1. Modified BufferCache to have a maxOpenFiles parameter. 2. BufferCache will not invalidate and flush pages upon last close of a file. 3. Pages of unreferenced files are invalidated and flushed lazily during a new openFile request.

git-svn-id: https://hyracks.googlecode.com/svn/branches/hyracks_indexes@471 123451ca-8445-de46-9d55-352943316053
18 files changed