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  • Want to know how SQL Server logging works?

    - by Jonathan Kehayias
    Have you ever wondered why SQL Server logging works the way it does?  While I have long understood the importance behind the SQL Server Transaction Log, I have never actually understood exactly why it works the way it does, despite having attended Paul Randal’s ( Blog / Twitter ) session at PASS Summit last year.  Over the last few months I have been working on writing a book on troubleshooting the most common problems that I see asked on the forums, and as a part of that I have been digging...(read more)

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  • Making Use of Plan Explorer in my own Environment

    - by Jonathan Kehayias
    Back in October 2010, I briefly blogged about the SQL Sentry Plan Explorer in my blog post wrap up for SQL Bits 7 and how impressed I was with what I saw from a Alpha demo standpoint from Greg Gonzalez ( Blog | Twitter ) while I was at SQLBits 7 in York.  To be 100% honest and transparent, Greg gave me early access to this tool after discussing it at SQLBits 7, and I had the opportunity to test a number of pre-Beta releases where I was able to offer significant feedback and submit bugs in the...(read more)

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  • Book review: Microsoft System Center Enterprise Suite Unleashed

    - by BuckWoody
    I know, I know – what’s a database guy doing reading a book on System Center? Well, I need it from time to time. System Center is actually a collection of about 7 different products that you can use to manage and monitor your software and hardware, from drive space through Microsoft Office, UNIX systems, and yes, SQL Server. It’s that last part I care about the most, and so I’ve dealt with Data Protection Manager and System Center Operations Manager (I call it SCOM) in SQL Server. But I wasn’t familiar with the rest of the suite nor was I as familiar as I needed to be with the “Essentials” release – a separate product that groups together the main features of System Center into a single offering for smaller organizations. These companies usually run with a smaller IT shop, so they sometimes opt for this product to help them monitor everything, including SQL Server. So I picked up “Microsoft System Center Enterprise Suite Unleashed” by Chris Amaris and a cast of others. I don’t normally like to get a technical book by multiple authors – I just find that most of the time it’s quite jarring to switch from author to author, but I think this group did pretty well here.  The first chapter on introducing System Center has helped me talk with others about what the product does, and which pieces fit well together with SQL Server. The writing is well done, and I didn’t find a jump from author to author as I went along. The information is sequential, meaning that they lead you from install to configuration and then use. It’s very much a concepts-and-how-to book, and a big one at that – over 950 pages of learning! It was a pretty quick read, though, since I skipped the installation parts and there are lots of screenshots. While I’m not sure you’d be an expert on the product when you finish reading this book, but I would say you’re more than halfway there. I would say it suits someone that learns through examples the best, since they have a lot of step-by-step examples I do recommend that you take a look if you have to interact with this product, or even if you are a smaller shop and you’re the primary IT resource. The last few chapters deal with System Center Essentials, and honestly it was the best part of the book for me. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • General monitoring for SQL Server Analysis Services using Performance Monitor

