[Xapian-discuss] Atomic DB rebuilds

[Olly Betts]

On Mon, Oct 04, 2004 at 06:16:29PM +0100, James Aylett wrote:
> What if your backing filestore isn't a Unix semantics file system?
> Windows supplies full reliable locking, but I can't remember if its
> equivalent to symlinks is solid for this sort of thing (the things
> that are used low-level by the POSIX emulation layer - I'm not even
> sure if they're normally accessible on NTFS anyway).

I think if you're trying to use symlinks on a system which doesn't
really have symlinks, you deserve whatever you get.

The Windows POSIX layer is essentially only there so Microsoft salesmen
can tick the "supports POSIX" box when required to in order to get a
contract.

> I've had many problems, incidentally, with ln -sf not actually
> updating the symlink, as it should do. Which is one reason why I don't
> trust 'em.

At least in the GNU implementation, "ln -sf" actually calls unlink
rather than creating a temporary symlink and renaming it over the top
(this appears to be what POSIX says should happen).  So "ln -sf"
certainly isn't atomic.

We're getting away from the original issue here.  I doubt Sam is
accessing his databases over NFS, and I'd be stunned if he was accessing
them over NFS to a Windows server.

Cheers,
    Olly