A closer look at everything related to SQL Server

Archive for the ‘Uncategorized’ Category

2020 Pandemic’s Silver Lining

For most of us, year 2020 would be remembered well into the future just as we all can never forget year 2001 for 9/11 attacks or year 2008 for global financial crisis. There are lot of bad news around these events which are mostly true and should be taken into account. But there are also some heart warming and good news (silver lining) around these event as well, that do not get as much attention as their bad news counterparts.

I am focusing my post on the current, COVID-19 Pandemic situation. Here I have put together a short list of businesses that are doing good by their governments and towards their employees during this life altering year on Earth. I know there will be many more stories like that out there and I hope you share them when you get a chance. These types of positive stories provide hope which is much needed. In all of the animal kingdom, humans are the only one who need hope as a survival tool among many other tools.

Airbnb CEO, Brian Chesky, sent a very open and honest letter on May 20th, 2020. While he was giving the sad news of letting go of 25% of employees due to current Pandemic and also insecurity about the future business, yet he was able to be transparent and empathetic at the same time. Read the letter and tell me if your eyes did not get wet.

Some business in UK, such as IKEA and Primark, have voluntarily repaid more than 215 million pounds to the Government for its help with furloughed employees. So far more than 80,000 businesses have repaid the money back. The total CJRS package is 3.5 billion pounds and repaid money is a tiny fraction of it. But it is still encouraging that some companies are honest and not thinking about filling their pockets in times of this human tragedy.

Comcast CEO, Brian Roberts, and other top executive announced on April 1st, 2020, that they will donate 100% of their salaries to charities who are helping COVID-19 relief effort. Furthermore, company earmarked $500 millions to support its employees continued wellbeing. This is certainly a very inspiring news.

Microsoft, my employer, has shut down all its physical stores early on. But all the hourly employees were kept on payroll and within a month most of them were retrained. These employees now offered the same valuable support to our customers from home, virtually. This became a great opportunity for many employees to become part of the tech teams which they may have never dreamed of before. Based on the success of this model, Microsoft decided in June 2020 to close all its stores permanently, except the 4. Microsoft has also worked with schools and other not for profit organizations by donating software such as Teams and technical talents resources. These organizations otherwise would not have survived this Pandemic on their own.

What is the one common thing among these companies that I mentioned here (and other similar companies)?

They all are businesses to make profit but when situation affects human beings at this level of suffering, they don’t sit quite, they come forward and do the right thing.


My Best Books list of 2020

I am a voracious reader. Many of you will find this information surprising because I don’t think I have shared this detail anywhere else before. I read both fiction and non-fiction books. I mostly listen to audio books. In this blog post I will reveal my 10 best books reading of 2020. 5 of them fiction and 5 of them non-fiction. I will share my thoughts on why I like them. I hope you leave comments after reading this blog. I would love to hear from you. ūüôā

I discovered in 2016 GoodReads, a very good site for keeping track of all the books that I read. Here is the screenshot that shows that in the beginning of this year I set the goal to read 75 books and as of today I have read 86 books. Kudos to me for over achieving :). But really, COVID19 situation this year has helped this goal. It looks like I will be able finish 3 more book by the end of this year. I know there is nothing good about COVID19 situation. But we are humans and we are resilient and we find hope and good in every situation.

I want you to know that it is very hard to pick and choose best books because, I look at ratings and reviews of a book from various sources before choosing to read it. Of course the description of the book must interest me first. I save them in Goodreads “Want to Read” list. I do have subscription to Audible. But most of the books I borrow from the local library.

Top 5 Non-Fiction Books of 2020:

  • The Choice: Embrace the Possible by Edith Eger
    • In this book author Edith Eger, uses her own personal trial and tribulations through Nazi’s death camp and ended up becoming therapist in her 50s. She specializes in treating PSTD in soldiers returning from war. She also overcame another personal setback in her later life after Auschwitz. She shares her deepest feelings and what helped her make the choices that she did.
    • I found this book very inspiring. It strengthens my belief in human race’s resiliency in face of no matter what. This brings to my mind “Where there is will there is way”. Also people or their loved ones who are suffering from PTSD (post-traumatic stress disorder) can learn and grow from the insight she shared in this book. According to author there is always a choice that we make at a critical junction that determines our future. Even under extreme circumstances such as under Nazi’s captivity, when you think you have lost all your humanity, you still have a choice. There is that little voice inside you that tells you to live or die, to give up or to fight. In her situation, I think some luck has also played a role but it was author’s tenaciousness that allowed her to take advantage of those lucky breaks.
  • Dare to Lead by Berne Brown
    • The author is a rock star when it comes to train and inspire leadership team of any company. Her main lessons in this book is to lead with Empathy. She unpacks many new terms of leadership such as lead from heart or how to be your authentic self or have rumble meeting. There is a wealth of many new ideas based on her research.
    • I like this book because it is motivating and calls you too take action right away. It gives you strategies that you can use at work and at home. Whether you are a people’s manager, a parent or a friend, this book is for you. She gives many of her own life examples of the events she faced herself and in doing so she relate to her audience and inspire them to take action too.
  • The Gift of Forgiveness by Katherine Schwarzeneggar Pratt
    • Author has interviewed many survivals who decided to forgive their perpetrator. I recognized many of the events because they made main news media such as TV and newspapers. Although each person interviewed for this book forgave their villian for a different reason, yet each one teaches us a great lesson in forgiveness.
    • I like this book because author starts with her own life story of breakup of a great friendship and how the process of writing this book has encouraged her to overcome her despondency and how she made up with her childhood friend later in her life. If you have to choose only one book from my blog, then I would recommend choose this one.
  • The Ride of a Lifetime by Robert Iger
    • This book is written by Disney’s current CEO Robert Iger. There are many lessons to be learned from his long career track. The tone and language used in this book makes you feel he is your friend telling you his life story. There were setbacks, there were family problems and there were lucky breaks. But above all Robert was good at maintaining relationships. There is mention of Apple and Disney deal and friendship between author and Steve Jobs. It is cool to hear from CEO himself about various deals Disney made with its partners and various acquisitions Disney made over the years.
    • I like this book because of author’s down to earth attitude. He has revealed many mistakes he made in his career and does not shy away from being accountable for them. But good part is that he always used the lesson learned from past mistakes in his new endeavors. This book gave me firsthand insight into how too much stress at work can have negative consequences on our health.
  • Talking to Strangers by Malcolm Gladwell
    • The main idea of this book is that we don’t know about strangers and if need arises to talk to them, we need to be prepared how to talk to them. This is basically an insightful book on clever communication techniques. When I say clever, I don’t mean dirty tricks. All his ideas are based on science and research and makes total sense. Most of us will never have to do hostage negotiations but the principles learned from this book will be similarly effective at work when we have a new team member or we have a new manager or we are working with a new client.
    • Since I had the audio version of this book, I was able to listen to the actual scientists and psychologists explaining ideas in their own words when author was talking to them. Author is an engaging story teller and I advise you to listen to this book instead of reading it to get an interesting experience.

