QDPMA - SQL Server Performance Consultant - Joe Chang

About Joe, Contact: jchang6 @ yahoo.com

Joe's travel plans 2016

no current travel planned for the remainder of 2016.
Open to suggestions for 2017

Prague, 3 Dec?

I made this for a talk a few years ago. I liked is so much that it is now in all my slides.
Of course, that does not mean it is complete, so please send feedback via Joe on SQLblogs


In previous articles, I have discussed processor and system architecture, server systems, and performance benchmarks, often mixing more than one topic. Going forward, I will consolidate each topic into separate collections:

Query Optimizer and Performance  formerly "The SQL Server Cost-Based Optimizer"
  Feature: kCura Relativity 2013-04, updated 2013-09
  Path to In-Memory Databases - Hekaton

Server Systems  2016-04 (interim)

  Transaction IO Performance on Violin (2015-02),
  SAN IO Performance Problems (2015-02),
  Storage Performance 2014

System Architecture  
  Amdahl Revisted Update 2015-05

Processor Architectures  
  Feature: Hyper-Threading performance on TPC-H queries.

Performance Benchmarks  
  2014 Q2 update.

TPC-H Studies
 SQL Server scaling and other characteristics are investigated using the TPC-H data generator and test queries. The test conditions are not identical with publication requirements.

Performance Tools

ExecStats is my own SQL Server performance analysis and data collection tool. Please try it out and send feedback. SQL Exec Stats has been combined with SQL System as of 2012 Q4,

I am abandoning the specific build links with a generic that should point to the latest. The general link should normally be for the latest build, but it will be the last .NET 3.5 for the time being.

Download       Exec Stats (latest, .NET 4.00, 2016-06-24)
check the build date, I am having problems with this link.

For the last several months, the principle mode of dm_exec_query_stats grouping was a hybrid of query hash and batch via sql_handle. The issue was that the same SQL/query hash would be assigned to the first batch encountered. The new version reintroduces batch mode, which is also a hybrid, first using the sql_handle + offset. However, any query hash for the the end is -1 is grouped by query hash. This should work for most cases, but please advise if not.

Exec Stats 2016-06-24 minor fixes.

Exec Stats 2016-04-16 minor fixes.

Exec Stats 2016-03-11 minor fixes.
Exec Stats 2016-03-03 now using dm_os_performance_counters instead of Windows API calls for SQL Server performance counters. Windows Server 2012 did not return values, and I could not find any discussion of this matter.

Exec Stats 2016-02-08 minor

Exec Stats 2015-12-16 SQL Server 2008R2 RTM fix, exception handling

Exec Stats 2015-11-04 New batch mode, query hash option

The version below might work with 2005. The recent versions were meant to simultaneously group by both query_hash and sql_handle (using the first sql_handle if a query_hash has multiple sql_handles). SQL Server 2005 does not have query_hash, so I am just inputting a fake value, losing this part of the functionality.

Exec Stats 2015-10-06 Update Gembox dll

Exec Stats 2015-06-15 fix for Azure, and other circumstances when full network address (host.domain.com) is required. Also, using a hot-fix version of Gembox.

Exec Stats 2015-05-27 trap if no printer installed
Exec Stats 2015-05-25 special test build - VAS committed
Exec Stats 2015-05-20 There have been many changes since the previous build,
please provide feedback and report any bugs
There is a problem, possibly with Windows Server 2012, any version of SQL Server
The SQL Server performance counters that should have instances report back as not having any.
The Windows Performance Monitor sees the instances, so something is going on.

Exec Stats 2015-03-17 perf ctr auto print to xps

2015-03-11 partition key not lead annotated
2015-03-09 additional general DMVs
2015-03-07 minor - SQL Source + tick marks
2015-02-18 perf ctr font size in config.
2015-02-15 fixed bug in opening previously generated *.dat files.
should also be able to open previously saved perf ctr files (*.bin).
2015-02-04 now on Gembox 3.9.
2015-01-11 (.NET 4.51), fixed: Mx CPU was previously inadvertently reported also as Mx Dur.
I am hoping this fixes the problem for SQL Server 2005. The previous build had references to columns not in the 2005 DMV's, typically with regard to compressed data, but others as well.
2014-11-10 A problem has been reported with the above (and probably other recent versions against SQL Server 2005. I would appreciate assistance in the tracking down the specific SQL statement that is not supported on 2005.
2014-11-03 New version, simultaneously grouping by query hash for SQL and batch for procedures.
2014-08-09 Last of the old version, grouping by query hash.
2014-08-07 connection parks in tempdb I have reverted back to .NET 3.5 because I have a client that cannot move to 4 or 4.5.
I am working on a significant overhaul, consolidating the 3 separate dm_exec_query_stat modes into a single option that displays execution statistics by Batch (sqlhandle), Statement (sqlhandle+offset) and by query hash on separate pages. For the moment, this involves processing up to 64K entries from dm_exec_query_stats, exiting when the combined plan size exceeds 300MB or there abouts. This version is probably stable enough for general use.
interim build intended for Windows Server 2008 R2 using the new Processor Information object instead of Processor. Has not been tested on W2K8 original yet. Later builds will report the processor frequency once issues are worked out.

