@Override
 protected EmptyResult shardOperation(OptimizeRequest request, ShardRouting shardRouting) {
   IndexShard indexShard =
       indicesService
           .indexServiceSafe(shardRouting.shardId().getIndex())
           .shardSafe(shardRouting.shardId().id());
   indexShard.optimize(request);
   return EmptyResult.INSTANCE;
 }