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  • SQL SERVER – Beginning New Weekly Series – Memory Lane – #001

    - by pinaldave
    I am introducing a new series today.  This series is called “Memory Lane.”  From the last six years and 2,300 articles, there are fantastic articles I keep revisiting.  Sometimes when I read old blog posts I think I should have included something or added a bit more to the topic.  But for many articles, I still feel they are fantastic (even after six years) and could be read again and again. I have also found that after six years of blogging, readers will write to me and say “Pinal, why don’t you write about X, Y or Z.”  The answer is: I already did!  It is here on the blog, or in the comments, or possibly in one of my books.  The solution has always been there, it is simply a matter of finding it and presenting it again.  That is why I have created Memory Lane.  I will be listing the best articles from the same week of the past six years.  You will find plenty of reading material every Saturday from articles of SQLAuthority past. 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 Query to Display Foreign Key Relationships and Name of the Constraint for Each Table in Database My blogging journey began with this blog post. As many of you know my journey began with creating a repository of my scripts. This was very first script which I had written to find out foreign key relationship and constraints. The same query was updated later on using the new SYS schema modification in SQL Server. Version 1: Using sys.schema Version 2: Using sys.schema and additional columns 2007 Milestone Posts – 1 Year (365 blogs) and 1 Million Views When I reached 1st week of Nov in 2007 SQLAuthority.com blog had around 365 blog posts and 1 Million Views. I was not obsessed with the statistics before but this was indeed an interesting moment for me as I was blogging for myself and did not realize that so many people are reading my blog. In year 2006 there were not many bloggers so blogging was new to me as well. I was learning it as I go. 2008 Stored Procedure WITH ENCRYPTION and Execution Plan If you have stored procedure and its code is encrypted when you execute it what will be displayed in the execution plan. There are two kinds of execution plans 1) Estimated and 2) Actual. It will be indeed interesting to know what is displayed in both the cases when Stored Procedure is encrypted. What is your guess? Now go ahead and click on here and figure out your answer. If the user is not able to login into SQL Server due to any error or issues there were two different blog post addresses the same issue here and here. 2009 It seems like Nov is the month of SQLPASS month. In 2009 on the same week I was in USA attending SQLPASS event. I had a fantastic experience attending the event. Here are the blog posts covering the subject Day 1, Day 2, Day 3, Day 4 2010 Finding the last backup time for all the databases This little script is very powerful and instantly gives details when was the last time your database backup performed. If you are reading this blog post – I say just go ahead and check if everything is alright on your server and you have all the necessary latest backup. It is better to be safe than sorrow. Version 1: Above script was improved to get more details about the database Version 2: This version of the script will include pretty much have all the backup related information in a single script. Do not miss to save it for future use. Are you a Database Administrator or a Database Developer? Three years ago I created a very small survey and the results which I have received are very interesting. The question was asking what is the profile of the visitor of that blog post and I noticed that DBA and Developers have balanced with little inclination towards Developers. Have you voted so far? If not, go ahead! 2011 New Book Released – SQL Server Interview Questions And Answers One year ago, on November 3, 2011 I published my book SQL Server Interview Questions and Answers.  The book has a lot of great reviews, and we have even received emails telling us this book was a life changer because it helped get them a great new job.  I don’t think anyone can get a job just from my book.  It was the individual who studied hard and took it seriously, and was determined to learn something new.  The book might have helped guide them and show them the topics to study, but they spent their own energy on it.  It was their own skills that helped them pass the exam. So, in this very first installment, I would like to thank the readers for accepting our book, for giving it great reviews and for using it and sharing it.  Our goal in writing this book was to help others, and it seems like we succeeded. 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 – Beginning New Weekly Series – Memory Lane – #002

