Hi, On Fri, Feb 08, 2013 at 03:45:29PM +0100, Stefan Sperling wrote: > I cannot tell you what happened here and why the revisions in the > mirro are empty. That sure is concerning. > > However there are known race conditions in svnsync in Subversion 1.6. > See http://subversion.apache.org/docs/release-notes/1.7.html#atomic-revprops > > So you should definitely wrap svnsync in a tool like lockfile (part of > procmail), or upgrade to 1.7.
Note that directory creation/removal are the only FS mechanism which is guaranteed to be atomic, on UNIX (POSIX?) at least. Thus if lockfile isn't available/installable, as a manual mechanism you could fetch a tempfile name (obviously to be globally used by *all* svnsync script users!), and use that name to create a directory, run svnsync on success and then remove it. (or probably better use a static GUID value in the directory name) Be careful about "solutions" other than lockfile - some of these appear to be terribly unsafe (some newer Ubuntu-introduced "atomic locking" package comes to mind - which then executes anyway after a measly timeout!). Andreas Mohr
