This renders covered indexes ineffective when shardingState.needShardChunkManager(pq.ns()) is true. Not sure if this is true in all sharding setups or just some.
                DiskLoc cl = _c->currLoc();
                if ( _chunkManager && ! _chunkManager->belongsToMe( cl.obj() ) ) { // TODO: should make this covered at some point
                    _nChunkSkips++;
                    // log() << "TEMP skipping un-owned chunk: " << _c->current() << endl;
                }
- is related to
- 
                    SERVER-3334 Stop processing bson fields in projection.transform after projections met (esp. _id) -         
- Backlog
 
-