    - by Testas
    A recent customer engagement required a setup of a monitoring solution for SSAS, due to the time restrictions placed upon this, native Windows Performance Monitor (Perfmon) and SQL Server Profiler Monitoring Tools was used as using a third party tool would have meant the customer providing an additional monitoring server that was not available.I wanted to outline the performance monitoring counters that was used to monitor the system on which SSAS was running. Due to the slow query performance that was occurring during certain scenarios, perfmon was used to establish if any pressure was being placed on the Disk, CPU or Memory subsystem when concurrent connections access the same query, and Profiler to pinpoint how the query was being managed within SSAS, profiler I will leave for another blogThis guide is not designed to provide a definitive list of what should be used when monitoring SSAS, different situations may require the addition or removal of counters as presented by the situation. However I hope that it serves as a good basis for starting your monitoring of SSAS. I would also like to acknowledge Chris Webb’s awesome chapters from “Expert Cube Development” that also helped shape my monitoring strategy:http://cwebbbi.spaces.live.com/blog/cns!7B84B0F2C239489A!6657.entrySimulating ConnectionsTo simulate the additional connections to the SSAS server whilst monitoring, I used ascmd to simulate multiple connections to the typical and worse performing queries that were identified by the customer. A similar sript can be downloaded from codeplex at http://www.codeplex.com/SQLSrvAnalysisSrvcs.     File name: ASCMD_StressTestingScripts.zip. Performance MonitorWithin performance monitor,  a counter log was created that contained the list of counters below. The important point to note when running the counter log is that the RUN AS property within the counter log properties should be changed to an account that has rights to the SSAS instance when monitoring MSAS counters. Failure to do so means that the counter log runs under the system account, no errors or warning are given while running the counter log, and it is not until you need to view the MSAS counters that they will not be displayed if run under the default account that has no right to SSAS. If your connection simulation takes hours, this could prove quite frustrating if not done beforehand JThe counters used……  Object Counter Instance Justification System Processor Queue legnth N/A Indicates how many threads are waiting for execution against the processor. If this counter is consistently higher than around 5 when processor utilization approaches 100%, then this is a good indication that there is more work (active threads) available (ready for execution) than the machine's processors are able to handle. System Context Switches/sec N/A Measures how frequently the processor has to switch from user- to kernel-mode to handle a request from a thread running in user mode. The heavier the workload running on your machine, the higher this counter will generally be, but over long term the value of this counter should remain fairly constant. If this counter suddenly starts increasing however, it may be an indicating of a malfunctioning device, especially if the Processor\Interrupts/sec\(_Total) counter on your machine shows a similar unexplained increase Process % Processor Time sqlservr Definately should be used if Processor\% Processor Time\(_Total) is maxing at 100% to assess the effect of the SQL Server process on the processor Process % Processor Time msmdsrv Definately should be used if Processor\% Processor Time\(_Total) is maxing at 100% to assess the effect of the SQL Server process on the processor Process Working Set sqlservr If the Memory\Available bytes counter is decreaing this counter can be run to indicate if the process is consuming larger and larger amounts of RAM. Process(instance)\Working Set measures the size of the working set for each process, which indicates the number of allocated pages the process can address without generating a page fault. Process Working Set msmdsrv If the Memory\Available bytes counter is decreaing this counter can be run to indicate if the process is consuming larger and larger amounts of RAM. Process(instance)\Working Set measures the size of the working set for each process, which indicates the number of allocated pages the process can address without generating a page fault. Processor % Processor Time _Total and individual cores measures the total utilization of your processor by all running processes. If multi-proc then be mindful only an average is provided Processor % Privileged Time _Total To see how the OS is handling basic IO requests. If kernel mode utilization is high, your machine is likely underpowered as it's too busy handling basic OS housekeeping functions to be able to effectively run other applications. Processor % User Time _Total To see how the applications is interacting from a processor perspective, a high percentage utilisation determine that the server is dealing with too many apps and may require increasing thje hardware or scaling out Processor Interrupts/sec _Total  The average rate, in incidents per second, at which the processor received and serviced hardware interrupts. Shoulr be consistant over time but a sudden unexplained increase could indicate a device malfunction which can be confirmed using the System\Context Switches/sec counter Memory Pages/sec N/A Indicates the rate at which pages are read from or written to disk to resolve hard page faults. This counter is a primary indicator of the kinds of faults that cause system-wide delays, this is the primary counter to watch for indication of possible insufficient RAM to meet your server's needs. A good idea here is to configure a perfmon alert that triggers when the number of pages per second exceeds 50 per paging disk on your system. May also want to see the configuration of the page file on the Server Memory Available Mbytes N/A is the amount of physical memory, in bytes, available to processes running on the computer. if this counter is greater than 10% of the actual RAM in your machine then you probably have more than enough RAM. monitor it regularly to see if any downward trend develops, and set an alert to trigger if it drops below 2% of the installed RAM. Physical Disk Disk Transfers/sec for each physical disk If it goes above 10 disk I/Os per second then you've got poor response time for your disk. Physical Disk Idle Time _total If Disk Transfers/sec is above  25 disk I/Os per second use this counter. which measures the percent time that your hard disk is idle during the measurement interval, and if you see this counter fall below 20% then you've likely got read/write requests queuing up for your disk which is unable to service these requests in a timely fashion. Physical Disk Disk queue legnth For the OLAP and SQL physical disk A value that is consistently less than 2 means that the disk system is handling the IO requests against the physical disk Network Interface Bytes Total/sec For the NIC Should be monitored over a period of time to see if there is anb increase/decrease in network utilisation Network Interface Current Bandwidth For the NIC is an estimate of the current bandwidth of the network interface in bits per second (BPS). MSAS 2005: Memory Memory Limit High KB N/A Shows (as a percentage) the high memory limit configured for SSAS in C:\Program Files\Microsoft SQL Server\MSAS10.MSSQLSERVER\OLAP\Config\msmdsrv.ini MSAS 2005: Memory Memory Limit Low KB N/A Shows (as a percentage) the low memory limit configured for SSAS in C:\Program Files\Microsoft SQL Server\MSAS10.MSSQLSERVER\OLAP\Config\msmdsrv.ini MSAS 2005: Memory Memory Usage KB N/A Displays the memory usage of the server process. MSAS 2005: Memory File Store KB N/A Displays the amount of memory that is reserved for the Cache. Note if total memory limit in the msmdsrv.ini is set to 0, no memory is reserved for the cache MSAS 2005: Storage Engine Query Queries from Cache Direct / sec N/A Displays the rate of queries answered from the cache directly MSAS 2005: Storage Engine Query Queries from Cache Filtered / Sec N/A Displays the Rate of queries answered by filtering existing cache entry. MSAS 2005: Storage Engine Query Queries from File / Sec N/A Displays the Rate of queries answered from files. MSAS 2005: Storage Engine Query Average time /query N/A Displays the average time of a query MSAS 2005: Connection Current connections N/A Displays the number of connections against the SSAS instance MSAS 2005: Connection Requests / sec N/A Displays the rate of query requests per second MSAS 2005: Locks Current Lock Waits N/A Displays thhe number of connections waiting on a lock MSAS 2005: Threads Query Pool job queue Length N/A The number of queries in the job queue MSAS 2005:Proc Aggregations Temp file bytes written/sec N/A Shows the number of bytes of data processed in a temporary file MSAS 2005:Proc Aggregations Temp file rows written/sec N/A Shows the number of bytes of data processed in a temporary file 

