overview terminology

Wim Lewis wiml at omnigroup.com
Fri Jun 14 21:38:28 UTC 2002

On Friday, June 14, 2002, at 12:31  PM, Russell S. Ireland wrote:
> I am somewhat confused by some descriptions used in a few of the inn 
> man pages.
> 	Makedbz rebuilds dbz(3) database."
> So what is the actual datbase?  The history file?  The overview 
> directory
> structure?

The DBZ database is an index file which makes it faster to find records 
in the history file. Originally it was a hash table which allowed you to 
look up a message-ID and get the byte offset of that message's line in 
the history file without having to scan through the history file. I 
don't know if that's still how it's implemented, but AFAIK that's still 
its purpose.

> 	"WARNING: If you're trying to rebuild the overview
>        database, be sure to delete or zero out the existing
>        database before you start [....]"
> Again, the use of "database" seems ambiguous.  I would love to heed this
> warning, so what exactly do I delete or zero out?  Which file(s)?

This depends on what overview database method you're using --- the 
'ovmethod' entry in inn.conf. I'm using buffindexed, and so my overview 
database is stored in a few files listed in buffindexed.conf; I zero 
those out by dd'ing from /dev/zero before rebuilding my overview 

   - Articles are stored somewhere (in CNFS, or one-file-per-article in 
traditional methods, etc.)
   - The history file is a simple list of what articles the server knows 
it has and where they're stored.
   - The dbz database is an index for fast access to the history file.
   - The overview database (which is only needed/used if you have 
readers, not if you're purely a feed) can be stored in one of a number 
of ways and is separate from the history file.

> So if I have placed a tarball of another server's articles on my new 
> server,
> do I need to run makedbz AND makehistory to get a current history and
> overview?  Or is makehistory -O -F -f history.n sufficient?

Yes, I think you need to run makedbz as well. The example in the 
makehistory man page fits your situation pretty well --- INN's various 
indexes are out of date since you've modified the spool by hand, so you 
want it to scan the spool and rebuild the indexes from the actual 
article data.


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