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• SQL SERVER – Beginning SQL Server: One Step at a Time – SQL Server Magazine

  - by pinaldave

  I am glad to announce that along with SQLAuthority.com, I will be blogging on the prominent site of SQL Server Magazine. My very first blog post there is already live; read here: Beginning SQL Server: One Step at a Time. My association with SQL Server Magazine has been quite long, I have written nearly 7 to 8 SQL Server articles for the print magazine and it has been a great experience. I used to stay in the United States at that time. I moved back to India for good, and during this process, I had put everything on hold for a while. Just like many things, “temporary” things become “permanent” – coming back to SQLMag was on hold for long time. Well, this New Year, things have changed – once again, I am back with my online presence at SQLMag.com. Everybody is a beginner at every task or activity at some point of his/her life: spelling words for the first time; learning how to drive for the first time, etc. No one is perfect at the start of any task, but every human is different. As time passes, we all develop our interests and begin to study our subject of interest. Most of us dream to get a job in the area of our study – however things change as time passes. I recently read somewhere online (I could not find the link again while writing this one) that all the successful people in various areas have never studied in the area in which they are successful. After going through a formal learning process of what we love, we refuse to stop learning, and we finally stop changing career and focus areas. We move, we dare and we progress. IT field is similar to our life. New IT professionals come to this field every day. There are two types of beginners – a) those who are associated with IT field but not familiar with other technologies, and b) those who are absolutely new to the IT field. Learning a new technology is always exciting and overwhelming for enthusiasts. I am working with database (in particular) for SQL Server for more than 7 years but I am still overwhelmed with so many things to learn. I continue to learn and I do not think that I should ever stop doing so. Just like everybody, I want to be in the race and get ahead in learning the technology. For the same, I am always looking for good guidance. I always try to find a good article, blog or book chapter, which can teach me what I really want to learn at this stage in my career and can be immensely helpful. Quite often, I prefer to read the material where the author does not judge me or assume my understanding. I like to read new concepts like a child, who takes his/her first steps of learning without any prior knowledge. Keeping my personal philosophy and preference in mind, I will be blogging on SQL Server Magazine site. I will be blogging on the beginners stuff. I will be blogging for them, who really want to start and make a mark in this area. I will be blogging for all those who have an extreme passion for learning. I am happy that this is a good start for this year. One of my resolutions is to help every beginner. It is totally possible that in future they all will grow and find the same article quite ‘easy‘ – well when that happens, it indicates the success of the article and material! Well, I encourage everybody to read my SQL Server Magazine blog – I will be blogging there frequently on various topics. To begin, we will be talking about performance tuning, and I assure that I will not shy away from other multiple areas. Read my SQL Server Magazine Blog: Beginning SQL Server: One Step at a Time I think the title says it all. Do leave your comments and feedback to indicate your preference of subject and interest. I am going to continue writing on subject, and the aim is of course to help grow in this field. 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, SQLAuthority News, T SQL, Technology

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• LWJGL - Eclipse error [on hold]

