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• SQL SERVER – ColumnStore Index – Batch Mode vs Row Mode

  - by pinaldave

  What do you do when you are in a hurry and hear someone say things which you do not agree or is wrong? Well, let me tell you what I do or what I recently did. I was walking by and heard someone mentioning “Columnstore Index are really great as they are using Batch Mode which makes them seriously fast.” While I was passing by and I heard this statement my first reaction was I thought Columnstore Index can use both – Batch Mode and Row Mode. I stopped by even though I was in a hurry and asked the person if he meant that Columnstore indexes are seriously fast because they use Batch Mode all the time or Batch Mode is one of the reasons for Columnstore Index to be faster. He responded that Columnstore Indexes can run only in Batch Mode. However, I do not like to confront anybody without hearing their complete story. Honestly, I like to do information sharing and avoid confronting as much as possible. There are always ways to communicate the same positively. Well, this is what I did, I quickly pull up my earlier article on Columnstore Index and copied the script to SQL Server Management Studio. I created two versions of the script. 1) Very Large Table 2) Reasonably Small Table. I a query which uses columnstore index on both of the versions. I found very interesting result of the my tests. I saved my tests and sent it to the person who mentioned about that Columnstore Indexes are using Batch Mode only. He immediately acknowledged that indeed he was incorrect in saying that Columnstore Index uses only Batch Mode. What really caught my attention is that he also thanked me for sending him detail email instead of just having argument where he and I both were standing in the corridor and neither have no way to prove any theory. Here is the screenshots of the both the scenarios. 1) Columnstore Index using Batch Mode 2) Columnstore Index using Row Mode Here is the logic behind when Columnstore Index uses Batch Mode and when it uses Row Mode. A batch typically represents about 1000 rows of data. Batch mode processing also uses algorithms that are optimized for the multicore CPUs and increased memory throughput.  Batch mode processing spreads metadata access costs and overhead over all the rows in a batch.  Batch mode processing operates on compressed data when possible leading superior performance. Here is one last point – Columnstore Index can use Batch Mode or Row Mode but Batch Mode processing is only available in Columnstore Index. I hope this statement truly sums up the whole concept. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Index, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQLAuthority News – Technology and Online Learning – Personal Technology Tip

  - by pinaldave

  This is the fourth post in my series about Personal Technology Tips and Tricks, and I knew exactly what I wanted to write about.  But at first I was conflicted.   Is online learning really a personal tip?  Is it really a trick that no one knows?  However, I have decided to stick with my original idea because online learning is everywhere.  It’s a trick that we can’t – and shouldn’t – overlook.  Here are ten of my ideas about how we should be taking advantage of online learning. 1) Get ahead in the work place.  We all know that a good way to become better at your job, and to become more competitive for promotions and raises.  Many people overlook online learning as a way to get job training, though, thinking it is a path for people still seeking their high school or college diplomas.  But take a look at what companies like Pluralsight offer, and you might be pleasantly surprised. 2) Flexibility.  Some of us remember the heady days of college with nostalgia, others remember it with loathing.  A lot of bad memories come from remembering the strict scheduling and deadlines of college.  But with online learning, the classes fit into your free time – you don’t have to schedule your life around classes.  Even better, there are usually no homework or test deadlines, only one final deadline where all work must be completed.  This allows students to work at their own pace – my next point. 3) Learn at your own pace.  One thing traditional classes suffer from is that they are highly structured.  If you work more quickly than the rest of the class, or especially if you work more slowly, traditional classes do not work for you.  Online courses let you move as quickly or as slowly as you find necessary. 4) Fill gaps in your knowledge.  I’m sure I am not the only one who has thought to myself “I would love to take a course on X, Y, or Z.”  The problem is that it can be very hard to find the perfect class that teaches exactly what you’re interested in, at a time and a price that’s right.  But online courses are far easier to tailor exactly to your tastes. 5) Fits into your schedule.  Even harder to find than a class you’re interested in is one that fits into your schedule.  If you hold down a job – even a part time job – you know it’s next to impossible to find class times that work for you.  Online classes can be taken anytime, anywhere.  On your lunch break, in your car, or in your pajamas at the end of the day. 6) Student centered.  Online learning has to stay competitive.  There are hundreds, even thousands of options for students, and every provider has to find a way to lure in students and provide them with a good education.  The best kind of online classes know that they need to provide great classes, flexible scheduling, and high quality to attract students – and the student benefit from this kind of attention. 7) You can save money.  The average cost for a college diploma in the US is over $20,000.  I don’t know about you, but that is not the kind of money I just have lying around for a rainy day.  Sometimes I think I’d love to go back to school, but not for that price tag.  Online courses are much, much more affordable.  And even better, you can pick and choose what courses you’d like to take, and avoid all the “electives” in college. 8) Get access to the best minds in the business.  One of the perks of being the best in your field is that you are one person who knows the most about something.  If students are lucky, you will choose to share that knowledge with them on a college campus.  For the hundreds of other students who don’t live in your area and don’t attend your school, they are out of luck.  But luckily for them, more and more online courses is attracting the best minds in the business, and if you enroll online, you can take advantage of these minds, too. 9) Save your time.  Getting a four year degree is a great decision, and I encourage everyone to pursue their Bachelor’s – and beyond.  But if you have already tried to go to school, or already have a degree but are thinking of switching fields, four years of your life is a long time to go back and redo things.  Getting your online degree will save you time by allowing you to work at your own pace, set your own schedule, and take only the classes you’re interested in. 10) Variety of degrees and programs.  If you’re not sure what you’re interested in, or if you only need a few classes here and there to finish a program, online classes are perfect for you.  You can pick and choose what you’d like, and sample a wide variety without spending too much money. I hope I’ve outlined for everyone just a few ways that they could benefit from online learning.  If you’re still unconvinced, just check out a few of my other articles that expand more on these topics. Here are the blog posts relevent to developer trainings: Developer Training - Importance and Significance - Part 1 Developer Training – Employee Morals and Ethics – Part 2 Developer Training – Difficult Questions and Alternative Perspective - Part 3 Developer Training – Various Options for Developer Training – Part 4 Developer Training – A Conclusive Summary- Part 5 Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Developer Training, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Developer Training

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• SQL SERVER – Log File Growing for Model Database – model Database Log File Grew Too Big

