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  • SQL SERVER – Concat Strings in SQL Server using T-SQL – SQL in Sixty Seconds #035 – Video

    - by pinaldave
    Concatenating  string is one of the most common tasks in SQL Server and every developer has to come across it. We have to concat the string when we have to see the display full name of the person by first name and last name. In this video we will see various methods to concatenate the strings. SQL Server 2012 has introduced new function CONCAT which concatenates the strings much efficiently. When we concat values with ‘+’ in SQL Server we have to make sure that values are in string format. However, when we attempt to concat integer we have to convert the integers to a string or else it will throw an error. However, with the newly introduce the function of CONCAT in SQL Server 2012 we do not have to worry about this kind of issue. It concatenates strings and integers without casting or converting them. You can specify various values as a parameter to CONCAT functions and it concatenates them together. Let us see how to concat the values in Sixty Seconds: Here is the script which is used in the video. -- Method 1: Concatenating two strings SELECT 'FirstName' + ' ' + 'LastName' AS FullName -- Method 2: Concatenating two Numbers SELECT CAST(1 AS VARCHAR(10)) + ' ' + CAST(2 AS VARCHAR(10)) -- Method 3: Concatenating values of table columns SELECT FirstName + ' ' + LastName AS FullName FROM AdventureWorks2012.Person.Person -- Method 4: SQL Server 2012 CONCAT function SELECT CONCAT('FirstName' , ' ' , 'LastName') AS FullName -- Method 5: SQL Server 2012 CONCAT function SELECT CONCAT('FirstName' , ' ' , 1) AS FullName Related Tips in SQL in Sixty Seconds: SQL SERVER – Concat Function in SQL Server – SQL Concatenation String Function – CONCAT() – A Quick Introduction 2012 Functions – FORMAT() and CONCAT() – An Interesting Usage A Quick Trick about SQL Server 2012 CONCAT Function – PRINT A Quick Trick about SQL Server 2012 CONCAT function What would you like to see in the next SQL in Sixty Seconds video? 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 Tagged: Excel

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  • SQL SERVER – Resolving SQL Server Connection Errors – SQL in Sixty Seconds #030 – Video

    - by pinaldave
    One of the most famous errors related to SQL Server is about connecting to SQL Server itself. Here is how it goes, most of the time developers have worked with SQL Server and knows pretty much every error which they face during development language. However, hardly they install fresh SQL Server. As the installation of the SQL Server is a rare occasion unless you are DBA who is responsible for such an instance – the error faced during installations are pretty rare as well. I have earlier written an article about this which describes how to resolve the errors which are related to SQL Server connection. Even though the step by step directions are pretty simple there are many first time IT Professional who are not able to figure out how to resolve this error. I have quickly built a video which is covering most of the solutions related to resolving the connection error. In the Fix SQL Server Connection Error article following workarounds are described: SQL Server Services TCP/IP Settings Firewall Settings Enable Remote Connection Browser Services Firewall exception of sqlbrowser.exe Recreating Alias Related Tips in SQL in Sixty Seconds: SQL SERVER – FIX : ERROR : (provider: Named Pipes Provider, error: 40 – Could not open a connection to SQL Server) (Microsoft SQL Server, Error: ) SQL SERVER – Could not connect to TCP error code 10061: No connection could be made because the target machine actively refused it SQL SERVER – Connecting to Server Using Windows Authentication by SQLCMD SQL SERVER – Fix : Error: 15372 Failed to generate a ser instance od SQL Server due to a failure in starting the process for the user instance. The connection will be closed SQL SERVER – Dedicated Access Control for SQL Server Express Edition – An error occurred while obtaining the dedicated administrator connection (DAC) port. SQL SERVER – Fix : Error: 4064 – Cannot open user default database. Login failed. Login failed for user What would you like to see in the next SQL in Sixty Seconds video? 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 Tagged: Excel

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  • SQL SERVER – Color Coding SQL Server Management Studio Status Bar – SQL in Sixty Seconds #023 – Video

    - by pinaldave
    I often see developers executing the unplanned code on production server when they actually want to execute on the development server. Developers and DBAs get confused because when they use SQL Server Management Studio (SSMS) they forget to pay attention to the server they are connecting. It is very easy to fix this problem. You can select different color for a different server. Once you have different color for different server in the status bar, it will be easier for developer easily notice the server against which they are about to execute the script. Personally when I work on SQL Server development, here is the color code, which I follow. I keep Green for my development server, blue for my staging server and red for my production server. Honestly color coding does not signify much but different color for different server is the key here. More Tips on SSMS in SQL in Sixty Seconds: Generate Script for Schema and Data in SQL Server – SQL in Sixty Seconds #021  Remove Debug Button in SQL Server Management Studio – SQL in Sixty Seconds #020  Three Tricks to Comment T-SQL in SQL Server Management Studio – SQL in Sixty Seconds #019  Importing CSV into SQL Server – SQL in Sixty Seconds #018   Tricks to Replace SELECT * with Column Names – SQL in Sixty Seconds #017 I encourage you to submit your ideas for SQL in Sixty Seconds. We will try to accommodate as many as we can. 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 – Summary of Month – Wait Type – Day 28 of 28