Top 5 Fiction Books of 2020:

  • The Garden of Evening Mist by Tan Twan Eng
    • This is a historical fiction book. The main character is Nakamura Aritomo a Japanese artist who was once Emperor’s gardener. The book setting is in Malaysia in 1940 under British rule. Yun Ling is the one who is narrating the story. The very exotic and delicate details in this book is what makes it most memorable. It left me with a feeling of melancholy for the characters in the end and I felt I knew them personally.
    • I like this book because of its historical component. I was never introduced to the history of Malaysia and British rule. I am very familiar of British ruling history of Indian subcontinent. So it was interesting to see the similarities and differences of Malayan occupation. Another main touching point to me was the depiction of characters in such a way that they seemed real life although they all were fictional characters but it felt like they were part of the history.
  • When Crickets Cry by Charles Martin
    • This is a very heart warming and unforgettable story of sacrifice. There are many one liners to remember such as ” All hearts stop, Annie. What matters most is what you do with it when its pumping”. Reese could not save his wife Emma from heart failure, even though he was a heart surgeon. He blamed himself for 5 years before he met Annie, a 7-year old girl.
    • I like this book because between the moments of despair there were little moments of pleasures and they were so beautiful that it teared the eyes and involuntarily I started to pray for the characters in the book.
  • 10 Minutes and 38 seconds by Elif Shafak
    • The setting of this book is Istanbul, Turkey in 1990. The story revolves around the problems of sex works in Istanbul. The story begins with few street kids finding the body of a prostitute in a dumpster. Her name was Leila and story of her life passes before her eyes before her brain dies in 10 minutes and 38 seconds after her death.
    • I like this story because it depicts what true friendship means and after reading it, you may wish for friends like Liela’s who were there for her both in good and bad times. It saddened me to see that her family did not supported her when she needed them. It has sensitive material so if you are weak of heart, please do not read it.
  • The Signature of All Things by Elizabeth Gilbert
    • This is another book of historical fiction. I do prefer this genre of fiction. This is the story of Henry Whittaker, a richest man in Philadelphia in 1800s and his daughter Alma and adopted daughter Prudence. The story takes you around the globe; from Philadelphia to Tahiti to Amsterdam and to London. This is a book club material with solid arguments to be made on both sides.
    • I like this book because of the portrayal of strong women in Henry’s life. Another important point in the book is there is no age limit when you can set out for adventure; you only need a strong purpose. Or on the other hand taking extreme adventure (going out of your comfort zone) can bring purpose to your life. You will never know it till you give it a try.
  • Dear Edward by Ann Napoltano
    • How would you feel if you were the sole survivor of the plane crash that was flying 184 people? Guilty? This is what happened to Edward, a twelve-year-old boy. His whole family died in the flight crash. A true friendship saved him. This book also goes into the back stories of some of the other passengers of that unlucky flight. This is a true story but fictionalized for this book.
    • I like this book because the author was not only able to bring out the pain Edward was feeling but also made us feel the real pain. Very cleverly crafted book and the sensitive emotions are handled very carefully. This is the story about coming to terms with your grief which never goes away but how you can still move on with your life.

I hope you enjoyed reading this blog. Please share the books you have read and if you have read any of the books I have mentioned here, I like to hear what you think about them.

TempDB Bottlenecks and More

There has been many articles, documents and blog posts written about various problems and resolutions of TempDB. This is my effort at understanding and gathering relevant information about TempDB bottlenecks in one place for myself and any audience of this blog.


Tempdb is a SQL Server temporary system database. Everytime SQL Server restarts, new Tempdb database is created. Whatever data was stored in the tempdb is lost. When TempDB gets recreated its data and log files reset to their last configured size. SQL Server records only enough information in the tempdb transaction log to roll back a transaction, but not to redo transactions during database recovery. This feature increases the performance of INSERT statements in tempdb. Tempdb database is always in Simple recovery mode. If you try to change it to Full Recovery mode, you will receive the following error message.

If you try to backup TempDB, you will get another error saying backup and restore is not allowed on TempDB database.

This system database is used by all the other user databases on SQL Server instance for their temporary work. It is the most busy database on almost all production SQL Servers. Here is a short list of few of the features that use tempdb.

  • Temporary tables, table variables, and table-valued functions.
  • Work tables associated with Cursors, Order By, Group by and Hash Query Plans.
  • Version stores used by Read Committed Snapshot Isolation
  • Index creation, Online index creation
  • User-defined functions

These objects stored in TempDB are categorized as following:

USER OBJECTS – such as temporary local and global tables, table variables, table-valued functions etc.

INTERNAL OBJECTS – such as objects created to support indexing operations and query execution like work tables.

VERSION STORES – such as created when RSCI or SI isolation levels are used by transactions.

Following TSQL code uses DMV sys.dm_db_file_space_usage to get the TempDB space usage, separating out the above 3 categories.

— tempdb data file usage
SUM(user_object_reserved_page_count) * 8 AS usr_obj_kb,
SUM(internal_object_reserved_page_count) * 8 AS internal_obj_kb,
SUM(version_store_reserved_page_count) * 8 AS version_store_kb,
SUM(unallocated_extent_page_count) * 8 AS freespace_kb,
SUM(mixed_extent_page_count) * 8 AS mixedextent_kb
FROM sys.dm_db_file_space_usage;


Problem 1: TempDB database grows out of disk space and only option left is to restart the SQL Server service.

There could be many ways to approach the resolution. But I believe monitoring the space usage is the best weapon. Here is a great post by William Durkin, who creates an Extended Event session to monitor space usage of data and log files of TempDB database.

— XEvent Session to track tempdb file growths
ADD EVENT sqlserver.database_file_size_change(
SET collect_database_name = ( 0 )
ACTION (sqlserver.client_app_name, sqlserver.client_hostname,
sqlserver.database_id, sqlserver.session_nt_username,
WHERE ([database_id] = ( 2 )))
ADD TARGET package0.event_file
( SET filename = N’TempDBFileGrowth.xel’,
max_file_size = ( 10 ), max_rollover_files = ( 5 ))

Create this Extended Event session for monitoring tempdb space usage. But be careful, this is for troubleshooting only. You can leave it running continuously but first change the dispatch_latency to 30 seconds which is the default. Dispatch latency controls how often XEvent data in buffer pool will be flushed and written to the disk. If this frequency is very low, on busy systems, it could affect the performance of SQL Server.

