问题描述:
系统中多个功能不定期出现“Unable to get error message (6107) (0).”错误,即分布式事务超时,但报出错误的部分功能根本没有使用分布式事务。
原因分析:
推测是存在分布式事务未提交的情况,回到线程池后被复用造成的,例如:
系统中A功能存在分布式事务未提交的问题,处理A功能的线程执行完成后回到线程池,B功能复用了处理A功能的线程,A功能未提交的分布式事务将B功能的代码也包含进去了,依次类推可能还有C、D等功能,直到A功能开启的分布式事务超时报出6107错误,而报错的B或C、D等功能本身是没有问题的。
Demo验证:
1: ThreadPool.SetMinThreads(1, 1);
2: ThreadPool.SetMaxThreads(1, 1);
3:
4: ThreadPool.QueueUserWorkItem((x) =>
5: {
6: Console.WriteLine("33: " + Thread.CurrentThread.ManagedThreadId);
7: TransactionScope ts = new TransactionScope(TransactionScopeOption.Required, new TimeSpan(0, 0, 10));
8: using (OracleConnection conn = new OracleConnection(connstr))
9: {
10: conn.Open();
11: var cmd = conn.CreateCommand();
12: cmd.CommandText = @"update workitem set name = 'yyxx' where workitemid = '64365dc4-41d7-4057-af68-012d552660e2'";
13: cmd.ExecuteNonQuery();
14: conn.Close();
15: }
16: Thread.Sleep(100);
17: Console.WriteLine("33: end");
18: });
19:
20: ThreadPool.QueueUserWorkItem((x) => {
21: Console.WriteLine("44: " + Thread.CurrentThread.ManagedThreadId);
22: try
23: {
24: while (true)
25: {
26: using (OracleConnection conn = new OracleConnection(connstr))
27: {
28: conn.Open();
29: var cmd = conn.CreateCommand();
30: cmd.CommandText = @"update workitem set name = 'xxyy' where workitemid = '68265741-4433-42e9-b7e7-63ae1ce8bbc8'";
31: cmd.ExecuteNonQuery();
32: conn.Close();
33: }
34: Thread.Sleep(100);
35: }
36: }
37: catch (Exception e)
38: {
39: Console.WriteLine(e);
40: }
41: Console.WriteLine("44: end");
42: });
解决方法:
使用HttpModule 分别在beginRequest和endRequest中判断是否已包含了事务上下文
如果beginRequest中没有事务,endRequest时有未提交事务,则说明当前请求对应的是问题源头;
如果beginRequest和endRequest都有,说明当前请求是线程复用后的受害者。
示例如下:
1: protected void context_EndRequest(object sender, EventArgs e)
2: {
3: Debug.WriteLine(Thread.CurrentThread.ManagedThreadId);
4: Type t = typeof(Transaction);
5: FieldInfo field = t.GetField("complete", BindingFlags.Instance | BindingFlags.NonPublic);
6: if (Transaction.Current != null)
7: {
8: bool isComplete = (bool) field.GetValue(Transaction.Current);
9: if (!isComplete)
10: {
11: Debug.WriteLine(
12: string.Format(@"Creation Time: {0}\r\nDistributedIdentifier:{1}\r\nLocalIdentifier:{2}",
13: Transaction.Current.TransactionInformation.CreationTime,
14: Transaction.Current.TransactionInformation.DistributedIdentifier,
15: Transaction.Current.TransactionInformation.LocalIdentifier));
16: //Transaction.Current.Rollback();
17: //Transaction.Current.Dispose();
18: }
19: }
20: }