    - by pinaldave
    I am glad to announce that the month of Wait Types and Queues very successful. I am glad that it was very well received and there was great amount of participation from community. I am fortunate to have some of the excellent comments throughout the series. I want to dedicate this series to all the guest blogger – Jonathan, Jacob, Glenn, and Feodor for their kindness to take a participation in this series. Here is the complete list of the blog posts in this series. I enjoyed writing the series and I plan to continue writing similar series. Please offer your opinion. SQL SERVER – Introduction to Wait Stats and Wait Types – Wait Type – Day 1 of 28 SQL SERVER – Signal Wait Time Introduction with Simple Example – Wait Type – Day 2 of 28 SQL SERVER – DMV – sys.dm_os_wait_stats Explanation – Wait Type – Day 3 of 28 SQL SERVER – DMV – sys.dm_os_waiting_tasks and sys.dm_exec_requests – Wait Type – Day 4 of 28 SQL SERVER – Capturing Wait Types and Wait Stats Information at Interval – Wait Type – Day 5 of 28 SQL SERVER – CXPACKET – Parallelism – Usual Solution – Wait Type – Day 6 of 28 SQL SERVER – CXPACKET – Parallelism – Advanced Solution – Wait Type – Day 7 of 28 SQL SERVER – SOS_SCHEDULER_YIELD – Wait Type – Day 8 of 28 SQL SERVER – PAGEIOLATCH_DT, PAGEIOLATCH_EX, PAGEIOLATCH_KP, PAGEIOLATCH_SH, PAGEIOLATCH_UP – Wait Type – Day 9 of 28 SQL SERVER – IO_COMPLETION – Wait Type – Day 10 of 28 SQL SERVER – ASYNC_IO_COMPLETION – Wait Type – Day 11 of 28 SQL SERVER – PAGELATCH_DT, PAGELATCH_EX, PAGELATCH_KP, PAGELATCH_SH, PAGELATCH_UP – Wait Type – Day 12 of 28 SQL SERVER – FT_IFTS_SCHEDULER_IDLE_WAIT – Full Text – Wait Type – Day 13 of 28 SQL SERVER – BACKUPIO, BACKUPBUFFER – Wait Type – Day 14 of 28 SQL SERVER – LCK_M_XXX – Wait Type – Day 15 of 28 SQL SERVER – Guest Post – Jonathan Kehayias – Wait Type – Day 16 of 28 SQL SERVER – WRITELOG – Wait Type – Day 17 of 28 SQL SERVER – LOGBUFFER – Wait Type – Day 18 of 28 SQL SERVER – PREEMPTIVE and Non-PREEMPTIVE – Wait Type – Day 19 of 28 SQL SERVER – MSQL_XP – Wait Type – Day 20 of 28 SQL SERVER – Guest Posts – Feodor Georgiev – The Context of Our Database Environment – Going Beyond the Internal SQL Server Waits – Wait Type – Day 21 of 28 SQL SERVER – Guest Post – Jacob Sebastian – Filestream – Wait Types – Wait Queues – Day 22 of 28 SQL SERVER – OLEDB – Link Server – Wait Type – Day 23 of 28 SQL SERVER – 2000 – DBCC SQLPERF(waitstats) – Wait Type – Day 24 of 28 SQL SERVER – 2011 – Wait Type – Day 25 of 28 SQL SERVER – Guest Post – Glenn Berry – Wait Type – Day 26 of 28 SQL SERVER – Best Reference – Wait Type – Day 27 of 28 SQL SERVER – Summary of Month – Wait Type – Day 28 of 28 Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Optimization, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, SQLServer, T SQL, Technology

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  • SQL SERVER – Wait Stats – Wait Types – Wait Queues – Day 0 of 28

    - by pinaldave
    This blog post will have running account of the all the blog post I will be doing in this month related to SQL Server Wait Types and Wait Queues. SQL SERVER – Introduction to Wait Stats and Wait Types – Wait Type – Day 1 of 28 SQL SERVER – Signal Wait Time Introduction with Simple Example – Wait Type – Day 2 of 28 SQL SERVER – DMV – sys.dm_os_wait_stats Explanation – Wait Type – Day 3 of 28 SQL SERVER – DMV – sys.dm_os_waiting_tasks and sys.dm_exec_requests – Wait Type – Day 4 of 28 SQL SERVER – Capturing Wait Types and Wait Stats Information at Interval – Wait Type – Day 5 of 28 SQL SERVER – CXPACKET – Parallelism – Usual Solution – Wait Type – Day 6 of 28 SQL SERVER – CXPACKET – Parallelism – Advanced Solution – Wait Type – Day 7 of 28 SQL SERVER – SOS_SCHEDULER_YIELD – Wait Type – Day 8 of 28 SQL SERVER – PAGEIOLATCH_DT, PAGEIOLATCH_EX, PAGEIOLATCH_KP, PAGEIOLATCH_SH, PAGEIOLATCH_UP – Wait Type – Day 9 of 28 SQL SERVER – IO_COMPLETION – Wait Type – Day 10 of 28 SQL SERVER – ASYNC_IO_COMPLETION – Wait Type – Day 11 of 28 SQL SERVER – PAGELATCH_DT, PAGELATCH_EX, PAGELATCH_KP, PAGELATCH_SH, PAGELATCH_UP – Wait Type – Day 12 of 28 SQL SERVER – FT_IFTS_SCHEDULER_IDLE_WAIT – Full Text – Wait Type – Day 13 of 28 SQL SERVER – BACKUPIO, BACKUPBUFFER – Wait Type – Day 14 of 28 SQL SERVER – LCK_M_XXX – Wait Type – Day 15 of 28 Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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  • SQL SERVER – Delay Command in SQL Server – SQL in Sixty Seconds #055

    - by Pinal Dave
    Have you ever needed WAIT or DELAY function in SQL Server?  Well, I personally have never needed it but I see lots of people asking for the same. It seems the need of the function is when developers are working with asynchronous applications or programs. When they are working with an application where user have to wait for a while for another application to complete the processing. If you are programming language developer, it is very easy for you to make the application wait for command however, in SQL I personally have rarely used this feature.  However, I have seen lots of developers asking for this feature in SQL Server, hence I have decided to build this quick video on the same subject. We can use WAITFOR DELAY ‘timepart‘ to create a SQL Statement to wait. Let us see the same concept in following SQL in Sixty Seconds Video: Related Tips in SQL in Sixty Seconds: Delay Function – WAITFOR clause – Delay Execution of Commands What would you like to see in the next SQL in Sixty Seconds video? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Database, Pinal Dave, PostADay, SQL, SQL Authority, SQL in Sixty Seconds, SQL Interview Questions and Answers, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology, Video Tagged: Identity

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  • SQL SERVER – Four Posts on Removing the Bookmark Lookup – Key Lookup

    - by pinaldave
    In recent times I have observed that not many people have proper understanding of what is bookmark lookup or key lookup. Increasing numbers of the questions tells me that this is something developers are encountering every single day but have no idea how to deal with it. I have previously written three articles on this subject. I want to point all of you looking for further information on the same post. SQL SERVER – Query Optimization – Remove Bookmark Lookup – Remove RID Lookup – Remove Key Lookup SQL SERVER – Query Optimization – Remove Bookmark Lookup – Remove RID Lookup – Remove Key Lookup – Part 2 SQL SERVER – Query Optimization – Remove Bookmark Lookup – Remove RID Lookup – Remove Key Lookup – Part 3 SQL SERVER – Interesting Observation – Execution Plan and Results of Aggregate Concatenation Queries In one of my recent class we had in depth conversation about what are the alternative of creating covering indexes to remove the bookmark lookup. I really want to this question open to all of you and see what community thinks about the same. Is there any other way then creating covering index or included index to remove his expensive keylookup? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Backup and Restore, SQL Index, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLAuthority News, SQLServer, T SQL, Technology

