On Fri, Nov 17, 2000 at 05:06:27PM +0100, Peter van Dijk wrote:
> On Thu, Nov 16, 2000 at 10:29:28PM -0800, [EMAIL PROTECTED] wrote:
> > > I made two mistakes, when I wrote that I want to have a cdb ;-)
> > >
> > > We're currently experiencing some temporary performance problems with
> > > our qmail server. This is due to large smtproutes and rcpthosts files
> > > and some I/O bottleneck on the disk they're located.
> > >
> > > Mistake 1) A cdb wouldn't help with this problem, as its usually even
> > > slightly larger
> > > Mistake 2) virtualdomains is only read once and kept im memory. Making
> > > a cdb out of virtualdomains wouldn't help with the bottleneck ;-)
> >
> > Right. But you're assuming that qmail-send would read the whole of
> > virtualdomains in at startup when it's a cdb file. I would imagine
> > a more sensible strategy would be to read the relevant entry per
> > email - as is done with the other cdb files.
>
> Then the discussion is
> - reading it at HUP *once* and doing in-memory scans
> versus
> - a cdb lookup for every delivery.
>
> I can tell you now that reading it once will only in very rare
> conditions give worse performance.
True enough, but only virtualdomains has the opportunity to be read just once.
smtproutes and rcpthosts (and badmailfrom especially) are read on each invocation
of qmail-smtpd. One problem with the current setup is that control.c issues
64 bytes reads. I changed that on one system that had very large smtp control
files to do larger reads and it made a significant impact.
It also seems that Dan thinks at least some smtp control files are suited to
this setup: witness morercpthosts.
Regards.