Documentation to follow. Feedback is desired.

My plan is to use JSON but I have not done so at this time.

SQLExecStats documentation, in the process of being updated, ok, the documentation is seriously out of date. Every time I update the documentation, I make further changes to ExecStats, obsoleting the documentation changes just made - oh well.

Sometime I will try allow reading execution plans from SQL Trace files as well. I am contemplating implementing a very basic graphical plan. I would rather not do this as SQL Sentry has a well reviewed Plan Explorer, but it would be useful.

Standalone Articles

 Climate, not my field, but I had to look into it.

 About 64-bit

 Gigabit Ethernet

 SIMD Extensions for the Database Storage Engine

SQL Performance Tools (Obsolete)

Older versions have been removed. Send me an email if older versions are desired for some reason.

Trace Analysis

  Trace Analysis Build 2015-10-06

  Trace Analysis Build 2015-09-01

  Trace Analysis Build 2015-03-17

  Trace Analysis Build 2015-02-04

  Trace Analysis Build 2014-12-24

SQL Clone

As you can see, it has been many years since I worked on SQL Clone. SQL Server 2014 SP2 now has this functionality, see

  Build 2010-03-04
This is an interim update for scripting Roles. A more thorough update is due, when I get a chance.

  Build 2009-01-18

SQL Scripts

Below are some helpful scripts I have built up over the years. The first is an extension of sp_spaceused to provide table level summary.
spaceused with table level details (2013-09)
The next is spaceused at the index level
Index Summary with key and include columns, size, and dmv index usage stats.

An alternate to the index level space usage query is a system stored procedure, extending sp_helpindex.
sp_helpindex3 is my version of extended index information. It would be desired if the table and index sp_spaceused extensions could be made into system views, but apparently SQL Server does not allow modifications to system resource database anymore?

Older versions Table Spaceused Summary (2008?) reports size, indexes, and other info.
Spaceused Summary (2012-04) and Index Summary(old) with key and include columns, size, and dmv index usage stats.

Trace is my standard Profiler script. Be careful in collecting execution plan information, as this could have high overhead.

Events and Presentations


2015 Jun 20 SQL Saturday Bratislava Comprehensive Indexing 2015
2015 May 30 SQL Saturday New York Comprehensive Indexing 2015
OK, same slidedeck for both.

2015 Mar 04 Copenhagen, SQL Rally Nordic,  
Automating Execution Plan Analysis 2015 (Updated 2015-03-06)

2015 Jan 22, Oslo SQL Server User Group Norway at Teknologihuset
Statistics That Need Special Attention


Joe presented at SQL Saturday Oslo, 30 Aug 2014
Modern Performance 2014 Oslo

Redmond, 31 May 2014   Automating Execution Plan Analysis for Comprehensive (Whole DB?) Performance.

NOVA, 19 May 2014 Modern Performance 2014

SQL Saturday Atlanta, 3 May 2014

SQL Saturday Budapest, 1 Mar 2014
I was at SQL Saturday Boston on 29 Mar, but not presenting.


2013 Oct 6 at Silicon Valley Code Camp

Modern Performance 2013 (updated 2013-10-06, original 10-03)
Note: Modern Performance-SVCC, the SQL Performance 2013-Riyadh and the 2012 Automating Performance-Copenhagen slidedecks are all on the same topic.

2013 May at SQL Saturday Riyadh, Saudi Arabia

Storage 2013

SQL Performance 2013 (Special Topics)

2012 Oct 2 & 3 at SQL Rally Nordic, Copenhagen

Automating Performance Data Collection, Analysis etc.

Presented at SQL PASS Deutschland

I presented at Munich on 10 Jan 2013. Will put up slides soon?

SQL PASS Deutschland

SQL Server Query Optimizer Cost Formulas 2010-Dec?

2011 SQL Saturday Trinidad Presentations

Performance for Small/Medium Business

SQLBits 2010

I presented a session at SQLBits on 1 Oct 2010 in York, England. (if this where New York was named after?) Anyways, I tried to squeeze 4-5 hours of material into 1 hour. So I will try to write up everything and collect it here.

  1) NUMA System Architecture
  2) Storage Performance for Data Warehouse
  3) Parallel Execution Plans Part I, Part II, Part III
  4) TPC-H Benchmarks, SF100, SF300, SF1000, SF3000
  5) TPC-H Studies at SF10

Slidedecks: SQLBits Presentations

SQL Server 2008 Presentations

SQL Server Query Optimizer Cost Formulas

Storage Configuration, NOVA 2009

SQL Server 2005 Presentations

SQL Server 2005 Performance Enhancements for Large Queries

SQL Server 2000 Presentations from past conferences

Execution Plan Cost Formulas

Quantitative Performance Analysis, CMG2004

Loop Merge and Hash Joins

Insert Update Delete

Large Data Operations

Parallel Execution Plans

Storage Performance, Connections Spring 2005 ?


Joe on SQLblogs

Joe on SQL-Server-Performance

Solid Quality Journal

In case anyone is interested, the old frameset page is here wframeset.html. I never figured out how to code it.