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  • SQL SERVER – Standard Reports from SQL Server Management Studio – SQL in Sixty Seconds #016 – Video

    - by pinaldave
    SQL Server management Studio 2012 is wonderful tool and has many different features. Many times, an average user does not use them as they are not aware about these features. Today, we will learn one such feature. SSMS comes with many inbuilt performance and activity reports, but we do not use it to the full potential. Connect to SQL Server Node >> Right Click on it >> Go to Reports >> Click on Standard Reports >> Pick Any Report. Please note that some of the reports can be IO intensive and not suggested to run during business hours! More on Standard Reports: SQL SERVER – Out of the Box – Activity and Performance Reports from SSSMS SQL SERVER – Generate Report for Index Physical Statistics – SSMS SQL SERVER – Configure Management Data Collection in Quick Steps I encourage you to submit your ideas for SQL in Sixty Seconds. We will try to accommodate as many as we can. 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 – Subquery or Join – Various Options – SQL Server Engine Knows the Best – Part 2

    - by pinaldave
    This blog post is part 2 of the earlier written article SQL SERVER – Subquery or Join – Various Options – SQL Server Engine knows the Best by Paulo R. Pereira. Paulo has left excellent comment to earlier article once again proving the point that SQL Server Engine is smart enough to figure out the best plan itself and uses the same for the query. Let us go over his comment as he has posted. “I think IN or EXISTS is the best choice, because there is a little difference between ‘Merge Join’ of query with JOIN (Inner Join) and the others options (Left Semi Join), and JOIN can give more results than IN or EXISTS if the relationship is 1:0..N and not 1:0..1. And if I try use NOT IN and NOT EXISTS the query plan is different from LEFT JOIN too (Left Anti Semi Join vs. Left Outer Join + Filter). So, I found a case where EXISTS has a different query plan than IN or ANY/SOME:” USE AdventureWorks GO -- use of SOME SELECT * FROM HumanResources.Employee E WHERE E.EmployeeID = SOME ( SELECT EA.EmployeeID FROM HumanResources.EmployeeAddress EA UNION ALL SELECT EA.EmployeeID FROM HumanResources.EmployeeDepartmentHistory EA ) -- use of IN SELECT * FROM HumanResources.Employee E WHERE E.EmployeeID IN ( SELECT EA.EmployeeID FROM HumanResources.EmployeeAddress EA UNION ALL SELECT EA.EmployeeID FROM HumanResources.EmployeeDepartmentHistory EA ) -- use of EXISTS SELECT * FROM HumanResources.Employee E WHERE EXISTS ( SELECT EA.EmployeeID FROM HumanResources.EmployeeAddress EA UNION ALL SELECT EA.EmployeeID FROM HumanResources.EmployeeDepartmentHistory EA ) When looked into execution plan of the queries listed above indeed we do get different plans for queries and SQL Server Engines creates the best (least cost) plan for each query. Click on image to see larger images. Thanks Paulo for your wonderful contribution. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, Readers Contribution, SQL, SQL Authority, SQL Joins, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – Subquery or Join – Various Options – SQL Server Engine knows the Best

    - by pinaldave
    This is followup post of my earlier article SQL SERVER – Convert IN to EXISTS – Performance Talk, after reading all the comments I have received I felt that I could write more on the same subject to clear few things out. First let us run following four queries, all of them are giving exactly same resultset. USE AdventureWorks GO -- use of = SELECT * FROM HumanResources.Employee E WHERE E.EmployeeID = ( SELECT EA.EmployeeID FROM HumanResources.EmployeeAddress EA WHERE EA.EmployeeID = E.EmployeeID) GO -- use of in SELECT * FROM HumanResources.Employee E WHERE E.EmployeeID IN ( SELECT EA.EmployeeID FROM HumanResources.EmployeeAddress EA WHERE EA.EmployeeID = E.EmployeeID) GO -- use of exists SELECT * FROM HumanResources.Employee E WHERE EXISTS ( SELECT EA.EmployeeID FROM HumanResources.EmployeeAddress EA WHERE EA.EmployeeID = E.EmployeeID) GO -- Use of Join SELECT * FROM HumanResources.Employee E INNER JOIN HumanResources.EmployeeAddress EA ON E.EmployeeID = EA.EmployeeID GO Let us compare the execution plan of the queries listed above. Click on image to see larger image. It is quite clear from the execution plan that in case of IN, EXISTS and JOIN SQL Server Engines is smart enough to figure out what is the best optimal plan of Merge Join for the same query and execute the same. However, in the case of use of Equal (=) Operator, SQL Server is forced to use Nested Loop and test each result of the inner query and compare to outer query, leading to cut the performance. Please note that here I no mean suggesting that Nested Loop is bad or Merge Join is better. This can very well vary on your machine and amount of resources available on your computer. When I see Equal (=) operator used in query like above, I usually recommend to see if user can use IN or EXISTS or JOIN. As I said, this can very much vary on different system. What is your take in above query? I believe SQL Server Engines is usually pretty smart to figure out what is ideal execution plan and use it. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Joins, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – Tricks to Comment T-SQL in SSMS – SQL in Sixty Seconds #019 – Video

    - by pinaldave
    Code commeting is the one of the most common tasks developers perform. There are two major reasons why developer comment code. 1) During Debug 2) Documenting the code. While debugging the T-SQL code I have often seen developers struggling to comment code.  They spend (or waste) more time in commenting and uncommenting  than doing actual debugging of the procedure.  When I see developer struggling to comment the code I feel little uncomfortable as commenting should be a very easy task over. Today we will see three quick method to comment T-SQL code in Query Editor. There are three different method to comment and uncomment statements in SQL Server Management Studio Using Keyboard Shortcuts Using Tool Bar Using Menu Bar Method 1: Using Keyboard Shortcuts Commenting the statement – CTRL+K, CTRL+C Commenting the statement – CTRL+K, CTRL+U Method 2: Using Tool Bar Using Tool bar buttons. (See Video) Method 3: Using Menu Bar Commenting the statement – Menu Bar >> Edit >> Advanced >> Click on Comment Selection. Unommenting the statement – Menu Bar >> Edit >> Advanced >> Click on Uncomment Selection. More on Importing CSV Data: Two Different Ways to Comment Code – Explanation and Example I encourage you to submit your ideas for SQL in Sixty Seconds. We will try to accommodate as many as we can. 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 – Introduction to Extended Events – Finding Long Running Queries