    - 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 Query to Find ByteSize of All the Tables in Database This was my second blog post and today I do not remember what was the business need which has made me build this query. It was built for SQL Server 2000 and it will not directly run on SQL Server 2005 or later version now. It measured the byte size of the tables in the database. This can be done in many different ways as well for example SP_HELPDB as well SP_HELP. I wish to build similar script in 2005 and later version. 2007 This week I had completed my – 1 Year (365 blogs) and very first 1 Million Views. I was pretty excited at that time with this new achievement. SQL SERVER Versions, CodeNames, Year of Release When I started with SQL Server I did not know all the names correctly for each version and I often used to get confused with this. However, as time passed by I started to remember all the codename as well. In this blog post I have not included SQL Server 2012′s code name as it was not released at the time. SQL Server 2012′s code name is Denali. Here is the question for you – anyone know what is the internal name of the SQL Server’s next version? Searching String in Stored Procedure I have already started to work with 2005 by this time and I was personally converting each of my stored procedures to SQL Server 2005 compatible. As we were upgrading from SQL Server 2000 to SQL Server 2005 we had to search each of the stored procedures and make sure that we remove incompatible code from it. For example, syscolumns of SQL Server 2000 was now being replaced by sys.columns of SQL Server 2005. This stored procedure was pretty helpful at that time. Later on I build few additional versions of the same stored procedure. Version 1: This version finds the Stored Procedures related to Table Version 2: This is specific version which works with SQL Server 2005 and later version 2008 Clear Drop Down List of Recent Connection From SQL Server Management Studio It happens to all of us when we connected to some remote client server and we never ever have to connect to it again. However, it keeps on bothering us that the name shows up in the list all the time. In this blog post I covered a quick tip about how we can remove the same. I also wrote a small article about How to Check Database Integrity for all Databases and there was a funny question from a reader requesting T-SQL code to refresh databases. 2009 Stored Procedure are Compiled on First Run – SP is taking Longer to Run First Time A myth is quite prevailing in the industry that Stored Procedures are pre-compiled and they should always run faster. It is not true. Stored procedures are compiled on very first execution of it and that is the reason why it takes longer when it executes first time. In this blog post I had a great time discussing the same concept. If you do not agree with it, you are welcome to read this blog post. Removing Key Lookup – Seek Predicate – Predicate – An Interesting Observation Related to Datatypes Performance Tuning is an interesting concept and my personal favorite one. In many blog posts I have described how to do performance tuning and how to improve the performance of the queries. In this quick quick tip I have explained how one can remove the Key Lookup and improve performance. Here are very relevant articles on this subject: Article 1 | Article 2 | Article 3 2010 Recycle Error Log – Create New Log file without a Server Restart During one of the consulting assignments I noticed DBA restarting server to create new log file. This is absolutely not necessary and restarting server might have many other negative impacts. There is a common sp_cycle_errorlog which can do the same task efficiently and properly. Have you ever used this SP or feature? Additionally I had a great time presenting on SQL Server Best Practices in SharePoint Conference. 2011 SSMS 2012 Reset Keyboard Shortcuts to Default It is very much possible that we mix up various SQL Server shortcuts and at times we feel like resetting it to default. In SQL Server 2012 it is not easy to do it, there is a process to follow and I enjoyed blogging about it. Fundamentals of Columnstore Index Columnstore index is introduced in SQL Server 2012 and have been a very popular subject. It increases the speed of the server dramatically as well can be an extremely useful feature with Datawharehousing. However updating the columnstore index is not as simple as a simple UPDATE statement. Read in a detailed blog post about how Update works with Columnstore Index. Additionally, you can watch a Quick Video on this subject. SQL Server 2012 New Features I had decided to explore SQL Server 2012 features last year and went through pretty much every single concept introduced in separate blog posts. Here are two blog posts where I describe how SQL Server 2012 functions works. Introduction to CUME_DIST – Analytic Functions Introduction to FIRST _VALUE and LAST_VALUE – Analytic Functions OVER clause with FIRST_VALUE and LAST_VALUE – Analytic Functions I indeed enjoyed writing about SQL Server 2012 functions last year. Have you gone through all the new features which are introduced in SQL Server 2012? If not, it is still not late to go through them. 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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  • BIP BIServer Query Debug

