[Dovecot] Dovecot 1.0-test45 indexing issues

[dovecot at spam.turbolink.net]

We're currently on dovecot 0.99.10 with a few modifications (including one
very nasty hack for the blank line at the beginning of the mailbox bug).

We're using mbox all around.

Everything works smoothly but we still ocasionally get corrupt mailboxes
and indexes that need to be wiped out.

I setup 1.0-test45 on one of our mailservers to start testing it and ran
into a few issues.  The first one is if I try to use mail_read_mmaped=yes
I get this error:

Error: POP3(sobo1): file istream-raw-mbox.c: line 410 (istream_raw_mbox_get_body_size):
assertion failed: (rstream->mail_size != (uoff_t)-1)

for every mailbox.

If I switch to mail_read_mmaped=no everything works, but performance is
extremely bad.  I have a few test mailboxes with about 20k messages and if
I toggle a message flag from unread to read, dovecot seems to re-read the
entire mailbox up to that message (I saw this with strace).

Is this how supposed to work??  I don't see behavior like this on 0.99.10,
and on a mailbox with any substantial number of messages it really slows
things down.

Thanks for any input.

- Mike