[Exim] DEFER: MYSQL: query failed: Lost connection to MySQL …

hi,

i use exim with mysql and get the above message in paniclog - let's say
every 100.000 deliveries.

so i guess i'll never find out the real error - i guess the
mysql-database hangs.

when i look through the log files i cannot figure out to which msg-id this
error belong's to.
the mysql query contains the domain and the local-part but there is no
msg-id around with the same username and domain.

so i suggest the these mail has been swallowed with no error-message sent
back.
i even tried to "exigrep" 10 mesages before this error to see if all the
messages are completed.

my questions:

1.)
i guess the message which made this error must somehow get into the queue.
so how can i find it?

2.)
is there a posibillity to freeze messages which get an panic mysql error,
or give a 2nd attemt to deliver it?


robert