我想为我的数据库调用编写一些包装代码(使用 C# 和 Microsoft 技术来访问数据库)，在出现“ transient ”异常时自动重试。我所说的暂时性是指最终很有可能会解决的事情(相对于永远不会起作用的逻辑错误)。我能想到的例子包括:

• 僵局
• 连接超时
• 命令超时

我曾计划使用 SqlException 的错误编号来发现这些错误。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;

(如有任何错误，请原谅 - 我只是临时写的。我也意识到我可以很好地把它包起来......)

所以关键问题是:我应该将哪些数字视为“ transient ”(我意识到我认为的 transient 可能与其他人认为的 transient 不同)。我在这里找到了一个不错的列表:

https://msdn.microsoft.com/en-us/library/cc645603.aspx

但它的体积庞大且注释非常有用。 有没有其他人建立了他们用于类似事情的列表？

更新

最后，我们选择了“错误列表”——如果错误是已知“非暂时性错误”列表中的一个——这通常是程序员错误。我已经包含了我们用作答案的数字列表。

最佳答案

sql Azure 中有一个类 [SqlDatabaseTransientErrorDetectionStrategy.cs] 用于 transient 故障处理。它涵盖了几乎所有类型的可以被认为是 transient 的异常代码。它还是 Retry strategy 的完整实现。

在此处添加代码片段以供将来引用:

/// <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
}

进一步检查sql异常返回的错误号的switch case:

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;
}

查看完整 source here .

关于c# - SQL Server transient 异常编号，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/35630829/