Scalability of 'spam.whitelist.rules' facility

[Gareth]

On Mon, 2007-05-21 at 10:35, Res wrote:
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> On Mon, 21 May 2007, --[ UxBoD ]-- wrote:
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> > Why not migrate them to MySQL and use the SQLBlackWhiteList.pm that is
> > available from the MailWatch package ?
> 
> This might be fine on low loaded systems, but to do a lookup for every 
> email on major networks would fail, as sql would not keep up unless you
> clustered and nobody is going to do that just for whitelisting.
> 
> I've seen it with vpopmail for instance the cdb file can handle over 6000 
> concurrent connections with no ill affect, sql spits farts and dies at 
> 1/5th of that value unless you cluster, so it's a pointless expense.

It doesn't work like that though. When the mailscanner instance starts
the code loads the contents of the black/whitelist into memory and then
checks to see if any changes have been made every 15 minutes.
This reduces the load on the sql server but of course does increase
memory usage and the startup time for the mailscanner process.