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Blog Post: How It Works: sp_server_diagnostics – spinlock backoffs

SQL Server Support Content

There are numerous articles outlining how spinlocks work so I won’t cover the details in this post. Instead, I want to focus on the spinlockbackoffs value recorded in the sp_server_diagnostics output. Component = System <system spinlockBackoffs ...read more

on 12 Dec 2014
Blog Post: Read this if you have transactional replication configured and plan to upgrade from SQL 2008/2008 R2 to SQL 2012/2014

SQL Server Support Content

SQL Server online documentation makes very clear that you need to 'drain' your replicated transactions before doing any upgrade if you have replicated databases. Below are requirements for transactional replication: Make sure that the Log ...read more

on 17 Jul 2014
Blog Post: Capping CPU using Resource Governor – The Concurrency Mathematics

SQL Server Support Content

Here is what you need to know: A = πr 2 Okay, not really as that is the formula for the area of a circle but it does set the stage for this discussion. I have been working with the CAP_CPU_PERCENT (RESOURCE POOL) setting as it relates to concurrency ...read more

on 21 May 2014
Blog Post: How It Works: Behavior of a 1 Trillion Row Index Build (Gather Streams from SORT)

SQL Server Support Content

I ran into this behavior working on a 1 trillion row, spatial index build but the behavior can apply to any Gather Streams operator, retaining the sort order as rows pass though it. I was just surprised a bit by the behavior until I dug deeper ...read more

on 29 Apr 2014
Blog Post: SQL Server 2014: TEMPDB Hidden Performance Gem

SQL Server Support Content

I ran across a change for TEMPDB BULK OPERATIONS (Select into, table valued parameters (TVP), create index with SORT IN TEMPDB, …) that you will benefit from. For example, I have a Create Index … WITH SORT IN TEMPDB that takes ~1 minute in SQL Server ...read more

on 9 Apr 2014
Blog Post: How It Works: FileStream (RsFx) Garbage Collection–Part (2)

SQL Server Support Content

In a previous post I outlined the basics of File Stream, garbage collection: http://blogs.msdn.com/b/psssql/archive/2011/06/23/how-it-works-filestream-rsfx-garbage-collection.aspx This post continues the discussion, outlining specific details as to how ...read more

on 4 Apr 2014
Blog Post: I think I am getting duplicate query plan entries in SQL Server’s procedure cache

SQL Server Support Content

Before the post dives into the subject I need to point out that Keith did most of the work. I just kept pestering him with various scenarios until he sent me the e-mail content I needed. Thanks Keith – Keith devised a set of steps that ...read more

on 3 Apr 2014
Blog Post: As The World Turns: SQL Server NUMA Memory Node and the Operating System Proximity

SQL Server Support Content

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 ...read more

on 4 Feb 2014
Blog Post: Spatial Indexing: From 4 Days to 4 Hours

SQL Server Support Content

Over the past month I have been involved in the optimization of a Spatial Index creation/rebuild. Microsoft has several fixes included in the SQL Server 2012 SP1 CU7 Release I have been asked by several people to tell the story of how I was able ...read more

on 19 Nov 2013
Blog Post: SharePoint Adventures : When connectivity is not connectivity

SQL Server Support Content

I’m always amazed that issues usually come in batches. I was looped into a few cases that had the following symptoms. They were running SharePoint 2010 and Reporting Services 2012 SP1. When they went to use a data source with Windows ...read more

on 17 May 2013
Blog Post: After applying Service Pack 1 for SQL Server 2012 you may encounter a known issue! Details inside…..

SQL Server Support Content

I’d like to make you aware of an issue that may occur after installing Service Pack 1 for SQL Server 2012. Some of the symptoms are: The Windows Installer process (MSIExec.exe) repeatedly starts and attempts to repair specific SQL Server assemblies. Your ...read more

on 31 Jul 2013
Blog Post: When Does sp_prepare Return Metadata

SQL Server Support Content

I was running an RML Utilities Suite test pass and encountered varying behavior from our sp_prepare suite. Here is what I uncovered. The command sp_prepare returns (or does not return) metadata depending on the server version. For the client ...read more

on 23 Jul 2013
Blog Post: Using PowerShell to discover Reporting Services 2012 in SharePoint

SQL Server Support Content

I was recently going through an exercise of documenting how to discover certain aspects of Reporting Services for some Kerberos work. RS 2012 in SharePoint is a totally different game though. The easiest way I could discover certain items ...read more

on 30 Apr 2013
Blog Post: AlwaysON - HADRON Learning Series: lock_redo_blocked/redo worker Blocked on Secondary Replica

SQL Server Support Content

The topic I received most in my inbox this week was redo blocked on a secondary while attempting to acquire SCH-M (schema modify) lock. First of all, this is expected behavior and you can monitor for this with your standard blocking activities (sys.dm_exec_requests ...read more

on 26 Apr 2013
Blog Post: How It Works: Always On–When Is My Secondary Failover Ready?

