Autosaving stacks corrupted on network drives

[Mike Kerner]

I'm saying that it is possible to access the same file from the same share
from multiple machines and leave the file in an indeterminate or corrupted
state, afterwards, especially if both machines accessing the share are
trying to save changes to said file.  The purpose of the semaphore would be
to stop the simultaneous access of the file from multiple machines.


On Wed, Oct 25, 2017 at 11:54 AM, Bob Sneidar via use-livecode <
use-livecode at lists.runrev.com> wrote:

> I thought the OS takes care of that. Are we saying that when saving to a
> network share this process of creating the semaphore file does not happen?
>
> Bob S
>
>
> > On Oct 24, 2017, at 16:01 , Mike Kerner via use-livecode <
> use-livecode at lists.runrev.com> wrote:
> >
> > Possible solutions:
> > 1) Do what LibreOffice does.  Create an invisible semaphore file that the
> > stack checks for on open.  If it exists, the open is rejected and the
> stack
> > immediately closes.  This will keep secondary and simultaneous users from
> > getting their grubby paws into the stack before the save/sync is
> complete.
> > As part of this solution, I would suggest any quit/closeStack event has a
> > built in delay to confirm that the sync/save has completed before
> removing
> > the semaphore.  This is still tricky as you are at the mercy of the
> > sync/save tool, however, if you're clever, you can use the service's api
> to
> > check, separately, if the sync/save is complete before you let LC finish
> > closing down.
> > 2) Split the data out into a separate data file or better into a database
> > (because most databases use transactions, with greatly minimizes the
> > probability of corruption).
>
>
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