Subject: Re: increasing FD_SETSIZE to 1024 or 2048?
To: Jonathan Stone <jonathan@DSG.Stanford.EDU>
From: Todd Vierling <>
List: current-users
Date: 07/04/2000 16:21:11
On Tue, 4 Jul 2000, Jonathan Stone wrote:

: I am doing lookups of from 100,000 to 1 million unique hostnames, or
: unique IP addresess. For that application,c aching is largely useless
: (since the input queries are unique).  I do lots of lookups in parallel.

This scale is something probably better suited to UDP lookups and sendto(),
but I digress....

I can understand that named is a possible exception, and again, you can (or
we can, in the base source tree) modify it such that it redefines FD_SETSIZE
to a larger number for its own use.

This isn't like SOMAXCONN, which has to be modified at the kernel level (and
made visible to user source).  This is an application-definable constant
that dynamically resizes whenever you re#define it in the application.  
There simply is no need to make everyone else spend more time copying mostly
empty fd_set's when the application has a Very Simple way to increase its
own pool.

-- Todd Vierling (