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Re: Missing requirement in draft-sparks-genarea-imaparch? (was Re: New Version Notification - draft-sparks-genarea-imaparch-05.txt)

2013-03-28 16:14:46


On Thu, 28 Mar 2013, SM wrote:

Hi Eric,
At 05:13 28-03-2013, Burger Eric wrote:
Rather than guessing all of the bad things that could happen, I would offer
it would be better to say what we mean, like:
        The IMAP interface MUST NOT provide any IMAP facilities that modify
the underlying message and message metadata, such as mailbox, flags, marking
for deletion, etc. If the client is authenticated and authorized, the IMAP
interface MUST provide per-user marking of the underlying message as read or
flagged.

The IMAP interface is a front-end to the read-only mailboxes (archive).  It's
easier to do what is mentioned above.

Something to ponder:
I use the IMAP interface once, mark a bunch of things as read, and then
decide never to use the IMAP interface ever again. How long does the server
need to keep my (per-user) marking metadata? E.g., besides CPU and I/O
issues, there is a potentially unbounded storage problem as well. It is
unbounded because in IMAP I can assign any kind of label (marking) to a
message, even ones I make up.

One thought for an approach to a solution:
1. per-user markings expire after X time units (six months?)
2. per-user markings may take up at most X storage units (512KB?)

I would go for both.

Per-user metadata can be incredibly useful - I might label things by
project, work group, draft, mumble, or foo. I would not want to limit the
labels to red or green. However, we need some predictable limit as well.

Any spec on this point should be re. minimum retention time, not a limit.
I frankly think that any limits based on storage units are suspect as
there is probably no way to related the impact of such limits to the
resulting user experience. In any case, the spec should be of the form:

1. per-user marking must be retained for at least X time units (6 months?)
2. At least X storage units must be provided for per-user markings.

Dave Morris