    - by Tim Dexter
    With some help from Bryan, I have uncovered a way of being able to debug or at least log what BIServer is doing when BIP sends it a query request. This is not for those of you querying the database directly but if you are using the BIServer and its datamodel to fetch data for a BIP report. If you have written or used the query builder against BIServer and when you run the report it chokes with a cryptic message, that you have no clue about, read on. When BIP runs a piece of BIServer logical SQL to fetch data. It does not appear to validate it, it just passes it through, so what is BIServer doing on its end? As you may know, you are not writing regular physical sql its actually logical sql e.g. select Jobs."Job Title" as "Job Title", Employees."Last Name" as "Last Name", Employees.Salary as Salary, Locations."Department Name" as "Department Name", Locations."Country Name" as "Country Name", Locations."Region Name" as "Region Name" from HR.Locations Locations, HR.Employees Employees, HR.Jobs Jobs The tables might not even be a physical tables, we don't care, that's what the BIServer and its model are for. You have put all the effort into building the model, just go get me the data from where ever it might be. The BIServer takes the logical sql and uses its vast brain to work out what the physical SQL is, executes it and passes the result back to BIP. select distinct T32556.JOB_TITLE as c1, T32543.LAST_NAME as c2, T32543.SALARY as c3, T32537.DEPARTMENT_NAME as c4, T32532.COUNTRY_NAME as c5, T32577.REGION_NAME as c6 from JOBS T32556, REGIONS T32577, COUNTRIES T32532, LOCATIONS T32569, DEPARTMENTS T32537, EMPLOYEES T32543 where ( T32532.COUNTRY_ID = T32569.COUNTRY_ID and T32532.REGION_ID = T32577.REGION_ID and T32537.DEPARTMENT_ID = T32543.DEPARTMENT_ID and T32537.LOCATION_ID = T32569.LOCATION_ID and T32543.JOB_ID = T32556.JOB_ID ) Not a very tough example I know but you get the idea. How do I know what the BIServer is up to? How can I find out what the issue might be if BIServer chokes on my query? There are a couple of steps: In the Administrator tool you need to set the logging level for the Administrator user to something greater than the default '0'. '7' is going to give you the max. Just remember to take it back down after you have finished the debug. I needed to bounce my BIServer service Now here's the secret sauce. Prefix the following to your BIP query set variable LOGLEVEL = 7; Set the log level to that you have in the admin tool Now run your BIP report. With the prefix in place; BIServer will write to the NQQuery.log file. This is located in the ./OracleBI/server/Log directory. In there you are going to find the complete process the BIServer has gone through to try and get the data back for you A quick note, if the BIServer can, its going to hit that great BIEE cache to get your data and you may not see the full log. IF this is the case. Get inot hte Administration page (via the browser login) and clear out your BIP report cursor. Then re-run. This will hopefully help out if you are trying to debug that annoying BIP report that will not run or is getting some strange data. Don't forget to turn that logging level back down once you are done. This will avoid the DBA screaming at you for sucking up all the disk space on the system.

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  • Why is my mssql query failing?

    - by Eric Reynolds
    connect(); $arr = mssql_fetch_assoc(mssql_query("SELECT Applications.ProductName, Applications.ProductVersion, Applications.ProductSize, Applications.Description, Applications.ProductKey, Applications.ProductKeyID, Applications.AutomatedInstaller, Applications.AutomatedInstallerName, Applications.ISO, Applications.ISOName, Applications.Internet, Applications.InternetURL, Applications.DatePublished, Applications.LicenseID, Applications.InstallationGuide, Vendors.VendorName FROM Applications INNER JOIN Vendors ON Applications.VendorID = Vendors.VendorID WHERE ApplicationID = ".$ApplicationID)); $query1 = mssql_query("SELECT Issues.AppID, Issues.KnownIssues FROM Issues WHERE Issues.AppID=".$ApplicationID); $issues = mssql_fetch_assoc($query1); $query2 = mssql_query("SELECT ApplicationInfo.AppID, ApplicationInfo.Support_Status, ApplicationInfo.UD_Training, ApplicationInfo.AtomicTraining, ApplicationInfo.VendorURL FROM software.software_dbo.ApplicationInfo WHERE ApplicationInfo.AppID = ".$ApplicationID); $row = mssql_fetch_assoc($query2); function connect(){ $connect = mssql_connect(DBSERVER, DBO, DBPW) or die("Unable to connect to server"); $selected = mssql_select_db(DBNAME, $connect) or die("Unable to connect to database"); return $connect; } Above is the code. The first query/fetch_assoc works perfectly fine, however the next 2 queries fail and I cannot figure out why. Here is the error statement that shows up from php: Warning: mssql_query() [function.mssql-query]: message: Invalid object name 'Issues'. (severity 16) in /srv/www/htdocs/agreement.php on line 47 Warning: mssql_query() [function.mssql-query]: General SQL Server error: Check messages from the SQL Server (severity 16) in /srv/www/htdocs/agreement.php on line 47 Warning: mssql_query() [function.mssql-query]: Query failed in /srv/www/htdocs/agreement.php on line 47 Warning: mssql_fetch_assoc(): supplied argument is not a valid MS SQL-result resource in /srv/www/htdocs/agreement.php on line 48 Warning: mssql_query() [function.mssql-query]: message: Invalid object name 'software.software_dbo.ApplicationInfo'. (severity 16) in /srv/www/htdocs/agreement.php on line 51 Warning: mssql_query() [function.mssql-query]: General SQL Server error: Check messages from the SQL Server (severity 16) in /srv/www/htdocs/agreement.php on line 51 Warning: mssql_query() [function.mssql-query]: Query failed in /srv/www/htdocs/agreement.php on line 51 Warning: mssql_fetch_assoc(): supplied argument is not a valid MS SQL-result resource in /srv/www/htdocs/agreement.php on line 52 The error clearly centers around the fact that the query is not executing. In my database I have a table called Issues and a table called ApplicationInfo so I am unsure why it is telling me that they are invalid objects. Any help would be appreciated. Thanks, Eric R.