  - by pinaldave

  After reading my earlier article SQL SERVER – master Database Log File Grew Too Big, I received an email recently from another reader asking why does the log file of model database grow every day when he is not carrying out any operation in the model database. As per the email, he is absolutely sure that he is doing nothing on his model database; he had used policy management to catch any T-SQL operation in the model database and there were none. This was indeed surprising to me. I sent a request to access to his server, which he happily agreed for and within a min, we figured out the issue. He was taking the backup of the model database every day taking the database backup every night. When I explained the same to him, he did not believe it; so I quickly wrote down the following script. The results before and after the usage of the script were very clear. What is a model database? The model database is used as the template for all databases created on an instance of SQL Server. Any object you create in the model database will be automatically created in subsequent user database created on the server. NOTE: Do not run this in production environment. During the demo, the model database was in full recovery mode and only full backup operation was performed (no log backup). Before Backup Script Backup Script in loop DECLARE @FLAG INT SET @FLAG = 1 WHILE(@FLAG < 1000) BEGIN BACKUP DATABASE [model] TO  DISK = N'D:\model.bak' SET @FLAG = @FLAG + 1 END GO After Backup Script Why did this happen? The model database was in full recovery mode and taking full backup is logged operation. As there was no log backup and only full backup was performed on the model database, the size of the log file kept growing. Resolution: Change the backup mode of model database from “Full Recovery” to “Simple Recovery.”. Take full backup of the model database “only” when you change something in the model database. Let me know if you have encountered a situation like this? If so, how did you resolve it? It will be interesting to know about your experience. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Backup and Restore, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – DMV – sys.dm_os_wait_stats Explanation – Wait Type – Day 3 of 28

  - by pinaldave

  The key Dynamic Management View (DMV) that helps us to understand wait stats is sys.dm_os_wait_stats; this DMV gives us all the information that we need to know regarding wait stats. However, the interpretation is left to us. This is a challenge as understanding wait stats can often be quite tricky. Anyway, we will cover few wait stats in one of the future articles. Today we will go over the basic understanding of the DMV. The Official Book OnLine Reference for DMV is over here: sys.dm_os_wait_stats. I suggest you all to refer this for all the accuracy. Following is a statement from the online book: “Specific types of wait times during query execution can indicate bottlenecks or stall points within the query. Similarly, high wait times, or wait counts server wide can indicate bottlenecks or hot spots in interaction query interactions within the server instance.” This is the statement which has inspired me to write this series. Let us first run the following statement from DMV. SELECT * FROM sys.dm_os_wait_stats ORDER BY wait_time_ms DESC GO Above statement will show us few of the columns. Here it is quick explanation of each of the column. wait_type – this is the name of the wait type. There can be three different kinds of wait types – resource, queue and external. waiting_tasks_count – this incremental counter is a good indication of frequent the wait is happening. If this number is very high, it is good indication for us to investigate that particular wait type. It is quite possible that the wait time is considerably low, but the frequency of the wait is much high. wait_time_ms – this is total wait accumulated for any type of wait. This is the total wait time and includes singal_wait_time_ms. max_wait_time_ms – this indicates the maximum wait type ever occurred for that particular wait type. Using this, one can estimate the intensity of the wait type in past. Again, it is not necessary that this max wait time will occur every time; so do not over invest yourself here. signal_wait_time_ms – this is the wait time when thread is marked as runnable and it gets to the running state. If the runnable queue is very long, you will find that this wait time becomes high. Additionally, please note that this DMV does not show current wait type or wait stats. This is cumulative view of the all the wait stats since server (instance) restarted or wait stats have been cleared. In future blog post, we will also cover two more DMVs which can be helpful to identify wait-related issues. ?sys.dm_os_waiting_tasks sys.dm_exec_requests Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL DMV, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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• SQL SERVER – Reduce the Virtual Log Files (VLFs) from LDF file

  - by pinaldave

  Earlier, I wrote a quite note on SQL SERVER – Detect Virtual Log Files (VLF) in LDF. Because of this I got responses suggesting too many VLFs are bad for log file. This prompts to a simple question: “How many is ‘too many’ VLFs?” I suggest that you go and read an article written by Kimberly over here. I am sure that you are going to have a clear understanding of what a good number for your VLFs is from that article. If you have lots of VLFs, you can reduce them right away using the following method: (I am just attempting to write a working script over here.) USE AdventureWorks GO BACKUP LOG AdventureWorks TO DISK='d:\adtlog.bak' GO -- Get Logical file name of the log file sp_helpfile GO DBCC SHRINKFILE(AdventureWorks_Log,TRUNCATEONLY) GO ALTER DATABASE AdventureWorks MODIFY FILE (NAME = AdventureWorks_Log,SIZE = 1GB) GO DBCC LOGINFO GO Again, here I have assumed that your initial log size is 1 GB, but in reality you should select the number based on your own ideal size of the log file. If your log file grows to 10 GB every day, you may want to put the value as 10 GB. For accuracy, read what Kimberly’s original article says over here. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Validating Spatial Object as NULL using IsNULL

  - by pinaldave

  Follow up questions are the most fun part of writing a blog post. Earlier I wrote about SQL SERVER – Validating Spatial Object with IsValidDetailed Function and today I received a follow up question on the same subject. The question was mainly about how NULL is handled by spatial functions. Well, NULL is NULL. It is very easy to work with NULL. There are two different ways to validate if the passed in the value is NULL or not. 1) Using IsNULL Function IsNULL function validates if the object is null or not, if object is not null it will return you value 0 and if object is NULL it will return you the value NULL. DECLARE @p GEOMETRY = 'Polygon((2 2, 3 3, 4 4, 5 5, 6 6, 2 2))' SELECT @p.ISNULL ObjIsNull GO DECLARE @p GEOMETRY = NULL SELECT @p.ISNULL ObjIsNull GO 2) Using IsValidDetailed Function IsValidateDetails function validates if the object is valid or not. If the object is valid it will return 24400: Valid but if the object is not valid it will give message with the error number. In case object is NULL it will return the value as NULL. DECLARE @p GEOMETRY = 'Polygon((2 2, 3 3, 4 4, 5 5, 6 6, 2 2))' SELECT @p.IsValidDetailed() IsValid GO DECLARE @p GEOMETRY = NULL SELECT @p.IsValidDetailed() IsValid GO When to use what? Now you can see that there are two different ways to validate the NULL values. I personally have no preference about using one over another. However, there is one clear difference between them. In case of the IsValidDetailed Function the return value is nvarchar(max) and it is not always possible to compare the value with nvarchar(max). Whereas the ISNULL function returns the bit value of 0 when the object is null and it is easy to determine if the object is null or not in the case of ISNULL function. Additionally, ISNULL function does not check if the object is valid or not and will return the value 0 if the object is not NULL. Now you know even though either of the function can be used in place of each other both have very specific use case. Use the one which fits your business case. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Spatial Database, SQL Spatial

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• SQLAuthority News – Reliving TechEd with Vinod Kumar at Bangalore User Groups

