An SPRequest object was not disposed - determine where this object was allocated

Question

I have the SPRequest object was not disposed error.

12/10/2013 14:21:03.03  w3wp.exe (0x260C)                           0x1700  SharePoint Foundation           Performance                     nask    Monitorable An SPRequest object was not disposed before the end of this thread.  To avoid wasting system resources, dispose of this object or its parent (such as an SPSite or SPWeb) as soon as you are done using it.  This object will now be disposed.  Allocation Id: {D54D46CA-238E-4E42-8F2B-FB04C280C8DD}  To determine where this object was allocated, set Microsoft.SharePoint.Administration.SPWebService.ContentService.CollectSPRequestAllocationCallStacks = true.   28e11e24-7b30-444d-98b9-1056cfc7f62a

At the end of which it says to determine where this object was allocated, set

Microsoft.SharePoint.Administration.SPWebService.ContentService.CollectSPRequestAllocationCallStacks = true

I have done this using this powershell

Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue

$file = $Env:CommonProgramFiles+"\Microsoft Shared\Web Server Extensions\14\ISAPI\Microsoft.SharePoint.dll"       
[System.Reflection.Assembly]::LoadFile($file) | out-null

# Get Content Service of the farm
$contentService = [Microsoft.SharePoint.Administration.SPWebService]::ContentService

# Display and change the setting of property "CollectSPRequestAllocationCallStacks"
write-host "Current: " $contentService.CollectSPRequestAllocationCallStacks 

$contentService.CollectSPRequestAllocationCallStacks = $true
$contentService.Update()
write-host "    New: " $contentService.CollectSPRequestAllocationCallStacks 

the script works but doesnt change the message in the log.

On this page and elsewhere it suggests setting the following registry key (creating if necessary)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\HeapSettings

New Dword Value = 1

This hasn't worked either.

I have used SPDisposeCheck and it doesnt return anything. I don't believe this link or this link provides any more information either.

My questions are

Is there anything else I can do to determine where the object was allocated?

If this message is shown to occur in Microsoft SharePoint code, what can I do to fix and what is the risk of doing nothing?

UPDATE
I noticed the error is also appearing when the list item is updated.

On Clicking Save in my custom web part this code is run..

        SPItem item = UpdateListItem();
        if (item != null)
        {
            Redirect(item.ID);
        }

UpdateListItem does the following

private SPListItem UpdateListItem()
{
    SPList list = SPContext.Current.Web.Lists[ListName];
    if (list != null)
    {
        SPListItem item = null;
        if (Item != null)
        {
            item = Item;

            item["EventReceiverInProcess"] = true;
            item.Update();

        }

        return item;
    }

    return null;
}

Item is a property..

protected override SPListItem Item
{
    get
    { 
        var result = (SPListItem)RequestIDField.Item;
        if (result != null && result.ID > 0)
        {
            return result;
        }
        else
        {
            return null;
        }
    }
}

The SPRequest object was not disposed error appears on completing the Redirect line, which basically redirects to the same page, but if I dont execute the line the error still appears.

I've commented out all code in my ItemUpdating(SPItemEventProperties properties) method.

The line that causes the error to appear is item.Update();

Update 2

I've found these two links which appear to be somewhat related to my issue

http://blog.furuknap.net/splist-rootfolder-causes-dispose-problem http://solutionizing.net/2009/01/09/splist-parentweb-leaks-revisited/

However updating the code to do the following hasn't worked

private SPListItem UpdateListItem()
{
    SPList list = SPContext.Current.Web.Lists[ListName];
    if (list != null)
    {
        SPListItem item = null;
        if (Item != null)
        {
            item = Item;

            item["EventReceiverInProcess"] = true;
            item.Update();

                if (item.Web != null)
                {
                    item.Web.Dispose();
                }

                if (item.ParentList.ParentWeb != null)
                {
                    item.ParentList.ParentWeb.Dispose();
                }

                if (item.ParentList.Lists.Web != null)
                {
                    item.ParentList.Lists.Web.Dispose();
                }

        }

        return item;
    }

    return null;
}

Update 3
For a bit more clarity in tracking this down, I have commented out the whole SPItemEventReceiver class on this list.

Not sure if relevant but as a bit of extra information this list has custom security applied, and it has a managed meta data column.

Update 4

After removing basically all my custom code and still getting the error, I went the other way and went with ootb functionality which still generates the error. (Updated to Service Pack 2)

1. create new web application in central admin
2. create new site collection based on team template in central admin
3. in site collection add a site column of type managed meta data
4. in site collection create a custom list
5. Update the list settings, add the managed meta data site column
6. Add new item on list - (see image)
7. confirm error message in log
8. edit list and remove the managed meta data site column
9. add new item to list

10. confirm error not in log

    

This is basically exactly the same behaviour as seen here -

Memory leak in Microsoft.Sharepoint.Taxonomy.TaxonomyItemEventReceivers?

Answer 1

I can't see a place where you leave an open web opened - the risk is higher resource usage for a longer time, if you dispose properly you would need less resources.

If this event receiver is not used frequently, I would ignore it.

Answer 2

Can you show some code in what your doing in your list event? Somewhere you're not disposing of the spweb or spsite object.

Just like when you use itemUpdating event and then you update the list it would run into an endless loop, adding this.EventFiringEnabled = false; would solve it. In your case I need to see code to know exactly what is causing it to show that error. There is a leak somwhere within the event reciver.

So your looping once and the object is disposed and then it loops again with the same spweb / spsite object but it fails becasue the object doesnt exist. this.EventFiringEnabled = false; forces no method to run before you update, so you update first and then what ever other function is going to run does run.

http://www.sharepointassist.com/2009/11/19/error-request-not-found-in-the-trackedrequests/

Answer 3

I see the real problem now: You recurse with your item.update() call. The memory leak could occur when SharePoint stops this recursion.

You should prevent recursion with this: this.EventFiringEnabled = false;

And enable it afterwards: this.EventFiringEnabled = true;

See this blog post: http://www.mattjimison.com/blog/2011/05/11/disable-event-receivers-during-an-update/

Additionally: Dont dispose the properties.Web - its taken care of automatically: http://blogs.technet.com/b/stefan_gossner/archive/2008/12/05/disposing-spweb-and-spsite-objects.aspx