Problem 2: Tempdb PFS and SGAM page contentions.

Imagine a particular SQL Server instance processing concurrent queries. Each one of them creating tiny temp tables, use them and then drop them. These temporary tables are stored in Tempdb database. PFS page in the tempdb data file keeps track of all the page allocations and deallocations. Only one thread at a time can make changes in PFS and as a result you can see it creates a bottleneck. This behavior of Tempdb is known as PFS Page Contention. This issue can be resolved by having multiple Tempdb data files. The guidance is that you should start with 1 data file per CPU core till you reach 8 files. Add more files in chunk of 4 if you are still seeing PFS page contentions. You also need to enable trace flag 1117 to have these multiple files grow at same rate. This is a server wide setting so it changes the behavior of all user databases on the instance and not only TempDB.

Sometimes Tempdb reports contention in SGAM page. This happens when SQL Server searches for a mixed pages to allocate to a new object created and scans SGAM page. This results in severe contention on the SGAM page when multiple mixed-page allocations are underway. Deallocation activities also modify this page and create more contentions. In this situation, trace flag 1118 can be implemented to allow SQL Server to allocate full extents to the new objects. This is a server wide setting so it changes the behavior of all user databases on the instance and not only TempDB. Monitor this behavior using DMV sys.dm_os_waiting_tasks. You will notice wait types along with resource_description such as 2:1:1 and 2:1:3 (PFS and SGAM Pages in TempDB database in File 1).

[owt].[session_id], [owt].[exec_context_id],
[owt].[wait_duration_ms], [owt].[wait_type],
[owt].[blocking_session_id], [owt].[resource_description],
CASE [owt].[wait_type]
RIGHT ([owt].[resource_description],
CHARINDEX (N’=’, REVERSE ([owt].[resource_description])) – 1)
END AS [Node ID],
[es].[program_name], [est].text,
[er].[database_id], [eqp].[query_plan],
FROM sys.dm_os_waiting_tasks [owt]
INNER JOIN sys.dm_exec_sessions [es] ON
[owt].[session_id] = [es].[session_id]
INNER JOIN sys.dm_exec_requests [er] ON
[es].[session_id] = [er].[session_id]
OUTER APPLY sys.dm_exec_sql_text ([er].[sql_handle]) [est]
OUTER APPLY sys.dm_exec_query_plan ([er].[plan_handle]) [eqp]
[es].[is_user_process] = 1
[owt].[session_id], [owt].[exec_context_id];

The above query is from Paul Randal. Another useful blog about Tempdb is from Pamela Lahoud of Microsoft.

You will see later in this blog post that since SQL Server 2016, trace flags 1117 and 1118 are not needed because they are now the default behavior of TempDB database.

Problem 3: Tempdb Metadata contentions

Third type of bottleneck we see in Tempdb is from system tables. This is also known as metadata contention and it is occurring because of hardware improvements which enables creation and deletion of temporary objects at a faster rate in TempDB database. This is a good thing because we want TempDB to be faster but it created another type of contention which has to do with keeping track of all these metadata changes in the system table. SQL Server 2019 has pretty much resolved this issue by providing an option to place the TempDB system tables on In-Memory files. In-memory tables do not face any latches or locks as it is in RAM and not on the disk. Since these system tables only contain tempdb metadata their footprint is not that big on the SQL Server memory.

You can use the following script to view all the sessions that are waiting for page-related wait types and get information about the objects that the pages belong to. sys.fn_PageResCracker is a new function available in SQL Server 2019 that takes the Page_resource value from sys.dm_db_exec_requests dmv and give you the detail of locks and latches at the page level.

USE master

er.session_id, er.wait_type, er.wait_resource,
OBJECT_NAME(page_info.[object_id],page_info.database_id) as [object_name],
SUBSTRING(st.text, (er.statement_start_offset/2)+1,
((CASE er.statement_end_offset
ELSE er.statement_end_offset
END – er.statement_start_offset)/2) + 1) AS statement_text,
page_info.database_id,page_info.[file_id], page_info.page_id, page_info.[object_id],
page_info.index_id, page_info.page_type_desc
FROM sys.dm_exec_requests AS er
CROSS APPLY sys.dm_exec_sql_text(er.sql_handle) AS st
CROSS APPLY sys.fn_PageResCracker (er.page_resource) AS r
CROSS APPLY sys.dm_db_page_info(r.[db_id], r.[file_id], r.page_id, ‘DETAILED’) AS page_info
WHERE er.wait_type like ‘%page%’

Problem 4: Version Store growth in read-only secondary replica

If you have Availability Group setup for your SQL Server instance, make sure to monitor version store growth in Tempdb database on secondary replica. In addition to following query, you can also monitor this with performance counters like Version Store Size (KB), Version Cleanup rate (KB/s) and Version Generation rate (KB/s). Here is an interesting write up about this problem on AG secondaries.

— Version store usage
SELECT DB_NAME(database_id) AS [database_name], reserved_page_count, reserved_space_kb
FROM sys.dm_tran_version_store_space_usage
ORDER BY reserved_space_kb DESC;


  1. Optimizing SQL Server Eager Writes

One long standing issue with TempDB in the past was that when you perform SELECT INTO temporary table operation, poor performance on disk I/O occurred in tempdb database. This was resolved in SQL Server 2014 RTM and back ported to SQL Server 2012 SP2 CU1. SQL Server has a concept of Eager Writes that prevent flooding the buffer pool with pages that are newly created from bulk activities and need to be written to disk. SQL Server 2014 enhancements now relaxes the need to flush these pages to the tempdb data files as quickly as the older versions because it recognizes objects created in tempdb would be temporary.

2. Tempdb Installation Defaults

Having multiple tempdb data files to remove PFS and SGAM page contentions has been long standing recommendations from Microsoft. Prior to SQL Server 2016, DBAs would manually add the additional TempDB data files after installing SQL Servers. and enable trace flags 1118 and 1117 to evenly grow these files. SQL Server 2016 installation now includes this step in the setup. It recognizes the number of CPU cores and based on that gives the option of creating multiple files. You can change the no. of files, file location etc. Also there is no need to use the previously mentioned trace flags, as this has now became the default behavior of TempDB database.

3. Tempdb system tables move to In-Memory OLTP

Once again SQL Server 2019 brought a huge improvement to TempDB performance. You can enable “Optimize for Tempdb Metadata” feature and it will put all the TempDB metadata (system tables) in memory. This takes away all type of pagelatch_XX wait types. When temporary objects are created and removed at super fast pace, due to huge improvements in hardware, disk is no longer the bottleneck for these operations. These metadata objects reside in RAM (memory) now.


