From: Bill Davidsen (davidsen@prodigy.com)
Date: Mon Mar 06 2000 - 14:37:06 CST
Brad Templeton <brad@templetons.com> write:
> On Fri, Mar 03, 2000 at 07:47:09PM +0000, Andrew Gierth wrote:
> So what about adding 'em? That does solve all the issues, at a cost of
> disk space in the history file. Disk space is hardly expensive.
And then you add the name of the group(s), and you give up fixed length
records, and you force implementations which mmap() history to jump to
64 bit machines... this is only cheap if you don't write the code or
provide the hardware to do it.
> But they must do other things, like interpret cancel messages, no? How
> do they do cancel messages if they don't have a history file mapping msgids
> to numbers? They can use this to either replace-in-place or add something
> to the xref line.
The history file doesn't map MID to numbers. There are no number except
in overview, and masters don't run overview. The hash algorithm maps
MIDs to hash codes, which you then do look up in the history file. There
is no group or article number in the history. And there is no Xref line,
unless the replaces comes very quickly after the original, master (hub
by Andrew's terms) has small spool. In some cases tiny, since any xref
slave can feed other xref slaves once the article numbers are assigned.
> This disturbs the "purity" of the xref line but it is a local header, and is
> not meant to be pure.
>
> One would start with an xref containing the current intended article number,
> but the local node could decide to add the old number to that line, or
> store the article under the old number.
You pretty much can't change an article after it's in the buffer, unless
you want to copy it over with changes. At least not with the circular
buffers used by the most popular news software implementations.
This doesn't mean you can't get the same effect, just that the
implementation I think you envision doesn't fit all that well into
current implementations, many of which assume that an article doesn't
change after it's laid in a buffer.
-- -bill davidsen (davidsen@prodigy.com) "The secret to procrastination is to put things off until the last possible moment - but no longer" -me