  - by pinaldave

  TechEd India 2012 was held in Bangalore last March 21 to 23, 2012. Just like every year, this event is bigger, grander and inspiring. Here is my blog post reviewing the event SQLAuthority News – #TechEdIn – TechEd India 2012 Memories and Photos. For me this is family event – I get to meet my friends who are dear as my family. I like to call User Groups as family too. Family shares life’s personal happiness and experience – the same way User Group shares professional experiences and quite often UG members become just like family member. When I learned that follower user group together building up a unique event I was pretty excited to learn who is going to be speaker for the event. BDotNet.in – Bangalore .NET Usergroup BITPro.in – Bangalore ITPro Usergroup It was indeed joy when I learned that presenter will be Vinod Kumar, who is integral part of user groups and hardcore SQL Server enthusiast. Vinod Kumar is going to present on following two sessions which are both focused on internals of the Windows and SQL Server. Understanding Windows with SysInternals Tools – This session will cover various tools from usage of Memory, x86 architecture, x64, WOW mode, Page faults, Virtual Memory mapping, OOM scenario, Perf Tool, PAL tool, Logman and more. Peeling the Onion: SQL Server Internals Demystified – This session will cover advanced disk formats, SQL Server 2012 security changes, memory changes, indirect checkPoint and more. I am very excited as this time I will get opportunity to sit in front rows (as I will be reaching there to get best possible position) and learn. I am looking forward to the event and I hope you will join us as well. Event Details: Date: Saturday, April 7, 2012 (10:30am until 1:30pm) Venue: Microsoft, Domlur, Bangalore. Event Details: https://www.facebook.com/events/139444029517882/ This session is FREE for all and everybody and anybody can walk in. Community Blog Posts Here are few of the blog post written by the community on this subject. Vinod Kumar on Reliving #TechEdIn at Blr UG Manas Dash on Reliving TechEd India 2012 with Vinod Kumar Sudeepta Ganguly on SysInternals n SQLInternals with Vinod Kumar Lohith Re Live TechEd India 2012 with Vinod Kumar  Reference: Pinal Dave (http://blog.sqlauthority.com) http://www.youtube.com/watch?v=oRw-p4mahLU Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, T SQL, Technology, Video

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• SQL SERVER – Powershell – Get a List of Fixed Hard Drive and Free Space on Server

  - by pinaldave

  Earlier I have written this article SQL SERVER – Get a List of Fixed Hard Drive and Free Space on Server. I recently received excellent comment by MVP Ravikanth. He demonstrated that how the same can be done using Powershell. It is very sweet and quick solution. Here is the powershell script. Run the same in your powershell windows. Get-WmiObject -Class Win32_LogicalDisk | Select -Property DeviceID, @{Name=’FreeSpaceMB’;Expression={$_.FreeSpace/1MB} } | Format-Table -AutoSize Well, I ran this script in my powershell window, it gave me following result – very accurately and easily. Thanks Ravikanth one more time for excellent tip. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Stored Procedure, SQL Tips and Tricks, T SQL, Technology Tagged: Powershell

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• SQL SERVER – guest User and MSDB Database – Enable guest User on MSDB Database

  - by pinaldave

  I have written a few articles recently on the subject of guest account. Here’s a quick list of these articles: SQL SERVER – Disable Guest Account – Serious Security Issue SQL SERVER – Force Removing User from Database – Fix: Error: Could not drop login ‘test’ as the user is currently logged in. SQL SERVER – Detecting guest User Permissions – guest User Access Status One of the advices which I gave in all the three blog posts was: Disable the guest user in the user-created database. Additionally, I have mentioned that one should let the user account become enabled in MSDB database. I got many questions asking if there is any specific reason why this should be kept enabled, questions like, “What is the reason that MSDB database needs guest user?” Honestly, I did not know that the concept of the guest user will create so much interest in the readers. So now let’s turn this blog post into questions and answers format. Q: What will happen if the guest user is disabled in MSDB database? A:  Lots of bad things will happen. Error 916 - Logins can connect to this instance of SQL Server but they do not have specific permissions in a database to receive the permissions of the guest user. Q: How can I determine if the guest user is enabled or disabled for any specific database? A: There are many ways to do this. Make sure that you run each of these methods with the context of the database. For an example for msdb database, you can run the following code: USE msdb; SELECT name, permission_name, state_desc FROM sys.database_principals dp INNER JOIN sys.server_permissions sp ON dp.principal_id = sp.grantee_principal_id WHERE name = 'guest' AND permission_name = 'CONNECT' There are many other methods to detect the guest user status. Read them here: Detecting guest User Permissions – guest User Access Status Q: What is the default status of the guest user account in database? A: Enabled in master, TempDb, and MSDB. Disabled in model database. Q: Why is the default status of the guest user disabled in model database? A: It is not recommended to enable the guest in user database as it can introduce serious security threat. It can seriously damage the database if configured incorrectly. Read more here: Disable Guest Account – Serious Security Issue Q: How to disable guest user? A: REVOKE CONNECT FROM guest Q: How to enable guest user? A: GRANT CONNECT TO guest Did I miss any critical question in the list? Please leave your question as a comment and I will add it to this list. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Security, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQLAuthority News – Android Efficiency Tips and Tricks – Personal Technology Tip #003

  - by pinaldave

  I use my phone for lots of things.  I use it mainly to replace my tablet – I can e-mail, take and edit photos, and do almost everything I can do on a laptop with this phone.  And I am sure that there are many of you out there just like me.  I personally have a Galaxy S3, which uses the Android operating system, and I have decided to feature it as the third installment of my Technology Tips and Tricks series. 1) Shortcut to your favorite contacts on home screen Access your most-called contacts easily from your home screen by holding your finger on any empty spot on the home screen.  A menu will pop up that allows you to choose Shortcuts, and Contact.  You can scroll through your contact list and then just tap on the name of the person you want to be able to dial with a single click. 2) Keep track of your data usage Yes, we all should keep a close eye on our data usage, because it is very easy to go over our limits and then end up with a giant bill at the end of the month.  Never get surprised when you open that mobile phone envelope again.  Go to Settings, then Data Usage, and you can find a quick rundown of your usage, how much data each app uses, and you can even set alarms to let you know when you are nearing the limits.   Better yet, you can set the phone to stop using data when it reaches a certain limit. 3) Bring back Good Grammar We often hear proclamations about the downfall of written language, and how texting abbreviations, misspellings, and lack of punctuation are the root of all evil.  Well, we can show all those doomsdayers that all is not lost by bringing punctuation back to texting.  Usually we leave it off when we text because it takes too long to get to the screen with all the punctuation options.  But now you can hold down the period (or “full stop”) button and a list of all the commonly-used punctuation marks will pop right up. 4) Apps, Apps, Apps and Apps And finally, I cannot end an article about smart phones without including a list of my favorite apps.  Here are a list of my Top 10 Applications on my Android (not counting social media apps). Advanced Task Killer – Keeps my phone snappy by closing un-necessary apps WhatsApp - my favorite alternate to Text SMS Flipboard - my ‘timepass’ moments Skype – keeps me close to friends and family GoogleMaps - I am never lost because of this one thing Amazon Kindle – Books my best friends DropBox - My data always safe Pluralsight Player – Learning never stops for me Samsung Kies Air – Connecting Phone to Computer Chrome – Replacing default browser I have not included any social media applications in the above list, but you can be sure that I am linked to Twitter, Facebook, Google+, LinkedIn, and YouTube. Reference: Pinal Dave (http://blog.SQLAuthority.com)   Filed under: Best Practices, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL, Technology Tagged: Android, Personal Technology