    - by pinaldave
    The job of an SQL Consultant is very interesting as always. The month before, I was busy doing query optimization and performance tuning projects for our clients, and this month, I am busy delivering my performance in Microsoft SQL Server 2005/2008 Query Optimization and & Performance Tuning Course. I recently read white paper about Extended Event by SQL Server MVP Jonathan Kehayias. You can read the white paper here: Using SQL Server 2008 Extended Events. I also read another appealing chapter by Jonathan in the book, SQLAuthority Book Review – Professional SQL Server 2008 Internals and Troubleshooting. After reading these excellent notes by Jonathan, I decided to upgrade my course and include Extended Event as one of the modules. This week, I have delivered Extended Events session two times and attendees really liked the said course. They really think Extended Events is one of the most powerful tools available. Extended Events can do many things. I suggest that you read the white paper I mentioned to learn more about this tool. Instead of writing a long theory, I am going to write a very quick script for Extended Events. This event session captures all the longest running queries ever since the event session was started. One of the many advantages of the Extended Events is that it can be configured very easily and it is a robust method to collect necessary information in terms of troubleshooting. There are many targets where you can store the information, which include XML file target, which I really like. In the following Events, we are writing the details of the event at two locations: 1) Ringer Buffer; and 2) XML file. It is not necessary to write at both places, either of the two will do. -- Extended Event for finding *long running query* IF EXISTS(SELECT * FROM sys.server_event_sessions WHERE name='LongRunningQuery') DROP EVENT SESSION LongRunningQuery ON SERVER GO -- Create Event CREATE EVENT SESSION LongRunningQuery ON SERVER -- Add event to capture event ADD EVENT sqlserver.sql_statement_completed ( -- Add action - event property ACTION (sqlserver.sql_text, sqlserver.tsql_stack) -- Predicate - time 1000 milisecond WHERE sqlserver.sql_statement_completed.duration > 1000 ) -- Add target for capturing the data - XML File ADD TARGET package0.asynchronous_file_target( SET filename='c:\LongRunningQuery.xet', metadatafile='c:\LongRunningQuery.xem'), -- Add target for capturing the data - Ring Bugger ADD TARGET package0.ring_buffer (SET max_memory = 4096) WITH (max_dispatch_latency = 1 seconds) GO -- Enable Event ALTER EVENT SESSION LongRunningQuery ON SERVER STATE=START GO -- Run long query (longer than 1000 ms) SELECT * FROM AdventureWorks.Sales.SalesOrderDetail ORDER BY UnitPriceDiscount DESC GO -- Stop the event ALTER EVENT SESSION LongRunningQuery ON SERVER STATE=STOP GO -- Read the data from Ring Buffer SELECT CAST(dt.target_data AS XML) AS xmlLockData FROM sys.dm_xe_session_targets dt JOIN sys.dm_xe_sessions ds ON ds.Address = dt.event_session_address JOIN sys.server_event_sessions ss ON ds.Name = ss.Name WHERE dt.target_name = 'ring_buffer' AND ds.Name = 'LongRunningQuery' GO -- Read the data from XML File SELECT event_data_XML.value('(event/data[1])[1]','VARCHAR(100)') AS Database_ID, event_data_XML.value('(event/data[2])[1]','INT') AS OBJECT_ID, event_data_XML.value('(event/data[3])[1]','INT') AS object_type, event_data_XML.value('(event/data[4])[1]','INT') AS cpu, event_data_XML.value('(event/data[5])[1]','INT') AS duration, event_data_XML.value('(event/data[6])[1]','INT') AS reads, event_data_XML.value('(event/data[7])[1]','INT') AS writes, event_data_XML.value('(event/action[1])[1]','VARCHAR(512)') AS sql_text, event_data_XML.value('(event/action[2])[1]','VARCHAR(512)') AS tsql_stack, CAST(event_data_XML.value('(event/action[2])[1]','VARCHAR(512)') AS XML).value('(frame/@handle)[1]','VARCHAR(50)') AS handle FROM ( SELECT CAST(event_data AS XML) event_data_XML, * FROM sys.fn_xe_file_target_read_file ('c:\LongRunningQuery*.xet', 'c:\LongRunningQuery*.xem', NULL, NULL)) T GO -- Clean up. Drop the event DROP EVENT SESSION LongRunningQuery ON SERVER GO Just run the above query, afterwards you will find following result set. This result set contains the query that was running over 1000 ms. In our example, I used the XML file, and it does not reset when SQL services or computers restarts (if you are using DMV, it will reset when SQL services restarts). This event session can be very helpful for troubleshooting. Let me know if you want me to write more about Extended Events. I am totally fascinated with this feature, so I’m planning to acquire more knowledge about it so I can determine its other usages. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Training, SQLServer, T SQL, Technology Tagged: SQL Extended Events

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  • SQL SERVER – Generate Report for Index Physical Statistics – SSMS

    - by pinaldave
    Few days ago, I wrote about SQL SERVER – Out of the Box – Activity and Performance Reports from SSSMS (Link). A user asked me a question regarding if we can use similar reports to get the detail about Indexes. Yes, it is possible to do the same. There are similar type of reports are available at Database level, just like those available at the Server Instance level. You can right click on Database name and click Reports. Under Standard Reports, you will find following reports. Disk Usage Disk Usage by Top Tables Disk Usage by Table Disk Usage by Partition Backup and Restore Events All Transactions All Blocking Transactions Top Transactions by Age Top Transactions by Blocked Transactions Count Top Transactions by Locks Count Resource Locking Statistics by Objects Object Execute Statistics Database Consistency history Index Usage Statistics Index Physical Statistics Schema Change history User Statistics Select the Reports with name Index Physical Statistics. Once click, a report containing all the index names along with other information related to index will be visible, e.g. Index Type and number of partitions. One column that caught my interest was Operation Recommended. In some place, it suggested that index needs to be rebuilt. It is also possible to click and expand the column of partitions and see additional details about index as well. DBA and Developers who just want to have idea about how your index is and its physical statistics can use this tool. Click to Enlarge Note: Please note that I will rebuild my indexes just because this report is recommending it. There are many other parameters you need to consider before rebuilding indexes. However, this tool gives you the accurate stats of your index and it can be right away exported to Excel or PDF writing by clicking on the report. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Index, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, SQL Utility, T SQL, Technology

