move mails between mailboxes

[Arjen de Korte]

Citeren Tom Doenen <tom at inkblu.org>:

> Hello,
>
> i am using dovecot 2.3.4.1
>
> I am tyring to make a script using the doveadm move command to move  
> old emails into a subfolder of the users INBOX ; say all mails from  
> 2016 into INBOX/2016.
> Selecting and moving is not the issue; everything works just i am  
> amazed that the (test) mail client Thunderbird downloads all mails  
> in INBOX/2016 after the move.
>
> When i make an IMAP move of all 2016-mails in Thunderbird; mails are  
> moved between the mailboxes without any mails being (re-)downloaded.
> So what am i missing here?

That's because in that case Thunderbird will know that the mails are  
moved between the mailboxes and will tell the server to move the  
messages and then do the move locally (without downloading the  
messages again). If you do this on the server, the client has no idea  
these are the same mesasages and will procede to delete them from the  
original location and download them again from the new location. The  
same happens if you move them in Thunderbird on one device and you  
have a second device. Even if it also uses Thunderbird, it will have  
to download them again.