Anaylyze Httpwebrequest Hangs With A Vb Debugdiag Script

**Problem! All available connections used up. ** HttpRequest URI:http://10.10.10.10/Service/Service.asmx ServicePoint – ConnectionLimit:12 CurrentConnections:14 ConnectionGroupName: MyConnectionPool

**No Hang Problems found ** HttpRequest URI:http://Mydev/output.asmx/test?&Name=test2 ServicePoint – ConnectionLimit:10 CurrentConnections:1 ConnectionGroupName:

<%@ Language = vbscript %><%@ Category = Crash/Hang Analyzers %><%@ Description = Template System.Net analysis script to build from…%><%@ TopLevelScript = True %><% Option Explicit Dim g_Progress Dim g_Debugger Dim g_HttpObjectOffsets Dim g_SvcPointObjectOffsets Dim g_UriObjectOffsets Dim g_StringObjectOffsets Dim g_MaxConnectionErrorThreads ‘ array of thread id’s that have exceed max connection. Dim g_MaxConnectionWarningThreads ‘ array of thread id’s that have 50% max connection. main() ‘ this kicks off everything sub main() Dim a_DataFile Dim i Dim a_NumberOfDumps Manager.Write “System.Net sample analysis script
” Manager.Progress.SetOverallRange 0,100 Manager.Progress.OverallPosition = 10 Manager.Progress.OverallStatus=”Initializing” a_NumberOfDumps = Manager.DataFiles.Count ‘ for each data file specified… for i=0 to a_NumberOfDumps-1 ‘ get the dump a_DataFile = Manager.DataFiles(i) Manager.Progress.OverallStatus=”Starting analysis of: ” & a_DataFile ‘ get an instance of a debugger set g\_Debugger = Manager.GetDebugger(a\_DataFile)Manager.Write “

Analysis of: ” & a\_DataFile & “

” if g_Debugger.IsCrashDump then Manager.ReportInformation “DebugDiag determined that this dump file (” & a\_DataFile & “) is a crash ” &\_ “dump and this script does not analyze crashes (only hangs). Please run analysis using a crash Script.” end if ‘ try to load the managed debugging extension if(LoadSOS)then ‘ initialize some object information for performance initGlobals ‘ walk all threads but report only specific managed ones walkManagedThreads reportErrors else ‘ todo end if ‘ done with the debugger, so close it Manager.CloseDebugger a_DataFile Manager.Progress.OverallPosition = 100/a_NumberOfDumps * (i+1) next end sub sub initGlobals() set g_HttpObjectOffsets = CreateObject(“Scripting.Dictionary”) ManagedFieldOffsets g\_HttpObjectOffsets, Array(“\_ServicePoint”, “\_Uri”, “\_HttpRequestHeaders”, “\_Proxy”,”\_ConnectionGroupName”),”system.dll!System.Net.HttpWebRequest” set g_SvcPointObjectOffsets = CreateObject(“Scripting.Dictionary”) ManagedFieldOffsets g\_SvcPointObjectOffsets, Array(“m\_ConnectionLimit”, “m_CurrentConnections”),”system.dll!System.Net.ServicePoint” set g_UriObjectOffsets = CreateObject(“Scripting.Dictionary”) ManagedFieldOffsets g\_UriObjectOffsets, Array(“m\_String”), “system.dll!System.Uri” set g_StringObjectOffsets = CreateObject(“Scripting.Dictionary”) ManagedFieldOffsets g\_StringObjectOffsets, Array( “m\_firstChar”), “mscorlib.dll!System.String” g_MaxConnectionErrorThreads = “” g_MaxConnectionWarningThreads = “” end sub

‘ this starts the analysis… sub walkManagedThreads() Dim aCmdOutput Dim aStackOutput Dim aThreadInfo Dim aDebugThread Dim aNumThreads Dim aAddr Dim i Dim aFoundIdx Dim bFoundFirstThread bFoundFirstThread =false set aThreadInfo = g_Debugger.ThreadInfo aNumThreads = aThreadInfo.Count Manager.Progress.SetCurrentRange 0,aNumThreads Manager.Progress.CurrentStatus=”Finding threads waiting on ‘System.Net.HttpWebRequest.GetResponse()’ or ‘System.Net.HttpWebRequest.SubmitRequest()'” for i=0 to aNumThreads-1 Manager.Progress.CurrentPosition = i set aDebugThread = aThreadInfo(i) if Not( aDebugThread is nothing ) then aStackOutput = g_Debugger.Execute(“~” & aDebugThread.ThreadID & “e!CLRStack”) aFoundIdx = InStr(aStackOutput,”System.Net.HttpWebRequest.GetResponse”) if (aFoundIdx = 0)then aFoundIdx = InStr(aStackOutput,”System.Net.HttpWebRequest.SubmitRequest”) end if ‘ highlight the call??? ‘is the tread processing GetResponse? if (aFoundIdx <> 0) then if Not(bFoundFirstThread) then bFoundFirstThread=true Manager.Write “