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  • Understanding Column Properties for a SQL Server Table

    Designing a table can be a little complicated if you don’t have the correct knowledge of data types, relationships, and even column properties. In this tip, Brady Upton goes over the column properties and provides examples. "It really helped us isolate where we were experiencing a bottleneck"- John Q Martin, SQL Server DBA. Get started with SQL Monitor today to solve tricky performance problems - download a free trial

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  • July, the 31 Days of SQL Server DMO’s – Day 29 (sys.dm_os_buffer_descriptors)

    - by Tamarick Hill
    The sys.dm_os_buffer_descriptors Dynamic Management View gives you a look into the data pages that are currently in your SQL Server buffer pool. Just in case you are not familiar with some of the internals to SQL Server and how the engine works, SQL Server only works with objects that are in memory (buffer pool). When an object such as a table needs to be read and it does not exist in the buffer pool, SQL Server will read (copy) the necessary data page(s) from disk into the buffer pool and cache it. Caching takes place so that it can be reused again and prevents the need of expensive physical reads. To better illustrate this DMV, lets query it against our AdventureWorks2012 database and view the result set. SELECT * FROM sys.dm_os_buffer_descriptors WHERE database_id = db_id('AdventureWorks2012') The first column returned from this result set is the database_id column which identifies the specific database for a given row. The file_id column represents the file that a particular buffer descriptor belongs to. The page_id column represents the ID for the data page within the buffer. The page_level column represents the index level of the data page. Next we have the allocation_unit_id column which identifies a unique allocation unit. An allocation unit is basically a set of data pages. The page_type column tells us exactly what type of page is in the buffer pool. From my screen shot above you see I have 3 distinct type of Pages in my buffer pool, Index, Data, and IAM pages. Index pages are pages that are used to build the Root and Intermediate levels of a B-Tree. A Data page would represent the actual leaf pages of a clustered index which contain the actual data for the table. Without getting into too much detail, an IAM page is Index Allocation Map page which track GAM (Global Allocation Map) pages which in turn track extents on your system. The row_count column details how many data rows are present on a given page. The free_space_in_bytes tells you how much of a given data page is still available, remember pages are 8K in size. The is_modified signifies whether or not a page has been changed since it has been read into memory, .ie a dirty page. The numa_node column represents the Nonuniform memory access node for the buffer. Lastly is the read_microsec column which tells you how many microseconds it took for a data page to be read (copied) into the buffer pool. This is a great DMV for use when you are tracking down a memory issue or if you just want to have a look at what type of pages are currently in your buffer pool. For more information about this DMV, please see the below Books Online link: http://msdn.microsoft.com/en-us/library/ms173442.aspx Follow me on Twitter @PrimeTimeDBA

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  • Red Gate Rolls Out the Red Carpet for SQL Server Users

    SQL in the City, the unique event for database developers and administrators organized by Red Gate Software, hits the streets of London and Seattle this fall. Now in its fourth year, it features presentations by some of the world’s top SQL Server speakers. Can 41,000 DBAs really be wrong? Join 41,000 other DBAs who are following the new series from the DBA Team: the 5 Worst Days in a DBA’s Life. Part 3, As Corrupt As It Gets, is out now – read it here.

