c# - Restart concurrent tasks as soon as they fail for x number of times -

i have console app making http queries , adding/updating products in database according response. fail , need retried few times.

the way came use dictionary store product id , task. can check task results , re-run.

this working strikes me inefficient. tasks not being re-created until tasks have finished. more efficient if restarted can't figure out how this. every retry involves query database id stored.

i made small app shows how retrying failed requests.

can suggest more efficient method retrying?

class program {     private static void main(string[] args)     {         httpquery m = new httpquery();         var task = task.run(() => m.start());         task.waitall(task);         console.writeline("finished");         console.readline();     }  } class httpquery {     public async task start()     {         // dictionary key represent reference needs processed , bool whether has completed or not         concurrentdictionary<int, task<bool>> monitor = new concurrentdictionary<int, task<bool>>();          // start async tasks.          console.writeline("starting first try");         (int = 0; < 1000; i++)         {             console.write(i+",");             monitor[i] = this.query(i);         }         // wait completion         await task.whenall(monitor.values.toarray());         console.writeline();         // start retries         // number of retries per query         int retries = 10;         int count = 0;         // check if max retries exceeded or completed         while (count < retries && monitor.any(x => x.value.result == false))         {             // make list of numbers failed             list<int> retrylist = monitor.where(x => x.value.result == false).select(x => x.key).tolist();             console.writeline("starting try number: " + (count+1) + ", processing: " + retrylist.count);             // create list of tasks wait             list<task<bool>> towait = new list<task<bool>>();             foreach (var in retrylist)             {                 console.write(i + ",");                 monitor[i] = this.query(i);                 towait.add(monitor[i]);             }              // wait completion             await task.whenall(towait.toarray());             console.writeline();             count++;         }          console.writeline("ended");         console.readline();      }     public async task<bool> query(int i)     {         // simulate http request may or may not fail         random r = new random();         int delay = * r.next(1, 10);         await task.delay(delay);         if (r.next(0,2) == 1)         {             return true;         }         else         {             return false;         }       } } 

you can create method , wrap these ugly retry logic. of ugly code goes away :)

public async task start() {     const int maxnumberoftries = 10;     list<task<bool>> tasks = new list<task<bool>>();     (int = 0; < 1000; i++)     {         tasks.add(this.querywithretry(i, maxnumberoftries));     }     await task.whenall(tasks); }  public async task<bool> querywithretry(int i, int numoftries) {     int tries = 0;     bool result;         {         result = await query(i);         tries++;     } while (!result && tries < numoftries);      return result; }