Re: [Evolution] IMAP - Junk and Trash folder appear twice

[Patrick O'Callaghan <poc usb ve>]

On Mon, 2016-05-16 at 14:45 +0100, Pete Biggs wrote:
> The "marked as deleted" paradigm comes from the time when removing a
> message from a mail folder was a very time expensive process - MBOX
> was
> the standard with all the messages from a folder held in one big
> file.
> When you want to remove a message, the system had to copy all the
> messages up until the deleted one into a new file, skip over the
> relevant message, then copy the rest of the messages, then rename the
> old MBOX file, then rename the new MBOX file, then delete the old
> MBOX.
> It is a very disk intensive process and with large mailboxes can take
> quite a while to do.  Hence any messages you want to delete are
> marked
> as deleted, then the mailbox is purged at a later time when all
> messages so far deleted are all removed in one go.

An additional penalty with MBOX implementations is that deleting a
message by moving it to a real Trash folder can put the user over a
disk quota limit because the move consists of copy+delete, i.e.
deleting messages to save space can't be done because you don't have
enough space! Not a myth, I've seen this happen.

In modern implementations where the move is an atomic operation this
won't happen.

poc