Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!iuvax!purdue!decwrl!sgi!vjs@rhyolite.wpd.sgi.com
From: vjs@rhyolite.wpd.sgi.com (Vernon Schryver)
Newsgroups: news.software.b
Subject: Re: Cnews active min field AND nn database expire
Summary: caution
Message-ID: <37422@sgi.SGI.COM>
Date: 4 Jul 89 21:53:50 GMT
References: <1989Jun25.174800.13276@utzoo.uucp> <10931@ibmpcug.UUCP> <352@texas.dk>
Sender: daemon@sgi.SGI.COM
Organization: Silicon Graphics, Inc., Mountain View, CA
Lines: 40

In article <352@texas.dk>, storm@texas.dk (Kim F. Storm) writes:
> lmb@vicom.com (Larry Blair) writes:
> 
> >henry@utzoo.uucp (Henry Spencer) writes:
> >> Any sensible news reader has
> >> to be prepared to go in and read the directory itself to find out what
> >> articles are really present.  Given that, what use is min?
> 
> >Apparently the newly posted NN newsreader isn't sensible.  It maintains
> >an article database on which a crude expire is performed, based on the
> >min field. 
> 
> I agree with Henry Spencer that reading the spool directory is the best
> way to do things, and I am starting an investigation on how this can be
> done in nn (which currently uses the min field to determine whether expire 
> is necessary on the database).
> ...
>
> Kim F. Storm        storm@texas.dk        Tel +45 429 174 00
> Texas Instruments, Marielundvej 46E, DK-2730 Herlev, Denmark


Reading the spool tree directly may be fine if it is small.  It is a
dangerous idea if the tree is big.

Sgi.sgi.com expires at 32 days, and some newsgroups (esp. internal ones)
have thousands of active articles.  Most people here nfs mount /usr/lib/new
and /usr/spool/news, and execute readers in the former.  (Posting uses Mark
Callow's postnews-mail hack.  sgi:/etc/rmtab has 620 lines.)  This works
fine, except when several people decide to `find /`, or as has happened
recently, tell nn to do whatever it does to initialize itself.  Whether
measured in ethernet traffic, load on bridges and routers, load on the NFS
server, or latency for everyone else, the results are not pretty.

Pity a system with slower file or network systems.


Vernon Schryver
Silicon Graphics
vjs@sgi.com