Re: [imap5] ERASE command as part of MOVE

[Bron Gondwana <[e-mail]>]

On Sat, Jun 02, 2012 at 01:27:58AM +0300, Timo Sirainen wrote:
> On 2.6.2012, at 1.23, Bron Gondwana wrote:
> 
> > This probably shits the purists as much as anything else.
> > But I can tell you for sure that the FastMail web interface
> > does its "Delete Permanently" as: 
> > 
> >    $Res = $Self->store($Uids, "+flags", "(\\seen \\deleted)")
> >         && $Self->uidexpunge($Uids)
> >         && $Self->refresh_count('');
> > 
> > Which is an extra roundtrip to the server and an extra lock and
> > parse of the mailbox index.
> 
> It doesn't need to be an extra roundtrip. You can run uidexpunge even if store fails and it doesn't do anything bad. By avoiding the extra roundtrip it is possible for the server to optimize the STORE+EXPUNGE into equivalent of ERASE. (Dovecot does halfway that - it for example doesn't rename maildir files on STORE stage, just unlinks them on EXPUNGE.)

Not so easy if you want to delete the messages by sequence number of
course.

TAG ERASE 1:10

Isn't implementable as a pipelined command, it would have to be

TAG1 STORE 1:10 +Flags \Deleted
TAG2 UID EXPUNGE UID1,UID2,UID3,UID4,UID5..UID10

So how does Dovecot handle a crash or filesystem error during that
intermediate stage?  Replay an action log?  What if the file can't
be renamed, but it's already replied to a client saying "yes, your
flag store succeeded"?

Bron.