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Microsoft.Web.Administration內存泄漏

[英]Microsoft.Web.Administration memory leak

具有Windows服務,該服務除其他外,可監視IIS應用程序池。 如果任何池已配置了應用程序且未運行,則將啟動該池(池)。 一段時間以來,它一直運行良好。 最近發現該服務正在泄漏內存。 查看內存轉儲的罪魁禍首是用於檢查應用程序池的Microsoft.Web.Administration。 唯一可拋棄的對象是ServerManager,我在using塊中擁有它。 已經找到有關此泄漏的其他報告,但尚未解決。 (請參閱http://msdn.microsoft.com/zh-cn/library/microsoft.web.administration.servermanager(v=vs.90).aspx#CommunityContent中的用戶注釋)

轉儲Microsoft.Web.Administration.ServerManager的所有根(此轉儲中為481)時,我只能看到其中一個根。 假設這是當前迭代。

不知道為什么這些Web.Administration對象不能被收集,即使它們似乎沒有被植根(?)。 關於如何解決此泄漏的任何想法?

我將代碼移至控制台應用程序,並在此復制了泄漏。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using Microsoft.Web.Administration;

namespace Web.Administration.LeakExample
{
    public static class ServerManagerExtensions
    {
        /// <summary>
        /// Returns the application counts for application pools under the specified ServerManager.
        /// Application pools without applications will not be returned.
        /// </summary>
        /// <param name="manager"></param>
        /// <returns></returns>
        public static Dictionary<string, uint> GetPoolApplicationCounts(this ServerManager manager)
        {
            if (manager == null)
            {
                throw new ArgumentNullException();
            }

            var appCounts = new Dictionary<string, uint>(manager.ApplicationPools.Count);
            foreach (var app in manager.Sites.SelectMany(site => site.Applications))
            {
                if (!appCounts.ContainsKey(app.ApplicationPoolName))
                {
                    appCounts.Add(app.ApplicationPoolName, 1);
                }
                else
                {
                    appCounts[app.ApplicationPoolName]++;
                }
            }

            return appCounts;
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            while (!Console.KeyAvailable)
            {
                Console.WriteLine("Checking App Pools...");

                using (var manager = new ServerManager())
                {
                    var appCounts = manager.GetPoolApplicationCounts();

                    var appPools = manager.ApplicationPools.Where(pool => appCounts.ContainsKey(pool.Name));

                    foreach (
                        var pool in
                            appPools.Where(
                                pool => (pool.State != ObjectState.Started) && (pool.State != ObjectState.Starting)))
                    {
                        var state = pool.Start();

                        if ((state == ObjectState.Started) || (state == ObjectState.Starting))
                        {
                            Console.WriteLine("Started app pool \"{0}\"", pool.Name);
                        }
                        else
                        {
                            Console.WriteLine("Failed to start app pool \"{0}\". state:{1}", pool.Name, state);
                        }
                    }
                }

                Console.WriteLine("Sleeping...");
                Thread.Sleep(1000);
            }
        }
    }
}

WinDbg會話:

> !dumpheap -stat

606b778c      479         5748 System.Runtime.Remoting.Activation.ConstructionLevelActivator
00472088      480         5760 System.Collections.Generic.Dictionary`2+ValueCollection[[System.String, mscorlib],[Microsoft.Web.Administration.Interop.IAppHostElement, Microsoft.Web.Administration]]
00471d5c      480         5760 System.Collections.Generic.SortedList`2+ValueList[[System.String, mscorlib],[Microsoft.Web.Administration.Configuration, Microsoft.Web.Administration]]
00194568      481         5772 Web.Administration.LeakExample.Program+<>c__DisplayClass3
00198438      480         7680 Microsoft.Web.Administration.Interop.AppHostWritableAdminManager
0047199c      481         7696 System.Linq.Enumerable+<>c__DisplayClassf`1[[Microsoft.Web.Administration.ApplicationPool, Microsoft.Web.Administration]]
606cc200      958        11496 System.Char
00471e2c      479        11496 System.Collections.Generic.SortedList`2+SortedListValueEnumerator[[System.String, mscorlib],[Microsoft.Web.Administration.Configuration, Microsoft.Web.Administration]]
0047090c      479        11496 System.Collections.Generic.List`1+Enumerator[[Microsoft.Web.Administration.Site, Microsoft.Web.Administration]]
004706f0      958        11496 Microsoft.Web.Administration.ConfigurationElementCollectionBase`1+<>c__DisplayClass4[[Microsoft.Web.Administration.Site, Microsoft.Web.Administration]]
00471aec      480        11520 System.Collections.Generic.List`1+Enumerator[[Microsoft.Web.Administration.ApplicationPool, Microsoft.Web.Administration]]
0047041c      480        11520 System.Collections.Generic.List`1[[Microsoft.Web.Administration.Site, Microsoft.Web.Administration]]
00196d58      480        11520 System.Collections.Generic.List`1[[Microsoft.Web.Administration.Configuration, Microsoft.Web.Administration]]
004715cc      481        11544 System.Collections.Generic.List`1[[Microsoft.Web.Administration.ApplicationPool, Microsoft.Web.Administration]]
0047103c     1437        17244 Microsoft.Web.Administration.ConfigurationElementCollectionBase`1+<>c__DisplayClass4[[Microsoft.Web.Administration.Application, Microsoft.Web.Administration]]
606ccfc8     1438        17256 System.Int32
00196a58      480        19200 System.Collections.Generic.SortedList`2[[System.String, mscorlib],[Microsoft.Web.Administration.Configuration, Microsoft.Web.Administration]]
0019660c      480        21120 Microsoft.Web.Administration.ConfigurationManager
00471130      958        22992 System.Collections.Generic.List`1+Enumerator[[Microsoft.Web.Administration.Application, Microsoft.Web.Administration]]
00470d68      960        23040 System.Collections.Generic.List`1[[Microsoft.Web.Administration.Application, Microsoft.Web.Administration]]
00198558      480        23040 System.Collections.Generic.Dictionary`2[[System.String, mscorlib],[Microsoft.Web.Administration.Interop.IAppHostElement, Microsoft.Web.Administration]]
00196a08      481        23088 Microsoft.Web.Administration.Configuration
00183170      481        23088 System.Collections.Generic.Dictionary`2[[System.String, mscorlib],[System.UInt32, mscorlib]]
606b7574      479        24908 System.Runtime.Remoting.Messaging.ConstructorCallMessage
00199e7c      479        24908 System.Linq.Enumerable+<SelectManyIterator>d__14`2[[Microsoft.Web.Administration.Site, Microsoft.Web.Administration],[Microsoft.Web.Administration.Application, Microsoft.Web.Administration]]
00199384      480        28800 System.Collections.Generic.Dictionary`2+Entry[[System.String, mscorlib],[Microsoft.Web.Administration.Interop.IAppHostElement, Microsoft.Web.Administration]][]
00470874      958        30656 System.Predicate`1[[Microsoft.Web.Administration.Site, Microsoft.Web.Administration]]
004718a8      962        30784 System.Linq.Enumerable+WhereEnumerableIterator`1[[Microsoft.Web.Administration.ApplicationPool, Microsoft.Web.Administration]]
001944d8      481        30784 Microsoft.Web.Administration.ServerManager
00195178      963        30816 System.Func`2[[Microsoft.Web.Administration.ApplicationPool, Microsoft.Web.Administration],[System.Boolean, mscorlib]]
606ccf90      968        31268 System.Int32[]
00197a50      480        32640 Microsoft.Web.Administration.SiteCollection
00194da0      481        32708 Microsoft.Web.Administration.ApplicationPoolCollection
004719f8     2874        34488 Microsoft.Web.Administration.ConfigurationElementCollectionBase`1+<>c__DisplayClass4[[Microsoft.Web.Administration.ApplicationPool, Microsoft.Web.Administration]]
0019810c      960        42240 Microsoft.Web.Administration.ConfigurationSection
00471098     1437        45984 System.Predicate`1[[Microsoft.Web.Administration.Application, Microsoft.Web.Administration]]
606cc1c8      961        46638 System.Char[]
001838d0      481        59644 System.Collections.Generic.Dictionary`2+Entry[[System.String, mscorlib],[System.UInt32, mscorlib]][]
606bedd0     5269        63228 System.UInt32
00470a7c      960        69120 Microsoft.Web.Administration.ApplicationCollection
00197c60      960        76800 Microsoft.Web.Administration.Site
00197ea8     1440        86400 Microsoft.Web.Administration.Application
00471a54     2874        91968 System.Predicate`1[[Microsoft.Web.Administration.ApplicationPool, Microsoft.Web.Administration]]
6067c684     4832       141272 System.Object[]
00195024     2886       196248 Microsoft.Web.Administration.ApplicationPool
606c7b20    16323       261168 System.__ComObject

