Data consistency in the context of information sharing requires maintenance of dependencies among information being shared. Transactional dependency ordering is implemented in a database system message queue, by associating a unique system commit time with each transactional message group. Read consistency is implemented in such a queue by allowing only messages with a fully determined order to be visible. A fully determined order is implemented through use of a high watermark, which guarantees that future transactions, for which messages are entering the queue, have commit times that are greater than the current high watermark. Therefore, only messages below the current high watermark are visible and can be dequeued, with no chance of other new messages enqueuing below the current high watermark.