[Zope] [zwiki] slow comments due to mail delivery, speculations

[Simon Michael]

Zopistas - I'd appreciate any comments you might have on this.  Also, I
wonder if it might be relevant to the zope.org slow posting issue recently
discussed on zope-web.

Simon Michael <simon@joyful.com> writes:
> I ran into the very slow comment issue last week and did some
> investigation. Using top on the server I saw some comments resulting in a
> runaway cpu-bound curl process. If I killed this process the pending
> comment in my web browser would immediately complete (successfully).
>
> The curl process was invoked by the mailin alias, which happens to be on
> the same server. My guess is that the server processes a comment from the
> web; as final step calls mailhost.send to deliver it to subscribers; this
> blocks until delivery is complete; it attempts to deliver to the local
> mailin alias, because I use the wiki's mailin address as a harmless To
> header; the alias tries to post to zope; some kind of zope
> multithreading/locking contention ensues, and the curl process starts
> taking an ever-increasing percentage of cpu. 
>
> On this theory and for efficiency I changed mailouts to use "To: ;"
> instead (ie no To:). Zwiki.org has been using this for the last couple of
> days and I haven't noticed the slow comments but I don't know if it was a
> fix. Unfortunately I did notice that it messes up wide replies, because
> you always get a "Cc: ;" - harmless but messy. So for now I have changed
> back to using "To: wikiaddress". Further investigation needed - I'd
> appreciate any further ideas on the runaway process scenario.

Best regards,
-Simon