Newsgroups: news.software.b
Path: utzoo!henry
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: Expire by Date:
Message-ID: <1991Mar14.194554.12750@zoo.toronto.edu>
Date: Thu, 14 Mar 1991 19:45:54 GMT
References: <1991Mar14.012332.20774@massey.ac.nz>
Organization: U of Toronto Zoology

In article <1991Mar14.012332.20774@massey.ac.nz> K.Spagnolo@massey.ac.nz (Ken Spagnolo) writes:
>... I can think of two situations where
>this is very important.  The first is when heaps of old articles appear,
>like in comp.os.minix recently.  5Mb of garbage must be gotten rid of...

This is being solved in a better way:  the garbage will be thrown away
on arrival rather than waiting for expire to do it.

>If we loose our feed for a few days for whatever reason (and it happens
>more often than one would hope), we then get say two days of news all 
>at once when things come right...
>... I'm forced to set the expiry time for all
>groups very low to get rid of this `lump'.

My own philosophy on this one tends to be "if your system doesn't have
enough resources in reserve to handle surges, then running news is a
poor idea".

Flipping the expiry criterion back and forth between arrival date and
posting date exacts a hideous penalty in execution time, because to do
expiry by posting date requires *reading* tens of thousands of articles
every time, to discover their posting dates.  One of the original motives
behind doing a new expire -- which is sort of what got C News started --
was getting away from scanning every article, which was intolerably slow
even when traffic was an order of magnitude lower.  The only way to make
this practical, really, would be to store the posting date centrally.
I'd rather avoid revamping the history-file format *again*.
-- 
"But this *is* the simplified version   | Henry Spencer @ U of Toronto Zoology
for the general public."     -S. Harris |  henry@zoo.toronto.edu  utzoo!henry