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  • Getting Dynamic in SSIS Queries

    - by ejohnson2010
    When you start working with SQL Server and SSIS, it isn’t long before you find yourself wishing you could change bits of SQL queries dynamically. Most commonly, I see people that want to change the date portion of a query so that you can limit your query to the last 30 days, for example. This can be done using a combination of expressions and variables. I will do this in two parts, first I will build a variable that will always contain the 1 st day of the previous month and then I will dynamically...(read more)

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  • Script to determine if you should update Build version

    - by NeilHambly
    Aaron Betrand has posted a great article on the Patch Tuesday Security Bulletin and I have quickly translated that into a SQL script to check your version and advise what you should be doing http://www.microsoft.com/technet/security/Bulletin/MS11-049.mspx Aaron's article: http://sqlblog.com/blogs/aaron_bertrand/archive/2011/06/14/security-updates-for-all-supported-versions-of-sql-server.aspx#comments Naturally ANY Script needs to be carefully vetted before it is used in your own environments;...(read more)

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  • Cloud Evolving, SQL Server Responding

    - by KKline
    Brent Ozar ( blog | twitter ) and I did an interview with TechTarget’s Brendan Cournoyer at last summer's Tech-Ed, which as turned into a podcast titled “Cloud efforts advance, SQL Server evolves.” The podcast covers all the major trends at the conference (like BI), virtualization features in Quest’s products (like Spotlight), Brent’s new book and MCM certification, and more. Here’s a link to hear it, appearing on 6/11/10: http://searchsqlserver.techtarget.com/podcast/Cloud-efforts-advance-SQL-Server-evolves....(read more)

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  • More info: a "stand-alone" installer for Management Studio Express 2008

    - by AaronBertrand
    Last February, I blogged about something I was initially very happy about: a stand-alone installer for Management Studio Express (SSMSE) 2008 . Now users could allegedly download a much smaller installer, and only install the client tools without having to install an instance of SQL Server Express. While the latter is true, the former remains a pipe dream. Bill Ramos stated in his 2009-02-20 announcement : "We teased out the Tools portion of SQL Server 2008 Express with Tools into it’s own download."...(read more)

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  • Intel Xeon E5 (Sandy Bridge-EP) and SQL Server 2012 Benchmarks

    - by jchang
    Intel officially announced the Xeon E5 2600 series processor based on Sandy Bridge-EP variant with upto 8 cores and 20MB LLC per socket. Only one TPC benchmark accompanied product launch, summary below. Processors Cores per Frequency Memory SQL Vendor TPC-E 2 x Xeon E5-2690 8 2.9GHz 512GB (16x32GB) 2012 IBM 1,863.23 2 x Xeon E7-2870 10 2.4GHz 512GB (32x16GB) 2008R2 IBM 1,560.70 2 x Xeon X5690 6 3.46GHz 192GB (12x16GB) 2008R2 HP 1,284.14 Note: the HP report lists SQL Server 2008 R2 Enterprise Edition...(read more)

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  • Cloud Evolving, SQL Server Responding

    - by KKline
    Brent Ozar ( blog | twitter ) and I did an interview with TechTarget’s Brendan Cournoyer at last summer's Tech-Ed, which as turned into a podcast titled “Cloud efforts advance, SQL Server evolves.” The podcast covers all the major trends at the conference (like BI), virtualization features in Quest’s products (like Spotlight), Brent’s new book and MCM certification, and more. Here’s a link to hear it, appearing on 6/11/10: http://searchsqlserver.techtarget.com/podcast/Cloud-efforts-advance-SQL-Server-evolves....(read more)

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  • SQL UserGroup Events & Service Broker

    - by NeilHambly
    I'm sure you are now aware of the SQL UserGroup events (both in London) on Wednesday 19th & Thrusday 20th evenings, If you have never been to one of the events before then I would highly reconmend attending one or both of them. Covering a wide range of subjects these meetings are an invaluable way to gain insights into various features from SQL experts (both presenters and attendees alike) frequently you will learn new insights and gain different perspectives on how to use those features...(read more)