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• SQL SERVER – What is Fill Factor and What is the Best Value for Fill Factor

  - by pinaldave

  Working in performance tuning area, one has to know about Index and Index Maintenance. For any Index the most important property is Fill Factor. Fill factor is the value that determines the percentage of space on each leaf-level page to be filled with data. In an SQL Server, the smallest unit is a page, which is made of  Page with size 8K. Every page can store one or more rows based on the size of the row. The default value of the Fill Factor is 100, which is same as value 0. The default Fill Factor (100 or 0) will allow the SQL Server to fill the leaf-level pages of an index with the maximum numbers of the rows it can fit. There will be no or very little empty space left in the page, when the fill factor is 100. I have written following two article about Fill Factor. What is Fill factor? – Index, Fill Factor and Performance – Part 1 What is the best value for the Fill Factor? – Index, Fill Factor and Performance – Part 2 I strongly encourage read them and provide your feedback. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Index, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Puzzle – Statistics are not Updated but are Created Once

  - by pinaldave

  After having excellent response to my quiz – Why SELECT * throws an error but SELECT COUNT(*) does not?I have decided to ask another puzzling question to all of you. I am running this test on SQL Server 2008 R2. Here is the quick scenario about my setup. Create Table Insert 1000 Records Check the Statistics Now insert 10 times more 10,000 indexes Check the Statistics – it will be NOT updated Note: Auto Update Statistics and Auto Create Statistics for database is TRUE Expected Result – Statistics should be updated – SQL SERVER – When are Statistics Updated – What triggers Statistics to Update Now the question is why the statistics are not updated? The common answer is – we can update the statistics ourselves using UPDATE STATISTICS TableName WITH FULLSCAN, ALL However, the solution I am looking is where statistics should be updated automatically based on algorithm mentioned here. Now the solution is to ____________________. Vinod Kumar is not allowed to take participate over here as he is the one who has helped me to build this puzzle. I will publish the solution on next week. Please leave a comment and if your comment consist valid answer, I will publish with due credit. Here is the script to reproduce the scenario which I mentioned. -- Execution Plans Difference -- Create Sample Database CREATE DATABASE SampleDB GO USE SampleDB GO -- Create Table CREATE TABLE ExecTable (ID INT, FirstName VARCHAR(100), LastName VARCHAR(100), City VARCHAR(100)) GO -- Insert One Thousand Records -- INSERT 1 INSERT INTO ExecTable (ID,FirstName,LastName,City) SELECT TOP 1000 ROW_NUMBER() OVER (ORDER BY a.name) RowID, 'Bob', CASE WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%2 = 1 THEN 'Smith' ELSE 'Brown' END, CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%20 = 1 THEN 'New York' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 5 THEN 'San Marino' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 3 THEN 'Los Angeles' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 7 THEN 'La Cinega' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 13 THEN 'San Diego' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 17 THEN 'Las Vegas' ELSE 'Houston' END FROM sys.all_objects a CROSS JOIN sys.all_objects b GO -- Display statistics of the table - none listed sp_helpstats N'ExecTable', 'ALL' GO -- Select Statement SELECT FirstName, LastName, City FROM ExecTable WHERE City  = 'New York' GO -- Display statistics of the table sp_helpstats N'ExecTable', 'ALL' GO -- Replace your Statistics over here -- NOTE: Replace your _WA_Sys with stats from above query DBCC SHOW_STATISTICS('ExecTable', _WA_Sys_00000004_7D78A4E7); GO -------------------------------------------------------------- -- Round 2 -- Insert Ten Thousand Records -- INSERT 2 INSERT INTO ExecTable (ID,FirstName,LastName,City) SELECT TOP 10000 ROW_NUMBER() OVER (ORDER BY a.name) RowID, 'Bob', CASE WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%2 = 1 THEN 'Smith' ELSE 'Brown' END, CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%20 = 1 THEN 'New York' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 5 THEN 'San Marino' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 3 THEN 'Los Angeles' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 7 THEN 'La Cinega' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 13 THEN 'San Diego' WHEN  ROW_NUMBER() OVER (ORDER BY a.name)%20 = 17 THEN 'Las Vegas' ELSE 'Houston' END FROM sys.all_objects a CROSS JOIN sys.all_objects b GO -- Select Statement SELECT FirstName, LastName, City FROM ExecTable WHERE City  = 'New York' GO -- Display statistics of the table sp_helpstats N'ExecTable', 'ALL' GO -- Replace your Statistics over here -- NOTE: Replace your _WA_Sys with stats from above query DBCC SHOW_STATISTICS('ExecTable', _WA_Sys_00000004_7D78A4E7); GO -- You will notice that Statistics are still updated with 1000 rows -- Clean up Database DROP TABLE ExecTable GO USE MASTER GO ALTER DATABASE SampleDB SET SINGLE_USER WITH ROLLBACK IMMEDIATE; GO DROP DATABASE SampleDB GO Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Index, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL Statistics, Statistics

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• SQL SERVER – Free Print Book on SQL Server Joes 2 Pros Kit