>.foreach (obj {!dumpheap -mt 001944d8 -short}){!gcroot -all obj}

    002ef124 003f0359 Web.Administration.LeakExample.Program.Main(System.String[]) [c:\Users\Chuck\Documents\Visual Studio 2012\Projects\Web.Administration.LeakExample\Web.Administration.LeakExample\Program.cs @ 74]
        ebp+70: 002ef148
            ->  02773270 System.Linq.Enumerable+WhereEnumerableIterator`1[[Microsoft.Web.Administration.ApplicationPool, Microsoft.Web.Administration]]
            ->  02772948 Microsoft.Web.Administration.ApplicationPoolCollection
            ->  02772060 Microsoft.Web.Administration.ServerManager

    002ef124 003f0359 Web.Administration.LeakExample.Program.Main(System.String[]) [c:\Users\Chuck\Documents\Visual Studio 2012\Projects\Web.Administration.LeakExample\Web.Administration.LeakExample\Program.cs @ 74]
        ebp+68: 002ef150
            ->  02773270 System.Linq.Enumerable+WhereEnumerableIterator`1[[Microsoft.Web.Administration.ApplicationPool, Microsoft.Web.Administration]]
            ->  02772948 Microsoft.Web.Administration.ApplicationPoolCollection
            ->  02772060 Microsoft.Web.Administration.ServerManager

    002ef124 003f0359 Web.Administration.LeakExample.Program.Main(System.String[]) [c:\Users\Chuck\Documents\Visual Studio 2012\Projects\Web.Administration.LeakExample\Web.Administration.LeakExample\Program.cs @ 74]
        ebp+78: 002ef140
            ->  027732c0 System.Linq.Enumerable+WhereEnumerableIterator`1[[Microsoft.Web.Administration.ApplicationPool, Microsoft.Web.Administration]]
            ->  02772948 Microsoft.Web.Administration.ApplicationPoolCollection
            ->  02772060 Microsoft.Web.Administration.ServerManager

    002ef124 003f0359 Web.Administration.LeakExample.Program.Main(System.String[]) [c:\Users\Chuck\Documents\Visual Studio 2012\Projects\Web.Administration.LeakExample\Web.Administration.LeakExample\Program.cs @ 74]
        ebp+6c: 002ef14c
            ->  02773270 System.Linq.Enumerable+WhereEnumerableIterator`1[[Microsoft.Web.Administration.ApplicationPool, Microsoft.Web.Administration]]
            ->  02772948 Microsoft.Web.Administration.ApplicationPoolCollection
            ->  02772060 Microsoft.Web.Administration.ServerManager

    002ef124 003f0359 Web.Administration.LeakExample.Program.Main(System.String[]) [c:\Users\Chuck\Documents\Visual Studio 2012\Projects\Web.Administration.LeakExample\Web.Administration.LeakExample\Program.cs @ 74]
        ebp+74: 002ef144
            ->  027732c0 System.Linq.Enumerable+WhereEnumerableIterator`1[[Microsoft.Web.Administration.ApplicationPool, Microsoft.Web.Administration]]
            ->  02772948 Microsoft.Web.Administration.ApplicationPoolCollection
            ->  02772060 Microsoft.Web.Administration.ServerManager

    002ef124 003f0359 Web.Administration.LeakExample.Program.Main(System.String[]) [c:\Users\Chuck\Documents\Visual Studio 2012\Projects\Web.Administration.LeakExample\Web.Administration.LeakExample\Program.cs @ 74]
        ebp+60: 002ef158
            ->  02772948 Microsoft.Web.Administration.ApplicationPoolCollection
            ->  02772060 Microsoft.Web.Administration.ServerManager

