// SERVER-2831 Demonstration of sparse index matching semantics in a multi index $or query. t = db.jstests_orh; t.drop(); t.ensureIndex({a: 1}, {sparse: true}); t.ensureIndex({b: 1, a: 1}); t.remove({}); t.save({b: 2}); assert.eq(1, t.count({a: null})); assert.eq(1, t.count({b: 2, a: null})); assert.eq(1, t.count({$or: [{b: 2, a: null}, {a: null}]})); // Is this desired? assert.eq(1, t.count({$or: [{a: null}, {b: 2, a: null}]}));