如果超时失败，C# 重试 Sql 查询

Question

有时我的查询超时并导致失败。重试执行查询的最佳方法是什么？

我在执行查询之前验证连接是否打开。但是，由于任何给定时间的服务器负载，可能需要 <1 分钟到 5 分钟以上的时间。我考虑过延长 CommandTimeout，但我认为这不是真正可行的方法。

这是我的sql查询代码。感谢您提供的所有帮助。

    private static void ExecuteQuery(string connectionString, string query)
    {
        SqlConnection connection = new SqlConnection(connectionString);
        DataTable output = new DataTable();

        try
        {
            //create new SqlAdataAdapter
            SqlDataAdapter command = new SqlDataAdapter {SelectCommand = new SqlCommand(query, connection)};

            //connect to Sqldb
            connection.Open();

            //validate connection to database before executing query
            if (connection.State != ConnectionState.Open) return;
            Console.WriteLine("Connection successful\nExecuting query...");

            //set connection timeout
            command.SelectCommand.CommandTimeout = 200;

            //create new dataSet in order to input output of query to
            DataSet dataSet = new DataSet();

            //fill the dataSet
            command.Fill(dataSet, "capacity");
            DataTable dtTable1 = dataSet.Tables["capacity"];

            Console.WriteLine("There are " + dtTable1.Rows.Count + " clusters within the capacity anlaysis.");

            output = dtTable1;
        }
        catch (Exception e)
        {
            Console.WriteLine("Unable to execute capacity (all records) query due to {0}", e.Message);
        }
        finally
        {
            connection.Close();

            Declarations.NumOfClusters = output.Rows.Count;
            Declarations.finalIssues = Issues(output, 2m, 20, true);

            Console.WriteLine("\n---------------Successfully Created Capacity DataSet---------------\n");
        }
    }

Answer 1

使用 Palmer 库:https://github.com/mitchdenny/palmer

  Retry.On<Exception>().For(TimeSpan.FromSeconds(15)).With(context =>
  {
    // Code that might periodically fail due to some issues.
       ExecuteQuery(string connectionString, string query)
       if (contect.DidExceptionLastTime)
           Thread.Sleep(200); // what ever you wish
   });

引用github页面上的API。例如，您可以检查异常的上下文，并在确实发生异常时决定休眠一段时间。 您可以重试更具体的异常。 你可以永远尝试等等。