Core data app & data loss

  • I have a strange problem with my Core Data app, and not sure what to
    do about it.  This Core Data app was written several years ago and has
    been very stable under Tiger with no reported bugs.  However, when
    Leopard came out, about 10 people (less than 1% of the amount of
    users) told me that after they upgraded to Leopard, they experienced
    data loss with my app.  I haven' t been able to pinpoint it down, but
    it seems to occur after they perform some edits and then save (or Save
    As) the file.  Later they come back to the file only to find the file
    completely empty (file size zero K).  The app only saves file in XML
    format (not binary or SQLite format).

    This is obviously a very serious problem to these customers, and I
    have no idea where to look for the problem.  For all I know it's an OS
    problem.  Regardless, is there method I should exam?  The app
    overrides configurePersistentStoreCoordinatorForURL:ofType:error:
      (which I realize has been deprecated in OS 10.5) so it can prepare
    the metadata for the file.  Or maybe something in
    writeToURL:ofType:forSaveOperation:originalContentsURL:error:?  Any
    suggestions appreciated.

    Thanks,
    Kimo
  • On Dec 5, 2007, at 8:36 PM, Kimo wrote:

    > I have a strange problem with my Core Data app, and not sure what to
    > do about it.  This Core Data app was written several years ago and
    > has been very stable under Tiger with no reported bugs.  However,
    > when Leopard came out, about 10 people (less than 1% of the amount
    > of users) told me that after they upgraded to Leopard, they
    > experienced data loss with my app.  I haven' t been able to pinpoint
    > it down, but it seems to occur after they perform some edits and
    > then save (or Save As) the file.  Later they come back to the file
    > only to find the file completely empty (file size zero K).  The app
    > only saves file in XML format (not binary or SQLite format).
    >
    <http://www.cocoabuilder.com/archive/message/cocoa/2007/11/2/192085>

    mmalc
  • Wow, this one could have been nasty. I just got my first bug report
    from a user today with the same symptoms.Thanks mmalc for pointing out
    the previous post -- I missed it when it went by the first time.

    Barry

    On Dec 5, 2007 9:23 PM, mmalc crawford <mmalc_lists...> wrote:
    >
    > On Dec 5, 2007, at 8:36 PM, Kimo wrote:
    >
    >> I have a strange problem with my Core Data app, and not sure what to
    >> do about it.  This Core Data app was written several years ago and
    >> has been very stable under Tiger with no reported bugs.  However,
    >> when Leopard came out, about 10 people (less than 1% of the amount
    >> of users) told me that after they upgraded to Leopard, they
    >> experienced data loss with my app.  I haven' t been able to pinpoint
    >> it down, but it seems to occur after they perform some edits and
    >> then save (or Save As) the file.  Later they come back to the file
    >> only to find the file completely empty (file size zero K).  The app
    >> only saves file in XML format (not binary or SQLite format).
    >>
    > <http://www.cocoabuilder.com/archive/message/cocoa/2007/11/2/192085>
    >
    > mmalc
    >
  • I don’t know how Apple’s bug fixing process works, but this is a
    serious one
    and I can’t understand how it is possible not to get it fixed right
    now…?

    Is it impossible for engineers like the ones at Apple to find the
    cause of such a bug?
    Couldn’t they simply embed the changes-check trick in the inner save:
    method to
    prevent modest developers and their users from loosing data???

    I noticed this bug only after upgrading stores with the new versioning
    system and
    thought I might have done something wrong. Fortunately, Time Machine
    was there
    (as long as it didn’t, like yesterday, just corrupted my external
    drive, other frequently
    reported bug about Leopard that should really be addressed…).
    That was my 5 minutes angry moment of the day.

    Flofl.

    >> I have a strange problem with my Core Data app, and not sure what to
    >> do about it.  This Core Data app was written several years ago and
    >> has been very stable under Tiger with no reported bugs.  However,
    >> when Leopard came out, about 10 people (less than 1% of the amount
    >> of users) told me that after they upgraded to Leopard, they
    >> experienced data loss with my app.  I haven' t been able to pinpoint
    >> it down, but it seems to occur after they perform some edits and
    >> then save (or Save As) the file.  Later they come back to the file
    >> only to find the file completely empty (file size zero K).  The app
    >> only saves file in XML format (not binary or SQLite format).
    >>
    > <http://www.cocoabuilder.com/archive/message/cocoa/2007/11/2/192085>
    >
    > mmalc
  • On Dec 6, 2007, at 3:14 PM, Wdyp wrote:

    > I don’t know how Apple’s bug fixing process works, but this is a
    > serious one
    > and I can’t understand how it is possible not to get it fixed right
    > now…?
    > Is it impossible for engineers like the ones at Apple to find the
    > cause of such a bug?
    > Couldn’t they simply embed the changes-check trick in the inner
    > save: method to
    > prevent modest developers and their users from loosing data???
    >
    Discussion of patches in general doesn't belong on this list.

    Suffice to say that the problem is being addressed, but all bug fixes
    must fit in with OS update schedules.

    If you have any further issues, please take them up with DTS directly
    (see <http://developer.apple.com/>) or on another list.

    mmalc
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