OracleConnection连接请求超时

问题描述

.Net Core 3.1多线程控制台应用程序中存在问题；如果对 ThreadPool.QueueUserWorkItem 的调用数超过了在 ThreadPool.SetMaxThreads OracleConnection 将始终为“连接请求超时”引发异常。 / strong>。 “任务”是对Oracle中存储的proc的调用，该过程通过游标返回数据。在单个线程中一切正常，没有问题

.net Core 3.1中使用最新的nuget版本的Oracle.ManagedDataAccess.Client

尝试了Oracle连接字符串，池大小，连接生存时间连接超时等设置的许多组合。似乎没有任何帮助。一旦排队的任务数超过线程数，连接上的 Open 调用将引发异常。

使用OracleConfiguration跟踪会发现以下异常：

2020-09-23 21:30:51.997780 TID:6   (PRI) (ERR) (CP) PoolManager.CreateNewPR() (txnid=n/a) Oracle.ManagedDataAccess.Client.OracleException (0x80004005): Connection request timed out
   at OracleInternal.ConnectionPool.PoolManager`3.CreateNewPR(Int32 reqCount,Boolean bForPoolPopulation,ConnectionString csWithDiffOrNewPwd,OracleConnection connRefForCriteria,String instanceName,List`1 switchFailedInstNames)

一些线程处于以下状态“正在搜索空闲连接”：

2020-09-23 21:28:57.443815 TID:13  (PRI) (ENT) (CP) PoolManager.Get() MultiTenant : Searching for a idle connection,retryCountWithoutAffinity: 0

要复制的代码：

using Oracle.ManagedDataAccess.Client;
using Oracle.ManagedDataAccess.Types;
using System;
using System.Data;
using System.Diagnostics;
using System.Threading;

namespace OracleDBStoredProc
{
    class Program
    {
        private static Object lockObj = new Object();

        static void Main(string[] args)
        {
            int numThreads = 10;
            ThreadPool.SetMaxThreads(numThreads,numThreads);

            for (int i = 0; i < numThreads+ 1; i++)
            {
                string myMsg = $" TASK {i} ";
                ThreadPool.QueueUserWorkItem(CallToDatabase,myMsg);
                Console.WriteLine(myMsg + " created.");
            }

            Console.WriteLine("Finished");
            Console.ReadKey();
        }

        static void CallToDatabase(Object stateInfo)
        {

            OracleConfiguration.TraceOption = 1;
            OracleConfiguration.TraceFileLocation = @"C:\traces";
            OracleConfiguration.TraceLevel = 2;

            string taskName = (string)stateInfo;

            Console.WriteLine(taskName + "started");

            string constr = "User Id=MyUser;Password=MyPswd;Data Source=(DESCRIPTION= (ADDRESS= (PROTOCOL=tcp)(HOST=MyServer)(PORT=1521))(CONNECT_DATA= (SERVICE_NAME=myservice)))";

            OracleConnection con = new OracleConnection(constr);
            con.open();

            var cmd = new OracleCommand("MY_APP.GET_MY_DATA",con)
            {
                CommandType = CommandType.StoredProcedure
            };

            OracleParameter p1 = cmd.Parameters.Add("refcur_ret",OracleDbType.RefCursor,ParameterDirection.Output);
            p1.Direction = ParameterDirection.Output;

            cmd.ExecuteNonQuery();

            OracleDataReader reader1 = ((OracleRefCursor)p1.Value).GetDataReader();

            DataTable test = new DataTable();
            test.Load(reader1);

            reader1.Close();
            reader1.dispose();

            p1.dispose();

            cmd.dispose();

            con.Close();
            con.dispose();

            String msg = null;
            Thread thread = Thread.CurrentThread;
            lock (lockObj)
            {
                msg = String.Format("{0} thread information\t",taskName) +
                      String.Format("   Thr ID: {0}\t\t",thread.ManagedThreadId);
            }

            Console.WriteLine(msg);
        }
    }
}

解决方法

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.net-core-3.1 c#c#multithreading multithreading oracle oracle