  - by Zarkopafilis

  When I try to run my lwjgl project, an error pops . Here is the log file: # A fatal error has been detected by the Java Runtime Environment: # EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x6d8fcc0a, pid=5612, tid=900 # JRE version: 6.0_16-b01 Java VM: Java HotSpot(TM) Client VM (14.2-b01 mixed mode windows-x86 ) Problematic frame: V [jvm.dll+0xfcc0a] # If you would like to submit a bug report, please visit: http://java.sun.com/webapps/bugreport/crash.jsp # --------------- T H R E A D --------------- Current thread (0x016b9000): JavaThread "main" [_thread_in_vm, id=900, stack(0x00160000,0x001b0000)] siginfo: ExceptionCode=0xc0000005, reading address 0x00000000 Registers: EAX=0x00000000, EBX=0x00000000, ECX=0x00000006, EDX=0x00000000 ESP=0x001af4d4, EBP=0x001af524, ESI=0x016b9000, EDI=0x016b9110 EIP=0x6d8fcc0a, EFLAGS=0x00010246 Top of Stack: (sp=0x001af4d4) 0x001af4d4: 6da44bd8 016b9110 00000000 001af668 0x001af4e4: ffffffff 22200000 001af620 76ec39c2 0x001af4f4: 001af524 6d801086 0000000b 001afd34 0x001af504: 016b9000 016dd990 016b9000 00000000 0x001af514: 001af5f4 6d9ee000 6d9ef2f0 ffffffff 0x001af524: 001af58c 10008c85 016b9110 00000000 0x001af534: 00000000 000a0554 00000000 00000024 0x001af544: 00000000 00000000 001af6ac 00000000 Instructions: (pc=0x6d8fcc0a) 0x6d8fcbfa: e8 e8 d0 1d 08 00 8b 45 10 c7 45 d8 0b 00 00 00 0x6d8fcc0a: 8b 00 8b 48 08 0f b7 51 26 8b 40 0c 8b 4c 90 20 Stack: [0x00160000,0x001b0000], sp=0x001af4d4, free space=317k Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code) V [jvm.dll+0xfcc0a] C [lwjgl.dll+0x8c85] C [USER32.dll+0x18876] C [USER32.dll+0x170f4] C [USER32.dll+0x1119e] C [ntdll.dll+0x460ce] C [USER32.dll+0x10e29] C [USER32.dll+0x10e84] C [lwjgl.dll+0x1cf0] j org.lwjgl.opengl.WindowsDisplay.createWindow(Lorg/lwjgl/opengl/DrawableLWJGL;Lorg/lwjgl/opengl/DisplayMode;Ljava/awt/Canvas;II)V+102 j org.lwjgl.opengl.Display.createWindow()V+71 j org.lwjgl.opengl.Display.create(Lorg/lwjgl/opengl/PixelFormat;Lorg/lwjgl/opengl/Drawable;Lorg/lwjgl/opengl/ContextAttribs;)V+72 j org.lwjgl.opengl.Display.create(Lorg/lwjgl/opengl/PixelFormat;)V+12 j org.lwjgl.opengl.Display.create()V+7 j zarkopafilis.koding.io.javafx.Main.main([Ljava/lang/String;)V+16 v ~StubRoutines::call_stub V [jvm.dll+0xecf9c] V [jvm.dll+0x1741e1] V [jvm.dll+0xed01d] V [jvm.dll+0xf5be5] V [jvm.dll+0xfd83d] C [javaw.exe+0x2155] C [javaw.exe+0x833e] C [kernel32.dll+0x51154] C [ntdll.dll+0x5b2b9] C [ntdll.dll+0x5b28c] Java frames: (J=compiled Java code, j=interpreted, Vv=VM code) j org.lwjgl.opengl.WindowsDisplay.nCreateWindow(IIIIZZJ)J+0 j org.lwjgl.opengl.WindowsDisplay.createWindow(Lorg/lwjgl/opengl/DrawableLWJGL;Lorg/lwjgl/opengl/DisplayMode;Ljava/awt/Canvas;II)V+102 j org.lwjgl.opengl.Display.createWindow()V+71 j org.lwjgl.opengl.Display.create(Lorg/lwjgl/opengl/PixelFormat;Lorg/lwjgl/opengl/Drawable;Lorg/lwjgl/opengl/ContextAttribs;)V+72 j org.lwjgl.opengl.Display.create(Lorg/lwjgl/opengl/PixelFormat;)V+12 j org.lwjgl.opengl.Display.create()V+7 j zarkopafilis.koding.io.javafx.Main.main([Ljava/lang/String;)V+16 v ~StubRoutines::call_stub --------------- P R O C E S S --------------- Java Threads: ( = current thread ) 0x0179a400 JavaThread "Low Memory Detector" daemon [_thread_blocked, id=4460, stack(0x0b900000,0x0b950000)] 0x01795400 JavaThread "CompilerThread0" daemon [_thread_blocked, id=5264, stack(0x0b8b0000,0x0b900000)] 0x01790c00 JavaThread "Attach Listener" daemon [_thread_blocked, id=6080, stack(0x0b860000,0x0b8b0000)] 0x01786400 JavaThread "Signal Dispatcher" daemon [_thread_blocked, id=1204, stack(0x0b810000,0x0b860000)] 0x01759c00 JavaThread "Finalizer" daemon [_thread_blocked, id=5772, stack(0x0b7c0000,0x0b810000)] 0x01755000 JavaThread "Reference Handler" daemon [_thread_blocked, id=4696, stack(0x01640000,0x01690000)] =0x016b9000 JavaThread "main" [_thread_in_vm, id=900, stack(0x00160000,0x001b0000)] Other Threads: 0x01751c00 VMThread [stack: 0x015f0000,0x01640000] [id=4052] 0x0179c800 WatcherThread [stack: 0x0b950000,0x0b9a0000] [id=3340] VM state:not at safepoint (normal execution) VM Mutex/Monitor currently owned by a thread: None Heap def new generation total 960K, used 816K [0x037c0000, 0x038c0000, 0x03ca0000) eden space 896K, 91% used [0x037c0000, 0x0388c2c0, 0x038a0000) from space 64K, 0% used [0x038a0000, 0x038a0000, 0x038b0000) to space 64K, 0% used [0x038b0000, 0x038b0000, 0x038c0000) tenured generation total 4096K, used 0K [0x03ca0000, 0x040a0000, 0x077c0000) the space 4096K, 0% used [0x03ca0000, 0x03ca0000, 0x03ca0200, 0x040a0000) compacting perm gen total 12288K, used 2143K [0x077c0000, 0x083c0000, 0x0b7c0000) the space 12288K, 17% used [0x077c0000, 0x079d7e38, 0x079d8000, 0x083c0000) No shared spaces configured. Dynamic libraries: 0x00400000 - 0x00424000 C:\Program Files\Java\jre6\bin\javaw.exe 0x77550000 - 0x7768e000 C:\Windows\SYSTEM32\ntdll.dll 0x75a80000 - 0x75b54000 C:\Windows\system32\kernel32.dll 0x758d0000 - 0x7591b000 C:\Windows\system32\KERNELBASE.dll 0x759e0000 - 0x75a80000 C:\Windows\system32\ADVAPI32.dll 0x76070000 - 0x7611c000 C:\Windows\system32\msvcrt.dll 0x77250000 - 0x77269000 C:\Windows\SYSTEM32\sechost.dll 0x771a0000 - 0x77241000 C:\Windows\system32\RPCRT4.dll 0x76eb0000 - 0x76f79000 C:\Windows\system32\USER32.dll 0x76e60000 - 0x76eae000 C:\Windows\system32\GDI32.dll 0x77770000 - 0x7777a000 C:\Windows\system32\LPK.dll 0x75fd0000 - 0x7606e000 C:\Windows\system32\USP10.dll 0x770b0000 - 0x770cf000 C:\Windows\system32\IMM32.DLL 0x770d0000 - 0x7719c000 C:\Windows\system32\MSCTF.dll 0x7c340000 - 0x7c396000 C:\Program Files\Java\jre6\bin\msvcr71.dll 0x6d800000 - 0x6da8b000 C:\Program Files\Java\jre6\bin\client\jvm.dll 0x73a00000 - 0x73a32000 C:\Windows\system32\WINMM.dll 0x75610000 - 0x7565b000 C:\Windows\system32\apphelp.dll 0x6d7b0000 - 0x6d7bc000 C:\Program Files\Java\jre6\bin\verify.dll 0x6d330000 - 0x6d34f000 C:\Program Files\Java\jre6\bin\java.dll 0x6d290000 - 0x6d298000 C:\Program Files\Java\jre6\bin\hpi.dll 0x776e0000 - 0x776e5000 C:\Windows\system32\PSAPI.DLL 0x6d7f0000 - 0x6d7ff000 C:\Program Files\Java\jre6\bin\zip.dll 0x10000000 - 0x1004c000 C:\Users\theo\Desktop\workspace\JavaFX1\lib\natives\windows\lwjgl.dll 0x5d170000 - 0x5d238000 C:\Windows\system32\OPENGL32.dll 0x6e7b0000 - 0x6e7d2000 C:\Windows\system32\GLU32.dll 0x70620000 - 0x70707000 C:\Windows\system32\DDRAW.dll 0x70610000 - 0x70616000 C:\Windows\system32\DCIMAN32.dll 0x75b60000 - 0x75cfd000 C:\Windows\system32\SETUPAPI.dll 0x759b0000 - 0x759d7000 C:\Windows\system32\CFGMGR32.dll 0x76d70000 - 0x76dff000 C:\Windows\system32\OLEAUT32.dll 0x75db0000 - 0x75f0c000 C:\Windows\system32\ole32.dll 0x758b0000 - 0x758c2000 C:\Windows\system32\DEVOBJ.dll 0x74060000 - 0x74073000 C:\Windows\system32\dwmapi.dll 0x74b60000 - 0x74b69000 C:\Windows\system32\VERSION.dll 0x745f0000 - 0x7478e000 C:\Windows\WinSxS\x86_microsoft.windows.common-controls_6595b64144ccf1df_6.0.7600.16661_none_420fe3fa2b8113bd\COMCTL32.dll 0x75d50000 - 0x75da7000 C:\Windows\system32\SHLWAPI.dll 0x74370000 - 0x743b0000 C:\Windows\system32\uxtheme.dll 0x22200000 - 0x22206000 C:\Program Files\ESET\ESET Smart Security\eplgHooks.dll VM Arguments: jvm_args: -Djava.library.path=C:\Users\theo\Desktop\workspace\JavaFX1\lib\natives\windows -Dfile.encoding=Cp1253 java_command: zarkopafilis.koding.io.javafx.Main Launcher Type: SUN_STANDARD Environment Variables: PATH=C:/Program Files/Java/jre6/bin/client;C:/Program Files/Java/jre6/bin;C:/Program Files/Java/jre6/lib/i386;C:\Perl\site\bin;C:\Perl\bin;C:\Ruby200\bin;C:\Program Files\Common Files\Microsoft Shared\Windows Live;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files\Windows Live\Shared;C:\Users\theo\Desktop\eclipse; USERNAME=theo OS=Windows_NT PROCESSOR_IDENTIFIER=x86 Family 6 Model 37 Stepping 5, GenuineIntel --------------- S Y S T E M --------------- OS: Windows 7 Build 7600 CPU:total 4 (8 cores per cpu, 2 threads per core) family 6 model 37 stepping 5, cmov, cx8, fxsr, mmx, sse, sse2, sse3, ssse3, sse4.1, sse4.2, ht Memory: 4k page, physical 2097151k(1257972k free), swap 4194303k(4194303k free) vm_info: Java HotSpot(TM) Client VM (14.2-b01) for windows-x86 JRE (1.6.0_16-b01), built on Jul 31 2009 11:26:58 by "java_re" with MS VC++ 7.1 time: Wed Oct 23 22:00:12 2013 elapsed time: 0 seconds Code: Display.setDisplayMode(new DisplayMode(800,600)); Display.create();//Error here I am using JDK 6

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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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• How to use jQuery Date Range Picker plugin in asp.net

  - by alaa9jo

  I stepped by this page: http://www.filamentgroup.com/lab/date_range_picker_using_jquery_ui_16_and_jquery_ui_css_framework/ and let me tell you,this is one of the best and coolest daterangepicker in the web in my opinion,they did a great job with extending the original jQuery UI DatePicker.Of course I made enhancements to the original plugin (fixed few bugs) and added a new option (Clear) to clear the textbox. In this article I well use that updated plugin and show you how to use it in asp.net..you will definitely like it. So,What do I need? 1- jQuery library : you can use 1.3.2 or 1.4.2 which is the latest version so far,in my article I will use the latest version. 2- jQuery UI library (1.8): As I mentioned earlier,daterangepicker plugin is based on the original jQuery UI DatePicker so that library should be included into your page. 3- jQuery DateRangePicker plugin : you can go to the author page or use the modified one (it's included in the attachment),in this article I will use the modified one. 4- Visual Studio 2005 or later : very funny :D,in my article I will use VS 2008. Note: in the attachment,I included all CSS and JS files so don't worry. How to use it? First thing,you will have to include all of the CSS and JS files into your page like this: <script src="Scripts/jquery-1.4.2.min.js" type="text/javascript"></script> <script src="Scripts/jquery-ui-1.8.custom.min.js" type="text/javascript"></script> <script src="Scripts/daterangepicker.jQuery.js" type="text/javascript"></script> <link href="CSS/redmond/jquery-ui-1.8.custom.css" rel="stylesheet" type="text/css" /> <link href="CSS/ui.daterangepicker.css" rel="stylesheet" type="text/css" /> <style type="text/css"> .ui-daterangepicker { font-size: 10px; } </style> Then add this html: <asp:TextBox ID="TextBox1" runat="server" Font-Size="10px"></asp:TextBox><asp:Button ID="SubmitButton" runat="server" Text="Submit" OnClick="SubmitButton_Click" /> <span>First Date:</span><asp:Label ID="FirstDate" runat="server"></asp:Label> <span>Second Date:</span><asp:Label ID="SecondDate" runat="server"></asp:Label> As you can see,it includes TextBox1 which we are going to attach the daterangepicker to it,2 labels to show you later on by code on how to read the date from the textbox and set it to the labels Now we have to attach the daterangepicker to the textbox by using jQuery (Note:visit the author's website for more info on daterangerpicker's options and how to use them): <script type="text/javascript"> $(function() { $("#<%= TextBox1.ClientID %>").attr("readonly", "readonly"); $("#<%= TextBox1.ClientID %>").attr("unselectable", "on"); $("#<%= TextBox1.ClientID %>").daterangepicker({ presetRanges: [], arrows: true, dateFormat: 'd M, yy', clearValue: '', datepickerOptions: { changeMonth: true, changeYear: true} }); }); </script> Finally,add this C# code: protected void SubmitButton_Click(object sender, EventArgs e) { if (TextBox1.Text.Trim().Length == 0) { return; } string selectedDate = TextBox1.Text; if (selectedDate.Contains("-")) { DateTime startDate; DateTime endDate; string[] splittedDates = selectedDate.Split("-".ToCharArray(), StringSplitOptions.RemoveEmptyEntries); if (splittedDates.Count() == 2 && DateTime.TryParse(splittedDates[0], out startDate) && DateTime.TryParse(splittedDates[1], out endDate)) { FirstDate.Text = startDate.ToShortDateString(); SecondDate.Text = endDate.ToShortDateString(); } else { //maybe the client has modified/altered the input i.e. hacking tools } } else { DateTime selectedDateObj; if (DateTime.TryParse(selectedDate, out selectedDateObj)) { FirstDate.Text = selectedDateObj.ToShortDateString(); SecondDate.Text = string.Empty; } else { //maybe the client has modified/altered the input i.e. hacking tools } } } This is the way on how to read from the textbox,That's it!. FAQ: 1-Why did you add this code?: <style type="text/css"> .ui-daterangepicker { font-size: 10px; } </style> A:For two reasons: 1)To show the Daterangepicker in a smaller size because it's original size is huge 2)To show you how to control the size of it. 2- Can I change the theme? A: yes you can,you will notice that I'm using Redmond theme which you will find it in jQuery UI website,visit their website and download a different theme,you may also have to make modifications to the css of daterangepicker,it's all yours. 3- Why did you add a font size to the textbox? A: To make the design look better,try to remove it and see by your self. 4- Can I register the script at codebehind? A: yes you can 5- I see you have added these two lines,what they do? $("#<%= TextBox1.ClientID %>").attr("readonly", "readonly"); $("#<%= TextBox1.ClientID %>").attr("unselectable", "on"); A:The first line will make the textbox not editable by the user,the second will block the blinking typing cursor from appearing if the user clicked on the textbox,you will notice that both lines are necessary to be used together,you can't just use one of them...for logical reasons of course. Finally,I hope everyone liked the article and as always,your feedbacks are always welcomed and if anyone have any suggestions or made any modifications that might be useful for anyone else then please post it at at the author's website and post a reference to your post here.