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  • SQL SERVER – T-SQL Errors and Reactions – Demo – SQL in Sixty Seconds #005 – Video

    - by pinaldave
    We got tremendous response to video of Error and Reaction of SQL in Sixty Seconds #002. We all have idea how SQL Server reacts when it encounters T-SQL Error. Today Rick explains the same in quick seconds. After watching this I felt confident to answer talk about SQL Server’s reaction to Error. We received many request to follow up video of the earlier video. Many requested T-SQL demo of the concept. In today’s SQL in Sixty Seconds Rick Morelan has presented T-SQL demo of very visual reach concept of SQL Server Errors and Reaction. More on Errors: Explanation of TRY…CATCH and ERROR Handling Create New Log file without Server Restart Tips from the SQL Joes 2 Pros Development Series – SQL Server Error Messages I encourage you to submit your ideas for SQL in Sixty Seconds. We will try to accommodate as many as we can. 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 Tips and Tricks, SQLServer, T SQL, Video

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  • SQL Authority News – Download Microsoft SQL Server 2014 Feature Pack and Microsoft SQL Server Developer’s Edition

    - by Pinal Dave
    Yesterday I attended the SQL Server Community Launch in Bangalore and presented on Performing an effective Presentation. It was a fun presentation and people very well received it. No matter on what subject, I present, I always end up talking about SQL. Here are two of the questions I had received during the event. Q1) I want to install SQL Server on my development server, where can we get it for free or at an economical price (I do not have MSDN)? A1) If you are not going to use your server in a production environment, you can just get SQL Server Developer’s Edition and you can read more about it over here. Here is another favorite question which I keep on receiving it during the event. Q2) I already have SQL Server installed on my machine, what are different feature pack should I install and where can I get them from. A2) Just download and install Microsoft SQL Server 2014 Service Pack. Here is the link for downloading it. The Microsoft SQL Server 2014 Feature Pack is a collection of stand-alone packages which provide additional value for Microsoft SQL Server. It includes tool and components for Microsoft SQL Server 2014 and add-on providers for Microsoft SQL Server 2014. Here is the list of component this product contains: Microsoft SQL Server Backup to Windows Azure Tool Microsoft SQL Server Cloud Adapter Microsoft Kerberos Configuration Manager for Microsoft SQL Server Microsoft SQL Server 2014 Semantic Language Statistics Microsoft SQL Server Data-Tier Application Framework Microsoft SQL Server 2014 Transact-SQL Language Service Microsoft Windows PowerShell Extensions for Microsoft SQL Server 2014 Microsoft SQL Server 2014 Shared Management Objects Microsoft Command Line Utilities 11 for Microsoft SQL Server Microsoft ODBC Driver 11 for Microsoft SQL Server – Windows Microsoft JDBC Driver 4.0 for Microsoft SQL Server Microsoft Drivers 3.0 for PHP for Microsoft SQL Server Microsoft SQL Server 2014 Transact-SQL ScriptDom Microsoft SQL Server 2014 Transact-SQL Compiler Service Microsoft System CLR Types for Microsoft SQL Server 2014 Microsoft SQL Server 2014 Remote Blob Store SQL RBS codeplex samples page SQL Server Remote Blob Store blogs Microsoft SQL Server Service Broker External Activator for Microsoft SQL Server 2014 Microsoft OData Source for Microsoft SQL Server 2014 Microsoft Balanced Data Distributor for Microsoft SQL Server 2014 Microsoft Change Data Capture Designer and Service for Oracle by Attunity for Microsoft SQL Server 2014 Microsoft SQL Server 2014 Master Data Service Add-in for Microsoft Excel Microsoft SQL Server StreamInsight Microsoft Connector for SAP BW for Microsoft SQL Server 2014 Microsoft SQL Server Migration Assistant Microsoft SQL Server 2014 Upgrade Advisor Microsoft OLEDB Provider for DB2 v5.0 for Microsoft SQL Server 2014 Microsoft SQL Server 2014 PowerPivot for Microsoft SharePoint 2013 Microsoft SQL Server 2014 ADOMD.NET Microsoft Analysis Services OLE DB Provider for Microsoft SQL Server 2014 Microsoft SQL Server 2014 Analysis Management Objects Microsoft SQL Server Report Builder for Microsoft SQL Server 2014 Microsoft SQL Server 2014 Reporting Services Add-in for Microsoft SharePoint Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL

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  • SQL SERVER – Generate Database Script for SQL Azure

    - by pinaldave
    When talking about SQL Azure the common complain I hear is that the script generated from stand-along SQL Server database is not compatible with SQL Azure. This was true for some time for sure but not any more. If you have SQL Server 2008 R2 installed you can follow the guideline below to generate script which is compatible with SQL Azure. As above images are very clear I will not write more about them. SQL Azure does not support filegroups. Let us generate script for any table created on PRIMARY filegroup for standalong SQL Server and compare it with the script generated for SQL Azure. You can clearly see that there is no filegroup in the code generated for SQL Azure. Give it a try and please your comment here about what do you think about the same. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Add-On, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL Azure

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  • SQL SERVER – Microsoft SQL Server Migration Assistant V6.0 Released

    - by Pinal Dave
    Every company makes a different decision about the database when they start, but as they move forward they mature and make the decision which is based on their experience and best interest of the organization. Similarly, quite a many organizations make different decisions on database, like Sybase, MySQL, Oracle or Access and as time passes by they learn that now they want to move to a different platform. Microsoft makes it easy for SQL Server professional by releasing various Migration Assistant tools. Last week, Microsoft released Microsoft SQL Server Migration Assistant v6.0. Here are different tools released earlier last week to migrate various product to SQL Server. Microsoft SQL Server Migration Assistant v6.0 for Sybase SQL Server Migration Assistant (SSMA) is a free supported tool from Microsoft that simplifies database migration process from Sybase Adaptive Server Enterprise (ASE) to SQL Server and Azure SQL DB. SSMA automates all aspects of migration including migration assessment analysis, schema and SQL statement conversion, data migration as well as migration testing. Microsoft SQL Server Migration Assistant v6.0 for MySQL SQL Server Migration Assistant (SSMA) is a free supported tool from Microsoft that simplifies database migration process from MySQL to SQL Server and Azure SQL DB. SSMA automates all aspects of migration including migration assessment analysis, schema and SQL statement conversion, data migration as well as migration testing. Microsoft SQL Server Migration Assistant v6.0 for Oracle SQL Server Migration Assistant (SSMA) is a free supported tool from Microsoft that simplifies database migration process from Oracle to SQL Server and Azure SQL DB. SSMA automates all aspects of migration including migration assessment analysis, schema and SQL statement conversion, data migration as well as migration testing. Microsoft SQL Server Migration Assistant v6.0 for Access SQL Server Migration Assistant (SSMA) is a free supported tool from Microsoft that simplifies database migration process from Access to SQL Server. SSMA for Access automates conversion of Microsoft Access database objects to SQL Server database objects, loads the objects into SQL Server and Azure SQL DB, and then migrates data from Microsoft Access to SQL Server and Azure SQL DB. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: SQL Migration

