code: function shrinkRoundCacheObj(roundIndex, arrIndex, assocCachedObj){
      console.log("shrink Round Cache , begin roundIndex:" + roundIndex);
      var minIndex = Math.min.apply(Math, arrIndex);
      if(roundIndex - minIndex > 10000){
          console.log("shrink Round Cache, remove all");
          assocCachedObj = {};
      }
      else{
          for (var offset = minIndex; offset < roundIndex - MAX_ROUND_IN_CACHE; offset++){
              console.log("shrink Round Cache, remove roundIndex:" + offset);
              delete assocCachedObj[offset];
          }
      }
  }
docs: cache begin