Re: LW5: DNS Slow

On 27 May 2006, at 21:53, John C. Mallery wrote:


>
> 	* Does LispWorks invoke DNS in  a serial fashion for comm:get-host- 
> entry?  This will cause all parallel DNS requires to block until a  
> slow on completes or times out.
> 	* Can we get more fields from comm:get-host-entry than just the  
> documented fields?  In particular, can we get the the time to live  
> field so we could perform our own caching?

It seems to me unlikely that any application-level caching would be  
better than the caching is provided by the platform, although I don't  
know the details of what Mac OS does.  *Unless* name lookups are all  
being serialised in the application, in which case that might be the  
only choice.  Or I suppose if you're looking up huge numbers of names  
repetitively, when it can definitely be beneficial to cache in the  
application.

I've repeatedly been bitten by Java apps which cache name lookups by  
default and therefore need to be rebooted when something changes in DNS.

>
> 	* Are there configuration options the OS level that can improve  
> DNS performance? Caching?

I don't know if Mac OS has nscd or an equivalent, which is often  
helpful (but occasionally dangerous).  The other alternative is a  
local caching-only name server, which should be easy to set up.

--tim