  - by pinaldave

  Rick Morelan and I were discussing earlier this month that what we can give back to the community. We believe our books are very much successful and very well received by the community. The five books are a journey from novice to expert. The books have changed many lives and helped many get jobs as well pass the SQL Certifications. Rick is from Seattle, USA and I am from Bangalore, India. There are 12 hours difference between us. We try to do weekly meeting to catch up on various personal and SQL related topics. Here is one of our recent conversations. Rick and Pinal Pinal: Good Morning Rick! Rick: Good Morning…err… Good Evening to you – Pinal! Pinal: Hey Rick, did you read the recent email which I sent you – one of our reader is thanking us for writing Joes 2 Pros series. He wants to dedicate his success to us. Can you believe it? Rick: Yeah, he is very kind but did you tell him that it is all because of his hard work on learning subject and we have very little contribution in his success. Pinal: Absolutely, I told him the same – I said we just wrote the book but it is he who learned from it and proved himself in his job. It is all him! We were just igniters. Rick: Good response. Pinal: Hey Rick! Are we doing enough for the community? What can we do more? Rick: Hmmm… Let us do something more. Pinal: Remember once we discussed the idea of if anyone who buys our Joes 2 Pros Combo Kit in the next 2 weeks – we will send them SQL Wait Stats for free. What do you say? Rick: I agree! Great Idea! Let us do it. Free Giveaway Well Rick and I liked the idea of doing more. We have decided to give away free SQL Server Wait Stats books to everybody who will purchase Joes 2 Pros Combo Kit between today (Oct 15, 2012) and Oct 26, 2012. This is not a contest or a lucky winner opportunity. Everybody who participates will qualify for it. Combo Availability USA – Amazon India - Flipkart | Indiaplaza Note1: USA kit contains FREE 5 DVDs. India Kit does not contain 5 DVDs due to legal issues. Note2: Indian Kit is priced at special Indian Economic Price. Qualify for Free Giveaway You must have purchased our Joes 2 Pros Combo Kit of 5 books between Oct 15, 2012 and Oct 26, 2012. Purchase before Oct 15, 2012 and after Oct 26, 2012 will not qualify for this giveaway. Send your original receipt (email, order details) to following addresses: “[email protected];[email protected]” with the subject line “Joes 2 Pros Kit Promotion Free Offer”. Do not change the subject line or your email may be missed.  Clearly mention your shipping address with phone number and pin/zip code. Send your receipt before Oct 30, 2012. We will not entertain any conversation after Oct 30, 2012 cut off date. The Free books will be sent to USA and India address only. Availability USA - Amazon | India - Flipkart | Indiaplaza Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Joes 2 Pros, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Book Review, SQLServer, T SQL, Technology

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• SQL SERVER – Find First Non-Numeric Character from String

  - by pinaldave

  It is fun when you have to deal with simple problems and there are no out of the box solution. I am sure there are many cases when we needed the first non-numeric character from the string but there is no function available to identify that right away. Here is the quick script I wrote down using PATINDEX. The function PATINDEX exists for quite a long time in SQL Server but I hardly see it being used. Well, at least I use it and I am comfortable using it. Here is a simple script which I use when I have to identify first non-numeric character. -- How to find first non numberic character USE tempdb GO CREATE TABLE MyTable (ID INT, Col1 VARCHAR(100)) GO INSERT INTO MyTable (ID, Col1) SELECT 1, '1one' UNION ALL SELECT 2, '11eleven' UNION ALL SELECT 3, '2two' UNION ALL SELECT 4, '22twentytwo' UNION ALL SELECT 5, '111oneeleven' GO -- Use of PATINDEX SELECT PATINDEX('%[^0-9]%',Col1) 'Position of NonNumeric Character', SUBSTRING(Col1,PATINDEX('%[^0-9]%',Col1),1) 'NonNumeric Character', Col1 'Original Character' FROM MyTable GO DROP TABLE MyTable GO Here is the resultset: Where do I use in the real world – well there are lots of examples. In one of the future blog posts I will cover that as well. Meanwhile, do you have any better way to achieve the same. Do share it here. I will write a follow up blog post with due credit to you. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Server, SQL String, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Watch Online and Download – Inside of Next Generation SQL Server – Best Practices Analyzer using Microsoft Baseline Configuration Analyzer

  - by pinaldave

  I presented on subject Inside of Next Generation SQL Server – Denali online at Zeollar.com. This sessions are really fun as they are online, downloadable, and 100% demo oriented. I used SQL Server ‘Denali’ CTP 1 to present on the subject of What is New in Denali. My earlier session on the Topic of Best Practices Analyzer is also available to watch online here: SQL SERVER – Video – Best Practices Analyzer using Microsoft Baseline Configuration Analyzer I enjoyed presenting a lot on above two subjects. I would like to ask your opinion on the same. You can download the sessions and watch it yourself afterwords. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Documentation, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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• SQL SERVER – 2011 – Clipboard Ring – CTRL+SHIFT+V

  - by pinaldave

  While I was writing my earlier post SQL SERVER – 2011 – Multi-Monitor SSMS Windows, I found out that there is one more similar feature which existed in Visual Studio is also now part of SQL Server 2011 (Denali). The feature is called clipboard ring feature. This is how it works. Select Multiple object one by one using regular CTRL + X. Now instead of pasting using CTRL+V use CTRL+SHIFT+V. Well, you will see that that pasted value is rotating based on what you have earlier selected in CTRL+V. I was really happy as I think this is one of the feature of VS, I really wanted SSMS to have. Try it and let me know what you think of the same. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Detecting Leap Year in T-SQL using SQL Server 2012 – IIF, EOMONTH and CONCAT Function

  - by pinaldave

  Note: Tomorrow is February 29th. This blog post is dedicated to coming tomorrow – a special day :) Subu: “How can I find leap year in using SQL Server 2012?“ Pinal: “Are you asking me how to year 2012 is leap year using T-SQL – search online and you will find many example of the same.” Subu: “No. I am asking – How can I find leap year in using SQL Server 2012?“ Pinal: “Oh so you are asking – How can I find leap year in using SQL Server 2012?“ Subu: “Yeah - How can I find leap year in using SQL Server 2012?“ Pinal: “Let me do that for you – How can you find leap year in using SQL Server 2012?“ Indeed a fun conversation. Honestly, only reason I pasted our conversation here is – it was fun. What he was asking is that how to do it using new functions introduced in SQL Server 2012. Here is the article I have written which introduces all the new functions in SQL Server 2012 Summary of All the Analytic Functions – MSDN and SQLAuthority and 14 New Functions – A Quick Guide. There are many functions written to figure out to figure out if any year is Leap Year or not. The same I have written using T-SQL function over here. CREATE FUNCTION dbo.IsLeapYear (@year INT) RETURNS INT AS BEGIN RETURN(IIF(DATEPART(dd,(EOMONTH(CONCAT(@year,'0201')))) = 29,1,0)) END GO What I really like is that I was able to use three newly introduced function in SQL Server 2012 in above script. You can read more about them here. IIF, EOMONTH and CONCAT. You can validate above query by running following script. SELECT dbo.IsLeapYear('2011') 'IsLeapYear'; SELECT dbo.IsLeapYear('2012') 'IsLeapYear'; GO You will get result 1 if the year is leap year and 0 if year is not leap year. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL DateTime, SQL Function, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Automation Process Good or Ugly

