Good post but yuck. Amazing how many issues you avoid by avoiding ADSI, WMI, CDOEXM, and the other MSFT frameworks designed to make life "easier"... -- O'Reilly Active Directory Third Edition - http://www.joeware.net/win/ad3e.htm
_____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Alain Lissoir Sent: Saturday, December 02, 2006 12:37 PM To: ActiveDir@mail.activedir.org Subject: RE: [ActiveDir] 100% CPU utilization when querying Win32_Account on DC Let me step in here to give you some more background ... J WMI is a 3-tier architecture (See figure at <http://msdn.microsoft.com/library/en-us/wmisdk/wmi/wmi_architecture.asp> http://msdn.microsoft.com/library/en-us/wmisdk/wmi/wmi_architecture.asp). The SMS client runs at the level of the client API (3) and submits the WQL query to WMI at layer 2 (Core WMI service). This query is handled by WMI core. WMI Core looks after the class in the WQL query (i.e. Win32_Account) and locates the provider supporting it. In this case, the provider is CIMWin32 implemented by CIMWin32.DLL (I skip the explanation about how WMI does that unless someone is interested). Because that CIMWin32 provider does not support WQL query parsing and is not handling them by itself, WMI core takes the initiative to actually converts this query into a full enumeration request to the provider, meaning that the provider is actually building ALL instances of Win32_Account with all their characteristics. Once the collection is built, WMI core receives the result set and is then post-filtering the enumeration set to match the WHERE clause of the WQL query, which in turn returns the result set requested by the client (SMS in this case). This is the way how WMI core works with all WMI providers not supporting WQL queries natively (I mean supporting query at the level of the provider itself). Actually, this enumeration technique is implemented to support WQL queries even for providers not supporting WQL queries in their code by design. A WMI provider may have many capabilities (i.e. Get, Put, enumerations, events, etc) and one of them is to support WQL queries (which actually is off-loading WMI core do to the job I just described). This explanation does not solve your issue, here, but it gives you the explanation of the "why" where the actual solution is to implement a WMI provider that supports natively WQL queries and actually performs the right SAM or LDAP queries against AD (I mean properly scoped). It would be a sort of WMI provider converting WQL queries into SAM/LDAP queries to put it short. This class was created way before AD did exist. The presence of AD increases dramatically the number of accounts available. Although this class with this provider was working fine during the NT 4.0 time (yes, this class dates from that period), it is challenged in large AD infrastructure, Make a test with a small AD infrastructure where you have only 2000 accounts, and everything will be fine. I can bet that your AD installation is way bigger ... Now, if you use WMI a lot to query the SAM and AD and if you feel this is an area where some enhancements can be made, let it me know and I will be pleased to communicate this data point to the team in charge of WMI and the team in charge of Active Directory, So, we can let them know that it is an important scenario to enhance and support better. No commitments here, but I will be pleased to convey the message. Hope this helps a bit ... PS: However, if you feel you have WMI issues, you can always use the WMI Diagnosis Tool 1.0. You can find pointers to it (+Webcast) at http://www.lissware.net. Note, we will release the version 2.0 early next year. Regards, /Alain Alain LISSOIR <blocked::http://www.LissWare.Net> cid:114265316@01122006-02BE _____ <mailto:[EMAIL PROTECTED]> [EMAIL PROTECTED] Home Page: http://www.LissWare.Net <blocked::http://www.LissWare.Net> Where am I? http://map.LissWare.Net <blocked::http://map.LissWare.Net> _____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Guy Teverovsky Sent: Friday, December 01, 2006 7:36 AM To: ActiveDir@mail.activedir.org Subject: RE: [ActiveDir] 100% CPU utilization when querying Win32_Account on DC Thanks Susan, but I think this case is different - we are talking about different WMI class and in my case the query hangs and never returns results. The ITMU issue is probably a result of intensive load on the CPU when performing the query you pointed to, but in my case if I let it run for hours it still never finishes. I am far from being well versed in WMI, but I'd suspect that here the problem is caused by WMI not using paging in the query or very inefficient processing when using both LocalAccout=True and SidType=1 keys. Guy ________________________________________ From: [EMAIL PROTECTED] On Behalf Of Susan Bradley, CPA aka Ebitz - SBS Rocks [MVP] Sent: Friday, December 01, 2006 5:12 PM To: ActiveDir@mail.activedir.org Subject: Re: [ActiveDir] 100% CPU utilization when querying Win32_Account on DC http://www.myitforum.com/articles/8/view.asp?id=9048 http://www.myitforum.com/articles/8/view.asp?id=9284 Rod's been tracking that on myitforum and the Patch management listserve for a while now. Guy Teverovsky wrote: > > Hi all, > > Recently I had a case where we experiences high CPU utilization after > deploying SMS client to DCs. > By now we have identified that the issue was caused by an extension of > sms_def.mof file containing the definitions of information that should > be collected from the agent. > > The interesting part is that I was able to reproduce the behavior > without SMS agent. Just execute the following WMI query on your DC and > see the CPU spikes to 100% and will stay there till you kill the > wmiprvse.exe process: > *select * from Win32_Account where LocalAccount=True and SIDType=1* > > Now you do not need to explain to me that this is damn stupid to run > this type of query on a DC, yet I would expect the DC to be able > to handle the query, but what I see is that the query never returns - > it just hangs there choking up the CPU till you kill the WMI process. > > Almost the same behavior is observed when executing "wmic useraccount" > from the command line, but in this case the query does return the > results after a while (~2-3 minutes on ~2K user account AD). > > The only thing related to the issue that I was able to find is the > following KB: http://support.microsoft.com/kb/268715 > ("WMI Query Support for Win32_Group Is Not Optimized") where the > following query "SELECT * FROM Win32_Group WHERE Domain="workgroup" > AND Name="smith"" causes the identical behavior. But folks, we are > talking W2K3 with SP1 and not W2K pre-SP2. > > Any chance anyone has stumbled upon it ? Is aware of hotfix ? > > Thanks, > Guy > List info : http://www.activedir.org/List.aspx List FAQ : http://www.activedir.org/ListFAQ.aspx List archive: http://www.mail-archive.com/activedir@mail.activedir.org/
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