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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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• SQLAuthority News – Author Visit Review – TechMela Nepal – March 29-30, 2010

  - by pinaldave

  I was very fortunate to attend TechMela at Kathmandu, Nepal on 29th and 30th of March 2010. I would like to thank Allen Bailochan Tuladhar from Microsoft MDP Nepal for inviting me. Allen is a person with seemingly infinite energy and unlimited passion for Microsoft Technology. If you get an opportunity to spend just one hour with him, you will surely be more enthusiastic with regards to Microsoft Technology. And, I was lucky enough that I was able to spend about a total of 9 days with him in Kathmandu, working along with him in the Tech Community. TechMela Nepal Pinal at TechMela, Nepal TechMela is considered as one of the biggest events in Nepal, having been organized by Microsoft MDP Nepal. This event was attended by around 500 students and hundreds of Tech professionals. The event was handled very professionally and at very large scale. Every minor detail was properly planned and obviously thought out well. There were around 50+ volunteers from MS MDP who were monitoring this event systematically to make sure the event would run as smooth as planned. Attendees in Geek T-Shirts During this event, I was delighted to meet David Lim of Microsoft Singapore. He is very passionate in working for Microsoft Technology, as well as building deep relations with the Community. I was fortunate to spend my entire afternoon with him during the sight-seeing trip. We discussed various MS technologies and their community’s adoption as well as the way how each of us can be a part of the community activity. He also delivered excellent keynotes at the event. I must say that this is one of the most enjoyable keynotes I have ever attended. It was interesting and interactive, and I must say that I had the 70s feelings with all the fonts and graphics. I still remember him saying, “Yeah, I was a student and I know you.” Allen Tuladhar, David Lim, Pinal Dave and Guests After the keynote, everybody cheered when Allen came on stage to talk about the event and to introduce the agenda for the next two days. I must say that Allen is one of the most well-known people in Nepal. I was impressed with his popularity, and to prove this, when he got on the stage he had to wait for a long full minute before he was able to greet “Welcome” while the attendees were clapping and cheering. Technology Panelist at Techmela Kathmandu, Nepal This event was blessed with the top-of-the-top officials of various IT industries, Nepal ministries and the US Embassy. All the prominent personalities were present for panel discussion on the stage. The talk was done on various subjects. Also, the energy level which was set by Allen really echoed in the audience as they asked certain questions on different global as well local IT-related questions. The panel discussion really was discussion instead of usual monologue of one person. Pinal Dave presenting at TechMela Kathmandu, Nepal This was a two-day event and my session was on either of the day. I had a great participation from the audience on both days. The place where the event was organized had a capacity of around 500+ audience. Both of my sessions were heavily attended and volunteers did a fabulous job helping the attendees find empty seats or arrange some additional seats. I was overwhelmed with the interaction I have received in the large hall. Attendees were not so shy to express their thoughts, so both the sessions were followed up by top notch one-on-one conversations for a couple of hours. Pinal Dave presenting at TechMela Kathmandu, Nepal Pinal Dave presenting at TechMela Kathmandu, Nepal There are many questions that I have received during the event, and many of them can be interesting for all of us here so I will write detailed blog posts on these subjects. I also tried to participate in the gaming activities held at the event, but I felt I was kind of lost even if I was only playing for the very first minutes. This made me realize that I am really getting old for video games. Allen presenting at TechMela Kathmandu, Nepal Allen’s session on Digital Photography was very impressive as he demonstrated so many features of the Windows Live Product that at one point I felt he is MVP for Windows Live. In fact, he demonstrated how all the Microsoft products work together to give users an excellent desktop experience; no wonder he is an MVP for Windows Desktop Experience. Pinal Dave presending at TechMela Kathmandu, Nepal Any event has two common dilemmas – food and logistics. However, this event had excellent food and state-of-the-art organization. I was very glad that this two-day event turned out to be one of the most successful events in Nepal. I also noticed that almost all attendees rate their experience as beyond expectation and truly exceptional. Pinal Dave and Allen Bailochan Tuladhar If you ever get invited by Allen in any of his event, I strongly suggest that you drop all your plans and scheduled stuff, and accept his invitation. For sure, the event will be a very memorable one and would be your once-in-a-lifetime experience. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: MVP, Pinal Dave, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, T SQL, Technology

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• SQLAuthority News – Author Visit Review – TechMela Nepal – March 29-30, 2010

  - by pinaldave

  I was very fortunate to attend TechMela at Kathmandu, Nepal on 29th and 30th of March 2010. I would like to thank Allen Bailochan Tuladhar from Microsoft MDP Nepal for inviting me. Allen is a person with seemingly infinite energy and unlimited passion for Microsoft Technology. If you get an opportunity to spend just one hour with him, you will surely be more enthusiastic with regards to Microsoft Technology. And, I was lucky enough that I was able to spend about a total of 9 days with him in Kathmandu, working along with him in the Tech Community. TechMela Nepal Pinal at TechMela, Nepal TechMela is considered as one of the biggest events in Nepal, having been organized by Microsoft MDP Nepal. This event was attended by around 500 students and hundreds of Tech professionals. The event was handled very professionally and at very large scale. Every minor detail was properly planned and obviously thought out well. There were around 50+ volunteers from MS MDP who were monitoring this event systematically to make sure the event would run as smooth as planned. Attendees in Geek T-Shirts During this event, I was delighted to meet David Lim of Microsoft Singapore. He is very passionate in working for Microsoft Technology, as well as building deep relations with the Community. I was fortunate to spend my entire afternoon with him during the sight-seeing trip. We discussed various MS technologies and their community’s adoption as well as the way how each of us can be a part of the community activity. He also delivered excellent keynotes at the event. I must say that this is one of the most enjoyable keynotes I have ever attended. It was interesting and interactive, and I must say that I had the 70s feelings with all the fonts and graphics. I still remember him saying, “Yeah, I was a student and I know you.” Allen Tuladhar, David Lim, Pinal Dave and Guests After the keynote, everybody cheered when Allen came on stage to talk about the event and to introduce the agenda for the next two days. I must say that Allen is one of the most well-known people in Nepal. I was impressed with his popularity, and to prove this, when he got on the stage he had to wait for a long full minute before he was able to greet “Welcome” while the attendees were clapping and cheering. Technology Panelist at Techmela Kathmandu, Nepal This event was blessed with the top-of-the-top officials of various IT industries, Nepal ministries and the US Embassy. All the prominent personalities were present for panel discussion on the stage. The talk was done on various subjects. Also, the energy level which was set by Allen really echoed in the audience as they asked certain questions on different global as well local IT-related questions. The panel discussion really was discussion instead of usual monologue of one person. Pinal Dave presending at TechMela Kathmandu, Nepal This was a two-day event and my session was on either of the day. I had a great participation from the audience on both days. The place where the event was organized had a capacity of around 500+ audience. Both of my sessions were heavily attended and volunteers did a fabulous job helping the attendees find empty seats or arrange some additional seats. I was overwhelmed with the interaction I have received in the large hall. Attendees were not so shy to express their thoughts, so both the sessions were followed up by top notch one-on-one conversations for a couple of hours. Pinal Dave presending at TechMela Kathmandu, Nepal Pinal Dave presending at TechMela Kathmandu, Nepal Pinal Dave presending at TechMela Kathmandu, Nepal There are many questions that I have received during the event, and many of them can be interesting for all of us here so I will write detailed blog posts on these subjects. I also tried to participate in the gaming activities held at the event, but I felt I was kind of lost even if I was only playing for the very first minutes. This made me realize that I am really getting old for video games. Allen presending at TechMela Kathmandu, Nepal Allen’s session on Digital Photography was very impressive as he demonstrated so many features of the Windows Live Product that at one point I felt he is MVP for Windows Live. In fact, he demonstrated how all the Microsoft products work together to give users an excellent desktop experience; no wonder he is an MVP for Windows Desktop Experience. Pinal Dave presending at TechMela Kathmandu, Nepal Any event has two common dilemmas – food and logistics. However, this event had excellent food and state-of-the-art organization. I was very glad that this two-day event turned out to be one of the most successful events in Nepal. I also noticed that almost all attendees rate their experience as beyond expectation and truly exceptional. Pinal Dave and Allen Bailochan Tuladhar If you ever get invited by Allen in any of his event, I strongly suggest that you drop all your plans and scheduled stuff, and accept his invitation. For sure, the event will be a very memorable one and would be your once-in-a-lifetime experience. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: MVP, Pinal Dave, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, T SQL, Technology

