dovecot - Dec 2018 - Panic…

I have started getting these in my log. ?What does this mean and what do I need
to do?

?Panic: file mail-index-util.c: line 37 (mail_index_uint32_to_offset): assertion
failed: (offset < 0x40000000)
Dec 12 23:29:44 mail dovecot: imap(jeff at stariontech.com): Error: Raw
backtrace: /usr/lib64/dovecot/libdovecot.so.0(+0x3cafa) [0x7f38c5a2cafa] ->
/usr/lib64/dovecot/libdovecot.so.0(+0x3cb46) [0x7f38c5a2cb46] ->
/usr/lib64/dovecot/libdovecot.so.0(+0x16e2a) [0x7f38c5a06e2a] ->
/usr/lib64/dovecot/libdovecot-storage.so.0(mail_index_uint32_to_offset+0x74)
[0x7f38c5d0d3f4] -> /usr/lib64/dovecot/libdovecot-storage.so.0(+0x81abd)
[0x7f38c5cf3abd] ->
/usr/lib64/dovecot/libdovecot-storage.so.0(mail_cache_compress+0x77)
[0x7f38c5cf4247] ->
/usr/lib64/dovecot/libdovecot-storage.so.0(mail_index_sync_commit+0x1d2)
[0x7f38c5d08012] -> /usr/lib64/dovecot/libdovecot-storage.so.0(+0x5fd88)
[0x7f38c5cd1d88] -> /usr/lib64/dovecot/libdovecot-storage.so.0(+0x570a0)
[0x7f38c5cc90a0] ->
/usr/lib64/dovecot/libdovecot-storage.so.0(maildir_storage_sync_force+0x52)
[0x7f38c5cc94c2] ->
/usr/lib64/dovecot/libdovecot-storage.so.0(maildir_file_do+0x99)
[0x7f38c5cc9f49] -> /usr/lib64/dovecot/libdovecot-storage.so.0(+0x59b7f)
[0x7f38c5ccbb7f] ->
/usr/lib64/dovecot/libdovecot-storage.so.0(index_mail_set_seq+0x112)
[0x7f38c5cb64f2] ->
/usr/lib64/dovecot/libdovecot-storage.so.0(index_storage_search_next_nonblock+0x16b)
[0x7f38c5cbae9b] ->
/usr/lib64/dovecot/libdovecot-storage.so.0(mailbox_search_next_nonblock+0x20)
[0x7f38c5ca2240] ->
/usr/lib64/dovecot/libdovecot-storage.so.0(mailbox_search_next+0x26)
[0x7f38c5ca2296] -> dovecot/imap(imap_fetch_more+0x2bf) [0x41221f] ->
dovecot/imap(cmd_fetch+0x42c) [0x40a33c] -> dovecot/imap() [0x40f90d] ->
dovecot/imap() [0x40f9fa] -> dovecot/imap(client_handle_input+0x135)
[0x40fc25] -> dovecot/imap(client_input+0x5f) [0x41054f] ->
/usr/lib64/dovecot/libdovecot.so.0(io_loop_call_io+0x48) [0x7f38c5a37e98] ->
/usr/lib64/dovecot/libdovecot.so.0(io_loop_handler_run+0x9f) [0x7f38c5a38e0f]
-> /usr/lib64/dovecot/libdovecot.so.0(io_loop_run+0x28) [0x7f38c5a37e28]
-> /usr/lib64/dovecot/libdovecot.so.0(master_service_run+0x13)
[0x7f38c5a26293] -> dovecot/imap(main+0x2f9) [0x418849] ->
/lib64/libc.so.6(__libc_start_main+0x10
Dec 12 23:29:44 mail dovecot: master: Error: service(imap): child 11157 killed
with signal 6 (core dumps disabled)

-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<https://dovecot.org/pipermail/dovecot/attachments/20181212/960ee725/attachment.html>

On 13 Dec 2018, at 7.31, SH Development <listaccount at starionline.com>
wrote:
> 
> I have started getting these in my log.  What does this mean and what do I
need to do?
> 
>  Panic: file mail-index-util.c: line 37 (mail_index_uint32_to_offset):
assertion failed: (offset < 0x40000000)
Your dovecot.index.cache file has grown too huge. The only solution now is to
delete it, and perhaps try to shrink the number of mails in the folder as well.
The downside to deleting cache is that it may temporarily slow down performance
for accessing the folder, depending on the IMAP client.

Shouldn't an event of this type trigger a useful warning instead of a
cryptic programming error?

On Thu, Dec 13, 2018 at 07:42, Timo Sirainen <tss at iki.fi> wrote:
> On 13 Dec 2018, at 7.31, SH Development <listaccount at
starionline.com> wrote:
>>
>> I have started getting these in my log. What does this mean and what do
I need to do?
>>
>> Panic: file mail-index-util.c: line 37 (mail_index_uint32_to_offset):
assertion failed: (offset < 0x40000000)
>
> Your dovecot.index.cache file has grown too huge. The only solution now is
to delete it, and perhaps try to shrink the number of mails in the folder as
well. The downside to deleting cache is that it may temporarily slow down
performance for accessing the folder, depending on the IMAP client.
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<https://dovecot.org/pipermail/dovecot/attachments/20181213/caa7db42/attachment.html>

Btw, what sizes are we talking about here? I assume it would be really 
huuuge?
What's the max size of the .cache file and how many mails might create 
this size?

Kai