Incremental Updates

Peter A. Friend pafriend at
Fri Aug 26 21:00:17 UTC 2005

On Aug 26, 2005, at 12:27 PM, Erik Rozendaal wrote:

> The database format really isn't designed for incremental changes.   
> The
> multiple database approach I outlined in the e-mail to Peter Friend is
> probably easier.

This is an interesting approach. We are trying to avoid the IO  
overhead in loading such a large number of files. Another test was  
done where we copied the zone files to a tmpfs backed by ram. The  
combination of copy from disk to tmpfs and parsing from there was  
substantially cheaper than a parse from disk. I don't have detailed  
numbers yet. I am using the latest version.

> Another approach might be to have zonec load an existing database,  
> then
> parse the updated zone from the zone file and write a completely  
> new DB
> file.

Yes, that's exactly what I was proposing, I just didn't word it very  
well. And that's where I got stuck, since with the existing DB loaded  
into memory, I need to either delete the existing entry or just  
overwrite it. If it can be overwritten safely, then dumping the DB  
back to disk for eventual reload by nsd looks easy.


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