On Sun, 13 Jan 2013, Hannes Magnusson wrote:

> > @@ -437,6 +437,7 @@
> >  
> >  	mongo_read_preference read_pref;
> >  
> > +	int force_primary; /* If set to 1 then the connection selection will request a WRITE (primary) connection */
> 
> I don't actually see the need for this flag.
> Only database commands need to be "forcefully sent to the primary" - so why is that a cursor flag at all?

Database commands are normal queries, that use a cursor. So this flag 
is set by the commands so that the cursor forces a primary.