really makes me think that that area is just a comfortable way to access files on disk as memory areas; with the hope of propably better caching then not-memory-mapped files.
No, absolutely not. CreateFileMaping() does much the same thing as mmap() in Unix.
That would explain my disturbing impressions of performance of PostgreSQL on win32 rising when lowering shared_memory...
I don't know what your disturbing impressions are, but no it doesn't explain them.
