On Fri, 16 Jan 2026 19:29:03 -0800 Randy Bush via Postfix-users <[email protected]> wrote:
> On Fri, 16 Jan 2026 17:17:48 -0800, Viktor Dukhovni via > Postfix-users wrote: > > >> Why pcre as opposed to regex? i.e. > > Because PCRE is often more capable, and may be familiar from other > > contexts, but also because "bad advice", parsing header addresses > > with regular expressions is always a mistake. > > hmmmm. my unjustified instinct is that pcre is a bit heavier than > old fashioned regex. but, as i said, unjustified. and the load is > light, < 500 msg/hr make it past dnsbls etc. [snip] PCRE is often faster than POSIX in practice because it can short-circuit and use programmer-guided optimizations, but its backtracking can result in catastrophic performance degradation on patterns like ^(a+)+$. FWIW: I've A/B'd POSIX and PCRE a couple times on large text sample sizes, using REs typical of my use cases at the time, and always found PCRE to out-perform POSIX. Regards, Jim -- Note: My mail server employs *very* aggressive anti-spam filtering. If you reply to this email and your email is rejected, please accept my apologies and let me know via my web form at <http://jimsun.LinxNet.com/contact/scform.php>. _______________________________________________ Postfix-users mailing list -- [email protected] To unsubscribe send an email to [email protected]
