Syncing emails from external server like Gmail

[Vitalii]

On Sat, 11 Jul 2020 20:36:44 +0300
Sami Ketola <sami.ketola at dovecot.fi> wrote:

> > On 11. Jul 2020, at 14.22, Vitalii <vnagara at yandex.com> wrote:
> > 
> > Greeting
> > 
> > I've managed to backup my emails from external email server via
> > dsync and imapc: protocol like this:
> > 
> > doveadm -Dv -o imapc_user='user at gmail.com' -o imapc_password="pass"
> > -o imapc_host=imap.gmail.com backup -R -u duke at ejoom.com imapc:
> >   
> 
> It basicly does it to verify mail -> UID pairing. You can try to save
> imapc indexes locally by defining imapc location as: imapc:~/.imapc
> to see if it can be skipped.
> 
> Sami
> 

That's awesome Sami, thanks a lot.
For gmail.com account with 43000 emails it went down from 6 mins to
15seconds (24 times faster).
For yandex.com account with 15000 emails it went down from 32min to
28seconds (60 times faster).


I started testing it more and found out that it works as a
charm with new emails and move operations. However, it fails when I
delete (expunge) email on gmail server. On backup I get this error:

 Panic: file imapc-sync.c: line 328 (imapc_initial_sync_check):
 assertion failed: (mail_index_is_expunged(view, lseq) ||
 seq_range_exists(&ctx->mbox->delayed_expunged_uids, luid))

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