Xapian devel - Mar 2008 - Duplicate docids in mset

Hello,

I seem to be seeing a (very unfrequent) case where I get the same document
twice inside a result list (same xapian docid as last and first entries of
consecutive msets).

This was reported by a user running tests on a "CACM test collection and
evaluating the performance with trec eval software", not under normal
usage, where it would probably not be noticed.

Is there a known condition that would cause this ? Is it worth investigating ?

Regards,

J.F. Dockes

On Tue, Mar 11, 2008 at 07:15:07PM +0100, Jean-Francois Dockes
wrote:
> I seem to be seeing a (very unfrequent) case where I get the same document
> twice inside a result list (same xapian docid as last and first entries of
> consecutive msets).
> 
> This was reported by a user running tests on a "CACM test collection
and
> evaluating the performance with trec eval software", not under normal
> usage, where it would probably not be noticed.
> 
> Is there a known condition that would cause this ? Is it worth
investigating ?
Assuming that the database hasn't been modified between the two
searches, this shouldn't happen - the "split" results should be
the same
as the "unsplit".

So it would be interesting to find out what's causing this.  Is it
repeatable with the same query on the same data?

Cheers,
    Olly