <[email protected]> 
wrote:
   

 Is this you are looking for?

http://kafka.apache.org/07/documentation.html

On Fri, Feb 27, 2015 at 7:02 PM, Philip O'Toole <
[email protected]> wrote:

> There used to be available a very lucid page describing Kafka 0.7, its
> design, and the rationale behind certain decisions. I last saw it about 18
> months ago.  I can't find it now. Is it still available? I can find the 0.8
> version, it's up there on the site.
>
> Any help? Any links?
>
> Philip
>
> ------------------------------------
> http://www.philipotoole.com




-- 
-- Guozhang


   

Reply via email to