mailpost and crossposted mailing lists

[Kenichi Okada]

In the message <20011113002406.A1624 at us.ibm.com>
Scott Russell <lnxgeek at us.ibm.com> wrote:

> On Tue, Nov 13, 2001 at 10:01:04AM +0900, Katsuhiro Kondou wrote:
> > Or try mailpost in CURRENT.  It's capable of handling multiple
> > newsgroups.

> I'm lookin at the perl code for mailpost from CURRENT-20011116 and I want to
> as about the -c option which is used for cross post support.

> It looks like if I pass -c N to mailpost that the mailpost process will
> sleep for N seconds then check it's database to see if it can find another
> dup. If a dup is found it's newsgroup is added to the Newsgroups: header and
> the message is sent off.

If a dup is found (former mailpost), its newsgroup is added to
the Newsgroups: header on the database, but the message is not sent off.

Example: 

mailpost gateway of testlist at ibm.com -> newsgroup.lists.testlist
mailpost gateway of othertest at ibm.com -> newsgroup.lists.othertest

1. mailpost(A) receives testlist at ibm.com. 
   The mailpost(A) adds its newsgroups to the database, and sleeps.
   Now the Newsgroups: header on the database is `newsgroup.lists.testlist'.

2. mailpost(B) receives othertest at ibm.com. 
   Then the Newsgroups: header on the database is `newsgroup.lists.testlist'.
   The mailpost(B) adds its newsgroups to the database, and sleeps.
   Now the Newsgroups: header on the database is
   `newsgroup.lists.testlist,newsgroup.lists.othertest'.

3. The mailpost(A) awakes and exits, because the Newsgroups: header was
   changed on the database.

4. The mailpost(B) awakes. The Newsgroups: header was not changed 
   on the database, so the mailpost(B) posts the message actually.

> Did I miss something? In all this seems like a bad way to handle this
> because it appears to me that you could have two mailpost processes racing
> against each other. Please tell me if I'm wrong and show me?

-- 
Kenichi Okada
mailto:okada at opaopa.org