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  • Query by datetime in JDOQL / Java / GAE

    - by Jan Kuboschek
    I'm working on a GAE app. I want to query datastore and retrieve all records between startDate and endDate. Each record has a datetime field. I'm using a query similar to this (the below code is something I quickly grabbed - I'm not near my developer machine.): Query query = pm.newQuery(Employee.class); query.setFilter("lastName == lastNameParam"); query.setOrdering("hireDate desc"); query.declareParameters("String lastNameParam"); try { List results = (List) query.execute("Smith"); if (results.iterator().hasNext()) { for (Employee e : results) { // ... } } else { // ... no results ... } } finally { query.closeAll(); } How do I have to format the date to form a correctly working query? How is the datetime stamp stored in datastore? As timestamp? Fully formatted? I can't find ANY information on this. Please help.

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  • Top 10 collection completion - a monster in-query formula in MySQL?

    - by Andrew Heath
    I've got the following tables: User Basic Data (unique) [userid] [name] [etc] User Collection (one to one) [userid] [game] User Recorded Plays (many to many) [userid] [game] [scenario] [etc] Game Basic Data (unique) [game] [total_scenarios] I would like to output a table that shows the collection play completion percentage for the Top 10 users in descending order of %: Output Table [userid] [collection_completion] 3 95% 1 81% 24 68% etc etc In my mind, the calculation sequence for ONE USER is: grab user's total owned scenarios from User Collection joined with Game Basic Data and COUNT(gbd.total_scenarios) grab all recorded plays by COUNT(DISTINCT scenario) for that user Divide all recorded plays by total owned scenarios So that's 2 queries and a little PHP massage at the end. For a list of users sorted by completion percentage things get a little more complicated. I figure I could grab all users' collection totals in one query, and all users recorded plays in another, and then do the calcs and sort the final array in PHP, but it seems like overkill to potentially be doing all that for 1000+ users when I only ever want the Top 10. Is there a wicked monster query in MySQL that could do all that and LIMIT 10? Or is sticking with PHP handling the bulk of the work the way to go in this case?

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  • NHibernate Query object collection issue

    - by Mahesh
    Hi, I am new to NHibernate and need some information regarding the internal working of the engine: I have a table called Student and the design is as follows: RollNo Name City Postcode and there are 5 more columns like this. I have School class and mappings associated with it. I am querying RollNo and Name using session as given below: IQuery query = session.CreateQuery("SELECT RollNo,Name FROM Student); Executing query.List resulting in error because the query is returning object[][]. Now, I changed the query as given below: IQuery query = session.CreateQuery("FROM Student); Executing query.List on this query yeilds the desired results. But, the results contain more data than I want. Could you please let me know the query to which I can get RollNo and Name from Student and castable as Student collection. Thanks, Mahesh

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  • Don't display dynamic query in result

    - by Tom Andrews
    Hi all, Is it possible to hide a dynamic query from the result sets provided from a Stored Procedure? I am using the @@rowcount of the dynamic query to set a variable that is used to determine whether another query runs or not. The other query is used by code that I cannot change - hence why I am changing the Stored Procedure. The dynamic query returns as the first result set from the Stored Procedure is now the result of the dynamic query which currently is "breaking" the calling code. Thanks in advance

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  • codeigniter mulitple LIKE db query using associative array- but all from the same column name...?

