New submission from Ian Charnas <[EMAIL PROTECTED]>: fsync on OSX does not actually flush the file to disk as is desired. This is a problem because application developers rely on fsync for file integrity. SQLite [1] and MySQL [2] and other major database systems all use 'fullfsync' on OS X instead of fsync, because 'fullfsync' provides the desired behavior.
Because the documented behavior of python's fsync function is to "force write of file with filedescriptor to disk", I believe that on OS X the fullfsync call should be used instead of fsync. The supplied patch adds this functionality in a non-platform-specific way. It checks if there is a FULLFSYNC fcntl call available (using "#ifdef F_FULLFSYNC", where F_FULLFSYNC is defined in sys/fcntl.h), and if this symbol is defined then a fnctl(F_FULLFSYNC, fd, 0) is called instead of fsync. [1] SQLite uses fullfsync on all platforms that define it: http://www.sqlite.org/cvstrac/fileview?f=sqlite/src/os_unix.c [2] MySQL uses fullfsync only on the darwin platform and only when F_FULLFSYNC is defined as 51, which seems to be short-sighted in that this symbol may change value in future versions of OS X. To see this code, download a mysql 5.x source snapshot and open up mysql-<version-number>/innobase/os/os0file.c ---------- components: Library (Lib) files: fullfsync.patch keywords: patch messages: 70810 nosy: icharnas severity: normal status: open title: Change fsync to use fullfsync on platforms (like OS X) that have/need it type: behavior versions: Python 2.6 Added file: http://bugs.python.org/file11066/fullfsync.patch _______________________________________ Python tracker <[EMAIL PROTECTED]> <http://bugs.python.org/issue3512> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
