我想为我的数据库调用编写一些包装代码（使用C＃和Microsoft技术访问数据库），自动重试“瞬态”异常。通过瞬态，我的意思是有一个很好的机会最终会解决（对于逻辑错误，永远不会工作）。我能想到的例子包括：
我曾计划使用SqlException的错误号来发现这些错误。例如：
List<RunStoredProcedureResultType> resultSet = null;
int limit = 3;
for (int i = 0; i < limit; ++i)
{
bool isLast = i == limit - 1;
try
{
using (var db = /* ... */)
{
resultSet = db.RunStoredProcedure(param1, param2).ToList();
}
//if it gets here it was successful
break;
}
catch (SqlException ex)
{
if (isLast)
{
//3 transient errors in a row. So just kill it
throw;
}
switch (ex.Number)
{
case 1205: //deadlock
case -2: //timeout (command timeout?)
case 11: //timeout (connection timeout?)
// do nothing - continue the loop
break;
default:
//a non-transient error. Just throw the exception on
throw;
}
}
Thread.Sleep(TimeSpan.FromSeconds(1)); //some kind of delay - might not use Sleep
}
return resultSet;
（请原谅我的任何错误 - 我刚刚写了那篇文章。我也意识到我可以很好地把它包起来......）
所以关键问题是：我应该考虑什么数字'瞬态'（我意识到我认为瞬态可能与其他人认为瞬态不同）。我在这里找到了一个很好的清单：
https://msdn.microsoft.com/en-us/library/cc645603.aspx
但其庞大而且非常有用。 是否还有其他人建立了他们用于类似内容的列表？
更新
最后，我们选择了一个“错误列表” - 如果错误是已知的“非暂时性错误”列表中的一个 - 通常是程序员错误。我已经列出了我们正在使用的数字列表作为答案。
答案 0 :(得分：7)
在sql Azure中有一个类[SqlDatabaseTransientErrorDetectionStrategy.cs]用于临时故障处理。它涵盖了几乎所有类型的异常代码，可以视为瞬态代码。它也是Retry strategy的完整实现。
在此处添加代码段以供将来参考：
/// <summary>
/// Error codes reported by the DBNETLIB module.
/// </summary>
private enum ProcessNetLibErrorCode
{
ZeroBytes = -3,
Timeout = -2,
/* Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding. */
Unknown = -1,
InsufficientMemory = 1,
AccessDenied = 2,
ConnectionBusy = 3,
ConnectionBroken = 4,
ConnectionLimit = 5,
ServerNotFound = 6,
NetworkNotFound = 7,
InsufficientResources = 8,
NetworkBusy = 9,
NetworkAccessDenied = 10,
GeneralError = 11,
IncorrectMode = 12,
NameNotFound = 13,
InvalidConnection = 14,
ReadWriteError = 15,
TooManyHandles = 16,
ServerError = 17,
SSLError = 18,
EncryptionError = 19,
EncryptionNotSupported = 20
}
还有一个切换案例，用于检查sql异常中返回的错误号是否为
switch (err.Number)
{
// SQL Error Code: 40501
// The service is currently busy. Retry the request after 10 seconds. Code: (reason code to be decoded).
case ThrottlingCondition.ThrottlingErrorNumber:
// Decode the reason code from the error message to determine the grounds for throttling.
var condition = ThrottlingCondition.FromError(err);
// Attach the decoded values as additional attributes to the original SQL exception.
sqlException.Data[condition.ThrottlingMode.GetType().Name] =
condition.ThrottlingMode.ToString();
sqlException.Data[condition.GetType().Name] = condition;
return true;
// SQL Error Code: 10928
// Resource ID: %d. The %s limit for the database is %d and has been reached.
case 10928:
// SQL Error Code: 10929
// Resource ID: %d. The %s minimum guarantee is %d, maximum limit is %d and the current usage for the database is %d.
// However, the server is currently too busy to support requests greater than %d for this database.
case 10929:
// SQL Error Code: 10053
// A transport-level error has occurred when receiving results from the server.
// An established connection was aborted by the software in your host machine.
case 10053:
// SQL Error Code: 10054
// A transport-level error has occurred when sending the request to the server.
// (provider: TCP Provider, error: 0 - An existing connection was forcibly closed by the remote host.)
case 10054:
// SQL Error Code: 10060
// A network-related or instance-specific error occurred while establishing a connection to SQL Server.