    - by Inigo
    Hi, I'm trying to query my database using codeigniter's active record class. I have a number of blog posts stored in a table. The query is for a search function, which will pull out all the posts that have certain categories assigned to them. So the 'category' column of the table will have a list of all the categories for that post in no particular order, separated by commas, like so: Politics,History,Sociology.. etc. If a user selects, say, Politics and History, The titles of all the posts that have BOTH these categories should be returned. Right? So, the list of categories queried will be the array $cats. I thought this would work- foreach ($cats as $cat){ $this->db->like('categories',$cat); } By Producing this- $this-db-like('categories','Politics'); $this-db-like('categories','History'); (Which would produce- 'WHERE categories LIKE '%Politics%' AND categories LIKE '%History%') But it doesn't work, it seems to only produce the first statement. The problem I guess is that the column name is the same for each of the chained queries. There doesn't seem to be anything in the CI user guide about this (http://codeigniter.com/user_guide/database/active_record.html) as they seem to assume that each chained statement is going to be for a different column name. Does anyone know how I could do this? Thanks! edit- Of course it is not possible to use an associative array in one statement as it would have to contain duplicate keys- in this case every key would have to be 'categories'...

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  • Cannot use a Like query in a JSP prepared statement?

    - by SeerUK
    OK, first the query code and query: ps = conn.prepareStatement("select instance_id, ? from eam_measurement where resource_id in (select RESOURCE_ID from eam_res_grp_res_map where resource_group_id = ?) and DSN like '?' order by 2"); ps.setString(1,"SUBSTR(DSN,27,16)"); ps.setInt(2,defaultWasGroup); ps.setString(3,"%Module=jvmRuntimeModule:freeMemory%"); rs = ps.executeQuery(); while (rs.next()) { bla blah blah blah ... Returns an empty resultSet. Through basic debugging I have found its the 3rd bind that is the problem i.e. DSN like '?' I have tried all kinds of variations, the most sensible of which seemed to be using: DSN like concat('%',?,'%') bit that doesn' work as I am missing the ' ' either side of the concatenated string so I try DSN like ' concat('%',Module=P_STAG_JDBC01:poolSize,'%') ' order by 2 but I just can't seem to find a way to get them in that works. What am I missing? :) Thanks!

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  • What are the Limitations for Connecting to an Access Query in Excel

    - by thornomad
    I have an Access 2007 database that has a number of tables, some are fairly large (100,000+ records); I have created a union query to pull some of the same types of data from multiple tables into one large query for pivot table manipulation and reporting. For example: SELECT Language FROM Table1 UNION ALL SELECT Language FROM Table2 UNION ALL SELECT Language FROM Table3; This works. I found, quickly, however, that a union query will not show up when connecting to the datasource from Excel 2007. So, I created a second query to reference the union query. Like so: SELECT * FROM [The Above Union Query]; This query works and it, initially, was accessible from Excel. Time passed, I've added more data. Suddenly, when I connect to my Access database from Excel my query referencing the union has disappeared. MS Access shows no signs of an issue (data displays in Access) and my other non-union queries are showing up in Excel 2007 ... but not the one that references the union. What could be going on? Why did it disappear? I noticed if I switch some of the referenced tables in the union query to a smaller table (with less rows) all of sudden the query appears in Excel again. At least, I think that's what the difference is. I really can't put my finger on why some of the union queries won't show up and some will. Am stumped and need some guidance. Thanks.

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  • Table Adapter query Builder ASP.NET

    - by kmsony32
    I want to connect my Table adapter with the Oracle, for that I am preparing a sql query with the query builder. The query which is running fine in Oracle but makes syntax error with query builder.It shows unable to parse the query text. I am using case statement and joins within the query.

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  • SQL SERVER – Convert IN to EXISTS – Performance Talk

    - by pinaldave
    In recent training one of the attendee asked if I can show simple method to convert IN clause to EXISTS clause. Here is the simple example. 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 exists SELECT * FROM HumanResources.Employee E WHERE EXISTS ( SELECT EA.EmployeeID FROM HumanResources.EmployeeAddress EA WHERE EA.EmployeeID = E.EmployeeID) GO It is NOT necessary that every time when IN is replaced by EXISTS it gives better performance. However, in our case listed above it does for sure give better performance. Click on below image to see the execution plan. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – PAGEIOLATCH_DT, PAGEIOLATCH_EX, PAGEIOLATCH_KP, PAGEIOLATCH_SH, PAGEIOLATCH_UP – Wait Type – Day 9 of 28