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  • SQLRally and SQLRally - Session material

    - by Hugo Kornelis
    I had a great week last week. First at SQLRally Nordic , in Stockholm, where I presented a session on how improvements to the OVER clause can help you simplify queries in SQL Server 2012 enormously. And then I continued straight on into SQLRally Amsterdam , where I delivered a session on the performance implications of using user-defined functions in T-SQL. I understand that both events will make my slides and demo code downloadable from their website, but this may take a while. So those who do not...(read more)

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  • SQL Server Contains Equivalent

    - by Derek D.
    Many Oracle developers trying to find the SQL Server function compatible with their Contains clause will most likely accidently end up on this page. Therefore, this page will be devoted to them rather than the SQL Server’s Contains function which is used for full-text searching. The most similar function to Oracle’s contains is charindex. The usage [...]

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  • In defense of SELECT * in production code, in some limited cases?

    - by Alexander Kuznetsov
    It is well known that SELECT * is not acceptable in production code, with the exception of this pattern: IF EXISTS( SELECT * We all know that whenever we see code code like this: Listing 1. "Bad" SQL SELECT Column1 , Column2 FROM ( SELECT c. * , ROW_NUMBER () OVER ( PARTITION BY Column1 ORDER BY Column2 ) AS rn FROM data.SomeTable AS c ) AS c WHERE rn < 5 we are supposed to automatically replace * with an explicit list of columns, as follows: Listing 2. "Good" SQL SELECT Column1 , Column2 FROM...(read more)

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  • SQL Server MCM is too easy, is it?

    - by simonsabin
    We all know that Brent Ozar did the MCM training/certification over the past few weeks. He wrote an interesting article on Friday about the bad bits ( http://www.brentozar.com/archive/2010/04/sql-mcm-now-bad-stuff/ ) of the training and it lead me to thinking about the certification process again(I often think about it, and it appears often in response to something from Brent http://sqlblogcasts.com/blogs/simons/archive/2010/02/12/Whats-missing-in-the-SQL-Certification-process-.aspx ) This time what...(read more)

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  • PASS Summit 2012 PreCon - DBA-298-P Automate and Manage SQL Server with PowerShell

    - by AllenMWhite
    On Tuesday I presented an all-day pre-conference session on using PowerShell to automate and manage SQL Server. It was a very full day and we had a lot of great questions. One discussion in Module 6 was around scripting all the objects in a database, and I'd mentioned the script I wrote for the book The Red Gate Guide to SQL Server Team-based Development . When putting together the demos for the attendees to download I realized I'd placed that script in the Module 6 folder, so you don't need to go...(read more)

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  • Configuring SQL Server Audit Logging with Powershell

    - by Jonathan Kehayias
    One of the standard configuration options that I set on all SQL Server installs is to log Failed Login Attempts to the SQL Server Error Log.  I recently inherited an environment that this option wasn’t standardized across all of the servers and needed to configure it for multiple servers in a scripted manner.  There are a couple of ways to handle this kind of task.  First I could log on to every server in SSMS, open the Server Properties, and set the option on the Security sheet for...(read more)

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  • Temp Table Recompiles

    - by Derek D.
    If you landed on this article, then you most likely know that temp tables can cause recompilation. This happens because temp tables are treated just like regular tables by the SQL Server Engine. When the tables (in which underlying queries rely on) change significantly, SQL Server detects this change (using auto update statistics) [...]

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  • Handy SQL Server Function Series: Part 1