  - by pinaldave

  This blog post is written in response to T-SQL Tuesday hosted by SQL Server Insane Asylum. The idea of this post really caught my attention. Automation – something getting itself done after the initial programming, is my understanding of the subject. The very next thought was – is it good or evil? The reality is there is no right answer. However, what if we quickly note a few things, then I would like to request your help to complete this post. We will start with the positive parts in SQL Server where automation happens. The Good If I start thinking of SQL Server and Automation the very first thing that comes to my mind is SQL Agent, which runs various jobs. Once I configure any task or job, it runs fine (till something goes wrong!). Well, automation has its own advantages. We all have used SQL Agent for so many things – backup, various validation jobs, maintenance jobs and numerous other things. What other kinds of automation tasks do you run in your database server? The Ugly This part is very interesting, because it can get really ugly(!). During my career I have found so many bad automation agent jobs. Client had an agent job where he was dropping the clean buffers every hour Client using database mail to send regular emails instead of necessary alert related emails The best one – A client used new Missing Index and Unused Index scripts in SQL Agent Job to follow suggestions 100%. Believe me, I have never seen such a badly performing and hard to optimize database. (I ended up dropping all non-clustered indexes on the development server and ran production workload on the development server again, then configured with optimal indexes). Shrinking database is performance killer. It should never be automated. SQL SERVER – Shrinking Database is Bad – Increases Fragmentation – Reduces Performance The one I hate the most is AutoShrink Database. It has given me hard time in my career quite a few times. SQL SERVER – SHRINKDATABASE For Every Database in the SQL Server Automation is necessary but common sense is a must when creating automation. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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• SQL SERVER – DQS Error – Cannot connect to server – A .NET Framework error occurred during execution of user-defined routine or aggregate “SetDataQualitySessions” – SetDataQualitySessionPhaseTwo

  - by pinaldave

  Earlier I wrote a blog post about how to install DQS in SQL Server 2012. Today I decided to write a second part of this series where I explain how to use DQS, however, as soon as I started the DQS client, I encountered an error that will not let me pass through and connect with DQS client. It was a bit strange to me as everything was functioning very well when I left it last time.  The error was very big but here are the first few words of it. Cannot connect to server. A .NET Framework error occurred during execution of user-defined routine or aggregate “SetDataQualitySessions”: System.Data.SqlClient.SqlException (0×80131904): A .NET Framework error occurred during execution of user-defined routine or aggregate “SetDataQualitySessionPhaseTwo”: The error continues – here is the quick screenshot of the error. As my initial attempts could not fix the error I decided to search online and I finally received a wonderful solution from Microsoft Site. The error has happened due to latest update I had installed on .NET Framework 4. There was a  mismatch between the Module Version IDs (MVIDs) of the SQL Common Language Runtime (SQLCLR) assemblies in the SQL Server 2012 database and the Global Assembly Cache (GAC). This mismatch was to be resolved for the DQS to work properly. The workaround is specified here in detail. Scroll to subtopic 4.23 Some .NET Framework 4 Updates Might Cause DQS to Fail. The script was very much straight forward. Here are the few things to not to miss while applying workaround. Make sure DQS client is properly closed The NETAssemblies is based on your OS. NETAssemblies for 64 bit machine – which is my machine is “c:\windows\Microsoft.NET\Framework64\v4.0.30319″. If you have Winodws installed on any other drive other than c:\windows do not forget to change that in the above path. Additionally if you have 32 bit version installed on c:\windows you should use path as ”c:\windows\Microsoft.NET\Framework\v4.0.30319″ Make sure that you execute the script specified in 4.23 sections in this article in the database DQS_MAIN. Do not run this in the master database as this will not fix your error. Do not forget to restart your SQL Services once above script has been executed. Once you open the client it will work this time. Here is the script which I have bit modified from original script. I strongly suggest that you use original script mentioned 4.23 sections. However, this one is customized my own machine. /* Original source: http://bit.ly/PXX4NE (Technet) Modifications: -- Added Database context -- Added environment variable @NETAssemblies -- Main script modified to use @NETAssemblies */ USE DQS_MAIN GO BEGIN -- Set your environment variable -- assumption - Windows is installed in c:\windows folder DECLARE @NETAssemblies NVARCHAR(200) -- For 64 bit uncomment following line SET @NETAssemblies = 'c:\windows\Microsoft.NET\Framework64\v4.0.30319\' -- For 32 bit uncomment following line -- SET @NETAssemblies = 'c:\windows\Microsoft.NET\Framework\v4.0.30319\' DECLARE @AssemblyName NVARCHAR(200), @RefreshCmd NVARCHAR(200), @ErrMsg NVARCHAR(200) DECLARE ASSEMBLY_CURSOR CURSOR FOR SELECT name AS NAME FROM sys.assemblies WHERE name NOT LIKE '%ssdqs%' AND name NOT LIKE '%microsoft.sqlserver.types%' AND name NOT LIKE '%practices%' AND name NOT LIKE '%office%' AND name NOT LIKE '%stdole%' AND name NOT LIKE '%Microsoft.Vbe.Interop%' OPEN ASSEMBLY_CURSOR FETCH NEXT FROM ASSEMBLY_CURSOR INTO @AssemblyName WHILE @@FETCH_STATUS = 0 BEGIN BEGIN TRY SET @RefreshCmd = 'ALTER ASSEMBLY [' + @AssemblyName + '] FROM ''' + @NETAssemblies + @AssemblyName + '.dll' + ''' WITH PERMISSION_SET = UNSAFE' EXEC sp_executesql @RefreshCmd PRINT 'Successfully upgraded assembly ''' + @AssemblyName + '''' END TRY BEGIN CATCH IF ERROR_NUMBER() != 6285 BEGIN SET @ErrMsg = ERROR_MESSAGE() PRINT 'Failed refreshing assembly ' + @AssemblyName + '. Error message: ' + @ErrMsg END END CATCH FETCH NEXT FROM ASSEMBLY_CURSOR INTO @AssemblyName END CLOSE ASSEMBLY_CURSOR DEALLOCATE ASSEMBLY_CURSOR END GO Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Error Messages, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Weekly Series – Memory Lane – #005