    - by pinaldave
    It is very easy to say that you replace your hardware as that is not up to the mark. In reality, it is very difficult to implement. It is really hard to convince an infrastructure team to change any hardware because they are not performing at their best. I had a nightmare related to this issue in a deal with an infrastructure team as I suggested that they replace their faulty hardware. This is because they were initially not accepting the fact that it is the fault of their hardware. But it is really easy to say “Trust me, I am correct”, while it is equally important that you put some logical reasoning along with this statement. PAGEIOLATCH_XX is such a kind of those wait stats that we would directly like to blame on the underlying subsystem. Of course, most of the time, it is correct – the underlying subsystem is usually the problem. From Book On-Line: PAGEIOLATCH_DT Occurs when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Destroy mode. Long waits may indicate problems with the disk subsystem. PAGEIOLATCH_EX Occurs when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Exclusive mode. Long waits may indicate problems with the disk subsystem. PAGEIOLATCH_KP Occurs when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Keep mode. Long waits may indicate problems with the disk subsystem. PAGEIOLATCH_SH Occurs when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Shared mode. Long waits may indicate problems with the disk subsystem. PAGEIOLATCH_UP Occurs when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Update mode. Long waits may indicate problems with the disk subsystem. PAGEIOLATCH_XX Explanation: Simply put, this particular wait type occurs when any of the tasks is waiting for data from the disk to move to the buffer cache. ReducingPAGEIOLATCH_XX wait: Just like any other wait type, this is again a very challenging and interesting subject to resolve. Here are a few things you can experiment on: Improve your IO subsystem speed (read the first paragraph of this article, if you have not read it, I repeat that it is easy to say a step like this than to actually implement or do it). This type of wait stats can also happen due to memory pressure or any other memory issues. Putting aside the issue of a faulty IO subsystem, this wait type warrants proper analysis of the memory counters. If due to any reasons, the memory is not optimal and unable to receive the IO data. This situation can create this kind of wait type. Proper placing of files is very important. We should check file system for the proper placement of files – LDF and MDF on separate drive, TempDB on separate drive, hot spot tables on separate filegroup (and on separate disk), etc. Check the File Statistics and see if there is higher IO Read and IO Write Stall SQL SERVER – Get File Statistics Using fn_virtualfilestats. It is very possible that there are no proper indexes on the system and there are lots of table scans and heap scans. Creating proper index can reduce the IO bandwidth considerably. If SQL Server can use appropriate cover index instead of clustered index, it can significantly reduce lots of CPU, Memory and IO (considering cover index has much lesser columns than cluster table and all other it depends conditions). You can refer to the two articles’ links below previously written by me that talk about how to optimize indexes. Create Missing Indexes Drop Unused Indexes Updating statistics can help the Query Optimizer to render optimal plan, which can only be either directly or indirectly. I have seen that updating statistics with full scan (again, if your database is huge and you cannot do this – never mind!) can provide optimal information to SQL Server optimizer leading to efficient plan. Checking Memory Related Perfmon Counters SQLServer: Memory Manager\Memory Grants Pending (Consistent higher value than 0-2) SQLServer: Memory Manager\Memory Grants Outstanding (Consistent higher value, Benchmark) SQLServer: Buffer Manager\Buffer Hit Cache Ratio (Higher is better, greater than 90% for usually smooth running system) SQLServer: Buffer Manager\Page Life Expectancy (Consistent lower value than 300 seconds) Memory: Available Mbytes (Information only) Memory: Page Faults/sec (Benchmark only) Memory: Pages/sec (Benchmark only) Checking Disk Related Perfmon Counters Average Disk sec/Read (Consistent higher value than 4-8 millisecond is not good) Average Disk sec/Write (Consistent higher value than 4-8 millisecond is not good) Average Disk Read/Write Queue Length (Consistent higher value than benchmark is not good) Note: The information presented here is from my experience and there is no way that I claim it to be accurate. I suggest reading Book OnLine for further clarification. All of the discussions of Wait Stats in this blog is generic and varies from system to system. It is recommended that you test this on a development server before implementing it to a production server. 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, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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  • T-SQL Tuesday: What kind of Bookmark are you using?

    - by Kalen Delaney
    I’m glad there is no minimum length requirement for T-SQL Tuesday blog posts , because this one will be short. I was in the classroom for almost 11 hours today, and I need to be back tomorrow morning at 7:30. Way long ago, back in SQL 2000 (or was it earlier?) when a query indicated that SQL Server was going to use a nonclustered index to get row pointers, and then look up those rows in the underlying table, the plan just had a very linear look to it. The operator that indicated going from the nonclustered...(read more)

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  • SQL SERVER – Mirroring Configured Without Domain – The server network address TCP://SQLServerName:50