  1. Configure multiple tempdb data files. Start with 8 if you have 8 or more logical cores. Then add more in chunks of 4 if you still see PFS contention. Multiple files are beneficial even if all are on the same drive which is dedicated for Tempdb.
  2. Enable trace flag 1118 as a startup trace flag for SQL Server prior to SQL Server 2016. This prevents SGAM contentions.
  3. Enable trace flag 1117 as a startup trace flag for SQL Server prior to SQL Server 2016. This makes multiple tempdb files to grow equally.
  4. Always put the tempdb data and log files on fastest disk. Have it local to the machine rather than in SAN. It keeps your SAN path free for user database traffic
  5. Put Tempdb database on a separate volume then your user databases.
  6. Just pre-allocate the tempdb files as large as possible, with enough room to give you time to react to unforeseen scenarios such as SQL Server encounters long running query.
  7. Do not explicitly drop temp tables at the end of a stored procedure, they will get cleaned up when the session that created them ends.
  8. Do not alter temp tables after they have been created.
  9. Do not truncate temp tables.
  10. Move index creation statements on temp tables to the new inline index creation syntax that was introduced in SQL Server 2014.


The key to keep your TempDB healthy is proactive and continuous monitoring with DMVs and XEvents. Setup up proper alerting to notify when space usage reaches certain threshold. Document the TempDB configurations into your SOP (Standard Operating Procedure) documentation to be consistent across all your SQL Servers. Keep an eye on version store usage and be careful about their growth on read-only secondary replicas. Consider using Memory Optimized Tempdb Metadata feature of SQL Server 2019.

Automatic Soft NUMA

NUMA is basically a memory and CPU architecture inside the computer machine. NUMA stands for Non-Uniform Memory Access. The purpose of NUMA is for Scheduler (CPU) to have faster access to memory. Each CPU talks to memory controller to get the memory. When there are more than 8 CPUs, single memory controller becomes  bottleneck. This became a scalability issue. NUMA is a hardware configuration which was built to scale beyond the processor and memory limitations of traditional Symmetric-Multi-Process (SMP) systems. If there are 16 CPUs, there will 2 NUMA nodes (node 0 and 1). Each node will have its own memory controller and serves up to 8 CPU. CPU and Memory are partitioned at the hardware level to improve the access to memory. SQL Server is NUMA aware application. You don’t have to enable it. Almost all modern computer hardware now has this hardware NUMA.

I would highly recommend anyone new to NUMA to read this article written by SQLSkills team.

Following is the image of SMP configuration where all processors have equal access to memory and I/O. As you can imagine, increasing the number of CPU in this architecture will create a bottleneck because there is only one memory controller and one I/O controller.

Fig 1

In Fig 2 below you are seeing 2 NUMA nodes and CPU and Memory are partitioned. Each NUMA node gets its own memory and I/O controller.

Fig 2

Automatic Soft NUMA:

Modern processors have multiple cores per socket. Each socket is represented, usually, as a single NUMA node. The SQL Server database engine partitions various internal structures and partitions service threads per NUMA node. With processors containing 10 or more cores per socket, using software NUMA to split hardware NUMA nodes generally increases scalability and performance. Prior to SQL Server 2014 (12.x) SP2, software-based NUMA (soft-NUMA) required you to edit the registry to add a node configuration affinity mask, and was configured at the host level, rather than per instance. Starting with SQL Server 2014 (12.x) SP2 and SQL Server 2016 (13.x), soft-NUMA is configured automatically at the database-instance level when the SQL Server Database Engine service starts. Please read this  documentation and this documentation for more understanding.

Note 1: Hot-add processors are not supported by soft-NUMA

Note 2: Starting with SQL Server 2014 (12.x) SP2, use trace flag 8079 to allow SQL Server to use Automatic Soft-NUMA. Starting with SQL Server 2016 (13.x) this behavior is controlled by the engine and trace flag 8079 is not required.

The benefits of soft-NUMA include reducing I/O and lazy writer bottlenecks on computers with many CPUs. Soft NUMA allows you to further divide schedulers in smaller group. You can read a really good description about how NUMA works here

NUMA can match memory with CPUs through specialized hardware (hardware NUMA) or by configuring SQL Server memory (soft-NUMA). During startup, SQL Server configures itself based on underlying operating system and hardware configuration or the soft-NUMA setting. For both hardware and soft-NUMA, when SQL Server starts in a NUMA configuration, the SQL Server log records a multimode configuration message for each node, along with the CPU mask.

Here are couple of useful queries I use to find out about NUMA layout of my customer’s SQL Server. I am using Glenn’s Performance Queries modified on September 13, 2020.

— Get instance-level configuration values for instance  (Query 4) (Configuration Values)

SELECT name, value, value_in_use, minimum, maximum, [description], is_dynamic, is_advanced FROM sys.configurations WITH (NOLOCK) ORDER BY name OPTION (RECOMPILE);

In above query result,  focus on these settings:

  1. automatic soft-NUMA disabled (should be 0 in most cases)
  2. backup checksum default (should be 1)
  3. backup compression default (should be 1 in most cases)
  4. clr enabled (only enable if it is needed)
  5. cost threshold for parallelism (depends on your workload)
  6. lightweight pooling (should be zero)
  7. max degree of parallelism (depends on your workload and hardware)
  8. max server memory (MB) (set to an appropriate value, not the default)
  9. optimize for ad hoc workloads (should be 1)
  10. priority boost (should be zero)
  11. remote admin connections (should be 1)
  12. tempdb metadata memory-optimized (0 by default, some workloads may benefit by enabling)

Following query gives you some useful information about the composition and relative load on your NUMA nodes. You want to see an equal number of schedulers on each NUMA node.  Watch out if SQL Server 2019 Standard Edition has been installed on a physical or virtual machine with more than four sockets or more than 24 physical cores.

–SQL Server NUMA Node information  (Query 12) (SQL Server NUMA Info)

SELECT node_id, node_state_desc, memory_node_id, processor_group, cpu_count, online_scheduler_count, ¬† idle_scheduler_count, active_worker_count, avg_load_balance, resource_monitor_state FROM sys.dm_os_nodes WITH (NOLOCK)WHERE node_state_desc <> N’ONLINE DAC’ OPTION (RECOMPILE);

Automatic Soft-NUMA is enabled by default. It is recommended best practice to leave it enabled.

To disable Automatic Soft-NUMA, run the following command.