    - by Most Valuable Yak (Rob Volk)
    I've been preparing to give a presentation on SQL Server for a while now, and a topic that was recommended was SQL Server functions.  More specifically, the lesser-known functions (like @@OPTIONS), and maybe some interesting ways to use well-known functions (like using PARSENAME to split IP addresses)  I think this is a veritable goldmine of useful information, and researching for the presentation has confirmed that beyond my initial expectations.I even found a few undocumented/underdocumented functions, so for the first official article in this series I thought I'd start with 2 of each, COLLATIONPROPERTY() and COLLATIONPROPERTYFROMID().COLLATIONPROPERTY() provides information about (wait for it) collations, SQL Server's method for handling foreign character sets, sort orders, and case- or accent-sensitivity when sorting character data.  The Books Online entry for  COLLATIONPROPERTY() lists 4 options for code page, locale ID, comparison style and version.  Used in conjunction with fn_helpcollations():SELECT *, COLLATIONPROPERTY(name,'LCID') LCID, COLLATIONPROPERTY(name,'CodePage') CodePage, COLLATIONPROPERTY(name,'ComparisonStyle') ComparisonStyle, COLLATIONPROPERTY(name,'Version') Version FROM fn_helpcollations()You can get some excellent information. (c'mon, be honest, did you even know about fn_helpcollations?)Collations in SQL Server have a unique name and ID, and you'll see one or both in various system tables or views like syscolumns, sys.columns, and INFORMATION_SCHEMA.COLUMNS.  Unfortunately they only link the ID and name for collations of existing columns, so if you wanted to know the collation ID of Albanian_CI_AI_WS, you'd have to declare a column with that collation and query the system table.While poking around the OBJECT_DEFINITION() of sys.columns I found a reference to COLLATIONPROPERTYFROMID(), and the unknown property "Name".  Not surprisingly, this is how sys.columns finds the name of the collation, based on the ID stored in the system tables.  (Check yourself if you don't believe me)Somewhat surprisingly, the "Name" property also works for COLLATIONPROPERTY(), although you'd already know the name at that point.  Some wild guesses and tests revealed that "CollationID" is also a valid property for both functions, so now:SELECT *, COLLATIONPROPERTY(name,'LCID') LCID, COLLATIONPROPERTY(name,'CodePage') CodePage, COLLATIONPROPERTY(name,'ComparisonStyle') ComparisonStyle, COLLATIONPROPERTY(name,'Version') Version, COLLATIONPROPERTY(name,'CollationID') CollationID FROM fn_helpcollations() Will get you the collation ID-name link you…probably didn't know or care about, but if you ever get on Jeopardy! and this question comes up, feel free to send some of your winnings my way. :)And last but not least, COLLATIONPROPERTYFROMID() uses the same properties as COLLATIONPROPERTY(), so you can use either one depending on which value you have available.Keep an eye out for Part 2!

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  • Secret of SQL Trace Duration Column

    - by Dan Guzman
    Why would a trace of long-running queries not show all queries that exceeded the specified duration filter?  We have a server-side SQL Trace that includes RPC:Completed and SQL:BatchCompleted events with a filter on Duration >= 100000.  Nearly all of the queries on this busy OLTP server run in under this 100 millisecond threshold so any that appear in the trace are candidates for root cause analysis and/or performance tuning opportunities. After an application experienced query timeouts, the DBA looked at the trace data to corroborate the problem.  Surprisingly, he found no long-running queries in the trace from the application that experienced the timeouts even though the application’s error log clearly showed detail of the problem (query text, duration, start time, etc.).  The trace did show, however, that there were hundreds of other long-running queries from different applications during the problem timeframe.  We later determined those queries were blocked by a large UPDATE query against a critical table that was inadvertently run during this busy period. So why didn’t the trace include all of the long-running queries?  The reason is because the SQL Trace event duration doesn’t include the time a request was queued while awaiting a worker thread.  Remember that the server was under considerable stress at the time due to the severe blocking episode.  Most of the worker threads were in use by blocked queries and new requests were queued awaiting a worker to free up (a DMV query on the DAC connection will show this queuing: “SELECT scheduler_id, work_queue_count FROM sys.dm_os_schedulers;”).  Technically, those queued requests had not started.  As worker threads became available, queries were dequeued and completed quickly.  These weren’t included in the trace because the duration was under the 100ms duration filter.  The duration reflected the time it took to actually run the query but didn’t include the time queued waiting for a worker thread. The important point here is that duration is not end-to-end response time.  Duration of RPC:Completed and SQL:BatchCompleted events doesn’t include time before a worker thread is assigned nor does it include the time required to return the last result buffer to the client.  In other words, duration only includes time after the worker thread is assigned until the last buffer is filled.  But be aware that duration does include the time need to return intermediate result set buffers back to the client, which is a factor when large query results are returned.  Clients that are slow in consuming results sets can increase the duration value reported by the trace “completed” events.

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  • Managing Slowly Changing Dimension with MERGE Statement in SQL Server

    Slowly Changing Dimension (SCD) Transformation is a quick and easy way to manage smaller slowly changing dimensions but it has several limitations and does not perform well when the number of rows or columns gets larger. Arshad Ali explores some of the alternatives you can use for managing larger slowly changing dimensions. How to automate your .NET and SQL Server deploymentsDeploy .NET code and SQL Server databases in a single repeatable process with Red Gate Deployment Manager. Start deploying with a 28-day trial.

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