[Dovecot] sql dict: commit failed: MySQL server has gone away

[Mark Zealey]

Following on from this thread: 
http://www.dovecot.org/list/dovecot/2010-September/052704.html 
<https://owa2010.webfusion.com/owa/redir.aspx?C=a447887e3d204944a8c766142df41453&URL=http%3a%2f%2fwww.dovecot.org%2flist%2fdovecot%2f2010-September%2f052704.html> 
in 2.0.16 I am seeing the same issues. I believe this would be related 
to some timeouts set on our mysql servers which are pretty low (30 or 60 
seconds or so to drop idle connections). This is happening for imap, pop 
and lmtp processes when they try to update quotas stored in a mysql 
database; presumably it is the dict process that actually has these 
issues - the lmtp delivery isn't lasting longer than 1 second so 
shouldn't be seeing any timeouts there. This is always followed by the 
"Error: dict quota: Quota update failed, it's now desynced" line; 
presumably it is telling the truth but I'm not sure how I could tell.

We are also seeing this "MySQL server has gone away" issue in login 
processes but it isn't causing an issue there as presumably dovecot 
transparently retries rather than just giving up as it seems to in the 
quota updates. Any thoughts or advice would be appreciated.

Mark