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Re: IMAP4 List Command Extensions
Let me step back. AFAICT, there are two approaches to this:
1. Client sends LIST. When an interesting LIST response arrives, it
sends a STATUS command. As the STATUS commands' responses arrive, the
client has the information it wants.
2. Client sends LIST with some extension. For each mailbox matching the
supplied pattern, the server does the same work that STATUS would do,
and sends the result in a LIST response.
Do I understand it correctly?
Alternative 1 has a cost of two roundtrips, plus traffic costs for the
LIST responses and for the responses to STATUS, plus CPU costs for
LIST, STATUS and quite a bit of parsing.
Alternative 2 has a cost of one roundtrip, plus traffic for the LIST
responses, plus CPU cost for LIST including STATUS.
If we assume that there's 100 LIST responses and 10 interesting
mailboxes, then 1 costs one roundtrip more and 2 has 90 unnecessary
STATUS processings and 90 unnecessary transmitted UIDNEXT/UIDVALIDITY
pairs. (And of course, a client that implements 2 has to implement 1 as
well, or else it won't work with plain servers.)
Hm. I suppose I must misunderstand terribly, because I cannot see any
appeal in 2 at all.