Re: host name support in pg_hba.conf

Kristian Larsson <kristian@spritelink.net>

From: Kristian Larsson <kristian@spritelink.net>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Peter Eisentraut <peter_e@gmx.net>, pgsql-hackers@postgresql.org
Date: 2010-08-09T21:01:42Z
Lists: pgsql-hackers
On Mon, Aug 09, 2010 at 03:25:23PM -0400, Tom Lane wrote:
> Peter Eisentraut <peter_e@gmx.net> writes:
> > Here is a patch for host name support in pg_hba.conf.
> 
> My recollection is that the previous discussions got stuck on the cost
> of doing DNS lookups for every connect; and the obvious solution of
> trying to cache the names was shot down on the basis of not knowing when
> to flush the cache.  Have you decided that people who want this feature
> will just have to pay that cost?  If so, I think the documentation needs
> to be a bit more explicit about names being more expensive than IP
> addresses in pg_hba.conf.

I am also a bit scared of the startup cost for each connection.
 
In which order are things evaluated? What if I only include IP
addresses in my pg_hba, will it still cost me a DNS lookup or
two? 

Kind regards,
   Kristian. 

-- 
Kristian Larsson                                        KLL-RIPE
+46 704 264511			              kll@spritelink.net