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  • SQL SERVER – Remove Debug Button in SSMS – SQL in Sixty Seconds #020 – Video

    - by pinaldave
    SQL in Sixty Seconds is indeed tremendous fun to do. Every week, we try to come up with some new learning which we can share in Sixty Seconds. In this busy world, we all have sixty seconds to learn something new – no matter how much busy we are. In this episode of the series, we talk about another interesting feature of SQL Server Management Studio. In SQL Server Management Studio (SSMS) we have two button side by side. 1) Execute (!) and 2) Debug (>). It is quite confusing to a few developers. The debug button which looks like a play button encourages developers to click on the same thinking it will execute the code. Also developer with a Visual Studio background often click it because of their habit. However, Debug button is not the same as Execute button. In most of the cases developers want to click on Execute to run the query but by mistake they click on Debug and it wastes their valuable time. It is very easy to fix this. If developers are not frequently using a debug feature in SQL Server they should hide it from the toolbar itself. This will reduce the chances to incorrectly click on the debug button greatly as well save lots of time for developer as invoking debug processes and turning it off takes a few extra moments. In this Sixty second video we will discuss how one can hide the debug button and avoid confusion regarding execution button. I personally use function key F5 to execute the T-SQL code so I do not face this problem that often. More on Removing Debug Button in SSMS: SQL SERVER – Read Only Files and SQL Server Management Studio (SSMS) SQL SERVER – Standard Reports from SQL Server Management Studio – SQL in Sixty Seconds #016 – Video SQL SERVER – Discard Results After Query Execution – SSMS SQL SERVER – Tricks to Comment T-SQL in SSMS – SQL in Sixty Seconds #019 – Video SQL SERVER – Right Aligning Numerics in SQL Server Management Studio (SSMS) I encourage you to submit your ideas for SQL in Sixty Seconds. We will try to accommodate as many as we can. 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 – Introduction to Wait Stats and Wait Types – Wait Type – Day 1 of 28

    - by pinaldave
    I have been working a lot on Wait Stats and Wait Types recently. Last Year, I requested blog readers to send me their respective server’s wait stats. I appreciate their kind response as I have received  Wait stats from my readers. I took each of the results and carefully analyzed them. I provided necessary feedback to the person who sent me his wait stats and wait types. Based on the feedbacks I got, many of the readers have tuned their server. After a while I got further feedbacks on my recommendations and again, I collected wait stats. I recorded the wait stats and my recommendations and did further research. At some point at time, there were more than 10 different round trips of the recommendations and suggestions. Finally, after six month of working my hands on performance tuning, I have collected some real world wisdom because of this. Now I plan to share my findings with all of you over here. Before anything else, please note that all of these are based on my personal observations and opinions. They may or may not match the theory available at other places. Some of the suggestions may not match your situation. Remember, every server is different and consequently, there is more than one solution to a particular problem. However, this series is written with kept wait stats in mind. While I was working on various performance tuning consultations, I did many more things than just tuning wait stats. Today we will discuss how to capture the wait stats. I use the script diagnostic script created by my friend and SQL Server Expert Glenn Berry to collect wait stats. Here is the script to collect the wait stats: -- Isolate top waits for server instance since last restart or statistics clear WITH Waits AS (SELECT wait_type, wait_time_ms / 1000. AS wait_time_s, 100. * wait_time_ms / SUM(wait_time_ms) OVER() AS pct, ROW_NUMBER() OVER(ORDER BY wait_time_ms DESC) AS rn FROM sys.dm_os_wait_stats WHERE wait_type NOT IN ('CLR_SEMAPHORE','LAZYWRITER_SLEEP','RESOURCE_QUEUE','SLEEP_TASK' ,'SLEEP_SYSTEMTASK','SQLTRACE_BUFFER_FLUSH','WAITFOR', 'LOGMGR_QUEUE','CHECKPOINT_QUEUE' ,'REQUEST_FOR_DEADLOCK_SEARCH','XE_TIMER_EVENT','BROKER_TO_FLUSH','BROKER_TASK_STOP','CLR_MANUAL_EVENT' ,'CLR_AUTO_EVENT','DISPATCHER_QUEUE_SEMAPHORE', 'FT_IFTS_SCHEDULER_IDLE_WAIT' ,'XE_DISPATCHER_WAIT', 'XE_DISPATCHER_JOIN', 'SQLTRACE_INCREMENTAL_FLUSH_SLEEP')) SELECT W1.wait_type, CAST(W1.wait_time_s AS DECIMAL(12, 2)) AS wait_time_s, CAST(W1.pct AS DECIMAL(12, 2)) AS pct, CAST(SUM(W2.pct) AS DECIMAL(12, 2)) AS running_pct FROM Waits AS W1 INNER JOIN Waits AS W2 ON W2.rn <= W1.rn GROUP BY W1.rn, W1.wait_type, W1.wait_time_s, W1.pct HAVING SUM(W2.pct) - W1.pct < 99 OPTION (RECOMPILE); -- percentage threshold GO This script uses Dynamic Management View sys.dm_os_wait_stats to collect the wait stats. It omits the system-related wait stats which are not useful to diagnose performance-related bottleneck. Additionally, not OPTION (RECOMPILE) at the end of the DMV will ensure that every time the query runs, it retrieves new data and not the cached data. This dynamic management view collects all the information since the time when the SQL Server services have been restarted. You can also manually clear the wait stats using the following command: DBCC SQLPERF('sys.dm_os_wait_stats', CLEAR); Once the wait stats are collected, we can start analysis them and try to see what is causing any particular wait stats to achieve higher percentages than the others. Many waits stats are related to one another. When the CPU pressure is high, all the CPU-related wait stats show up on top. But when that is fixed, all the wait stats related to the CPU start showing reasonable percentages. It is difficult to have a sure solution, but there are good indications and good suggestions on how to solve this. I will keep this blog post updated as I will post more details about wait stats and how I reduce them. The reference to Book On Line is over here. Of course, I have selected February to run this Wait Stats series. I am already cheating by having the smallest month to run this series. :) Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: DMV, Pinal Dave, PostADay, SQL, SQL Authority, SQL Optimization, SQL Performance, 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 – Signal Wait Time Introduction with Simple Example – Wait Type – Day 2 of 28