    - by pinaldave
    Regular readers of my blog will be aware of my friend who called me few days ago with very a funny SQL Problem SQL SERVER – SSMS Query Command(s) completed successfully without ANY Results. This time, it did not take long before he called me up with another interesting problem, although the issue he was facing this time was not that interesting and also very specific to him, however, he insisted me to share with all of you. Let us understand his situation at first. My friend is preparing for DBA exam Exam 70-450: PRO: Designing, Optimizing and Maintaining a Database Server Infrastructure using Microsoft SQL Server 2008 and for the same, he was trying to set up replication on his local laptop. He had installed two different instances of SQL Server on his computer and every time when he started the mirroring, it failed with common error message. The server network address “TCP://SQLServer:5023? cannot be reached or does not exist. Check the network address name and that the ports for the local and remote endpoints are operational. (Microsoft SQL Server, Error: 1418) Well, before he contacted me, he searched online and checked my article written on the error in mirroring. However, he tried all the four suggestions, but it did not solve his problem. He called me at a reasonable time of late evening (unlike last time, which was midnight!). I even tried all the seven different suggestions myself, as previously proposed in my article; however, none of them worked. While looking at closely at services, I noticed something very simple. He was running all the instances on ‘Network Services’. In fact, his computer was a stand-alone computer. There was no network at all. Also, there was no domain or any other advance network concepts implemented. I just changed services from ‘Network Services’ to ‘Local System’ as his SQL Server was running on his local system and there were no network services. This prompted to restart the services. As this was not the production server and his development machine, we restarted the services on the laptop (do not restart services on production server without proper planning). After changing the ‘services log on’ account to localsystem, when he attempted to reconfigure the mirroring it worked right away. As usually in production server, proper domains are configured and advance network concepts are implemented I had never faced this type of problem earlier. My friend insisted to post this solution to his situation, wherein there was no domain configured and setting up mirroring was throwing an error. According to him, this is bound to help people, like him, who are preparing for certification using single system. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Error Messages, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL Certifications, SQL Mirroring

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  • SQL SERVER – World Shapefile Download and Upload to Database – Spatial Database

    - by pinaldave
    During my recent, training I was asked by a student if I know a place where he can download spatial files for all the countries around the world, as well as if there is a way to upload shape files to a database. Here is a quick tutorial for it. VDS Technologies has all the spatial files for every location for free. You can download the spatial file from here. If you cannot find the spatial file you are looking for, please leave a comment here, and I will send you the necessary details. Unzip the file to a folder and it will have the following content. Then, download Shape2SQL tool from SharpGIS. This is one of the best tools available to convert shapefiles to SQL tables. Afterwards, run the .exe file. When the file is run for the first time, it will ask for the database properties. Provide your database details. Select the appropriate shape files and the tool will fill up the essential details automatically. If you do not want to create the index on the column, uncheck the box beside it. The screenshot below is simply explains the procedure. You also have to be careful regarding your data, whether that is GEOMETRY or GEOGRAPHY. In this example,  it is GEOMETRY data. Click “Upload to Database”. It will show you the uploading process. Once the shape file is uploaded, close the application and open SQL Server Management Studio (SSMS). Run the following code in SSMS Query Editor. USE Spatial GO SELECT * FROM dbo.world GO This will show the complete map of world after you click on Spatial Results in Spatial Tab. In Spatial Results Set, the Zoom feature is available. From the Select label column, choose the country name in order to show the country name overlaying the country borders. Let me know if this tutorial is helpful enough. I am planning to write a few more posts about this later. Note: Please note that the images displayed here do not reflect the original political boundaries. These data are pretty old and can probably draw incorrect maps as well. I have personally spotted several parts of the map where some countries are located a little bit inaccurately. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Add-On, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Spatial, SQL Tips and Tricks, SQL Utility, T SQL, Technology

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  • SQL SERVER – How to See Active SQL Server Connections For Database

    - by Pinal Dave
    Another question received via email - “How do I I know which user is connected to my database with how many connection?” Here is the script which will give us answer to the question. SELECT DB_NAME(dbid) AS DBName, COUNT(dbid) AS NumberOfConnections, loginame FROM    sys.sysprocesses GROUP BY dbid, loginame ORDER BY DB_NAME(dbid) Here is the resultset: Reference: Pinal Dave (http://blog.SQLAuthority.com)Filed under: PostADay, SQL, SQL Authority, SQL DMV, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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  • SQL SERVER – List All the DMV and DMF on Server

