From Oracle FAQ
Row vs. block contention
"However, applications with 'hot' rows (the same row being accessed by processes on different nodes) will not work well."
Inter-instance 'data' syncing is on block level, not row level. So, the problem is not limited to 'hot' rows, the scope is hot blocks.
- Good point. Article was updated. Frank Naude 18:40, 18 September 2009 (UTC)