On 5/18/06, Beman Dawes <bdawes@acm.org> wrote:
- Some algorithms (Lehman & Yao's B-link tree concurrent locking algorithm, IIRC) don't work well with memory-mapped files, yet memory-mapped files are ideal when concurrent locking isn't an issue.
Locking doesn not work with MMF, that is true. In this particular case there may be workarounds involving MMF, such as a separate file, or shared memory segment, with flags corresponding to each record in the data file, indicating state of the record. Access to this structure should be protected with syncronization primitives. Of course, this workaround is not always appropriate. Again, the question is wherther it makes sense to use RAF when its efficiency cannot be exploited.
--Beman
-- Svyatoslav Trukhanov, Oleksii Ursulenko