SQL Server Support Content

I keep running into the question: “When will my secondary allow automatic failover?” Based on the question I did some extended research and I will try to summarize in is blog post. I don’t want to turn this post into a novel so I am ...read more

on 22 Apr 2013
Blog Post: Spatial Index is NOT used when SUBQUERY used

SQL Server Support Content

I have found the following link to be invaluable when working with and tuning SQL Server Spatial indexes: http://technet.microsoft.com/en-us/library/bb895265.aspx However, the link is not as clear as it could be about the Spatial index selections ...read more

on 9 Dec 2013
Blog Post: AppDomain unloading messages flooding the SQL Server error log

SQL Server Support Content

This blog is built directly from a customer reported issue. As I helped investigate the source of the issue I thought it would be of interest to a broader audience – hopefully you find this interesting, as well. Allow me to provide some history ...read more

on 30 Jan 2013
Blog Post: How It Works: SQL Server AlwaysOn Lease Timeout

SQL Server Support Content

The lease is used between the SQL Server resource DLL and the SQL Server instance to prevent split-brain from occurring for the availability group (AG). The lease is a standard signaling mechanism between the SQL Server resource DLL and the SQL Server ...read more

on 7 Sep 2012
Blog Post: DReplay Message: “Active connections exceed 8192, connection 8409 is waiting.”

SQL Server Support Content

This message was an interesting dive into the DReplay, session boundary logic that I thought I would share. Internally DReplay maintains a progressive, session queue. This queue is limited to 8192 entries and populated in connection replay ...read more

on 23 Jul 2013
Blog Post: How It Works: SQL Server (NUMA Local, Foreign and Away Memory Blocks)

SQL Server Support Content

The NODE an operating system page, physically belongs to can be acquired using the QueryVirtualMemoryEx Windows API. SQL Server uses this API to track locality of memory allocations. This blog is a very high level view of SQL Server behavior but ...read more

on 14 Dec 2012
Blog Post: How It Works: SQL Server 2012 Database Engine Task Scheduling

SQL Server Support Content

Over the years the SQL Server scheduling algorithms have been documented in various publications. Specifically, ‘ The Guru’s Guide to SQL Server Architecture and Internals’ has a chapter, written by the scheduler developer (Sameer) and Ken; and ...read more

on 13 Aug 2013
Blog Post: How It Works: Gotcha: *VARCHAR(MAX) caused my queries to be slower

SQL Server Support Content

The scenario: Table has a NTEXT column that the customer wanted converted to NVARCHAR(MAX) Data has both small and large storage for different rows Issued ALTER TABLE … ADD COLUMN …NVarCharColumn… NVARCHAR(MAX) Issued update MyTable set NVarCharColumn ...read more

on 3 Dec 2012
Blog Post: How It Works: Online Index Rebuild - Can Cause Increased Fragmentation

SQL Server Support Content

SQL Server Books Online alludes to the fragmentation possibility but does not fully explain that the Online Index rebuilding may increase fragmentation when it is allowed to run with MAX DOP > 1 and ALLOW_PAGE_LOCKS = OFF directives . The process of ...read more

on 5 Sep 2012
Blog Post: T-SQL Update Takes Much Longer Than The Matching Select Statement

SQL Server Support Content

I realize the title is generic and that is because the problem is generic. On the surface it would not surprise me that an update takes longer than a select. (A little bit anyway.) There is logging, updates to index rows, triggers, replication ...read more

on 21 Sep 2012
Blog Post: Strange Sch-S / Sch-M Deadlock on Machines with 16 or More Schedulers

SQL Server Support Content

Since it took me several days to track down this bug, and I did learn a couple of new things along the way, I thought I would share some of my work. 16 or More CPUS When a system presents SQL Server with 16 or more CPUs, and you are using a high end SQL ...read more

on 31 Aug 2012

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Browse by Tags

Blog Post: How It Works: sp_server_diagnostics – spinlock backoffs

Blog Post: Read this if you have transactional replication configured and plan to upgrade from SQL 2008/2008 R2 to SQL 2012/2014

Blog Post: Capping CPU using Resource Governor – The Concurrency Mathematics

Blog Post: How It Works: Behavior of a 1 Trillion Row Index Build (Gather Streams from SORT)

Blog Post: SQL Server 2014: TEMPDB Hidden Performance Gem

Blog Post: How It Works: FileStream (RsFx) Garbage Collection–Part (2)

Blog Post: I think I am getting duplicate query plan entries in SQL Server’s procedure cache

Blog Post: As The World Turns: SQL Server NUMA Memory Node and the Operating System Proximity

Blog Post: Spatial Indexing: From 4 Days to 4 Hours

Blog Post: SharePoint Adventures : When connectivity is not connectivity

Blog Post: After applying Service Pack 1 for SQL Server 2012 you may encounter a known issue! Details inside…..

Blog Post: When Does sp_prepare Return Metadata

Blog Post: Using PowerShell to discover Reporting Services 2012 in SharePoint

Blog Post: AlwaysON - HADRON Learning Series: lock_redo_blocked/redo worker Blocked on Secondary Replica

Blog Post: How It Works: Always On–When Is My Secondary Failover Ready?

Blog Post: Spatial Index is NOT used when SUBQUERY used

Blog Post: AppDomain unloading messages flooding the SQL Server error log

Blog Post: How It Works: SQL Server AlwaysOn Lease Timeout

Blog Post: DReplay Message: “Active connections exceed 8192, connection 8409 is waiting.”

Blog Post: How It Works: SQL Server (NUMA Local, Foreign and Away Memory Blocks)

Blog Post: How It Works: SQL Server 2012 Database Engine Task Scheduling

Blog Post: How It Works: Gotcha: *VARCHAR(MAX) caused my queries to be slower

Blog Post: How It Works: Online Index Rebuild - Can Cause Increased Fragmentation

Blog Post: T-SQL Update Takes Much Longer Than The Matching Select Statement

Blog Post: Strange Sch-S / Sch-M Deadlock on Machines with 16 or More Schedulers