Re: [Sqlgrey-users] [SPAM] Re: [SPAM] Re: Patches for SQLgrey

[Michal L. <ml...@lo...>]

Lionel Bouton wrote:

> I discouraged elaborate matchers for a reason : they are slow.
> If you use full IP or class-c, you are looking up a hash entry. If you
> do regex or prefix-based matching, this can become a full sequential
> search on a list and this part of the code is hit on each and every mail
> so it better be fast.

It needn't be slow if done smartly ;-)

What I have already (mostly) ready for checkin is roughly:
- instead of current $whitelist{IP}{ip} and $whitelist{C}{ip}
  have $whitelist{prefixlen}{ip} (and similar for IPv6).
  For example the entries would be:
	$whitelist{24}{"1.2.3.0"}
	$whitelist{24}{"10.20.30.0"}
	$whitelist{16}{"123.123.0.0"}
- Then for each incoming IP:
  foreach $prefix (sort(keys $whitelist)) {
        $masked_ip = apply_prefix($ip, $prefix);
	// Whitelist match?
	return 1 if (defined $whitelist{$prefix}{$masked_ip});
  }

Since there's not likely to be more than a handful of different
prefix-lenghts in $whitelist the overhead over the current
implementation is marginal. Instead of current two hash lookups (in
->{IP} and ->{C}) it may do perhaps three or four lookups, depending on
the number of different prefix-lengths. Definitely nowhere near
sequential search, don't worry ;-)

> Git (or Mercurial) would allow us to branch easily to prepare the fixes
> for 1.8.0 and the evolutions for 1.8.x at the same time. But Mercurial
> would be a speed bump for me :-(

I vote for SVN ;-) Then you can use git-svn, can't you? I never used it
myself though.

Michal
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