    - by pinaldave
    “How many DMVs and DVFs are there in SQL Server 2008?” – this question was asked to me in one of the recent SQL Server Trainings. Answer is very simple: SELECT name, type, type_desc FROM sys.system_objects WHERE name LIKE 'dm_%' ORDER BY name Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL DMV

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  • SQLAuthority News – Microsoft SQL Server Protocol Documentation Download

    - by pinaldave
    The Microsoft SQL Server protocol documentation provides detailed technical specifications for Microsoft proprietary protocols (including extensions to industry-standard or other published protocols) that are implemented and used in Microsoft SQL Server to interoperate or communicate with Microsoft products. The documentation includes a set of companion overview and reference documents that supplement the technical specifications with conceptual background, overviews of inter-protocol relationships and interactions, and technical reference information. Microsoft SQL Server Protocol Documentation Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: SQL, SQL Authority, SQL Documentation, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Use XQuery to Access XML in Emacs

    - by Gregory Burd
    There you are working on a multi-MB/GB/TB XML document or set of documents, you want to be able to quickly query the content but you don't want to load the XML into a full-blown XML database, the time spent setting things up is simply too expensive. Why not combine a great open source editor, Emacs, and a great XML XQuery engine, Berkeley DB XML? That is exactly what Donnie Cameron did. Give it a try.

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  • SQL SERVER – Change Database Access to Single User Mode Using SSMS

    - by pinaldave
    I have previously written about how using T-SQL Script we can convert the database access to single user mode before backup. I was recently asked if the same can be done using SQL Server Management Studio. Yes! You can do it from database property (Write click on database and select database property) and follow image. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Query, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL, Technology

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  • SQL Server – Learning SQL Server Performance: Indexing Basics – Video

    - by pinaldave
    Today I remember one of my older cartoon years ago created for Indexing and Performance. Every single time when Performance is discussed, Indexes are mentioned along with it. In recent times, data and application complexity is continuously growing.  The demand for faster query response, performance, and scalability by organizations is increasing and developers and DBAs need to now write efficient code to achieve this. DBA and Developers A DBA’s role is critical, because a production environment has to run 24×7, hence maintenance, trouble shooting, and quick resolutions are the need of the hour.  The first baby step into any performance tuning exercise in SQL Server involves creating, analysing, and maintaining indexes. Though we have learnt indexing concepts from our college days, indexing implementation inside SQL Server can vary.  Understanding this behaviour and designing our applications appropriately will make sure the application is performed to its highest potential. Video Learning Vinod Kumar and myself we often thought about this and realized that practical understanding of the indexes is very important. One can not master every single aspects of the index. However there are some minimum expertise one should gain if performance is one of the concern. We decided to build a course which just addresses the practical aspects of the performance. In this course, we explored some of these indexing fundamentals and we elaborated on how SQL Server goes about using indexes.  At the end of this course of you will know the basic structure of indexes, practical insights into implementation, and maintenance tips and tricks revolving around indexes.  Finally, we will introduce SQL Server 2012 column store indexes.  We have refrained from discussing internal storage structure of the indexes but have taken a more practical, demo-oriented approach to explain these core concepts. Course Outline Here are salient topics of the course. We have explained every single concept along with a practical demonstration. Additionally shared our personal scripts along with the same. Introduction Fundamentals of Indexing Index Fundamentals Index Fundamentals – Visual Representation Practical Indexing Implementation Techniques Primary Key Over Indexing Duplicate Index Clustered Index Unique Index Included Columns Filtered Index Disabled Index Index Maintenance and Defragmentation Introduction to Columnstore Index Indexing Practical Performance Tips and Tricks Index and Page Types Index and Non Deterministic Columns Index and SET Values Importance of Clustered Index Effect of Compression and Fillfactor Index and Functions Dynamic Management Views (DMV) – Fillfactor Table Scan, Index Scan and Index Seek Index and Order of Columns Final Checklist: Index and Performance Well, we believe we have done our part, now waiting for your comments and feedback. 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, SQLServer, T SQL, Technology, Video

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  • SQLAuthority News – Microsoft SQL Server 2005 Service Pack 4 RTM

    - by pinaldave
    Service Pack 4 (SP4) for Microsoft SQL Server 2005 is now available for download. SQL Server 2005 service packs are cumulative, and this service pack upgrades all service levels of SQL Server 2005 to SP4 . Download Microsoft SQL Server 2005 Service Pack 4 RTM 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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  • 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 – Single Wait Time Introduction with Simple Example – Wait Type – Day 2 of 28 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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