Hi all,
> I wouldn't actually be surprised if QM is like PI. Drifting away from U2 but the question was asked.... The initial implementation of dynamic files in QM was fairly close to that of PI/open but it was totally reworked long before the product went onto general release, resulting in some useful performance gains. Like UV, a QM dynamic file is represented by a directory but the DATA.30 and OVER.30 items become %0 and %1. Further items may exist to hold alternate key indices. The underlying mechanism of dynamic files is common to PI, PI/open, UV and QM but UniData goes its own way. Although a couple of the numbers have to be changed for UV, I think that the technical note at http://www.openqm.org/downloads/dynamic_files.pdf is largely applicable to UV, at least in principle. There are some substantial differences in how the two products perform split/merge operations, especially with regard to management of locking tables, but this is not the right forum to discuss this further. Interestingly, the UV Internals course used to state that the dynamic file hashing algorithm was the same one as static file type 18. Experiments suggest that this is not true and it looks as though UV uses the same public domain hashing algorithm that we chose for QM. As a useful tip for users running UV (or QM) on Windows systems, getting the Windows memory caching parameters set correctly can make a massive difference to performance. Martin Phillips Ladybridge Systems Ltd 17b Coldstream Lane, Hardingstone, Northampton NN4 6DB, England +44 (0)1604-709200 _______________________________________________ U2-Users mailing list U2-Users@listserver.u2ug.org http://listserver.u2ug.org/mailman/listinfo/u2-users