Managed Threads Waiting on ‘System.Net.HttpWebRequest.GetResponse()'

” end if Manager.Write “<A NAME=’ThreadAnchor” & aDebugThread.ThreadID & “‘>” ‘ dump managed objects on the stack aCmdOutput = g_Debugger.Execute(“~” & aDebugThread.ThreadID & “e!dso”) ‘ Collect the HttpWebRequest objects on the stack. aFoundIdx = InStr(aCmdOutput,”System.Net.HttpWebRequest”) while aFoundIdx <> 0 ‘ if we found an object of interest on the stack, ‘ sav the address fo the object and the thread ID. aAddr = Mid(aCmdOutput,aFoundIdx-9, 8) checkObj aAddr,aDebugThread.ThreadID ‘build error/warning strings here instead. ‘display total number of managed threads? ‘ look for another one… aFoundIdx = 0 ‘aCmdOutput.indexOf(“System.Net.HttpWebRequest”, aFoundIdx + 25) wend Manager.Write regexReplace(aStackOutput, “\n”, “
” ) end if end if next end sub

function regexReplace(aSrcStr, aPattern, aReplacement ) dim aRetStr dim aRegEx set aRegEx = New RegExp aRegEx.Pattern=aPattern aRegEx.Global=True aRetStr = aRegEx.Replace( aSrcStr,aReplacement) regexReplace = aRetStr end function

sub reportErrors() Dim i Dim threadList if Len(g_MaxConnectionErrorThreads) then Manager.ReportError “The number connections exceeds the number of available connections for these threads:” & g\_MaxConnectionErrorThreads,”Increase the number of connections available per this article: <a TARGET=\_blank href=’http:’msdn.microsoft.com/en-us/library/7af54za5.aspx’>Managing Connections</a>” end if end sub ”””””’/ Managed code helpers ””””””””’/ ‘ use .loadby to find where mscorwks is loaded and then load SOS from the same place function LoadSOS() Dim abSuccess Dim begPos Dim endPos Dim CmdOutput Dim Module abSuccess = false CmdOutput = g_Debugger.Execute(“.loadby sos mscorwks”) ‘todo, check CmdOutput to ensure SOS loaded! LoadSOS = true end function

‘ given an Array, populate a dictionary object with offets for these array items to be used later. sub ManagedFieldOffsets( dictObj ,aArray, aObject) Dim aStr Dim i Dim aCmdOutput ‘ get the Class information aCmdOutput = g_Debugger.Execute(“!DumpClass ” + getEEClass(aObject)) for each aStr in aArray dictObj.Add aStr, findOffset(aCmdOutput,aStr) next End Sub ‘ simple helper functions function getManagedLongVal( aObjAddr, aOffset ) getManagedLongVal = g_Debugger.Execute(“dt long ” & aObjAddr & “+” & aOffset) end function

function getManagedStringVal( aObjAddr, aOffset ) Dim retStr Dim aCmdOutput Dim aFoundIdx aCmdOutput = g_Debugger.Execute(“!do -nofields poi(” & aObjAddr & “+” & aOffset & “)”) aFoundIdx = InStr(aCmdOutput,”String:”) if (aFoundIdx <> 0) then retStr=trim( Mid(aCmdOutput, aFoundIdx + Len(“String:”))) end if getManagedStringVal = retStr end function ””””’ Helper Function – findOffset ‘ given a string, extract the field offset specified ‘ this is really an excercise it string parsing function findOffset(aCmdOutput, aField) Dim retStr retStr=”” Dim aFoundIdx Dim aBOL Dim sArray ‘ find the field aFoundIdx = InStr(1,aCmdOutput,aField,1) if aFoundIdx <> 0 then ‘ look backwards from there for the offset. ‘ find the previous line aBOL = InStrRev(aCmdOutput,Chr(10),aFoundIdx,1)+1 ‘need to strip all but one space from the string and make an array of the column values retStr=normalizeWhitespace(Mid(aCmdOutput,aBOL, aFoundIdx-aBOL)) sArray = Split(retStr) retStr=”” ‘ 7 columns total, offset is third column (0 based array) retStr = sArray(2) else ‘TODO Manager.Write “Did not find Field: ” & aField & “<<<<<<<<<<<<<<” end if findOffset= retStr end function ””””’ Helper Function – getEEClass ‘ given a string, extract the EEClass address ‘ theClass name is direct input to !Name2EE must be MODULENAME!CLASSNAM function getEEClass( theClassName ) Dim retStr retStr=”” Dim aCmdOutput Dim aFoundIdx Dim aEOL aCmdOutput = g_Debugger.Execute(“!Name2EE ” & theClassName) aFoundIdx = InStr(1,aCmdOutput,”EEClass:”,1) if (aFoundIdx <> 0) then aEOL = InStr(aFoundIdx,aCmdOutput,”Name:”,1) retStr = Mid(aCmdOutput, aFoundIdx + Len(“EEClass:”) , aEOL – (aFoundIdx + Len(“EEClass:”))) end if getEEClass= retStr end function

‘ utility functions

‘ utility function removing extra whitespace and replacing it with a single space ‘ for example ” some text here” will be converted to ” some text here” function normalizeWhitespace(stringToTrim) dim aRegEx set aRegEx = New RegExp aRegEx.Pattern=”\s+” aRegEx.Global=True normalizeWhitespace = aRegEx.Replace( stringToTrim,” “) end function

‘ calculate and save offsets for the Object fields we need ”””””””” Non-generic managed object helpers….