// The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server
// is configured to allow remote connections. (provider: TCP Provider, error: 0 - A connection attempt failed
// because the connected party did not properly respond after a period of time, or established connection failed
// because connected host has failed to respond.)"}
case 10060:
// SQL Error Code: 40197
// The service has encountered an error processing your request. Please try again.
case 40197:
// SQL Error Code: 40540
// The service has encountered an error processing your request. Please try again.
case 40540:
// SQL Error Code: 40613
// Database XXXX on server YYYY is not currently available. Please retry the connection later. If the problem persists, contact customer
// support, and provide them the session tracing ID of ZZZZZ.
case 40613:
// SQL Error Code: 40143
// The service has encountered an error processing your request. Please try again.
case 40143:
// SQL Error Code: 233
// The client was unable to establish a connection because of an error during connection initialization process before login.
// Possible causes include the following: the client tried to connect to an unsupported version of SQL Server; the server was too busy
// to accept new connections; or there was a resource limitation (insufficient memory or maximum allowed connections) on the server.
// (provider: TCP Provider, error: 0 - An existing connection was forcibly closed by the remote host.)
case 233:
// SQL Error Code: 64
// A connection was successfully established with the server, but then an error occurred during the login process.
// (provider: TCP Provider, error: 0 - The specified network name is no longer available.)
case 64:
// DBNETLIB Error Code: 20
// The instance of SQL Server you attempted to connect to does not support encryption.
case (int)ProcessNetLibErrorCode.EncryptionNotSupported:
return true;
}
请参阅完整的source here。
答案 1 :(得分：4)
很抱歉回答我自己的问题，但如果有人仍然感兴趣，我们刚刚开始构建我们自己的错误代码列表。不理想，但我们认为这不应该经常发生。
我们选择了一个不错的列表＆＃39;方法，而不是好的清单＆＃39;正如问题所暗示的那样。我们到目前为止的ID是：
PARAMETER_NOT_SUPPLIED = 201;
CANNOT_INSERT_NULL_INTO_NON_NULL = 515;
FOREGIN_KEY_VIOLATION = 547;
PRIMARY_KEY_VIOLATION = 2627;
MEMORY_ALLOCATION_FAILED = 4846;
ERROR_CONVERTING_NUMERIC_TO_DECIMAL = 8114;
TOO_MANY_ARGUMENTS = 8144;
ARGUMENT_IS_NOT_A_PARAMETER = 8145;
ARGS_SUPPLIED_FOR_PROCEDURE_WITHOUT_PARAMETERS = 8146;
STRING_OR_BINARY_TRUNCATED = 8152;
INVALID_POINTER = 10006;
WRONG_NUMBER_OF_PARAMETERS = 18751;
我们注意到的另一件事是，如果连接池超时，则不会收到SqlException - 而是会收到InvalidOperationException报告＆＃34; Timeout已过期＆＃34;。遗憾的是它不是SqlException，而是非常值得捕捉。
我会尝试更新任何内容。
答案 2 :(得分：2)
没有可重试代码的规范列表。其他球队之前遇到过这个问题。 EF团队制定了重试策略。您可能想要搜查他们的代码。但列表并不完整。我已经看到EF在GitHub上提交了修改列表的地方。
我也有这个问题。我添加了一些我从SELECT * FROM sys.messages WHERE language_id = 1033 AND text LIKE '%...%'挖出的明显错误代码。然后，我在应用程序遇到它们时添加了代码。
您还需要针对超时和网络错误重试特殊错误号。服务器无法生成该号码，因为连接已断开。我认为这个数字是-2，但你需要确定。
SQL Server定义的错误级别对于此目的是无用的（并且通常是大多数）。
答案 3 :(得分：1)
我们正在使用vendettamit的列表，并在遇到偶然发现的其他错误代码时继续对其进行扩展。重要的是要注意，对瞬态的定义是“值得重试，也许下次可以使用”，而不是不必要的SQL Server问题。到目前为止，我们已经添加了以下代码：
当您知道连接字符串正确时（例如，由于您最近才设法建立了连接），则可以添加以下代码。同样，您应该不要使用它们来重试建立初始连接，如果您的连接字符串中有错误的参数，这些也可能会弹出。