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• ASP.NET MVC Custom Profile Provider

  - by Ben Griswold

  It’s been a long while since I last used the ASP.NET Profile provider. It’s a shame, too, because it just works with very little development effort: Membership tables installed? Check. Profile enabled in web.config? Check. SqlProfileProvider connection string set? Check.  Profile properties defined in said web.config file? Check. Write code to set value, read value, build and test. Check. Check. Check.  Yep, I thought the built-in Profile stuff was pure gold until I noticed how the user-based information is persisted to the database. It’s stored as xml and, well, that was going to be trouble if I ever wanted to query the profile data.  So, I have avoided the super-easy-to-use ASP.NET Profile provider ever since, until this week, when I decided I could use it to store user-specific properties which I am 99% positive I’ll never need to query against ever.  I opened up my ASP.NET MVC application, completed steps 1-4 (above) in about 3 minutes, started writing my profile get/set code and that’s where the plan broke down.  Oh yeah. That’s right.  Visual Studio auto-generates a strongly-type Profile reference for web site projects but not for ASP.NET MVC or Web Applications.  Bummer. So, I went through the steps of getting a customer profile provider working in my ASP.NET MVC application: First, I defined a CurrentUser routine and my profile properties in a custom Profile class like so: using System.Web.Profile; using System.Web.Security; using Project.Core;   namespace Project.Web.Context {     public class MemberPreferencesProfile : ProfileBase     {         static public MemberPreferencesProfile CurrentUser         {             get             {                 return (MemberPreferencesProfile)                     Create(Membership.GetUser().UserName);             }         }           public Enums.PresenceViewModes? ViewMode         {             get { return ((Enums.PresenceViewModes)                     ( base["ViewMode"] ?? Enums.PresenceViewModes.Category)); }             set { base["ViewMode"] = value; Save(); }         }     } } And then I replaced the existing profile configuration web.config with the following: <profile enabled="true" defaultProvider="MvcSqlProfileProvider"          inherits="Project.Web.Context.MemberPreferencesProfile">        <providers>     <clear/>     <add name="MvcSqlProfileProvider"          type="System.Web.Profile.SqlProfileProvider, System.Web,          Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"          connectionStringName="ApplicationServices" applicationName="/"/>   </providers> </profile> Notice that profile is enabled, I’ve defined the defaultProvider and profile is now inheriting from my custom MemberPreferencesProfile class.  Finally, I am now able to set and get profile property values nearly the same way as I did with website projects: viewMode = MemberPreferencesProfile.CurrentUser.ViewMode; MemberPreferencesProfile.CurrentUser.ViewMode = viewMode;

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• Developer’s Life – Summary of Superhero Articles

  - by Pinal Dave

  Earlier this year, I wrote an article series where I talked about developer’s life and compared it with Superhero. I have got amazing response to this series and I have been receiving quite a lots of email suggesting that I should write more blog post about them. Currently I am not planning to write more blog post but I will soon continue another series. In this blog post, I have summarized the entire series. Let me know if you want me to write about any superhero. I will see what I can do about that hero. Developer’s Life – Every Developer is a Captain America Captain America was first created as a comic book character in the 1940’s as a way to boost morale during World War II.  Aimed at a children’s audience, his legacy faded away when the war ended.  However, he has recently has a major reboot to become a popular movie character that deals with modern issues. Developer’s Life – Every Developer is the Incredible Hulk The Incredible Hulk is possibly one of the scariest superheroes out there.  All superheroes are meant to be “out of this world” and awe-inspiring, but I think most people will agree with I say The Hulk takes this to the next level.  He is the result of an industrial accident, which is scary enough in it’s own right.  Plus, when mild-mannered Bruce Banner is angered, he goes completely out-of-control and transforms into a destructive monster that he cannot control and has no memories of. Developer’s Life – Every Developer is a Wonder Woman We have focused a lot lately on this “superhero series.”  I love fantasy books and movies, and I feel like there is a lot to be learned from them.  As I am writing this series, though, I have noticed that every super hero I write about is a man.  So today, I would like to talk about the major female super hero – Wonder Woman. Developer’s Life – Every Developer is a Harry Potter Harry Potter might not be a superhero in the traditional sense, but I believe he still has a lot to teach us and show us about life as a developer.  If you have been living under a rock for the last 17 years, you might not know that Harry Potter is the main character in an extremely popular series of books and movies documenting the education and tribulation of a young wizard (and his friends). Developer’s Life – Every Developer is Like Transformers Transformers may not be superheroes – they don’t wear capes, they don’t have amazing powers outside of their size and folding ability, they’re not even human (technically).  Part of their enduring popularity is that while we are enjoying over-the-top movies, we are learning about good leadership and strong personal skills. Developer’s Life – Every Developer is a Iron Man Iron Man is another superhero who is not naturally “super,” but relies on his brain (and money) to turn him into a fighting machine.  While traditional superheroes are still popular, a three-movie franchise and incorporation into the new Avengers series shows that Iron Man is popular enough on his own. Developer’s Life – Every Developer is a Sherlock Holmes I have been thinking a lot about how developers are like super heroes, and I have written two blog posts now comparing them to Spiderman and Superman.  I have a lot of love and respect for developers, and I hope that they are enjoying these articles, and others are learning a little bit about the profession.  There is another fictional character who, while not technically asuper hero, is very powerful, and I also think stands as a good example of a developer. That character is Sherlock Holmes.  Sherlock Holmes is a British detective, first made popular at the turn of the 19thcentury by author Sir Arthur Conan Doyle.  The original Sherlock Holmes was a brilliant detective who could solve the most mind-boggling crime through simple observations and deduction. Developer’s Life – Every Developer is a Chhota Bheem Chhota Bheem is a cartoon character that is extremely popular where I live.  He is my daughter’s favorite characters.  I like to say that children love Chhota Bheem more than their parents – it is lucky for us he is not real!  Children love Chhota Bheem because he is the absolute “good guy.”  He is smart, loyal, and strong.  He and his friends live in Dholakpur and fight off their many enemies – and always win – in every episode.  In each episode, they learn something about friendship, bravery, and being kind to others.  Chhota Bheem is a good role model for children, and I think that he is a good role model for developers are well. Developer’s Life – Every Developer is a Batman Batman is one of the darkest superheroes in the fantasy canon.  He does not come to his powers through any sort of magical coincidence or radioactive insect, but through a lot of psychological scarring caused by witnessing the death of his parents.  Despite his dark back story, he possesses a lot of admirable abilities that I feel bear comparison to developers. Developer’s Life – Every Developer is a Superman I enjoyed comparing developers to Spiderman so much, that I have decided to continue the trend and encourage some of my favorite people (developers) with another favorite superhero – Superman.  Superman is probably the most famous superhero – and one of the most inspiring. Developer’s Life – Every Developer is a Spiderman I have to admit, Spiderman is my favorite superhero.  The most recent movie recently was released in theaters, so it has been at the front of my mind for some time. Spiderman was my favorite superhero even before the latest movie came out, but of course I took my whole family to see the movie as soon as I could!  Every one of us loved it, including my daughter.  We all left the movie thinking how great it would be to be Spiderman.  So, with that in mind, I started thinking about how we are like Spiderman in our everyday lives, especially developers. I would like to know which Superhero is your favorite hero! Reference: Pinal Dave (http://blog.SQLAuthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: Developer, Superhero

