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CSS SQL Server Engineers

This is the official team Web Log for Microsoft Customer Service and Support (CSS) SQL Support. Posts are provided by the CSS SQL Escalation Services
  • Blog Post: As The World Turns: SQL Server NUMA Memory Node and the Operating System Proximity

    It felt a bit like ‘As The World Turns’ as I unraveled how the following worked so the title is a bit of a tribute to my grandmother.  She could not miss here ‘stories’ in the afternoon. Proximity Before I dive into the details I would like to talk about NUMA node proximity.    The...
  • Blog Post: How It Works: CMemThread and Debugging Them

    The wait type of CMemThread shows up in outputs such as sys.dm_exec_requests.  This post is intended to explain what a CMemThread is and what you might be able to do to avoid the waits.  The easiest way to describe a CMemThread is to talk about a standard Heap, HeapCreate and the options (with...
  • Blog Post: SQLCLR and sp_OA* procedures are not compatible

    We ran into an issue today that is a bug you may need to be aware of because of its behavior.   When a SQLCLR procedure calls back into the SQL Server (in proc provider) and executes sp_OA*, during the callback activity, it triggers a bug (currently filed and being evaluated) that results in...
  • Blog Post: How It Works: SQL Server 32 bit PAE/AWE on (SQL 2005, 2008, and 2008 R2) – Not Using As Much RAM As Expected!

    This issue was puzzling until we stepped through the code and studied it in some detail.   The report was “SQL Server won’t use the physical memory I expect it to use.” Scenario:   SQL Server 2008 R2, 32GB RAM  - SQL only using ~22GB of total memory and won’t use anymore. Let me try...
  • Blog Post: Assigning SQL Server, SQL Agent to a Processor Group (OOM, Hang, Performance Counters Always Zero for Buffer Pool, …)

    Suresh brought to my attention that we have been getting questions as to why SQL Server starts on group 1 and then group 2 and it is not predictable?  Then Tejas brought up another issues and since I worked on this way back before we released SQL 2008 R2 I went back to my notes to pull up some details...
  • Blog Post: AWE Allocated Values Reported Incorrectly (Large or Negative Value)

    I ran into an issue today that is documented but you have to know where to find it so I wanted to point it out. In the middle of a lengthy KB article # 907877 ( http://support.microsoft.com/kb/907877 ) the the following comment. "In a NUMA-enabled system, this value can be incorrect or negative...
  • Blog Post: How It Works: Soft NUMA, I/O Completion Thread, Lazy Writer Workers and Memory Nodes

    There seems to be some semantic(s) confusion on the books online description of SOFT NUMA.    The area of confusion is from the SQL Server 2008 Books Online section, shown below. Soft-NUMA SQL Server allows you to group CPUs into nodes referred to as soft-NUMA. You usually configure soft...
  • Blog Post: How It Works: SQL Server 2008 NUMA and Foreign Pages

    I have received numerous questions about 'foreign pages' so I have put this post together to answer the questions. The SQL Server buffer pool goes through three (3) distinct states. Initial / Ramp-up This state is established during buffer pool initialization and only transitions once committed buffers...
  • Blog Post: How It Works: What are the RING_BUFFER_RESOURCE_MONITOR telling me?

    The ring buffer records (which can be sent to XEvent) for Resource Monitor and Memory Broker are the key aspects to understanding RM.  The record is produced when a change is detected in state monitored by RM.    CREATE EVENT SESSION RingBufferInfo ON SERVER     ADD EVENT...
  • Blog Post: Fun with Locked Pages, AWE, Task Manager, and the Working Set…

    I realize that the topic of “locked pages’ and AWE can be confusing. I don’t blame anyone for being confused on this. I also realize we have blogged and talked about this topic many times perhaps “beating it to death”. And I certainly know this is not really fun to anyone(but it made for a catchy title...
  • Blog Post: Come on 64bit so we can leave the mem….

    I recently saw a question the other day about some errors that indicate memory pressure for the SQL Server Engine and how it might be related to the infamous “MemToLeave” for SQL Server. The problem with this situation was that the errors were happening on a 64bit version of SQL Server. So…I thought...
  • Blog Post: SQL Server and Large Pages Explained….