USE master; 


EXEC sp_configure ‘automatic soft-NUMA disabled’, ‘1’; 


My Experience – PASS Summit 2019

I attended PASS Summit 2019 in November last year, 6 months ago. Nice thing was that I took all my notes in OneNote which I had just recently started using. Then life got into my way and I totally forgot about it. Then COVID-19 happened and I still did not remember till today. So here it is.

This time, I didn’t purchase any PreCon. It is not because there were no good ones but the opposite that there were so many that I worried I will pay the steep price for one and it will not be as expected or I would wish later on that I had attended the other one. So I made a cowardly decision and went to none.

But I did enjoy spending time with several friends and met lot of people from my previous work places. No breakfast this time at PASS was a bummer. They gave us $25 Starbucks gift card in lieu of 3 day of breakfasts. Just to let organizer know, if they are reading this, a modest breakfast in Seattle was priced around $10 in 2019. Another suggestion, if prices for PASS merchandises are lowered, for example a $60 t-shirt down to $30 (not sacrificing the quality), I think more people would buy them and take souvenirs home from PASS summit and net profit in the end will come out to be the same. I will keep the rest of the suggestions to myself.

Disclaimer: These are my notes taken while attending sessions and any inaccuracies are my own.

Session: SQL Server 2019 new tools

Speaker: Vicky Harp (SQL Server tools team in Microsoft)

This was all demos, no slides session.

Since 2016 tools and Engine connection was broken when SSMS became available as a separate install from database engine installation.

Azure Data Studio (ADS) is a new tool to communicate with SQL Server engine and is more powerful than SSMS in some ways. But SSMS is going to stay. It is purely for SQL Server on Windows platform and it is a 32 bit application.

ADS supports hybrid environment and platform. Your job is to secure, HA and DR your data and not learn every new technology that comes your way. ADS serves this purpose very well. It is a one stop shop kind of tool. You can connect to windows, Linux and can even connect from your non windows client such as a Mac Book. It natively supports beside TSQL, PowerShell, Python, Scala, Spark, Java etc.

Notebook in ADS is another great feature. You can run the query typed in notebook and result and comments will be saved in the same notebook. You can create complete solution in it and can email this notebook to your colleague. You can open notebook in any other compatible tools such as SSMS. You can create SOP documents for your helpdesk team. It is not compatible with OneNote yet. But discussions on this subject is in progress.

There are lot of extensions available in ADS which further improves its usefulness. Extensions such as SQK server Agent, Admin Pack for SQL Server and SQL Server Profiler to name few are available. Each extension has multiple tasks.

SQL Server Edge running on IOT devices can analyze IOT data on the device itself instead of sending it to some server to analyze. Stream Analytics is used for this purpose.

Session: Working with SQL Server Containers

Speaker: Carlos Robles

Demos: C:\Users\amlalani\OneDrive\Training\PASS Summit 2019\SQL Server Containers

Why containers?

  • Containers are standard unit of software.
  • They provide security and isolation.
  • They are lightweight, portable and cross platform.
  • They are consistent and predictable and no surprises
  • Continuous Integration (CI) and Continuous Deliver (CD)
  • eliminates shared environments and resource contentions.

SQL Server as Application:

Before difficult to integrate, operational complexity,

Now Docker Compose uses YAML file for deployment

CI – Commit -> Trigger -> Notify -> Test

CD – Deliver -> Deploy

Jenkins is open source Automation Server. Pipelines are set of jobs.

Session: Intelligent Query and Performance

Speaker: Pedro Lopez and Joe Sack

  1. Intelligent DB vision:
    1. Anxiety free upgrades
    2. Don’t worry about regressions
    3. Query tuning assistance tools
  2. Performance IQP
    1. Resource Governor
    2. Soft NUMA became default in SQL Server 2019
    3. Many new improvements in newer version are not advertized so by just upgrading you get benefits out of the box.
  3. Management by default
    1. Accelerated Database Recovery ADR
    2. Online Resumable index creation
    3. Lightweight Profiling
    4. Automatic SQL
    5. Threat Protection
    6. GDPR questions can be answered with classification and vulnerability assessment tools

Memory Grant Feedback MGF:

Available in compatibility mode 140+

Memory misestimation can result in spills to disk and overestimation hurt concurrency.

If less than 50% memory need is granted, resulting in spills, then MGF will fix and add memory plus some buffer.

In 2017, Batch mode was introduced and was available for column-store indexes only.

In 2019, row-store Batch mode is available for all index types; row and column.

  1. Does Query optimizer has to do lot of work to first check if Query is eligible for Batch mode execution?

MFG has to learn again if plan is kicked out of cache for some reason.

Batch Mode Columnstore:

Built for Analytical workload and IO bound queries. Columnstore provides effective compression over traditional rowstore.

Rowstore Batch Mode:

If you cannot add Columnstore for some reason, maybe vendor does not support or table has trigger then Rowstore Batch Mode will come in handy. Adds new scan operator. Same for Heap and B-trees tables. Great for CPU bound queries.

Interleave MSTVFs:

Query processor treats it as a black box because it materializes at runtime only and QP cannot make any decision about the plan. SQL 2016 and prior version guesstimated 100 rows. Inefficient if 1000 or 10,000 rows actually returned. SQL 2017 + assumes 500 rows for 1st run and then adjusts. Downstream operations will benefit.

Batch Mode Adaptive Join (AJ):

If cardinality Estimate is wrong, wrong join operator will be selected in a plan which will be cached.

AJ will defer the choice of Hash or Nested join until after the first join input has been scanned.

Resource: aka.ms/IQP

Session: Data Classification

Speaker: Grant Fritchey

Security and compliance requirements are undeniable. It should be first and foremost.

Regulatory Landscape:

GDPR: European. Marriott and British Airways were fined. Half of UK firms are still not GDPR compliant.

FERPA: Department of Education law in US to protect adult student from parents. They don’t share any information even if the student is dependent and in hospital or sick.

HIPPA: Health regulation for medical industry. If a person has shared PII data knowingly they could go to jail.

CCPA: California flavor of GDPR regulation and will be enforced on Jan 1, 2020.

All of them have room for interpretation and none of them is perfect.

Session: Successfully communicate with Customer

Speaker: Dennise McInevney

Results of Bad communications:

Project Fails

Career hurt or ends

Frustration and stress

Time and Money wasted

  1. Empathy: Walk in your customer shoes. See their pain from their eyes. See how they use your product. See where can you help them.
  2. Us vs them mentality: Be one team. Make sure customer understands that you are on their side by you language and attitude.
  3. Talk/Speech: Be concise, clear and to the point in written and verbal communication
  4. Writing Skills:

Who are your customers? Identify them and identify their customers. Understand goals of both groups.