  - by pinaldave

  Here is the list of curetted articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2006 SQL SERVER – Cursor to Kill All Process in Database I indeed wrote this cursor and when I often look back, I wonder how naive I was to write this. The reason for writing this cursor was to free up my database from any existing connection so I can do database operation. This worked fine but there can be a potentially big issue if there was any important transaction was killed by this process. There is another way to to achieve the same thing where we can use ALTER syntax to take database in single user mode. Read more about that over here and here. 2007 Rules of Third Normal Form and Normalization Advantage – 3NF The rules of 3NF are mentioned here Make a separate table for each set of related attributes, and give each table a primary key. If an attribute depends on only part of a multi-valued key, remove it to a separate table If attributes do not contribute to a description of the key, remove them to a separate table. Correct Syntax for Stored Procedure SP Sometime a simple question is the most important question. I often see in industry incorrectly written Stored Procedure. Few writes code after the most outer BEGIN…END and few writes code after the GO Statement. In this brief blog post, I have attempted to explain the same. 2008 Switch Between Result Pan and Query Pan – SQL Shortcut Many times when I am writing query I have to scroll the result displayed in the result set. Most of the developer uses the mouse to switch between and Query Pane and Result Pane. There are few developers who are crazy about Keyboard shortcuts. F6 is the keyword which can be used to switch between query pane and tabs of the result pane. Interesting Observation – Use of Index and Execution Plan Query Optimization is a complex game and it has its own rules. From the example in the article we have discovered that Query Optimizer does not use clustered index to retrieve data, sometime non clustered index provides optimal performance for retrieving Primary Key. When all the rows and columns are selected Primary Key should be used to select data as it provides optimal performance. 2009 Interesting Observation – TOP 100 PERCENT and ORDER BY If you pull up any application or system where there are more than 100 SQL Server Views are created – I am very confident that at one or two places you will notice the scenario wherein View the ORDER BY clause is used with TOP 100 PERCENT. SQL Server 2008 VIEW with ORDER BY clause does not throw an error; moreover, it does not acknowledge the presence of it as well. In this article we have taken three perfect examples and demonstrated which clause we should use when. Comma Separated Values (CSV) from Table Column A Very common question – How to create comma separated values from a table in the database? The answer is also very common if we use XML. Check out this article for quick learning on the same subject. Azure Start Guide – Step by Step Installation Guide Though Azure portal has changed a quite bit since I wrote this article, the concept used in this article are not old. They are still valid and many of the functions are still working as mentioned in the article. I believe this one article will put you on the track to use Azure! Size of Index Table for Each Index – Solution Earlier I have posted a small question on this blog and requested help from readers to participate here and provide a solution. The puzzle was to write a query that will return the size for each index that is on any particular table. We need a query that will return an additional column in the above listed query and it should contain the size of the index. This article presents two of the best solutions from the puzzle. 2010 Well, this week in 2010 was the week of puzzles as I posted three interesting puzzles. Till today I am noticing pretty good interesting in the puzzles. They are tricky but for sure brings a great value if you are a database developer for a long time. I suggest you go over this puzzles and their answers. Did you really know all of the answers? I am confident that reading following three blog post will for sure help you enhance the experience with T-SQL. SQL SERVER – Challenge – Puzzle – Usage of FAST Hint SQL SERVER – Puzzle – Challenge – Error While Converting Money to Decimal SQL SERVER – Challenge – Puzzle – Why does RIGHT JOIN Exists 2011 DVM sys.dm_os_sys_info Column Name Changed in SQL Server 2012 Have you ever faced a situation where something does not work? When you try to fix it - you enjoy fixing it and started to appreciate the breaking changes. Well, this was exactly I felt yesterday. Before I begin my story, I want to candidly state that I do not encourage anybody to use * in the SELECT statement. Now the disclaimer is over – I suggest you read the original story – you will love it! Get Directory Structure using Extended Stored Procedure xp_dirtree Here is the question to you – why would you do something in SQL Server where you can do the same task in command prompt much easily. Well, the answer is sometime there are real use cases when we have to do such thing. This is a similar example where I have demonstrated how in SQL Server 2012 we can use extended stored procedure to retrieve directory structure. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – PREEMPTIVE and Non-PREEMPTIVE – Wait Type – Day 19 of 28

  - by pinaldave

  In this blog post, we are going to talk about a very interesting subject. I often get questions related to SQL Server 2008 Book-Online about various Preemptive wait types. I got a few questions asking what these wait types are and how they could be interpreted. To get current wait types of the system, you can read this article and run the script: SQL SERVER – DMV – sys.dm_os_waiting_tasks and sys.dm_exec_requests – Wait Type – Day 4 of 28. Before we continue understanding them, let us study first what PREEMPTIVE and Non-PREEMPTIVE waits in SQL Server mean. PREEMPTIVE: Simply put, this wait means non-cooperative. While SQL Server is executing a task, the Operating System (OS) interrupts it. This leads to SQL Server to involuntarily give up the execution for other higher priority tasks. This is not good for SQL Server as it is a particular external process which makes SQL Server to yield. This kind of wait can reduce the performance drastically and needs to be investigated properly. Non-PREEMPTIVE: In simple terms, this wait means cooperative. SQL Server manages the scheduling of the threads. When SQL Server manages the scheduling instead of the OS, it makes sure its own priority. In this case, SQL Server decides the priority and one thread yields to another thread voluntarily. In the earlier version of SQL Server, there was no preemptive wait types mentioned and the associated task status with them was marked as suspended. In SQL Server 2005, preemptive wait types were not listed as well, but their associated task status was marked as running. In SQL Server 2008, preemptive wait types are properly listed and their associated task status is also marked as running. Now, SQL Server is in Non-Preemptive mode by default and it works fine. When CLR, extended Stored Procedures and other external components run, they run in Preemptive mode, leading to the creation of these wait types. There are a wide variety of preemptive wait types. If you see consistent high value in the Preemptive wait types, I strongly suggest that you look into the wait type and try to know the root cause. If you are still not sure, you can send me an email or leave a comment about it and I will do my best to help you reduce this wait type. Read all the post in the Wait Types and Queue series. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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• SQL SERVER – Effect of Collation on Resultset – SQL in Sixty Seconds #026 – Video

  - by pinaldave

  Collation is a very important concept but often ignored. I have often seen developers either not understanding this or ignored it – this is plain wrong. In simple word we can say Collation is the language or interpreting done by SQL Server. Well, in today’s SQL in Sixty Seconds we are going to observe how collation affects the resultset. Today’s blog post is inspired from my earlier blog post SQL SERVER – Effect of Case Sensitive Collation on Resultset. I strongly encourage you to read this earlier blog post for sample code as well additional explanation related to the concept shared in today’s SQL in Sixty Seconds. Here is the code used in the video. USE TempDB GO -- Sample Data Building CREATE TABLE ColTable (Col1 VARCHAR(15) COLLATE Latin1_General_CI_AS, Col2 VARCHAR(14) COLLATE Latin1_General_CS_AS) ; INSERT ColTable(Col1, Col2) VALUES ('Apple','Apple'), ('apple','apple'), ('pineapple','pineapple'), ('Pineapple','Pineapple'); GO -- Retrieve Data SELECT * FROM ColTable GO -- Retrieve Data SELECT * FROM ColTable ORDER BY Col1 GO -- Retrieve Data SELECT * FROM ColTable ORDER BY Col2 GO -- Clean up DROP TABLE ColTable GO Related Tips in SQL in Sixty Seconds: SQL SERVER – Effect of Case Sensitive Collation on Resultset Example of Width Sensitive and Width Insensitive Collation Collation and Collation Sensitivity – Quiz – Puzzle – 6 of 31 Change Collation of Database Column – T-SQL Script Find Collation of Database and Table Column Using T-SQL Default Collation of SQL Server 2008 Cannot resolve collation conflict for equal to operation If we like your idea we promise to share with you educational material. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Database, Pinal Dave, PostADay, SQL, SQL Authority, SQL in Sixty Seconds, SQL Query, SQL Scripts, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL, Technology, Video

