[marcmac]

It's a bit more complicated than that, since you've got to keep track of the volume that the message is on, too. This is a Q&D that I put together for 3.1.x, but it'll probably work with 4.x, too. Run it as the zimbra user.

#!/usr/bin/perl

# OK, there's 2 MAILBOX_*_BITS values in the VOLUME table.
# Take the mailbox ID, right-shift it by MAILBOX_BITS, and take the lowest MAILBOX_GROUP_BITS of the result.
# That's your mailbox hash.
# Take the message ID, right-shift it by FILE_BITS, and take the lowest FILE_GROUP_BITS of the result.  That's your msgid hash.
# I think.
# <mbx-hash>/<mbx-id>/msg/<msgid-hash>/<msgid>-<mod_content>.msg

my ($fbits, $fgbits, $mbits, $mgbits, $basepath) = split (' ',`echo "select file_bits, file_group_bits, mailbox_bits, mailbox_group_bits, path from volume where type='1'" | mysql -N zimbra`);

chomp $basepath;

my $mbmask = sprintf "1" x $mgbits;
my $fmask = sprintf "1" x $fgbits;

foreach (`echo "select id, account_id, comment from mailbox" | mysql -N zimbra`) {
    chomp;
    my $path = "$basepath/";
    my ($id, $aid, $nm) = (split);
    my $mbhash = $id >> $mbits;
    $mbhash &= $mbmask;
    $path .= $mbhash."/".$id."/msg/";
    foreach my $msgstuff (`echo "select id,mod_content from mail_item where blob_digest is not null;" | mysql -N mailbox${id}`) {
        chomp $msgstuff;
        if ($msgstuff eq "") {next;}
        my ($msgid, $modContent) = split (' ',$msgstuff);
        my $msghash = $msgid >> $fbits;
        $msghash &= $fmask;
        my $nm = $msgid;
        if ($modContent) {$nm .= "-$modContent";}
        my $npath = $path.$msghash."/".$nm.".msg";
        print $npath."\n";
    }
}