Locking may be done at the fragment level, allowing easy reintegration, but is perhaps too coarse. For small fragments with low write probability, it is good to do fragment locking. Otherwise, tuple-level locking is much more complicated and reintegration is much more expensive. Perhaps both should be used, with fragment level locking used for simple reintegration, falling back to tuple-level analysis if fragment level locking failed. The motivation for Bayou comes from observations of mobile computing.
Connections are expensive, frequent, and often intermittent.
It is unlikely that collaborating agents are likely to be guaranteed simultaneous connections. Bayou accommodates these applications by helping them manage weakly consistent data. Bayou does not attempt to be transparent. Applications should use specific knowledge of their data, along with the knowledge that data may be stale, to detect and resolve conflicts. Two applications are studied, a bibliographic database and a meeting room scheduler.