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• SQLAuthority News – A Successful Community TechDays at Ahmedabad – December 11, 2010

  - by pinaldave

  We recently had one of the best community events in Ahmedabad. We were fortunate that we had SQL Experts from around the world to have presented at this event. This gathering was very special because besides Jacob Sebastian and myself, we had two other speakers traveling all the way from Florida (Rushabh Mehta) and Bangalore (Vinod Kumar).There were a total of nearly 170 attendees and the event was blast. Here are the details of the event. Pinal Dave Presenting at Community Tech Days On the day of the event, it seemed to be the coldest day in Ahmedabad but I was glad to see hundreds of people waiting for the doors to be opened some hours before. We started the day with hot coffee and cookies. Yes, food first; and it was right after my keynote. I could clearly see that the coffee did some magic right away; the hall was almost full after the coffee break. Jacob Sebastian Presenting at Community Tech Days Jacob Sebastian, an SQL Server MVP and a close friend of mine, had an unusual job of surprising everybody with an innovative topic accompanied with lots of question-and-answer portions. That’s definitely one thing to love Jacob, that is, the novelty of the subject. His presentation was entitled “Best Database Practices for the .Net”; it really created magic on the crowd. Pinal Dave Presenting at Community Tech Days Next to Jacob Sebastian, I presented “Best Database Practices for the SharePoint”. It was really fun to present Database with the perspective of the database itself. The main highlight of my presentation was when I talked about how one can speed up the database performance by 40% for SharePoint in just 40 seconds. It was fun because the most important thing was to convince people to use the recommendation as soon as they walk out of the session. It was really amusing and the response of the participants was remarkable. Pinal Dave Presenting at Community Tech Days My session was followed by the most-awaited session of the day: that of Rushabh Mehta. He is an international BI expert who traveled all the way from Florida to present “Self Service BI” session. This session was funny and truly interesting. In fact, no one knew BI could be this much entertaining and fascinating. Rushabh has an appealing style of presenting the session; he instantly got very much interaction from the audience. Rushabh Mehta Presenting at Community Tech Days We had a networking lunch break in-between, when we talked about many various topics. It is always interesting to get in touch with the Community and feel a part of it. I had a wonderful time during the break. Vinod Kumar Presenting at Community Tech Days After lunch was apparently the most difficult session for the presenter as during this time, many people started to fall sleep and get dizzy. This spot was requested by Microsoft SQL Server Evangelist Vinod Kumar himself. During our discussion he suggested that if he gets this slot he would make sure people are up and more interactive than during the morning session. Just like always, this session was one of the best sessions ever. Vinod is true to his word as he presented the subject of “Time Management for Developer”. This session was the biggest hit in the event because the subject was instilled in the mind of every participant. Vinod Kumar Presenting at Community Tech Days Vinod’s session was followed by his own small session. Due to “insistent public demand”, he presented an interesting subject, “Tricks and Tips of SQL Server“. In 20 minutes he has done another awesome job and all attendees wanted more of the tricks. Just as usual he promised to do that next time for us. Vinod’s session was succeeded by Prabhjot Singh Bakshi’s session. He presented an appealing Silverlight concept. Just the same, he did a great job and people cheered him. Prabhjot Presenting at Community Tech Days We had a special invited speaker, Dhananjay Kumar, traveling all the way from Pune. He always supports our cause to help the Community in empowering participants. He presented the topic about Win7 Mobile and SharePoint integration. This was something many did not even expect to be possible. Kudos to Dhananjay for doing a great job. Dhananjay Kumar Presenting at Community Tech Days All in all, this event was one of the best in the Community Tech Days series in Ahmedabad. We were fortunate that legends from the all over the world were present here to present to the Community. I’d say never underestimate the power of the Community and its influence over the direction of the technology. Vinod Kumar Presenting trophy to Pinal Dave Vinod Kumar Presenting trophy to Pinal Dave This event was a very special gathering to me personally because of your support to the vibrant Community. The following awards were won for last year’s performance: Ahmedabad SQL Server User Group (President: Jacob Sebastian; Leader: Pinal Dave) – Best Tier 2 User Group Best Development Community Individual Contributor – Pinal Dave Speakers I was very glad to receive the award for our entire Community. Attendees at Community Tech Days I want to say thanks to Rushabh Mehta, Vinod Kumar and Dhananjay Kumar for visiting the city and presenting various technology topics in Community Tech Days. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: MVP, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, T SQL, Technology

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• SQL SERVER – Database Dynamic Caching by Automatic SQL Server Performance Acceleration

  - by pinaldave

  My second look at SafePeak’s new version (2.1) revealed to me few additional interesting features. For those of you who hadn’t read my previous reviews SafePeak and not familiar with it, here is a quick brief: SafePeak is in business of accelerating performance of SQL Server applications, as well as their scalability, without making code changes to the applications or to the databases. SafePeak performs database dynamic caching, by caching in memory result sets of queries and stored procedures while keeping all those cache correct and up to date. Cached queries are retrieved from the SafePeak RAM in microsecond speed and not send to the SQL Server. The application gets much faster results (100-500 micro seconds), the load on the SQL Server is reduced (less CPU and IO) and the application or the infrastructure gets better scalability. SafePeak solution is hosted either within your cloud servers, hosted servers or your enterprise servers, as part of the application architecture. Connection of the application is done via change of connection strings or adding reroute line in the c:\windows\system32\drivers\etc\hosts file on all application servers. For those who would like to learn more on SafePeak architecture and how it works, I suggest to read this vendor’s webpage: SafePeak Architecture. More interesting new features in SafePeak 2.1 In my previous review of SafePeak new I covered the first 4 things I noticed in the new SafePeak (check out my article “SQLAuthority News – SafePeak Releases a Major Update: SafePeak version 2.1 for SQL Server Performance Acceleration”): Cache setup and fine-tuning – a critical part for getting good caching results Database templates Choosing which database to cache Monitoring and analysis options by SafePeak Since then I had a chance to play with SafePeak some more and here is what I found. 5. Analysis of SQL Performance (present and history): In SafePeak v.2.1 the tools for understanding of performance became more comprehensive. Every 15 minutes SafePeak creates and updates various performance statistics. Each query (or a procedure execute) that arrives to SafePeak gets a SQL pattern, and after it is used again there are statistics for such pattern. An important part of this product is that it understands the dependencies of every pattern (list of tables, views, user defined functions and procs). From this understanding SafePeak creates important analysis information on performance of every object: response time from the database, response time from SafePeak cache, average response time, percent of traffic and break down of behavior. One of the interesting things this behavior column shows is how often the object is actually pdated. The break down analysis allows knowing the above information for: queries and procedures, tables, views, databases and even instances level. The data is show now on all arriving queries, both read queries (that can be cached), but also any types of updates like DMLs, DDLs, DCLs, and even session settings queries. The stats are being updated every 15 minutes and SafePeak dashboard allows going back in time and investigating what happened within any time frame. 6. Logon trigger, for making sure nothing corrupts SafePeak cache data If you have an application with many parts, many servers many possible locations that can actually update the database, or the SQL Server is accessible to many DBAs or software engineers, each can access some database directly and do some changes without going thru SafePeak – this can create a potential corruption of the data stored in SafePeak cache. To make sure SafePeak cache is correct it needs to get all updates to arrive to SafePeak, and if a DBA will access the database directly and do some changes, for example, then SafePeak will simply not know about it and will not clean SafePeak cache. In the new version, SafePeak brought a new feature called “Logon Trigger” to solve the above challenge. By special click of a button SafePeak can deploy a special server logon trigger (with a CLR object) on your SQL Server that actually monitors all connections and informs SafePeak on any connection that is coming not from SafePeak. In SafePeak dashboard there is an interface that allows to control which logins can be ignored based on login names and IPs, while the rest will invoke cache cleanup of SafePeak and actually locks SafePeak cache until this connection will not be closed. Important to note, that this does not interrupt any logins, only informs SafePeak on such connection. On the Dashboard screen in SafePeak you will be able to see those connections and then decide what to do with them. Configuration of this feature in SafePeak dashboard can be done here: Settings -> SQL instances management -> click on instance -> Logon Trigger tab. Other features: 7. User management ability to grant permissions to someone without changing its configuration and only use SafePeak as performance analysis tool. 8. Better reports for analysis of performance using 15 minute resolution charts. 9. Caching of client cursors 10. Support for IPv6 Summary SafePeak is a great SQL Server performance acceleration solution for users who want immediate results for sites with performance, scalability and peak spikes challenges. Especially if your apps are packaged or 3rd party, since no code changes are done. SafePeak can significantly increase response times, by reducing network roundtrip to the database, decreasing CPU resource usage, eliminating I/O and storage access. SafePeak team provides a free fully functional trial www.safepeak.com/download and actually provides a one-on-one assistance during such trial. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, Pinal Dave, PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQL Utility, T SQL, Technology

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• Developer Training – A Conclusive Summary- Part 5