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• SQL SERVER – Question to You – When to use Function and When to use Stored Procedure

  - by pinaldave

  This week has been very interesting week. I have asked few questions to users and have received remarkable participation on the subject. Q1) SQL SERVER – Puzzle – SELECT * vs SELECT COUNT(*) Q2) SQL SERVER – Puzzle – Statistics are not Updated but are Created Once Keeping the same spirit up, I am asking the third question over here. Q3) When to use User Defined Function and when to use Stored Procedure in your development? Personally, I believe that they are both different things - they cannot be compared. I can say, it will be like comparing apples and oranges. Each has its own unique use. However, they can be used interchangeably at many times and in real life (i.e., production environment). I have personally seen both of these being used interchangeably many times. This is the precise reason for asking this question. When do you use Function and when do you use Stored Procedure? What are Pros and Cons of each of them when used instead of each other? If you are going to answer that ‘To avoid repeating code, you use Function’ - please think harder! Stored procedure can do the same. In SQL Server Denali, even the stored procedure can return the result just like Function in SELECT statement; so if you are going to answer with ‘Function can be used in SELECT, whereas Stored Procedure cannot be used’ - again think harder! (link). Now, what do you say? I will post the answers of all the three questions with due credit next week. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, Readers Question, SQL, SQL Authority, SQL Function, SQL Puzzle, SQL Query, SQL Server, SQL Stored Procedure, SQL Tips and Tricks, SQLServer, T SQL, Technology

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• SQL SERVER – DMV – sys.dm_exec_query_optimizer_info – Statistics of Optimizer

  - by pinaldave

  Incredibly, SQL Server has so much information to share with us. Every single day, I am amazed with this SQL Server technology. Sometimes I find several interesting information by just querying few of the DMV. And when I present this info in front of my client during performance tuning consultancy, they are surprised with my findings. Today, I am going to share one of the hidden gems of DMV with you, the one which I frequently use to understand what’s going on under the hood of SQL Server. SQL Server keeps the record of most of the operations of the Query Optimizer. We can learn many interesting details about the optimizer which can be utilized to improve the performance of server. SELECT * FROM sys.dm_exec_query_optimizer_info WHERE counter IN ('optimizations', 'elapsed time','final cost', 'insert stmt','delete stmt','update stmt', 'merge stmt','contains subquery','tables', 'hints','order hint','join hint', 'view reference','remote query','maximum DOP', 'maximum recursion level','indexed views loaded', 'indexed views matched','indexed views used', 'indexed views updated','dynamic cursor request', 'fast forward cursor request') All occurrence values are cumulative and are set to 0 at system restart. All values for value fields are set to NULL at system restart. I have removed a few of the internal counters from the script above, and kept only documented details. Let us check the result of the above query. As you can see, there is so much vital information that is revealed in above query. I can easily say so many things about how many times Optimizer was triggered and what the average time taken by it to optimize my queries was. Additionally, I can also determine how many times update, insert or delete statements were optimized. I was able to quickly figure out that my client was overusing the Query Hints using this dynamic management view. If you have been reading my blog, I am sure you are aware of my series related to SQL Server Views SQL SERVER – The Limitations of the Views – Eleven and more…. With this, I can take a quick look and figure out how many times Views were used in various solutions within the query. Moreover, you can easily know what fraction of the optimizations has been involved in tuning server. For example, the following query would tell me, in total optimizations, what the fraction of time View was “reference“. As this View also includes system Views and DMVs, the number is a bit higher on my machine. SELECT (SELECT CAST (occurrence AS FLOAT) FROM sys.dm_exec_query_optimizer_info WHERE counter = 'view reference') / (SELECT CAST (occurrence AS FLOAT) FROM sys.dm_exec_query_optimizer_info WHERE counter = 'optimizations') AS ViewReferencedFraction Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL DMV, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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• SQL SERVER – Puzzle to Win Print Book – Explain Value of PERCENTILE_CONT() Using Simple Example

  - by pinaldave

  From last several days I am working on various Denali Analytical functions and it is indeed really fun to refresh the concept which I studied in the school. Earlier I wrote article where I explained how we can use PERCENTILE_CONT() to find median over here SQL SERVER – Introduction to PERCENTILE_CONT() – Analytic Functions Introduced in SQL Server 2012. Today I am going to ask question based on the same blog post. Again just like last time the intention of this puzzle is as following: Learn new concept of SQL Server 2012 Learn new concept of SQL Server 2012 even if you are on earlier version of SQL Server. On another note, SQL Server 2012 RC0 has been announced and available to download SQL SERVER – 2012 RC0 Various Resources and Downloads. Now let’s have fun following query: USE AdventureWorks GO SELECT SalesOrderID, OrderQty, ProductID, PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY ProductID) OVER (PARTITION BY SalesOrderID) AS MedianCont FROM Sales.SalesOrderDetail WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY SalesOrderID DESC GO The above query will give us the following result: The reason we get median is because we are passing value .05 to PERCENTILE_COUNT() function. Now run read the puzzle. Puzzle: Run following T-SQL code: USE AdventureWorks GO SELECT SalesOrderID, OrderQty, ProductID, PERCENTILE_CONT(0.9) WITHIN GROUP (ORDER BY ProductID) OVER (PARTITION BY SalesOrderID) AS MedianCont FROM Sales.SalesOrderDetail WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY SalesOrderID DESC GO Observe the result and you will notice that MidianCont has different value than before, the reason is PERCENTILE_CONT function has 0.9 value passed. For first four value the value is 775.1. Now run following T-SQL code: USE AdventureWorks GO SELECT SalesOrderID, OrderQty, ProductID, PERCENTILE_CONT(0.1) WITHIN GROUP (ORDER BY ProductID) OVER (PARTITION BY SalesOrderID) AS MedianCont FROM Sales.SalesOrderDetail WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY SalesOrderID DESC GO Observe the result and you will notice that MidianCont has different value than before, the reason is PERCENTILE_CONT function has 0.1 value passed. For first four value the value is 709.3. Now in my example I have explained how the median is found using this function. You have to explain using mathematics and explain (in easy words) why the value in last columns are 709.3 and 775.1 Hint: SQL SERVER – Introduction to PERCENTILE_CONT() – Analytic Functions Introduced in SQL Server 2012 Rules Leave a comment with your detailed answer by Nov 25's blog post. Open world-wide (where Amazon ships books) If you blog about puzzle’s solution and if you win, you win additional surprise gift as well. Prizes Print copy of my new book SQL Server Interview Questions Amazon|Flipkart If you already have this book, you can opt for any of my other books SQL Wait Stats [Amazon|Flipkart|Kindle] and SQL Programming [Amazon|Flipkart|Kindle]. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Function, SQL Puzzle, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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