Xapian 1.4.5 "Db block overwritten - are there multiple writers?" with Glass

[Olly Betts]

On Mon, Mar 05, 2018 at 09:48:52PM +0000, Olly Betts wrote:
> On Mon, Mar 05, 2018 at 08:52:47PM +0100, Sylvain Taverne wrote:
> > I've remarked the error occur when i'm trying to get stored values from a
> > database with a lot of stored values. I can reproduce the error with simple
> > python2 script i've posted on github
> > 
> >     https://github.com/staverne/xapian_test
> >     https://github.com/staverne/xapian_test/blob/master/test_xapian.py
> > 
> > The script always works with Chert backend but sometimes fail with Glass
> > backend.
> 
> Thanks, that's brilliant - I can reproduce with glass which means I should
> be able to pin down the cause (though it's likely to take a while as it
> took about 45 minutes to fail).

Just to update the status of this - I now have a C++ reproducer, and
have found that the transaction isn't needed to reproduce this.  It also
still reproduces when run under eatmydata [1], and together these bring
the time to reproduce down to 4-5 minutes.  Still longer than ideal, but
quick enough to start making some progress on narrowing down what's
happening.

Cheers,
    Olly

[1] https://www.flamingspork.com/projects/libeatmydata/