Requirements (How of things)  <  >   Goals (What of things)

  1. Understand customer goals first.
  2. Desired outcome second
  3. Understand business context



Jump to Solution

Listen carefully

Make assumptions

Ask Questions

Start designing

Be precise


Identify approver first

Write down everything in a place easily accessible.






Agile Tools like Jira which keeps the history

Hallway conversation

Shared document

Get Alignment

Get Sign off

Ensure clarity

Don’t skip

Pick up phone when necessary

Joint accountability

Record the outcome in writing

If you are bilingual and can speak customer language, that is a great skill.

What you can do?

  • Practice Active listening
  • Don’t multitask
  • Check for understanding
  • Summarize
  • Review the facts

Change is inevitable



Stress Out

Take a deep breath

Get Mad

Ask questions

Cast blame

Update requirement

Managing Expectation:

After things are signed off, we need to manage the expectations such as how often we will have meetings, how status of projects will be reported and such.

Reporting Status:

  • Consistent format and time
  • If you want others to follow the reporting tool, make sure you are seriously using it.
  • No surprises
  • Alert if not working as expected, missed dependencies or duration.

Show as you Go:

Sketches, diagrams, demos at regular cadence and be open to feedback.


Keep calm, communicate progress, what is okay to release , negotiate, trade off can happen.

Session: Adaptive QP to Intelligent QP

Speaker: Hugo Kornelis




Query Processing (QP)

  • Phase 1 – Optimization (Cardinality Estimates, Execution Plan)
  • Phase 2 – Execution (Actual Estimates)

Merge is better if data is properly sorted. Puts everything in first input in memory.

Nested loop reads 1st row and start finding matching row in second source.

AJ is new join type and it has 3 inputs.

Only problem is AJ for Batch mode which was for columnstore index.

Interleaved Execution:

MSTVF – don’t know how big result is going to be

1 or 100 is hard-coded value and can never be right. In 2017, as soon as QP detect MSTVF, it paused the execution and starts another process that materialize the MSTVF first. You get the number of rows and now QP can give you the correct plan. But this plan is now cached and next time MSTVF comes with different parameter, it may not work efficiently. So the problem remains.

QP in SQL Server 2019:

Memory Grant Feedback (MGF):

Determines during compile time base on cardinality estimate. If underestimate, spills to the disk (tempdb). If overestimates, wasted memory and impacts concurrency.

First execution of MGF improves 2nd execution.

  • Adjusts down if > 50% memory unused the first time
  • Adjusts up after any SPILL + some buffer.

Stores last exec plan, forgets after recompile. After adapting, certain time for example x threshold. If more than that it stops adapting.

Extended events are available to track this info.

*** Check this demo out and put it in PTO workshop ***

UDF Inlining:

FROID is a framework that plugs in optimizer before optimization takes place. It looks at all the statements in UDF and converts into relational table and sends to QP which then generates the plan.

Session: Batch Mode on Rowstore

Speaker: Nikko Neuberger

Speaker Tip #1: Telling story and showing pictures and cartoons and bold words on screen worked very good with audience. He got laughs and attention (5 minutes)

Speaker Tip #2: If demo fails, keep talking while working and may refer to Demo GOD.

Read execution plant Right to left and also left to Right.

Exec plan query executes from Left to Right.

Nikko displayed drama script of row execution. He got 3 attendees and had piles of pages in different color.

Sort operator asks for data page from table one at a time.

In batch mode, all data pages are given at the same time to sort operator saving time.

Rt click + Act Ex rows + Est Exec rows -> shows row mode

*** Ask MS to remove est execution because not adding value and cluttering the GUI.

Rt click + see Bath execution mode and storage as Rowstore

He made an interesting analogy comparing Batch mode vs Row mode. Fast cars like Ferrari or Mustang vs a bicycle. Batch mode need little more space to work as fast car need highway to go fast.

In a Demo1 of 150 vs 140, timing was 12 sec and 18 sec respectively. CPU in both execution was high but in 140 it was more IO.

In a Demo2, Batch mode on Rowstore did 11 sec and Batch mode on columnstore did 6.8 sec. Fantastic! Since table had columnstore index, batch mode kicks in by default.

Demo3 was about Batch Mode Heuristics. You can see waittype of Batch_mode_scan_on_rowstore in an extended event sessions for Full batch when your run following queries.

  • Select count of rows in a table
  • Query table of 1 GB size
  • Query table of 10 GB size
  • Disable Batch mode and run query
  • Run query with TOP(20) and order by

In 2019, you will need columnstore because

  • Batch mode w/o columnstore index will not have compression
  • No advance storage engine features. Makes a difference in Logical Reads. Does the aggregation in memory instead of reading and bringing pages to query optimizer.
  • Columnstore index will always result in Optimization level = FULL
  • Hekaton disables Batch mode scan when columns with LOB types are present.

Session: Hash Match, the Operator (2.5 hour session)

Speaker: Hugo Kornelis

Speaker tip: He engaged audience just like Nikko did in his session. The dramatization in the beginning really catches audience attention. He had roller coaster rides picture and a story to go with it and he gave credits to all the pictures he used. Nice way to introduce the topic.

He said he is going to discuss 500 lever content of deep dive internals of operators and some of them are not documented. Such as hashing, hashing function, hashing table etc.

*** Download demos from fastsqlserver.com

Hashing … Laundry that needs sorting. But in Query optimizer world hashing is not sorting it is categorizing or bucketizing similar things.

  • Input¬† — Any
  • Output — Integer 0 – 9999
  • Deterministic — same input gets same output values
  • Hash Collision — Different inputs getting same output values.

Hashing function — organized by hash value or heap or bucket. It stores in memory entirely.

  1. There are 7 pointers for each hash value.
  2. Store 6 pointers in each structure
  3. Create and connect new 7-pointer structure

3 phases for hash Table match

  1. Build — Always used, process top input, builds hash table
  2. Probe — not always used, process second input if there is one match, detects has collision.
  3. Final — Returns data from Hash Table

Look at hash match operator properties in execution plan, you will see

Probe residual — will appear only if there are hash collision. Upto 4 byte of data, SQL Server gaurantees to return without Probe residual. It is needed when any operation on the column is done, when any non-integer data is present and when integer data is less than 4 byte. Impact of Probe residual on performance is not expensive. It is just one extra test.

Build Phase — Assuming no spills to the disk and all hash table fits in the memory.

  • Inner Join — Most simplest. Computes the hash and goes into bucket and finds the match, returns a joined row and goes to work with another row.
  • Rt. Outer Join — If no matching row is found, it returns rows from the outer table.
  • Both join type cause blocking in the build phase. There is no Final phase for them. Order of row is mostly retained but not guaranteed in real world where spills may occur.

