On Thu, 26 Aug 2004 16:57:55 -0400 Kevin McCann <[EMAIL PROTECTED]> wrote:
> "SQLite uses POSIX advisory locks to implement locking on Unix. On > windows it uses the LockFile(), LockFileEx(), and UnlockFile() system > calls. SQLite assumes that these system calls all work as > advertised. If that is not the case, then database corruption can > result. One should note that POSIX advisory locking is known to be > buggy or even unimplemented on many NFS implementations (including > recent versions of Mac OS X) and that there are reports of locking > problems for network filesystems under windows. Your best defense is > to not use SQLite for files on a network filesystem." I've spent some time mucking about in this area and it is a minefield. Very simply, throwing out all of the messy details, there is only one operation which is atomic under the network filesystems: creat (2). The exceptions where creat(2) is not guaranteed atomic are for some of the more obscure cacheing network filesystes which attempt to be resilient across intermittent/bad connectivity and node failures. If you want to account for those filesystems as well then sorry, there's just no guaranteed correct locking methodology. Yes, it is that bad. -- J C Lawrence ---------(*) Satan, oscillate my metallic sonatas. [EMAIL PROTECTED] He lived as a devil, eh? http://www.kanga.nu/~claw/ Evil is a name of a foeman, as I live. _______________________________________________ Mailman-Developers mailing list [EMAIL PROTECTED] http://mail.python.org/mailman/listinfo/mailman-developers Unsubscribe: http://mail.python.org/mailman/options/mailman-developers/archive%40jab.org
