t.drop();
t.save( { x : 1 } );
t.save( { x : 2 } );
t.save( { x : 3 } );
t.ensureIndex( { x : 1 } );
t.update( { x : { $gt : 0 } } , { $inc : { x : 5 } } , false , true );
Description
Otherwise we'll continually update the same document. Our jstest for this didn't catch the issue because it used to use a collection scan for the underlying query execution.