Hi, For quite some time I see messages like this in my z3.log: 2010-03-02T16:27:14 WARNING ZopePublication Competing writes/reads at /BSPSite/act/++vh++http:zis.act.at:80/bankneu/++/images/sponsor_logo.png: database conflict error (oid 0x063f, class BTrees.OOBTree.OOBucket, serial this txn started with 0x038484dc7d5ac044 2010-03-02 14:52:29.379960, serial currently committed 0x038484ff3c6b5455 2010-03-02 15:27:14.160763) I followed an advice from the zope-dev list and added some debug messages in ZODB.Connection.py where the objects are registered for writing. The following debug messages (I print the key/values of the object in question) occur before and after the database conflict error: ------------------- 2010-03-02T16:27:14 DEBUG zbsp keys: ['6ZZzgjNK0p.bIIlruXb4JkDo-T0J-XipPcVFGtcj0 LH6dMdI9akYvg', ......... , '7MmOPQOlkAHoa3T nydH9IIgKBqoVyn3Q.yH6OXJeLj7epObIy3M5Lg'] ----------- 2010-03-02T16:27:14 DEBUG zbsp values: [<zope.session.session.SessionData object at 0x43723bec>, <zope.session.session.SessionData object at 0x4372356c>, <zope.session.session.SessionData object at 0x437233ec>, ......... <zope.session.session.SessionData object at 0x436b586c>, <zope.session.session.SessionData object at 0x436b532c>, <zope.session.session.SessionData object at 0x43640b6c>,<zope.session.session.SessionData object at 0x436b572c>] ------------------- So it seems these are the session data containers. I wonder why they are written? Perhaps this happens when somebody else is logging into the system (so a new session is added) and others are concurrently reading from the session? However, this would mean that the session mechanism has a flaw, as this is a standard procedure? Any ideas of how to fix this? Best Regards, Hermann -- hermann@qwer.tk GPG key ID: 299893C7 (on keyservers) FP: 0124 2584 8809 EF2A DBF9 4902 64B4 D16B 2998 93C7