Probe Phase

  • Lt. outer Join\Full outer Join — Marks the matched rows and returns the unmatched rows from the hash table. Adds a Final Phase for “Left returned” rows. No order for these rows is retained.
  • Lt. Semi Join (Exists) — Returns all the marked and matched rows from the hash table. No Final phase for them.
  • Lt. Anti Semi Join (not Exists) — returns all the unmarked and unmatched rows. Both semi and anti semi incur blocking in build and probe phase. All the output is produced in the Final Phase.
  • Rt. Semi Join — returns rows from Probe. Will not search for more rows when a first match is found.
  • Rt. Anti Semi Join — No match found return and no additional search is done. No final phase.

Hash match can also have 1 input.

Build Phase: (for aggregate)

Instead of adding to bucket, it searches if row already exists and does only update to the bucket. If no row found, adds a row and update the aggregation. This row is a place holder.

Final Phase — returns all aggregated rows from the hash table. There is no probe phase for it.


  • Select distinct(city) from customer — has match flow of distinct
  • Select city, count(*) from customer group by city — does hash aggregate

Hash Mach Scalar Aggregate:

Official name is Hash Match (Aggregate).

Stream aggregate more suitable for Select count(*) from table type of queries and is not supported in Batch mode. There is no Build Phase.

Hash match partial Aggregate:

Labelled differently in parallel parts of execution plan. There is no Build Phase. In compatibility mode 120 you can see this type of aggregate. No more visible in Modern SQL versions.

Hash Memory Usage:

Memory requested at the beginning of execution. Engine reserves at least requested memory. If requested memory not available, it waits. Tries to reserve up to requested memory before beginning execution. It does not provide a way to request additional memory during execution and hence when memory is insufficient, operators spell to tempdb on disk.

  • SQL Server 2016, batch mode may get extra memory during execution.
  • SQL Server 2017, batch mode on columnstore may get extra memory during execution
  • SQL Server 2019, all execution mode get extra memory during query execution.

Dynamic De-staging:

Happens when hash operator spills to disk.

  1. In-memory HJ — Never short of memory and everything fits nicely.
  2. Hybrid HJ — combines in-memory and Grace HJ. When out of memory, partitions buckets. If it is complex, then after 1st build and probe phases, does same as Grace HJ.
  3. Grace HJ — Algorithm is used when amount of data is more than the known memory. Divides set of buckets into partitions. Eg; buckets = 1 – 20,000. 5000 buckets at a time (hash partition function 1 – 4), 2 files for each partition is created. SQL server uses tempdb. They are actually structures in tempdb. Reads both inputs, stores rows in appropriate file. 1 file for build, 1 file for probe. Process each file individually.
  4. Recursive HJ — When Grace HJ mis-estimates partition size.
  • Dynamic Staging HM starts in memory.
  • Bail out happens when bucket size is larger than memory available. It abandons¬† further processing. HM then goes to Nested Loops or Sort and Merge join. Both are inefficient in this case.
  • Bit Vector filtering — is good. Always used when spills happen. In-memory bit map for has values of spilled partitions.
    1. Build: set bit for hash result of rows
    2. Probe: Check if bit is set for hash
      1. If set – write to file on disk
      2. If not – handle unmatched, don’t write to file

Memory Grant Computation:

Est size (row count + row size)

Note: For Var(char) data type it assumes to be 50% full

Est size (row count + row size) of probe input

Execution plan with multiple match operator.

Session: Query Store In-Depth

Speaker: Ola Hallengren

Query Store (QS) available since SQL Server 2016. It is like a flight recorder of query execution.

DBCC CLONEDATABASE includes query store Data.

Force a last know good plan after changing the compatibility level or cardinality estimation.

Disclaimer: These are my notes taken while attending sessions and any inaccuracies are my own.

GDPR – A new European Law to protect their citizens from Data breaches

I am hearing a lot about GDPR (General Data Protection Regulation) in past few months. I decided to do some digging up to know how it affects us in the United States. Those of you who directly want to go to the source of my information and avoid my 2 cents are welcome to check out these 2 links. This Law is explained in very easy terms for a layperson.



Those of you who are short on time and want to just get the skinny version, then keep on reading.

  1. This law is about protecting European Citizens from data breaches of companies inside and outside Europe
  2. This Law may affect us if and when we store data of EU citizens.
  3. This is for EU consumer safety.
  4. In case of a data breach, the companies even outside EU can become part of the lawsuit.
  5. To avoid the lawsuit, a USA based company have to provide the EU country representative with a notification within 3 days of a data breach.
  6. Companies can be fined if the governing body finds the proof that adequate data protection measures were not taken by the company whose data was breached.

It is good to keep this EU law on our radar even if our company is not storing EU consumer data. I think something like this law will become the norm in next 5 years across the global communities. After all, it is the responsibility of the company who collects and stores consumer data to provide safeguards to protect the data. The basic rationale of this law is simple. Since companies make a profit by using a consumer information, it is fair that they should spend a part of that profit to protect that information. This provides clear accountability on one hand and provides peace of mind to the citizens on the other hand. In my opinion, this is a win-win situation.

I would appreciate your comments on this topic.

What you like to LEARN?

Sneak-peek of Microsoft SQL Server 2016 running on SanDisk flash


Brief Recap of the session:

This technical briefing’s main objective was to demonstrate the latest and greatest features of SQL Server 2016 and how running it on SanDisk hardware multiplies the benefits of new features.

This demo was conducted in Microsoft Technology Center in Chicago and was jointly presented by Microsoft and SanDisk representatives. It was a 300-level advanced preview of the hardware and software without any sales pitch.

Their Fusion IoMemory card goes directly in the PCI slot on the server’s motherboard and they have parity NAND chips on that card for fault tolerance. Price went down considerably for the same product since the April 2015 for two reasons. First their Shanghai, Chaina NAND chip manufacture has become more efficient in producing high quality chips and secondly partnership with Microsoft and other hardware vendors such as Dell and HP.


These are some of the numbers we get with SanDisk flash when tables are stored as normal (i.e; on Sandisk without using columnstore feature of SQL Server).


SQL server 2016 has opened the clogged artery meaning flash drive performance is out of the charts. They were talking in terms of IOPS, throughput and latency. Now SQL server 2016 (compared to sql server 2014) using Sandisk or any flash drive can deliver IOPS in millions, Throughput in GBs and latencies in microseconds. The enhancement is due to the improved ColumnStore feature in SQL Server 2016. IO bottleneck for OLTP or OLAP load almost vanishes.


