This one has been bugging me for some days now.. and it took a while to narrow it down to my grsec kernel.. uhf. Well, here's the scenario:
Platform: P4, FedoraCore1, Apache 2.0.49, PHP 4.3.6, MySQL 3.23.58, Linux 2.4.26, latest grsec (not CVS), relaxed default ACL's.
Software: Photopost (PHP/MySQL).
Situation: showgallery.php?cat=all should return long listing of all galleries, but script fails intermittently (only succeeds around 33% of the time) with "Lost connection to server during query". Obviously this is not specific to this software, but it was with it that the problem showed up and was easily and sistematically reproduced. It seems to affect queries that return large amounts of data.
Workaround: boot non-grsec kernel (in this case latest FC's).
Logs: none that seem related
Ideas / thoughts: wanted
After many troubleshooting effort with mysql and php, a simple reboot to a "clean" kernel made the problem completely go away. Unfortunately, only after that i realized that the problem appeared at the same time i installed grsec's kernel. Grsec is interfering here in some obscure way. I was thinking of resource overstepping in some way, but to my knowledge that kind of situation is logged.
Anyway, anyone experienced(ing) similar behaviour?
Tks in advance