    - by pinaldave
    In this post, let’s delve a bit more in depth regarding wait stats. The very first question: when do the wait stats occur? Here is the simple answer. When SQL Server is executing any task, and if for any reason it has to wait for resources to execute the task, this wait is recorded by SQL Server with the reason for the delay. Later on we can analyze these wait stats to understand the reason the task was delayed and maybe we can eliminate the wait for SQL Server. It is not always possible to remove the wait type 100%, but there are few suggestions that can help. Before we continue learning about wait types and wait stats, we need to understand three important milestones of the query life-cycle. Running - a query which is being executed on a CPU is called a running query. This query is responsible for CPU time. Runnable – a query which is ready to execute and waiting for its turn to run is called a runnable query. This query is responsible for Signal Wait time. (In other words, the query is ready to run but CPU is servicing another query). Suspended – a query which is waiting due to any reason (to know the reason, we are learning wait stats) to be converted to runnable is suspended query. This query is responsible for wait time. (In other words, this is the time we are trying to reduce). In simple words, query execution time is a summation of the query Executing CPU Time (Running) + Query Wait Time (Suspended) + Query Signal Wait Time (Runnable). Again, it may be possible a query goes to all these stats multiple times. Let us try to understand the whole thing with a simple analogy of a taxi and a passenger. Two friends, Tom and Danny, go to the mall together. When they leave the mall, they decide to take a taxi. Tom and Danny both stand in the line waiting for their turn to get into the taxi. This is the Signal Wait Time as they are ready to get into the taxi but the taxis are currently serving other customer and they have to wait for their turn. In other word they are in a runnable state. Now when it is their turn to get into the taxi, the taxi driver informs them he does not take credit cards and only cash is accepted. Neither Tom nor Danny have enough cash, they both cannot get into the vehicle. Tom waits outside in the queue and Danny goes to ATM to fetch the cash. During this time the taxi cannot wait, they have to let other passengers get into the taxi. As Tom and Danny both are outside in the queue, this is the Query Wait Time and they are in the suspended state. They cannot do anything till they get the cash. Once Danny gets the cash, they are both standing in the line again, creating one more Signal Wait Time. This time when their turn comes they can pay the taxi driver in cash and reach their destination. The time taken for the taxi to get from the mall to the destination is running time (CPU time) and the taxi is running. I hope this analogy is bit clear with the wait stats. You can check the Signalwait stats using following query of Glenn Berry. -- Signal Waits for instance SELECT CAST(100.0 * SUM(signal_wait_time_ms) / SUM (wait_time_ms) AS NUMERIC(20,2)) AS [%signal (cpu) waits], CAST(100.0 * SUM(wait_time_ms - signal_wait_time_ms) / SUM (wait_time_ms) AS NUMERIC(20,2)) AS [%resource waits] FROM sys.dm_os_wait_stats OPTION (RECOMPILE); Higher the Signal wait stats are not good for the system. Very high value indicates CPU pressure. In my experience, when systems are running smooth and without any glitch the Signal wait stat is lower than 20%. Again, this number can be debated (and it is from my experience and is not documented anywhere). In other words, lower is better and higher is not good for the system. In future articles we will discuss in detail the various wait types and wait stats and their resolution. 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 DMV, SQL Performance, 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 – Single Wait Time Introduction with Simple Example – Wait Type – Day 2 of 28

    - by pinaldave
    In this post, let’s delve a bit more in depth regarding wait stats. The very first question: when do the wait stats occur? Here is the simple answer. When SQL Server is executing any task, and if for any reason it has to wait for resources to execute the task, this wait is recorded by SQL Server with the reason for the delay. Later on we can analyze these wait stats to understand the reason the task was delayed and maybe we can eliminate the wait for SQL Server. It is not always possible to remove the wait type 100%, but there are few suggestions that can help. Before we continue learning about wait types and wait stats, we need to understand three important milestones of the query life-cycle. Running - a query which is being executed on a CPU is called a running query. This query is responsible for CPU time. Runnable – a query which is ready to execute and waiting for its turn to run is called a runnable query. This query is responsible for Single Wait time. (In other words, the query is ready to run but CPU is servicing another query). Suspended – a query which is waiting due to any reason (to know the reason, we are learning wait stats) to be converted to runnable is suspended query. This query is responsible for wait time. (In other words, this is the time we are trying to reduce). In simple words, query execution time is a summation of the query Executing CPU Time (Running) + Query Wait Time (Suspended) + Query Single Wait Time (Runnable). Again, it may be possible a query goes to all these stats multiple times. Let us try to understand the whole thing with a simple analogy of a taxi and a passenger. Two friends, Tom and Danny, go to the mall together. When they leave the mall, they decide to take a taxi. Tom and Danny both stand in the line waiting for their turn to get into the taxi. This is the Signal Wait Time as they are ready to get into the taxi but the taxis are currently serving other customer and they have to wait for their turn. In other word they are in a runnable state. Now when it is their turn to get into the taxi, the taxi driver informs them he does not take credit cards and only cash is accepted. Neither Tom nor Danny have enough cash, they both cannot get into the vehicle. Tom waits outside in the queue and Danny goes to ATM to fetch the cash. During this time the taxi cannot wait, they have to let other passengers get into the taxi. As Tom and Danny both are outside in the queue, this is the Query Wait Time and they are in the suspended state. They cannot do anything till they get the cash. Once Danny gets the cash, they are both standing in the line again, creating one more Single Wait Time. This time when their turn comes they can pay the taxi driver in cash and reach their destination. The time taken for the taxi to get from the mall to the destination is running time (CPU time) and the taxi is running. I hope this analogy is bit clear with the wait stats. You can check the single wait stats using following query of Glenn Berry. -- Signal Waits for instance SELECT CAST(100.0 * SUM(signal_wait_time_ms) / SUM (wait_time_ms) AS NUMERIC(20,2)) AS [%signal (cpu) waits], CAST(100.0 * SUM(wait_time_ms - signal_wait_time_ms) / SUM (wait_time_ms) AS NUMERIC(20,2)) AS [%resource waits] FROM sys.dm_os_wait_stats OPTION (RECOMPILE); Higher the single wait stats are not good for the system. Very high value indicates CPU pressure. In my experience, when systems are running smooth and without any glitch the single wait stat is lower than 20%. Again, this number can be debated (and it is from my experience and is not documented anywhere). In other words, lower is better and higher is not good for the system. In future articles we will discuss in detail the various wait types and wait stats and their resolution. 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 DMV, SQL Performance, 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 – Update Statistics are Sampled By Default

