Redo log question

I recently created a new instance with three groups of redo logs, two members each. Each of the redo logs are 20mb each. The log_buffer parameter is set at 160k. Checkpoint is not turned on. This instance is basically a repository for inquiry so the logs will mostly be used for the weekly batch loads. We have been loading data into the instance successfully but I have noticed some messages in the alert log that concern me. The logs seem to be switching successfully most of the time but occasionally I see the message 'Can't allocate new sequence, checkpoint not complete'. The log doesn't seem to switch but instead seems to fill itself up again and then next time switches to the next log. This message is not an ORA message and I've looked in the reference manuals and I can't find anything related to it. There does not seem to be any pattern to it. Has anyone seen this before?

Thanks in advance. Rob Received on Thu Jan 01 1998 - 00:00:00 CST