  - by pinaldave

  Developer Training - Importance and Significance - Part 1 Developer Training – Employee Morals and Ethics – Part 2 Developer Training – Difficult Questions and Alternative Perspective - Part 3 Developer Training – Various Options for Developer Training – Part 4 Developer Training – A Conclusive Summary- Part 5 We have now reached the end of our series about developer training.  I hope you have come away thinking that training is the best way to advance in your company and that you are looking for training opportunities right now.  If you’re still not convinced here are a few things to keep in mind:  Training benefits the employer and the employee. A well trained employee is a happy employee, and a happy employee is more efficient and productive. Training an employee might be expensive, but it is less expensive than hiring a new person. Whether you are looking at him from the employee’s or the company’s point of view, there are always advantages to training. A Broader View This series is definitely written for Developer Training but it is not limited to developers only. There are IT Pro, System Admins, DBAs as well many other technology professionals; this article series is for all professionals in the world. The concepts and take away will remain common across all the platform and regardless of technology affiliation. Pass the Knowledge If I have to pick one advise which is extremely important related to training, I will pick – pass the knowledge. Once you have decided in favor of training, there is more to it than simply showing up and staying awake.  It is always a good idea to take notes – at the very least it will help you stay awake, but they will often serve as a good way to remember your training when you go back to work.  You can also use them to pass your new knowledge on to fellow employees, which can be very fun and rewarding. Right Place, Right Time and Right Training There are so many ways to get developer training.  In-person and on the job training is easy to come by and is the most usual type of training, but don’t overlook my favorite type of training: On Demand.  Being able to learn at your own pace, own place and on your own time will make training a realistic goal for almost every employee. I can think of nothing more important in life than furthering your education.  Especially when you work in a field that is constantly changing – like technology.  Whether you like it or not, training is incredibly important.  That is why I feel it is so important to receive training.  And because there are so many different training formats – live, online, through books, through people – I am certain that we all can find a way to be trained that best suits our goals and personalities. The Teacher Within If you think of anyone who is a master of the technology field or an incredibly successful developer (the obvious examples that spring to mind are Steve Jobs or Bill Gates), you will also find a teacher.  Both these individuals spent their lives developing better technology, but also educating other developers and the public about how to use these technologies and how it can change your life for the better.  I think that we all should strive to be like these wonderful teachers.  We might not be able to change the world, but we can certainly change a few lives around us. Even if we never turn into trainers ourselves , being trained as a student can be a good exercise.  We learn a lot and become better employees – and it would not be a stretch to say that this makes us better individuals, as well. Final Say I think learning and growing in your chosen field is not only a good idea, career-wise, but can be fun, too!  I for one never feel more alive than when I am learning about something I am really passionate about.  I think my job title – technology evangelist – explains how enthusiastic I am about this subject.  But please don’t think that I am thinking of this as someone who wants to train and educate others (although this is also one of my passions).  I am also a passionate student.  I enjoy learning new things and am always on the lookout for new ways to learn and new people to learn from. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Developer Training, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• Developer Training – Various Options for Maximum Benefit – Part 4

  - by pinaldave

  Developer Training - Importance and Significance - Part 1 Developer Training – Employee Morals and Ethics – Part 2 Developer Training – Difficult Questions and Alternative Perspective - Part 3 Developer Training – Various Options for Developer Training – Part 4 Developer Training – A Conclusive Summary- Part 5 If you have been reading this series, by now you are aware of all the pros and cons that can come along with training.  We’ve asked and answered hard questions, and investigated them “whys” and “hows” of training.  Now it is time to talk about all the different kinds of training that are out there! On Job Training The most common type of training is on the job training.  Everyone receives this kind of education – even experts who come in to consult have to be taught where the printer, pens, and copy machines are.  If you are thinking about more concrete topics, though, on the job training can be some of the easiest to come across.  Picture this: someone in the company whom you really admire is hard at work on a project.  You come up to them and ask to help them out – if they are a busy developer, the odds are that they will say “yes, please!”   If you phrase your question as an offer of help, you can receive training without ever putting someone in the awkward position of acting as a mentor.  However, some people may want the task of being a mentor.  It can never hurt to ask.  Most people will be more than willing to pass their knowledge along. Extreme Programming If your company and coworkers are willing, you can even investigate Extreme Programming.  This is a type of programming that allows small teams to quickly develop code and products that are released with almost immediate user feedback.  You can find more information at http://www.extremeprogramming.org/.  If this is something your company could use, suggest it to your supervisor.  Even if they say no, it will make it clear that you are a go-getter who is interested in new and exciting projects.  If the answer is yes, then you have the opportunity to get some of the best on the job training around. In Person Training Click on Image to Enlarge When you say the word “training,” most people’s minds go back to the classroom, an image they are familiar with.  While training doesn’t always have to be in a traditional setting, because it is so familiar it can also be the most valuable type of training.  There are many ways to get training through a live instructor.  Some companies may be willing to send a representative to you, where employees will get training, sometimes food and coffee, and a live instructor who can answer questions immediately.  Sometimes these trainers are also able to do consultations at the same time, which can invaluable to a company.  If you are the one to asks your supervisor for a training session that can also be turned into a consultation, you may stick in their minds as an incredibly dedicated employee.  If you can’t find a representative, local colleges can also be a good resource for free or cheap classes – or they may have representatives coming who are willing to take on a few more students. Benefits of On Demand Developer Training Of course, you can often get the best of all these types of training with online or On Demand training.  You can get the benefit of a live instructor who is willing to answer questions (although in this case, usually through e-mail or other online venues), there are often real-world examples to follow along – like on the job training – and best of all you can learn whenever you have the time or need.  Did a problem with your server come up at midnight when all your supervisors are safe at home and probably in bed?  No problem!  On Demand training is especially useful if you need to slow down, pause, or rewind a training session.  Not even a real-life instructor can do that! When I was writing this blog post, I felt that each of the subject, which I have covered can be blog posts of itself. However, I wanted to keep the the blog post concise and so touch based on three major training aspects 1) On Job Training 2) In Person Training and 3) Online training. Here is the question for you – is there any other kind of training methods available, which are effective and one should consider it? If yes, what are those, I may write a follow up blog post on the same subject next week. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Developer Training, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Spatial Database Queries – What About BLOB – T-SQL Tuesday #006

  - by pinaldave

  Michael Coles is one of the most interesting book authors I have ever met. He has a flair of writing complex stuff in a simple language. There are a very few people like that.  I really enjoyed reading his recent book, Expert SQL Server 2008 Encryption. I strongly suggest taking a look at it. This blog is written in response to T-SQL Tuesday #006: “What About BLOB? by Michael Coles. Spatial Database is my favorite subject. Since I did my TechEd India 2010 presentation, I have enjoyed this subject a lot. Before I continue this blog post, there are a few other blog posts, so I suggest you read them.  To help build the environment run the queries, I am going to present them in this single blog post. SQL SERVER – What is Spatial Database? – Developing with SQL Server Spatial and Deep Dive into Spatial Indexing This blog post explains the basics of Spatial Database and also provides a good introduction to Indexing concept. SQL SERVER – World Shapefile Download and Upload to Database – Spatial Database This blog post will enable you with how to load the shape file into database. SQL SERVER – Spatial Database Definition and Research Documents This blog post links to the white paper about Spatial Database written by Microsoft experts. SQL SERVER – Introduction to Spatial Coordinate Systems: Flat Maps for a Round Planet This blog post links to the white paper explaining coordinate system, as written by Microsoft experts. After reading the above listed blog posts, I am very confident that you are ready to run the following script. Once you create a database using the World Shapefile, as mentioned in the second link above,you can display the image of India just like the following. Please note that this is not an accurate political map. The boundary of this map has many errors and it is just a representation. You can run the following query to generate the map of India from the database spatial which you have created after following the instructions here. USE Spatial GO -- India Map SELECT [CountryName] ,[BorderAsGeometry] ,[Border] FROM [Spatial].[dbo].[Countries] WHERE Countryname = 'India' GO Now, let us find the longitude and latitude of the two major IT cities of India, Hyderabad and Bangalore. I find their values as the following: the values of longitude-latitude for Bangalore is 77.5833300000 13.0000000000; for Hyderabad, longitude-latitude is 78.4675900000 17.4531200000. Now, let us try to put these values on the India Map and see their location. -- Bangalore DECLARE @GeoLocation GEOGRAPHY SET @GeoLocation = GEOGRAPHY::STPointFromText('POINT(77.5833300000 13.0000000000)',4326).STBuffer(20000); -- Hyderabad DECLARE @GeoLocation1 GEOGRAPHY SET @GeoLocation1 = GEOGRAPHY::STPointFromText('POINT(78.4675900000 17.4531200000)',4326).STBuffer(20000); -- Bangalore and Hyderabad on Map of India SELECT name, [GeoLocation] FROM [IndiaGeoNames] I WHERE I.[GeoLocation].STDistance(@GeoLocation) <= 0 UNION ALL SELECT name, [GeoLocation] FROM [IndiaGeoNames] I WHERE I.[GeoLocation].STDistance(@GeoLocation1) <= 0 UNION ALL SELECT '',[Border] FROM [Spatial].[dbo].[Countries] WHERE Countryname = 'India' GO Now let us quickly draw a straight line between them. DECLARE @GeoLocation GEOGRAPHY SET @GeoLocation = GEOGRAPHY::STPointFromText('POINT(78.4675900000 17.4531200000)',4326).STBuffer(10000); DECLARE @GeoLocation1 GEOGRAPHY SET @GeoLocation1 = GEOGRAPHY::STPointFromText('POINT(77.5833300000 13.0000000000)',4326).STBuffer(10000); DECLARE @GeoLocation2 GEOGRAPHY SET @GeoLocation2 = GEOGRAPHY::STGeomFromText('LINESTRING(78.4675900000 17.4531200000, 77.5833300000 13.0000000000)',4326) SELECT name, [GeoLocation] FROM [IndiaGeoNames] I WHERE I.[GeoLocation].STDistance(@GeoLocation) <= 0 UNION ALL SELECT name, [GeoLocation] FROM [IndiaGeoNames] I1 WHERE I1.[GeoLocation].STDistance(@GeoLocation1) <= 0 UNION ALL SELECT '' name, @GeoLocation2 UNION ALL SELECT '',[Border] FROM [Spatial].[dbo].[Countries] WHERE Countryname = 'India' GO Let us use the distance function of the spatial database and find the straight line distance between this two cities. -- Distance Between Hyderabad and Bangalore DECLARE @GeoLocation GEOGRAPHY SET @GeoLocation = GEOGRAPHY::STPointFromText('POINT(78.4675900000 17.4531200000)',4326) DECLARE @GeoLocation1 GEOGRAPHY SET @GeoLocation1 = GEOGRAPHY::STPointFromText('POINT(77.5833300000 13.0000000000)',4326) SELECT @GeoLocation.STDistance(@GeoLocation1)/1000 'KM'; GO The result of above query is as displayed in following image. As per SQL Server, the distance between these two cities is 501 KM, but according to what I know, the distance between those two cities is around 562 KM by road. However, please note that roads are not straight and they have lots of turns, whereas this is a straight-line distance. What would be more accurate is the distance between these two cities by air travel. When we look at the air travel distance between Bangalore and Hyderabad, the total distance covered is 495 KM, which is very close to what SQL Server has estimated, which is 501 KM. Bravo! SQL Server has accurately provided the distance between two of the cities. SQL Server Spatial Database can be very useful simply because it is very easy to use, as demonstrated above. I appreciate your comments, so let me know what your thoughts and opinions about this are. 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: Spatial Database

