This sound like what would happen if read_policy=EVENTUAL_CONSISTENCY is
enabled. Are you setting this anywhere?

On Fri, Nov 19, 2010 at 9:37 AM, Sanjay <[email protected]> wrote:

> I'm pretty sure the data consistency is not in our application because
> of the characteristics of the problem.  I do not use Memcache or a per-
> instance in-memory cache, and perform direct reads from the datastore
> as the application is high-write, low-read.
>
> I can reproduce this problem at will by just refreshing a page that
> reloads the data from the datastore.  About 20% of the time I get an
> incorrect value.  The data is being written using a cron that fires
> every 10 minutes, and there are no other writers to this entry.  Thus
> I'm pretty sure that it's not being performed by an incorrect write.
> From the characteristics, it seems to me like there's an instance
> serving the application that is stale and serving bad data.  Perhaps
> this instance is in a different datacenter than the main set of
> instances, and thus Megastore replication has fallen behind, or is in
> an inconsistent state?
>
> I've been working with AppEngine for nearly the last year, and haven't
> seen this bizarre behavior before.
>
> Is there a way to escalate such issues for someone in Google to have a
> look?
>
> Thanks!
>
> On Nov 19, 8:31 am, Robert Kluin <[email protected]> wrote:
> > I did not see anything quite like that.  It sort of sounds like you
> > might have a cache bug.  Perhaps instance variables are being used as
> > cache?
> >
> > Robert
> >
> >
> >
> >
> >
> >
> >
> > On Fri, Nov 19, 2010 at 04:04, Sanjay <[email protected]> wrote:
> > > Hello,
> >
> > > Starting earlier today around the time of the App Engine deploy
> > > outage, I'm seeing a lot of data inconsistency.  Data written several
> > > minutes earlier cannot be read back consistently.  Even more
> > > surprisingly, just retrying the operation multiple times yields older
> > > versions of the same data.  Is anyone else seeing this?
> >
> > > Thanks,
> > > Sanjay
> >
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