    I gave a presentation on “debugging memory” at the recent Europe PASS Summit in April. In the talk, I mentioned that Large Pages would be used by SQL Server if you used trace flag 834. At the conference, Christian Bolton, a well-known MVP from the UK, mentioned to me that he thought he saw messages in...
  • Blog Post: An update for Standard SKU Support for Locked Pages….

    Note this article has been updated to include an update for SQL Server 2005 I posted in April that we would be releasing cumulative updates for SQL Server 2008 and 2005 to support the concept of Locked Pages for SQL Server Standard. SQL Server 2008 Cumulative Update 2 for SP1 was released yesterday to...
  • Blog Post: SQL Server reports working set trim warning message during early startup phase

    In the previous posts we have discussed the working set trim message “ A significant part of sql server process memory has been paged out ” that gets written to the SQL Server Error log. You can find the details about the various parameters that determine when this message is written to the error log...
  • Blog Post: SSIS 2005 and the .NET Garbage Collector

    I was troubleshooting an SSIS Out of Memory issue the other day which led us into how the .NET Garbage Collector (GC) works.  When debugging it, I found that we were using the Workstation GC with Concurrent GC On (this is the default for .NET applications).  The following blog discusses the...
  • Blog Post: SQL Server, Locked Pages, and Standard SKU…

    I made an announcement today while speaking at Europe PASS 2009 that we will be providing a method for customers using standard SKU for SQL Server 2005 and 2008 to use the ‘Locked Pages in Memory’ privilege to allow the server to use the AWE APIs. This is often referred to as “locked pages” for SQL Server...
  • Blog Post: Installing SQL Server 2005 SP3 or SQL Server 2008 on builds prior to XP SP3 Can lead to Bug Check (0xF4, Blue screen, Critical Process Termination)

    Due to a bug in Windows XP builds prior to the XP SP2 hot fix or XP SP3 release you may encounter one of the following bugs while attempting to install SQL Server 2008 or SQL Server 2005 SP3 based builds. An application that uses the Sxs.dll file crashes when you run the application on a Windows XP-based...
  • Blog Post: Query Performance issues associated with a large sized security cache

    In the past couple of months, SQL Server support team has come across some customers running into performance issues attributed to TokenAndPermUserStore in SQL Server 2005. This blog post attempts to compile all the information we have so far regarding this problem. TokenAndPermUserStore is one...
  • Blog Post: SQL Server 2005 Memory Limits and Related Questions

    I had a very nice conversation this week with one of the blog readers.   The question related to adding more memory to their server.   It lead to an exchange of various links that I think you might find handy.  We discussed the operating system limitations and the SQL Server...
  • Blog Post: SQL Server Working Set Trim Problems? - Consider...

    Microsoft support continues to receive a steady flow of cases indicating poor, SQL Server performance symptoms.   When the issue is narrowed down we are finding that the working set of SQL Server and many of the processes on the computer have been significantly trimmed. What we have found is...
  • Blog Post: How It Works: SQL Server 2005 NUMA Basics

    The Senior Escalation Engineers do various training and mentoring activities.  As I do this I thought I would try to propagate some of this information on the blog. I have received several questions on the SQL Server NUMA implementation this week. Much of this was covered in my 2006 PASS presentation...
  • Blog Post: SQL Server 2008 - Resource Governor Questions

    A couple of common questions have surfaced related to the SQL Server 2008 Resource Governor feature. The SQL Server 2008 BOL has a lot of good information so start don't forget to review that as well. Metadata and Runtime Data A set of DMVs exist for resource governor.  The ' dm_ ' indicates the...
  • Blog Post: Do I have to assign the Lock Pages in Memory privilege for Local System?

    IMPORTANT: The following KB article adds support for Locked Pages to SQL Server Standard Edition http://support.microsoft.com/kb/970070 NOTE: I've updated this because of some questions about 32bit systems. Some who attended one of my talks at the recent PASS conference asked me the following...
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