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• SQLAuthority News – Don’t Be Afraid To Fool The World – Video by John Sonmez

  - by Pinal Dave

  Sometime some words and statements grabs your attention and it is hard to stop thinking about that after a while. Something similar happened a few days ago when I read the twitter statement of my friend and Pluralsight author John Sonmez. He twitted few days ago very interesting statement. “I don’t know a single successful person, who doesn’t deep down think that have the world fooled. #fooltheworld” by John Sonmez. When I read it, I was extremely intrigued by this statement. I read it many times, I shared with my family and I just could not stop interpreting this statement. It was indeed fun to read it again and again and there are so many different meanings one can take away from the statement. I know John very well, he is a  wonderful person and have very positive energy for the life. I just had to request him to build a video around it. Right after 5 days of my request, John created a wonderful video around this subject. I watched it multiple times as it was a wonderful video. I am not going to write about what was in the video much as I suggest you to watch the video itself. Here is one of the personal stories I want to share which is absolutely relevant to this video. I think my story 100% resonant the story of John. A Real Story from My Past Three years ago, I submitted a session in one of the SharePoint conference as a SQL Server session. My session was accepted and I prepared it very well. I put more than 2 month’s time to prepare for the session and I was very excited to present the session. I reached to the event place traveling thousands of the miles and I was very much excited to present the session. However, there was a little mixed up in the session. There were multiple session which were similar to my session title. One of the other speakers also had proposed a database related session and was selected. When the material went to print the printing team got confused and by mistake swapped the sessions. The other speaker got Performance with SQL Server session and I had received Performance with SharePoint session. IT was indeed a big mixed up but now that is how it was in the event guide and it was marketed the same way everything in the event. A Big Mix Up I had to talk with the event organizer and we come to the conclusion that we all had good intention but things just got mixed up and now was the time when “The show must go on“. I had a great amount of hesitation to go and present the session as I had personally never worked with Sharepoint so close in my life and my session abstracted talked about SharePoint tricks in depth. Two hours before the session I took the help of one of my friend and installed the SharePoint on my box. He showed me a few things here and there but it was never a good enough time to learn everything which I wanted to learn. The Moments of Confidence I was very scared and nervous to go on the stage as a SharePoint was not something I felt comfortable. However, I decided to go on stage with confidence as a SharePoint expert. Though I did not know SharePoint at the best, I had confidence that whatever I know is correct and I will not misguide people. I had no intention to fool people but I had no intention to accept that I am a fool and you all wasted your time and money to dedicate your time to attend my session. I decided to be honest but at the same time decided to take the session beyond my expertise. The sixty minutes of the session went very fine and I was able to manage all the difficult question at a satisfactory level. When the session was over my feeling was that I would have not presented or talked any different if I had more knowledge of the SharePoint at that time. I think it was one of my best sessions and it was reflected in the session feedback as well. I was the best speaker across all the track and my session had highest ranking. I was delighted and I learned a very valuable lesson. I must go beyond my limits and knowledge. I must aim higher and work harder. I should not lie but I should have confidence that I have a good heart and I put 100% in my efforts.  Lessions Learned Since this incident I have learned a lot about SharePoint and I am now a regular speaker at various SharePoint conferences along with SQL Server sessions. I am motivated and I am not afraid. I know people have lots of expectation from me but I have learned not to judge myself before I do my best. I leave the judgement of my efforts to my audience. I do not take the burden of the feedback on me, even though I know my audience have expected from me. I know what I know and I put my best. I must go out, if I fail, I learn from my mistake but I must keep my progress trajectory very high. As John said in the video, sometime success is not something we can achieve 100% but we can keep on going near to it. As long as we do not lose our focus from our goal and do not deviate from our progress path, we are doing things right. Reference: Pinal Dave (http://blog.sqlauthority.com)  Filed under: About Me, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• Render MVCContrib Grid with No Header Row

  - by Ben Griswold

  The MVCContrib Grid allows for the easy construction of HTML tables for displaying data from a collection of Model objects. I add this component to all of my ASP.NET MVC projects.  If you aren’t familiar with what the grid has to offer, it’s worth the looking into. What you may notice in the busy example below is the fact that I render my column headers independent of the grid contents.  This allows me to keep my headers fixed while the user searches through the table content which is displayed in a scrollable div*.  Thus, I needed a way to render my grid without headers. That’s where Grid Renderers come into play.  <table border="0" cellspacing="0" cellpadding="0" class="projectHeaderTable">     <tr>         <td class="memberTableMemberHeader">             <%= Html.GridColumnHeader("Member", "Index", "MemberFullName")%>              </td>         <td class="memberTableRoleHeader">             <%= Html.GridColumnHeader("Role", "Index", "ProjectRoleTypeName")%>              </td>                <td class="memberTableActionHeader">             Action         </td>     </tr> </table> <div class="scrollContentWrapper"> <% Html.Grid(Model)     .Columns(column =>             {                 column.For(c => c.MemberFullName).Attributes(@class => "memberTableMemberCol");                 column.For(c => c.ProjectRoleTypeName).Attributes(@class => "memberTableRoleCol");                 column.For(x => Html.ActionLink("View", "Details", new { Id = x.ProjectMemberId }) + " | " +                                 Html.ActionLink("Edit", "Edit", new { Id = x.ProjectMemberId }) + " | " +                                 Html.ActionLink("Remove", "Delete", new { Id = x.ProjectMemberId }))                     .Attributes(@class => "memberTableActionCol").DoNotEncode();             })     .Empty("There are no members associated with this project.")     .Attributes(@class => "lbContent")     .RenderUsing(new GridNoHeaderRenderer<ProjectMemberDetailsViewModel>())     .Render(); %> </div> <div class="scrollContentBottom">     <!– –> </div> <%=Html.Pager(Model) %> Maybe you noticed the reference to the GridNoHeaderRenderer class above?  Yep, rendering the grid with no header is straightforward.   public class GridNoHeaderRenderer<T> :     HtmlTableGridRenderer<T> where T: class {     protected override bool RenderHeader()     {         // Explicitly returning true would suppress the header         // just fine, however, Render() will always assume that         // items exist in collection and RenderEmpty() will         // never be called.           // In other words, return ShouldRenderHeader() if you         // want to maintain the Empty text when no items exist.         return ShouldRenderHeader();     } } Well, if you read through the comments, there is one catch.  You might be tempted to have the RenderHeader method always return true.  This would work just fine but you should return the result of ShouldRenderHeader() instead so the Empty text will continue to display if there are no items in the collection. The GridRenderer feature found in the MVCContrib Grid is so well put together, I just had to share.  * Though you can find countless alternatives to the fixed headers problem online, this is the only solution that I’ve ever found to reliably work across browsers. If you know something I don’t, please share.