‘ Given an address of an object get the service point object address function getSvcPointFromReq(aHttpObjAddr)

Dim aRetStr aRetStr=”” Dim aCmdOutput aCmdOutput = g\_Debugger.Execute(“dd ” & aHttpObjAddr & “+” & g\_HttpObjectOffsets.Item(“_ServicePoint”) & ” L1″) aRetStr = Mid(aCmdOutput, Len(aCmdOutput) – 8,8) getSvcPointFromReq = Trim(aRetStr) end function

function getUriString(aObjAddr) Dim aRetStr Dim aCmdOutput Dim aFoundIdx aCmdOutput = g\_Debugger.Execute(“!do -nofields poi(poi(” & aObjAddr & “+” & g\_HttpObjectOffsets.Item(“\_Uri”) & “)+” & g\_UriObjectOffsets.Item(“m_String”) & “)” )

aFoundIdx = InStr(1,aCmdOutput,”String:”,1) if (aFoundIdx <> 0) then aRetStr=trim( Mid(aCmdOutput, aFoundIdx + Len(“String:”))) end if

getUriString = aRetStr

end function

function getConnectionGroupName(aObjAddr) getConnectionGroupName=g\_Debugger.Execute(“du poi(poi(” & aObjAddr & “+” & g\_HttpObjectOffsets.Item(“\_ConnectionGroupName”) & “)+” & g\_UriObjectOffsets.Item(“m\_String”) & “)+” & g\_StringObjectOffsets.Item(“m_firstChar”)).substr(9) end function

‘ obj is an address we can do !do on to get information from sub checkObj(aObjAddr, threadID) ‘get service point and see if it is OK. Dim bSvcPointErrorOrWarning bSvcPointErrorOrWarning = false Dim maxConn Dim currConn Dim connGroup Dim aCmdOutput Dim i Dim aFoundIdx aCmdOutput = getSvcPointFromReq(aObjAddr) if( (aCmdOutput<>”00000000″) And (aCmdOutput<>”????????”)) then maxConn = getManagedLongVal( aCmdOutput, g\_SvcPointObjectOffsets.Item(“m\_ConnectionLimit”)) currConn = getManagedLongVal( aCmdOutput, g\_SvcPointObjectOffsets.Item(“m\_CurrentConnections”)) connGroup = getManagedStringVal( aObjAddr, g\_HttpObjectOffsets.Item(“\_ConnectionGroupName”)) if(currConn>=maxConn) then ‘ report out info and error g\_MaxConnectionErrorThreads = g\_MaxConnectionErrorThreads & “<a href=’#ThreadAnchor” & threadID & “‘>” & threadID & “</a>, “ Manager.Write “
Problem! All available connections used up.
HttpRequest URI:” & getUriString(aObjAddr) & “
ServicePoint – ConnectionLimit:” & maxConn & ” CurrentConnections:” & currConn &”
ConnectionGroupName: ” & connGroup & “

” else if(((currConn)*2)>=maxConn) then ‘ report out info and error g\_MaxConnectionWarningThreads = g\_MaxConnectionWarningThreads & “<a href=’#ThreadAnchor” & threadID + “‘>” & threadID & “</a>, “ Manager.Write “
Warning, half of the availabe connections are being used
HttpRequest URI:” & getUriString(aObjAddr) & “
ServicePoint – ConnectionLimit:” & maxConn & ” CurrentConnections:” & currConn &”
ConnectionGroupName: ” & connGroup & “

” else ‘ no problems found Manager.Write “
 No Hang Problems found
HttpRequest URI:” & getUriString(aObjAddr) & “
ServicePoint – ConnectionLimit:” & maxConn & ” CurrentConnections:” & currConn &”
ConnectionGroupName: ” & connGroup & “

” end if end if end if End Sub %>

Jeff Sanders Technical Blog

I am a Microsoft employee that has worked on all aspects of the Web Stack for a long time. I hope these blogs are useful to you! Use this information at your own risk.

Anaylyze Httpwebrequest Hangs With A Vb Debugdiag Script

Analysis of: ” & a\_DataFile & “

Managed Threads Waiting on ‘System.Net.HttpWebRequest.GetResponse()'