[Dovecot] Re: Small change to make dovecot pop3uw-imapmigrationfriendly

[Brian Candler]

On Sun, May 30, 2004 at 01:20:31AM +0300, Timo Sirainen wrote:
> On Fri, 2004-05-28 at 20:56, Matthias Andree wrote:
> > "Oleg I. Vdovikin" <oleg at cs.msu.su> writes:
> > 
> > >     Yes, but I need at least transparent migration from uw-imap to dovecot.
> > 
> > We need transparent migration from any server, not just from UW Imap. It
> > can be a Perl/Python/Whatever script - it only runs one if Dovecot
> > stores the UIDLs in a file.
> 
> Would it be enough if Dovecot simply used "X-POP3-UID" (or something)
> header which contains the UID for the old server? That would have to be
> generated using some script though.
> 
> If the header doesn't exist, Dovecot would use it's internal method.

As long as the X-POP3-UID header is cached somewhere, it would be fine.

The main purpose of UIDL is for when clients leave mail on the server; each
time they connect they issue UIDL to check for new mail. So if they have
1000 messages held on the server, each time they log in you don't want to
have to open and read each of those 1000 files.

Same applies for message sizes for 'LIST' (where the message size counts
each newline as two bytes, \r\n). Some clients issue 'LIST' each time they
connect, so you don't want to have to open and read each message from start
to end just to count the number of newlines it contains.

Regards,

Brian.