Ok, nothing to worry about. The \Recent flag on messages will be
incorrect, but no information is lost.
The culprit:
Nov 6 14:38:58 mail4-core-2 dbmail/imap4d[15280]: Debug:[sql]
dbmysql.c,db_query(+287): query [UPDATE dbmail_messages SET recent_flag
= 0 WHERE message_idnr IN
(111121490,111119585,111119583,111118476,111115033,111114577,111114513,111114435,111113252,111110017,111109091,111108924,111108856,111107547,111104702,111098668,111096873,111095754,111093348,111092274,111090584,111089386,111088908,111088902,111088896,111088358,111085966,111074995,111074979,111068531,111065104,111065075,111058877,111056716,111051771,111046856,111043290,111042377,111040034,111039521,111039373,111037608,111034241,111007526,111006402,111006400,110997376,110997368,110997362,110994745,110994430,110992837,110991077,110990770,110989845,110987452,110954508,110946557,110945055,110942293,110941632,110940259,110938366,110932182,110931854,110928380,110927388,110926762,110924874,110923621,110923571,110923160,110922104,110920849,110920621,110919293,110918052,110917877,110917392,110916931,110916283,110915045,110913165,110909253,110908379,110907732,110907730
Apparently the line is too long for mysql to handle.
Try tweaking dbmail-imapsession.c, line 2088:
topslices = g_list_slices(recent,100);
setting it to someting like
topslices = g_list_slices(recent,50);
because that determines the number of message_idnrs in the IN(...) part
of the query.
But you may want to verify this by using TRACE_STDERR=5 rather than
syslog. For stderr logging the query will not be truncated so you can
capture it, and test it manually. Perhaps your max_allowed_packet in
my.cnf is too small. Check that first.
