Is there an aspect to get a transaction retry in case of deadlock? (like in DO 3.X)

This would be useful for us to have a systematic way of getting a retry in case of deadlock for webservices, ...

Updated at 17.05.2010 8:35:42

Well, this is not required for us ASAP, but this is important for us for webservice scenarios (etc...) : we could implement it "manually" for each service, but this introduce some duplicated code, so an aspect would be really welcome, especially if it is supported by Xtensive. We will need it for release : could this be done for your next release (4.3)?

By the way, this is really useful to give us the ticket's URL : with this we can know when a feature/bug is fixed without testing the latest nightly build ;) Could your team put the ticket's URL in forum posts when available?

Regards,

This thread was imported from our support forum. The original discussion may contain more detailed answer.

EDIT 25 February 2011

Here is a very simple implementation of a transaction retry aspect. Obviously it's not adapted for general use (do not work if session is already opened, use log4net, always commit transaction, ...)

Do you think this implementation will work in every case (if Session/transaction is not opened yet) ?

  [Serializable]
  [ProvideAspectRole(StandardRoles.Persistence)]
  public sealed class OpenSessionAndTrasactionWithRetry : MethodInterceptionAspect
  {
    private static log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

    private const int MaxRetryCount = 3;

    public override void OnInvoke(MethodInterceptionArgs args)
    {
      if (Session.Current != null)
      {
        log.Warn("Aspect OpenSession has been used, but a session is already opened, not opening session (no retry behavior)");
        args.Proceed();
        return;
      }

      for (int retry = 0; ; retry++)
      {
        try
        {
          using (Session session = Session.Open(Agent.Current.GetKernelModule<PersistenceModule>().Domain))
          using (TransactionScope t = Transaction.Open())
          {
            args.Proceed();
            t.Complete();
          }
          // call success : we can return here
          return;
        }
        catch (Exception ex)
        {
          if (ex is DeadlockException || ex is TransactionSerializationFailureException)
          {
            if (retry + 1 < MaxRetryCount)
            {
              log.Info("Deadlock detected : retrying transactional method");
              continue;
            }
            else
            {
              log.Warn("Deadlock detected on last try : giving up on transactional method");
              throw;
            }
          }
          else
          {
            throw;
          }
        }

      }
    }
  }