    002ef124 003f0359 Web.Administration.LeakExample.Program.Main(System.String[]) [c:\Users\Chuck\Documents\Visual Studio 2012\Projects\Web.Administration.LeakExample\Web.Administration.LeakExample\Program.cs @ 74]
        ebp+3c: 002ef17c
            ->  02772060 Microsoft.Web.Administration.ServerManager

    002ef124 003f0359 Web.Administration.LeakExample.Program.Main(System.String[]) [c:\Users\Chuck\Documents\Visual Studio 2012\Projects\Web.Administration.LeakExample\Web.Administration.LeakExample\Program.cs @ 74]
        ebp+4c: 002ef16c
            ->  027732c0 System.Linq.Enumerable+WhereEnumerableIterator`1[[Microsoft.Web.Administration.ApplicationPool, Microsoft.Web.Administration]]
            ->  02772948 Microsoft.Web.Administration.ApplicationPoolCollection
            ->  02772060 Microsoft.Web.Administration.ServerManager

    002ef124 003f0359 Web.Administration.LeakExample.Program.Main(System.String[]) [c:\Users\Chuck\Documents\Visual Studio 2012\Projects\Web.Administration.LeakExample\Web.Administration.LeakExample\Program.cs @ 74]
        ebp+40: 002ef178
            ->  02773270 System.Linq.Enumerable+WhereEnumerableIterator`1[[Microsoft.Web.Administration.ApplicationPool, Microsoft.Web.Administration]]
            ->  02772948 Microsoft.Web.Administration.ApplicationPoolCollection
            ->  02772060 Microsoft.Web.Administration.ServerManager

    002ef124 003f0359 Web.Administration.LeakExample.Program.Main(System.String[]) [c:\Users\Chuck\Documents\Visual Studio 2012\Projects\Web.Administration.LeakExample\Web.Administration.LeakExample\Program.cs @ 74]
        ebp+50: 002ef168
            ->  02772060 Microsoft.Web.Administration.ServerManager

Found 10 roots.

當我第一次閱讀該問題時,我想到的第一件事是,可以通過使用Windows激活服務(WAS)完全避免整個問題。

我對您發布的代碼的第一次了解使我感到您的問題可能與訪問/修改由foreach循環創建的各種閉包有關。

嘗試這些小的重構,看看是否有任何/全部能夠減少或消除問題或失敗的方法,從而提供了更多有關根本原因的信息:

  1. 通過立即調用.ToList()避免延遲執行LINQ查詢
  2. 無需重復使用ServerManager對象,而是在循環的每次迭代中創建一個新對象
  3. 由於您僅使用ApplicationPool.Name ,因此請重構:

    foreach (var app in manager.Sites.SelectMany(site => site.Applications))

對此:

foreach (var app in manager.Sites.SelectMany(site => site.Applications, 
   (s, a) => a.Name)
    .ToList())

我的假設是正在發生的事情:

  • using語句中創建ServerManager新實例
  • 在該對象引用上調用靜態擴展方法,該對象引用在內部使用ApplicationPools
  • 在構造IQueryable時,會立即再次使用ApplicationPools ,該IQueryable會立即使用(但不會完全執行foreach語句在內部使用yield return )並進行過濾。
  • 調用.Start()更改(突變) ServerManager對象引用所引用的ApplicationPool狀態
  • 其余的都不相關,因此循環可追溯到開始。 它仍然使用相同的ServerManager 由於該引用具有突變狀態(由於調用.Start() ),因此它可能已被GC標記並且從未被收集-該應用程序池從不返回后續迭代的結果,並且可能導致該引用的孤立記憶。

請記住,這只是一個假設!

我現在認為這不是真正的泄漏。 我嘗試按照Josh的建議對所有內容進行ToList()處理。 這不會影響內存使用。

我將GC.Collect()添加到循環中(僅用於測試目的),從而消除了“泄漏”。 我通過進行內存轉儲來驗證這一點,如果我在堆上沒有找到Web.Application對象。 這與我以前的轉儲中看到的所有Web.Application對象實際上都植根這一事實相吻合。 其他人沒有扎根,等待被收集。

.NET垃圾收集器的不確定性使我大跌眼鏡。 對不起,噪音。

我在這里找到了解決方案: www.tomanderson.me

建議使用

using (ServerManager sm = ServerManager.OpenRemote("localhost"))
{ /*..*/ }

對我有用。

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