Re: [Nmh-workers] Holes (was: nmh in near, medium, and far-term)

[Lyndon Nerenberg]

> > no. MH message numbers can have holes and can be reassigned. IMAP is
> > always 1..N, no holes.

Not quite true.  IMAP messages sequences are always 1..N contiguous, 
however the message UID space is not.  IMAP UIDs naturally map to MH's 
message-number file names, with the exception that you cannot 'packf' an 
IMAP mailbox (because IMAP message UIDs are immutable).

> You know, unless I'm missing something, the holes in our messages
> numbers could be considered a bug. I find it annoying to have to use
> "folder -pack" occasionally. If we kept our folders packed, then we
> could get rid of the folder -pack option.

The overhead of renumbering potentially every message file in a folder 
after every rmm is a potential performance killer.  Think 'rmm 1' in an 
NFS-mounted folder with 10K messages in it.  That's an absurd amount of 
traffic to throw at an NFS server on every message delete.

--lyndon