From: Charles Lindsey (chl@clw.cs.man.ac.uk)
Date: Fri Sep 18 1998 - 17:08:07 CDT
In <Pine.EzE87A.4rA-100000@fluffy.meow.org> greg andruk <gerglery@usa.net> writes:
>On Wed, 16 Sep 1998, Charles Lindsey wrote:
>> 7. Supersedes of a named article (i.e. replacing article includes Named:
>> header; supersede command refers to old-M-ID).
>{chomp}
>> Now remove both old-M-ID and P-ID from History file
>I think this is may be a problem with dbz. Unless I'm missing something
>right under my nose, it's an append-only database, and entries can only be
>removed by writing entire new text and index files.
Ugh!
Yes, this is a problem. Part of its solution is easy. Where I say "remove
ID from History and destroy article", replace with just "replace article".
And where I say "retrive article and look at its headers" add that if the
article cannot be found, then report an Error and reject (the article had
already been cancelled). Then cancels as I proposed them will work fine
(it is how CNEWS currently does its cancels, more or less).
There remains a problem with Supersedes, because we actually want to
create a new entry in History with the same P-ID, but pointing to a new
Xref for the article, so the P-ID would then appear in the History twice.
Has anybody (Henry?) any bright ideas here? Would the dbz index always
give you the revised one - or could it be made to? And not all
implementations of CNews use dbz. Or could we get away with deleting the
old one just from the .overview file?
Replacing an article will still work, oddly enough, because pointing to
the old Xref is OK (but if the newsgroups line was extended or reduced in
the process, it could get complicated).
Note that things finally get deleted from History during Expiry, so the
unwanted entries would disappear eventually
>If the history needs a major re-work to accommodate this kind of thing, so
>be it; but it's something to think about.
Yes, "thinking about" is probably the next move.
-- Charles H. Lindsey ---------At Home, doing my own thing------------------------ Email: chl@clw.cs.man.ac.uk Web: http://www.cs.man.ac.uk/~chl Voice/Fax: +44 161 437 4506 Snail: 5 Clerewood Ave, CHEADLE, SK8 3JU, U.K. PGP: 2C15F1A9 Fingerprint: 73 6D C2 51 93 A0 01 E7 65 E8 64 7E 14 A4 AB A5