Question

概述

我已经工作了很长时间，试图找到一个解决我的特定情况的帖子，但是已经空了。我正在尝试创建一个C＃.NET控制台应用程序，该应用程序将解析具有多个数据库还原定义的XML文件，然后使用SQL管理对象并行启动这些还原。每次还原后，用户可以指定他们希望针对新还原的数据库运行的零到多个SQL文件。每当我并行尝试这些作业中的4个以上时，处理针对数据库执行SQL文件的静态方法会在针对本地创建的ServerConnection调用ExecuteNonQuery（）方法时产生阻塞。我是否错误地实施了这个？关于如何使这项工作的任何建议？

尝试解决方案

使用Parallel.ForEach循环执行作业
使用Task.Factory.StartNew（）执行作业

在上述两种方法中，我都提到了两种静态方法：

使用SMO处理恢复的人。
使用SMO处理针对数据库执行SQL脚本的人。

致电代码

            Parallel.ForEach(restores.Restore,
            //new ParallelOptions {MaxDegreeOfParallelism = 4},
            restore => 
            {
                //Grab copies of the backup information
                string backup = restore.Backup;
                string server = restore.Server;
                string database = restore.Database;
                string[] patchFiles = restore.PatchFiles;

                //Begin by restoring the database from the backup file
                RestoreDatabaseFromBackup(backup, server, database);

                //Execute each patch file sequentially for the restore defintion
                foreach (string patchFile in patchFiles)
                {
                    ExecutePatchFile(patchFile, server, database);
                }
            });

ExecutePathFile方法

private static void ExecutePatchFile(string patchFile, string server, string database)
    {
        //Create directory for the log file (if it doesn't already exist)
        DirectoryInfo di = CreateLogFileDirectory(server, database);

        //Create the log file
        StreamWriter sw = File.CreateText(Path.Combine(di.FullName, Path.GetFileNameWithoutExtension(patchFile) + ".log"));

        Console.WriteLine("{0} : Beginning execution of {1} for {2} on {3}.", DateTime.Now, patchFile, database, server);

        //Verify that 'patchFile' exists and is of the right file extension
        if (!File.Exists(patchFile) || Path.GetExtension(patchFile) != ".sql")
        {
            Console.WriteLine("{0} : Could not execute {1} for {2} on {3}. Invalid SQL file.", DateTime.Now, Path.GetFileName(patchFile), database, server);
            sw.WriteLine("{0} : Could not execute {1} for {2} on {3}. Invalid SQL file.", DateTime.Now, Path.GetFileName(patchFile), database, server);
            sw.Close();
            return;
        }

        string script = File.ReadAllText(patchFile);

        try
        {
            //Build out connection string
            SqlConnectionStringBuilder sb = new SqlConnectionStringBuilder();
            sb.DataSource = server;
            sb.InitialCatalog = database;
            sb.IntegratedSecurity = true;

            //Create SqlConnection
            SqlConnection sqlCon = new SqlConnection(sb.ToString());
            //Set sqlCon to treat exceptions as infomessages
            sqlCon.FireInfoMessageEventOnUserErrors = true;

            //Create ServerConnection
            ServerConnection serverCon = new ServerConnection(sqlCon);

            serverCon.InfoMessage += new SqlInfoMessageEventHandler((sender, e) => ConnectionContext_InfoMessage(sender, e, sw));
            serverCon.ExecuteNonQuery(script, ExecutionTypes.ContinueOnError);
        }
        catch (Exception e)
        {
            throw e;
        }
        finally
        {
            sw.Close();
        }

    }

堆栈跟踪

System.Reflection.TargetInvocationException was unhandled by user code
  HResult=-2146232828
  Message=Exception has been thrown by the target of an invocation.
  Source=BatchDatabaseRestorer
  StackTrace:
       at BatchDatabaseRestorer.Program.ExecutePatchFile(String patchFile, String server, String database) in c:\Users\zannett\Documents\Visual Studio 2013\Projects\BatchDatabaseRestorer\BatchDatabaseRestorer\Program.cs:line 224
       at BatchDatabaseRestorer.Program.<Main>b__0(RestoresRestore restore) in c:\Users\zannett\Documents\Visual Studio 2013\Projects\BatchDatabaseRestorer\BatchDatabaseRestorer\Program.cs:line 83
       at System.Threading.Tasks.Parallel.<>c__DisplayClass21`2.<ForEachWorker>b__17(Int32 i)
       at System.Threading.Tasks.Parallel.<>c__DisplayClassf`1.<ForWorker>b__c()
  InnerException: Microsoft.SqlServer.Management.Common.ExecutionFailureException
       HResult=-2146233087
       Message=Parse error occurred while looking for GO statement. Line 0.
       Source=Microsoft.SqlServer.BatchParserClient
       StackTrace:
            at Microsoft.SqlServer.Management.Common.ExecuteBatch.GetStatements(String sqlCommand)
       InnerException: ManagedBatchParser.ParserException
            HResult=-2146233088
            Message=""
            Source=Microsoft.SqlServer.BatchParser
            StackTrace:
                 at ManagedBatchParser.Parser.Parse()
                 at Microsoft.SqlServer.Management.Common.ExecuteBatch.GetStatements(String sqlCommand)
            InnerException:

Answer 1

我相信当你让它在内部处理解析时，在多个ServerConnection实例上并行调用ExecuteNonQuery（）是一个问题。如果我自己沿着GO关键字拆分脚本，然后将命令作为StringCollection（每个可用的覆盖）传递，那么无论并行作业的数量如何，命令都会正常执行。这使我相信Microsoft.SqlServer.BatchParserClient对象或Microsoft.SqlServer.BatchParser对象与ExecuteNonQuery（）实现的并行执行不兼容。

Answer 2

我偶然发现了这个问题，因为我对我提出了同样的异常。我正在通过反射从字符串中解析DateTime，我很确定TargetInvocationException正在替换FormatException，因为我正在使用MethodInfo.Invoke来调用DateTime的解析方法。用通常的DateTime.Parse替换后，我得到了FormatException。所以我的字符串格式不正确或者解析器的状态不正确（文化等）。

所以我猜CLR正在用TargetInvocationException替换调用的函数引发的任何异常。您可以检查字符串并查找要解析的复杂对象，因为它似乎是导致问题的解析器。

使用SMO在并行执行ExecuteNonQuery时抛出TargetInvocationException

2 个答案: