Site Freezing (might be caused by Feed Manager)

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11/24/2009 10:08:32 PM
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Total Posts 2187

Site Freezing (might be caused by Feed Manager)

Windows Server 2008
MSSQL 2008
2.3.2.9

I had a problem with one of my sites (running a pre-release of 2.3.2.9) a few weeks ago where the site would freeze at what appeared to be "random" intervals. When the site froze, traffic to the site would just time-out. Of course resetting the AppPool took care of it and the site would come up. I tried a lot of different things, none of them worked. I eventually upgraded to 2.3.2.9 but the problem persisted. The log has a lot of Errors stating that there was a problem reading a feed URL. The feed was being exposed by an external source and other feeds weren't showing up in the log so I removed the feed from the Feed Manager. The problem stopped and the site has been running fine since.

Okay, two days ago I upgraded another site to 2.3.2.9 and now it is doing the same thing. The log shows numerous errors like the one below but there are errors for multiple feeds. All of the feeds which are erroring out are on the same site as the Feed Manager.

2009-11-23 14:03:30,808 ERROR mojoPortal.Web.FeedUI.FeedCache - There was a problem trying to read the feed for url http://acckc.org/blog33rss.aspx.  Ignoring.
System.Net.WebException: The operation has timed out
   at System.Net.HttpWebRequest.GetResponse()
   at Argotic.Common.SyndicationEncodingUtility.CreateWebResponse(Uri source, ICredentials credentials, IWebProxy proxy)
   at Argotic.Common.SyndicationEncodingUtility.CreateSafeNavigator(Uri source, ICredentials credentials, IWebProxy proxy, Encoding encoding)
   at Argotic.Syndication.GenericSyndicationFeed.Load(Uri source, ICredentials credentials, IWebProxy proxy, SyndicationResourceLoadSettings settings)
   at Argotic.Syndication.GenericSyndicationFeed.Create(Uri source)
   at mojoPortal.Web.FeedUI.FeedCache.GetRssFeedEntries(Int32 moduleId, Guid moduleGuid, Int32 entryCacheTimeout, Int32 maxDaysOld, Int32 maxEntriesPerFeed, Boolean enableSelectivePublishing)

I know this is probably something that will take a lot of work to find and I probably need to provide more information but at this point, I don't have anything else to provide. The AppPool never crashes so I don't have any errors other than the one above.

Let me know if there is something else you need me to provide and I will do what I can.

Thanks,
Joe D.

11/24/2009 10:20:37 PM
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Total Posts 2187

Re: Site Freezing (might be caused by Feed Manager)

Okay, I lied. I also have errors like the following:

2009-11-23 19:51:25,562 ERROR mojoPortal.Web.AppKeepAliveTask - System.Net.WebException: The operation has timed out
   at System.Net.HttpWebRequest.GetResponse()
   at mojoPortal.Web.AppKeepAliveTask.DoKeepAlive()

I hope this helps.

Thanks,
Joe D.

12/1/2009 10:40:38 AM
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Total Posts 18439

Re: Site Freezing (might be caused by Feed Manager)

Hi Joe,

I found a bug in the AppKeepAlive which may be/probably is the cause of this, though I have not been able to cause a hang in my dev environment this bug could theoretically be the culprit. I don't think those errors logged by the feed manager are the cause.

The problem I found (and have now fixed in my copy for the next release) is that multiple instances of the AppKeepAlive task could be spawned. I have added logic to check if another instance is already running and then end the new instance immediately after it is started if so.

If you look in Administration > Advanced Tools > TaskQueue and you see a AppKeepAlive task running then you touch web.config to recycle the app, you'll see 2 of them, do it again and you'll see 3, and so on. So theoretically it could just keep going and exhaust the thread pool and this would cause the site to hang.

I will try to get a release out soon with this fix but in the meantime it may be best to keep an eye on the taskqueu and if you see a bunch of AppKeepAlive tasks it may be best to disable that for now.

Best,

Joe

12/1/2009 11:17:50 AM
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Total Posts 2187

Re: Site Freezing (might be caused by Feed Manager)

Thanks for your hard work Joe. What you're describing as the problem makes a lot of sense. The second site I was having the issue on hasn't went down for some time now and I think that is because the last time I reset it, I stopped the site and app pool in IIS and then re-started them instead of just touching the web.config. Would that make a difference?

I anxiously await the next release.

Thanks again,
Joe D.

12/1/2009 11:59:43 AM
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Total Posts 18439

Re: Site Freezing (might be caused by Feed Manager)

While that solves the hang, I suspect it would still spin up the unfinished AppKeepAlive tasks after it restarts so I would look and see how many are running. I could put up an interim build with this fix if you need it right away, just let me know.

Best,

Joe

12/31/2009 3:09:03 PM
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Total Posts 115
mojoPortal Community Expert

Re: Site Freezing (might be caused by Feed Manager)

Was this issue fixed in 2.3.3.2? I just recently moved to a new server and this problem just starting showing up.

The specs below are what my site is running now. I was on Win2k3 before.

MojoPortal 2.3.3.2

Windows Server 2008R2

MSSQL 2008

1/2/2010 5:26:33 AM
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Total Posts 18439

Re: Site Freezing (might be caused by Feed Manager)

The issue with the AppKeepAlive task spawning multiple instances was fixed, also the task does better error logging now so if you are using the app keep alive task you might look for problems in the log.

Hope it helps,

Joe

1/7/2010 7:24:44 AM
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Total Posts 171
I am a Russian programmer

Re: Site Freezing (might be caused by Feed Manager)

I found a problem Site Freezing!

SQL Server latch waits

and in SQL Server errorlog (a lot of rows):

2010-01-07 15:33:53.39 spid65 Autogrow of file 'tempdev' in database 'tempdb' was cancelled by user or timed out after 26813 milliseconds. Use ALTER DATABASE to set a smaller FILEGROWTH value for this file or to explicitly set a new file size.

Statistics:

Size of tempdb: 337 mb

Size of mojoportal database: 181 mb

Free space: 19000 mb

Now I think I can fix ....

 

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