    - by pinaldave
    After reading my earlier post SQL SERVER – Create Primary Key with Specific Name when Creating Table on Statistics, I have received another question by a blog reader. The question is as follows: Question: Are the statistics sampled by default? Answer: Yes. The sampling rate can be specified by the user and it can be anywhere between a very low value to 100%. Let us do a small experiment to verify if the auto update on statistics is left on. Also, let’s examine a very large table that is created and statistics by default- whether the statistics are sampled or not. USE [AdventureWorks] GO -- Create Table CREATE TABLE [dbo].[StatsTest]( [ID] [int] IDENTITY(1,1) NOT NULL, [FirstName] [varchar](100) NULL, [LastName] [varchar](100) NULL, [City] [varchar](100) NULL, CONSTRAINT [PK_StatsTest] PRIMARY KEY CLUSTERED ([ID] ASC) ) ON [PRIMARY] GO -- Insert 1 Million Rows INSERT INTO [dbo].[StatsTest] (FirstName,LastName,City) SELECT TOP 1000000 '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)%10 = 1 THEN 'New York' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 5 THEN 'San Marino' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 3 THEN 'Los Angeles' ELSE 'Houston' END FROM sys.all_objects a CROSS JOIN sys.all_objects b GO -- Update the statistics UPDATE STATISTICS [dbo].[StatsTest] GO -- Shows the statistics DBCC SHOW_STATISTICS ("StatsTest"PK_StatsTest) GO -- Clean up DROP TABLE [dbo].[StatsTest] GO Now let us observe the result of the DBCC SHOW_STATISTICS. The result shows that Resultset is for sure sampling for a large dataset. The percentage of sampling is based on data distribution as well as the kind of data in the table. Before dropping the table, let us check first the size of the table. The size of the table is 35 MB. Now, let us run the above code with lesser number of the rows. USE [AdventureWorks] GO -- Create Table CREATE TABLE [dbo].[StatsTest]( [ID] [int] IDENTITY(1,1) NOT NULL, [FirstName] [varchar](100) NULL, [LastName] [varchar](100) NULL, [City] [varchar](100) NULL, CONSTRAINT [PK_StatsTest] PRIMARY KEY CLUSTERED ([ID] ASC) ) ON [PRIMARY] GO -- Insert 1 Hundred Thousand Rows INSERT INTO [dbo].[StatsTest] (FirstName,LastName,City) SELECT TOP 100000 '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)%10 = 1 THEN 'New York' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 5 THEN 'San Marino' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 3 THEN 'Los Angeles' ELSE 'Houston' END FROM sys.all_objects a CROSS JOIN sys.all_objects b GO -- Update the statistics UPDATE STATISTICS [dbo].[StatsTest] GO -- Shows the statistics DBCC SHOW_STATISTICS ("StatsTest"PK_StatsTest) GO -- Clean up DROP TABLE [dbo].[StatsTest] GO You can see that Rows Sampled is just the same as Rows of the table. In this case, the sample rate is 100%. Before dropping the table, let us also check the size of the table. The size of the table is less than 4 MB. Let us compare the Result set just for a valid reference. Test 1: Total Rows: 1000000, Rows Sampled: 255420, Size of the Table: 35.516 MB Test 2: Total Rows: 100000, Rows Sampled: 100000, Size of the Table: 3.555 MB The reason behind the sample in the Test1 is that the data space is larger than 8 MB, and therefore it uses more than 1024 data pages. If the data space is smaller than 8 MB and uses less than 1024 data pages, then the sampling does not happen. Sampling aids in reducing excessive data scan; however, sometimes it reduces the accuracy of the data as well. Please note that this is just a sample test and there is no way it can be claimed as a benchmark test. The result can be dissimilar on different machines. There are lots of other information can be included when talking about this subject. I will write detail post covering all the subject very soon. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Index, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL Statistics

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  • SQLAuthority News – Feature Pack for Microsoft SQL Server 2005 SP4

    - by pinaldave
    If you are still using SQL Server 2005 – I suggest that you consider migrating to later version of the SQL Server 2008/2008 R2. Due to any reason, you wanted to continue using SQL Server 2005, I suggest that you take a look at the Feature Pack for Microsoft SQL Server 2005 SP4. There are many different tools and features available in pack, which can be very handy and can solve issues. Microsoft ADOMD.NET Microsoft Core XML Services (MSXML) 6.0 Microsoft OLEDB Provider for DB2 Microsoft SQL Server Management Pack for MOM 2005 Microsoft SQL Server 2000 PivotTable Services Microsoft SQL Server 2000 DTS Designer Components Microsoft SQL Server Native Client Microsoft SQL Server 2005 Analysis Services 9.0 OLE DB Provider Microsoft SQL Server 2005 Backward Compatibility Components Microsoft SQL Server 2005 Command Line Query Utility Microsoft SQL Server 2005 Datamining Viewer Controls Microsoft SQL Server 2005 JDBC Driver Microsoft SQL Server 2005 Management Objects Collection Microsoft SQL Server 2005 Compact Edition Microsoft SQL Server 2005 Notification Services Client Components Microsoft SQL Server 2005 Upgrade Advisor Microsoft .NET Data Provider for mySAP Business Suite, Preview Version Reporting Add-In for Microsoft Visual Web Developer 2005 Express Microsoft Exception Message Box Data Mining Managed Plug-in Algorithm API for SQL Server 2005 Microsoft SQL Server 2005 Reporting Services Add-in for Microsoft SharePoint Technologies Microsoft SQL Server 2005 Data Mining Add-ins for Microsoft Office 2007 SQL Server 2005 Performance Dashboard Reports SQL Server 2005 Best Practices Analyzer Download Feature Pack for Microsoft SQL Server 2005 SP4 Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: SQL, SQL Authority, SQL Documentation, SQL Download, SQL Query, SQL Server, SQL Service Pack, SQL Tips and Tricks, SQLAuthority News, T SQL, Technology

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