These improvements directly affects the HA and DR environments. For example Always on Availability Group. Log transfer from one database to another, on the secondary, is much faster because of separating the redo process at the secondary server. AG, in synchronized mode, waits for the confirmation from the secondary server. Before sql server 2016, a record has to be written to the disk on the secondary and applied to the database before confirmation is sent to the Primary node. Now confirmation is sent as soon as the records is written to the disk. Redo process than run in the background at secondary server to apply the changes to the database. SQL 2016 AG now have load balancing feature included.


Another benefit is cost savings in SQL server license. Because most of the time sql load is IO bound and CPU hardly goes above 25% on average. These flash drives will make CPU work for what they are worth. So only 2 CPUs are needed for server load as big as 10 TB Datawarehouse.

My impressions:

Since our databases are not even 1 TB, the whole critical databases in production can be stored on these flash drives. Or we can have our log files and tempdb files on flash drives. There are lot of options. And when these cards are purchased with VM vendors, there is warranty included which replaces these cards when it fails without cost to us.

They also have caching feature, I think this a separate software based product that needed to be purchased separately and maybe useful for application level processes to run faster.

Another point is that we are skipping upgrade to SQL server 2014 so we are naturally going to upgrade to SQL server 2016 in year 2017. I think we can plan in 2016 for testing and purchasing these flash drives.

Additionally, these will also make our HA and DR very reliable in terms of failover.

In my opinion, we can take advantage of flash drives for production load in our VMs when we upgrade SQL Server to 2016.

Everything you need to know about FileStream feature of SQL Server 2012

FileStream directory

The file stream network path technically is this \\SQL Server name\Network Share Name\Database File stream Directory Name\<File Table Name>

  1. SQL Server Name ‚Äď (starting with \\)
  2. Windows Share Name ‚Äď It is visible in SQL Server Configuration tool -> SQL Server properties -> FileStream tab.
  3. Database File stream Directory Name ‚Äď It can be seen in Database Properties -> Options -> FILESTREAM Directory Name
  4. The last part is the file table name.

Some helpful FileStream queries

Exploration Queries:

SELECT DB_NAME(database_id) AS DatabaseName,non_transacted_access_desc, directory_name  FROM sys.database_filestream_options WHERE directory_name IS NOT NULL

SELECT directory_name,is_enabled,filename_collation_name FROM sys.filetables;

SELECT * FROM sys.tables WHERE is_filetable = 1

SELECT object_id, OBJECT_NAME(object_id) AS ‘Object Names’¬†¬†¬† FROM sys.filetable_system_defined_objects

— To get the root level UNC path of a file table

SELECT FileTableRootPath()

SELECT FileTableRootPath(N’file_table_name’)

Enable Disable Queries:


— Disable Non-Transactional write access.

ALTER DATABASE database_name


— Disable non-transactional access.


— Enable full non-transactional Access


Find locks held by filestream queries:

Open handles to the files stored in a FileTable can prevent the exclusive access that is required for certain administrative tasks. To enable urgent tasks, you may have to kill open file handles associated with one or more FileTables.

SELECT * FROM sys.dm_filestream_non_transacted_handles;

— To identify open files and the associated locks

SELECT opened_file_name    FROM sys.dm_filestream_non_transacted_handles

WHERE fcb_id IN        ( SELECT request_owner_id FROM sys.dm_tran_locks );

— Kill all open handles in all the filetables in the database.

EXEC sp_kill_filestream_non_transacted_handles;

— Kill all open handles in a single filetable.

EXEC sp_kill_filestream_non_transacted_handles @table_name = ‘filetable_name’;

— Kill a single handle.

EXEC sp_kill_filestream_non_transacted_handles @handle_id = integer_handle_id;

Code Re-usability:

— Use the relative path for portable code


DECLARE @root nvarchar(100);

DECLARE @fullpath nvarchar(1000);

SELECT @root = FileTableRootPath();

SELECT @fullpath = @root + file_stream.GetFileNamespacePath() FROM EDMS

WHERE name = N’document_name’;

PRINT @fullpath;

How FileStream works with some of the High Availability Features of SQL Server 2012?

 AlwaysOn Availability Groups and FileTables


When the database that contains FILESTREAM or FileTable data belongs to an AlwaysOn availability group:

  • FileTable functionality is partially supported by AlwaysOn Availability Groups. After a failover, FileTable data is accessible on the primary replica, but FileTable data is not accessible on readable secondary replicas.
  • The FILESTREAM and FileTable functions accept or return virtual network names (VNNs) instead of computer names.
  • All access to FILESTREAM or FileTable data through the file system APIs should use VNNs instead of computer names.

Replication and FileTables

Replication and related features (including transactional replication, merge replication, change data capture, and change tracking) are not supported with FileTables.

Setting up Log Shipping

I am doing log shipping since SQL Server 2000. I did it with SQL Server 2005. But for the 4 years that I worked with SQL Server 2008 R2, I did not work with Log shipping. Nothing has changed in SQL server 2012. But to refresh my memory, here I am writing down simple steps for setting up log shipping.

  1. Make sure database is in Full recovery mode. In this case primary server is PriSQL\Prod01 and primary database is PriDB.
  2. Pre-initialize the database at secondary. It means take the full backup of PriDB and a transaction log backup of primary database SecDB and restore on secondary SecSQL\DR01 in Standby mode.
  3. Right click the primary database, go to properties and select ‚ÄúEnable this as a primary database in a log shipping configuration‚ÄĚ.
  4. Select how frequently you are going to do log backups in ‚ÄúBackup Settings‚ÄĚ button. Also provide the path where log backup goes. Some other settings on this page are set as follows:
    1. Delete files older than: 72 hours
    2. Alert if no backup occurs within: 2 hours
    3. Backup schedule: Every 15 minutes
    4. Backup Path: E:\SQLBackups\PriDB_log
    5. Job name: LSBackup_PriDB
    6. Backup compression: Use default server setting.
  5. Add the secondary server. In this case it is SecSQL\DR01. Secondary database is SecDB.
    1. Tab- Initialize secondary Database:
      • Select database is already initialized.
    2. Tab- Copy files:
      • Destination folder for copied file F:\SQLBackups\LogShip
      • Set 72 hours for Delete copied files.
      • Copy job: LSCopy_PriSQL\prod01_PriDB
      • Copy Schedule: Every 15 minutes.
    3. Tab- Restore Transaction Logs
      • Restore job: LSRestore_PriSQL\prod01_PriDB
      • Restore Schedule: Every 15 minutes
      • Delay restoring: 1 minute
      • Alert if no restore occurs: 2 hours