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• SQLAuthority News – Meeting with Allen Bailochan Tuladhar – An Unlimited Experience

  - by pinaldave

  Allen  Tuladhar I recently came back from my 9-day trip in Nepal and I must say that this is one of the best trips I had in my lifetime. Allen Bailochan Tuladhar is a wonderful person and an extreme enthusiast for Microsoft Technology. Allen is the Chief Executive Officer of Unlimited Technologies Pvt Ltd., Country Manager of Microsoft MDP Nepal, the Member Secretary of Nepali Language in Information Technology, and member of the Steering Committee of the Government of Nepal. He is the person who keeps the Nepal’s Tech Community constantly motivating and taking it to the next level. I have met Allen for many times before, but this was the first time I was with him in Kathmandu, Nepal. I was very impressed with the amount of the work he does in the community. During my 9 days of stay, every single day was a new lesson for me. I was amazed and overwhelmed with the many things he does every single day. Not only he does he work closely with Government of Nepal ministry, but he is also the most known person in the Student Community. His expertise in the technical subject matter is not limited to one technology; rather, I have seen him actively engaging himself in  discussions of various tech topics. Allen presending at TechMela Kathmandu, Nepal Allen is currently active in working out to localize Windows and Office and incorporate it using the Nepali language. I was able to witness and experience how the localization works, as well as the procedure on how to do such. If you know the whole localization process, you must have realized how big and daunting of a process it is. I was glad that I became a part of it. Prominent Personality of Nepal on Panel Discussion Another great opportunity I had when I was at Allen’s office is that I have learned how the radio technology talk show works. Nepali Radio station has the weekly program in their local language, in which MS technology is discussed and industry leaders are invited to talk about their experience with the technology. I found the program so interesting because it has so much variety in terms of technology subjects. Well, my understanding of Nepali language is limited but I did understand quite a bit. Ravi, Nutan, Pinal, Gandip I got the chance to meet lots of Database Professionals as well. People in Nepal are very polite even though they are very strong in their technology fundamentals. I had in-depth discussion regarding High Availability scenarios, as well Query Tuning. Database professionals from the leading financial sectors of Nepal wanted me to visit their Data Center and help them out with a few advances. In no time, Allen organized a visit for me. He sent me a Nepali-speaking expert from his own organization to accompany me in overcoming any difficulties while I was on my way helping this financial district. Pinal (SQLAuthority) and Deependra (Unlimited) When I was going to Nepal, I was really not sure if I would be able to stay busy for 9 days straight in Community-related activity. However, on the 9th day I realize that I can still stay here for more than 9 days because in every single day, I feel enthusiastic enough to do something new. Allen Bailochan Tuladhar Even though I was working  very hard every day, I hardly had the chance to work with and talk to him one-on-one for the first few days. One of the evenings, Allen invited me to his home and we discussed about his future ideas. I was really surprised to see how much a man can do for his technical community and for his country. When I asked Allen’s wife and daughter if they ever think it’s getting too much with regards to Allen putting tough efforts to the community, their answer was something I did not expect. I found out that Allen’s wife manages all the back office and logistics of the community events and his daughter manages the websites. I felt that they do not have any complain,  and instead, their whole family is in this activity as deeply as it can get, which I thought is a very good thing. Pinal and Allen I want to end this post with an interesting story that happened during our lunch hour at one of the Nepali restaurants. While we were having our lunch and having some chitchat, Allen suddenly stood up and called several people walking along the pavement. He introduced them all to me as Microsoft Student Partners. He asked all of them to order their favorite dish and called the waiter to inform that he will pick up their tab. Figuring out the question written on my face, he just said one sentence: “They are all future technology professionals who are going to make all of us proud.” I guess I have a lot of things to learn. Hats off to Allen! Pinal and Allen at Microsoft MDP Unlimited Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: MVP, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, T SQL, Technology

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• SQL SERVER – Solution to Puzzle – Simulate LEAD() and LAG() without Using SQL Server 2012 Analytic Function

  - by pinaldave

  Earlier I wrote a series on SQL Server Analytic Functions of SQL Server 2012. During the series to keep the learning maximum and having fun, we had few puzzles. One of the puzzle was simulating LEAD() and LAG() without using SQL Server 2012 Analytic Function. Please read the puzzle here first before reading the solution : Write T-SQL Self Join Without Using LEAD and LAG. When I was originally wrote the puzzle I had done small blunder and the question was a bit confusing which I corrected later on but wrote a follow up blog post on over here where I describe the give-away. Quick Recap: Generate following results without using SQL Server 2012 analytic functions. I had received so many valid answers. Some answers were similar to other and some were very innovative. Some answers were very adaptive and some did not work when I changed where condition. After selecting all the valid answer, I put them in table and ran RANDOM function on the same and selected winners. Here are the valid answers. No Joins and No Analytic Functions Excellent Solution by Geri Reshef – Winner of SQL Server Interview Questions and Answers (India | USA) WITH T1 AS (SELECT Row_Number() OVER(ORDER BY SalesOrderDetailID) N, s.SalesOrderID, s.SalesOrderDetailID, s.OrderQty FROM Sales.SalesOrderDetail s WHERE SalesOrderID IN (43670, 43669, 43667, 43663)) SELECT SalesOrderID,SalesOrderDetailID,OrderQty, CASE WHEN N%2=1 THEN MAX(CASE WHEN N%2=0 THEN SalesOrderDetailID END) OVER (Partition BY (N+1)/2) ELSE MAX(CASE WHEN N%2=1 THEN SalesOrderDetailID END) OVER (Partition BY N/2) END LeadVal, CASE WHEN N%2=1 THEN MAX(CASE WHEN N%2=0 THEN SalesOrderDetailID END) OVER (Partition BY N/2) ELSE MAX(CASE WHEN N%2=1 THEN SalesOrderDetailID END) OVER (Partition BY (N+1)/2) END LagVal FROM T1 ORDER BY SalesOrderID, SalesOrderDetailID, OrderQty; GO No Analytic Function and Early Bird Excellent Solution by DHall – Winner of Pluralsight 30 days Subscription -- a query to emulate LEAD() and LAG() ;WITH s AS ( SELECT 1 AS ldOffset, -- equiv to 2nd param of LEAD 1 AS lgOffset, -- equiv to 2nd param of LAG NULL AS ldDefVal, -- equiv to 3rd param of LEAD NULL AS lgDefVal, -- equiv to 3rd param of LAG ROW_NUMBER() OVER (ORDER BY SalesOrderDetailID) AS row, SalesOrderID, SalesOrderDetailID, OrderQty FROM Sales.SalesOrderDetail WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ) SELECT s.SalesOrderID, s.SalesOrderDetailID, s.OrderQty, ISNULL( sLd.SalesOrderDetailID, s.ldDefVal) AS LeadValue, ISNULL( sLg.SalesOrderDetailID, s.lgDefVal) AS LagValue FROM s LEFT OUTER JOIN s AS sLd ON s.row = sLd.row - s.ldOffset LEFT OUTER JOIN s AS sLg ON s.row = sLg.row + s.lgOffset ORDER BY s.SalesOrderID, s.SalesOrderDetailID, s.OrderQty No Analytic Function and Partition By Excellent Solution by DHall – Winner of Pluralsight 30 days Subscription /* a query to emulate LEAD() and LAG() */ ;WITH s AS ( SELECT 1 AS LeadOffset, /* equiv to 2nd param of LEAD */ 1 AS LagOffset, /* equiv to 2nd param of LAG */ NULL AS LeadDefVal, /* equiv to 3rd param of LEAD */ NULL AS LagDefVal, /* equiv to 3rd param of LAG */ /* Try changing the values of the 4 integer values above to see their effect on the results */ /* The values given above of 0, 0, null and null behave the same as the default 2nd and 3rd parameters to LEAD() and LAG() */ ROW_NUMBER() OVER (ORDER BY SalesOrderDetailID) AS row, SalesOrderID, SalesOrderDetailID, OrderQty FROM Sales.SalesOrderDetail WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ) SELECT s.SalesOrderID, s.SalesOrderDetailID, s.OrderQty, ISNULL( sLead.SalesOrderDetailID, s.LeadDefVal) AS LeadValue, ISNULL( sLag.SalesOrderDetailID, s.LagDefVal) AS LagValue FROM s LEFT OUTER JOIN s AS sLead ON s.row = sLead.row - s.LeadOffset /* Try commenting out this next line when LeadOffset != 0 */ AND s.SalesOrderID = sLead.SalesOrderID /* The additional join criteria on SalesOrderID above is equivalent to PARTITION BY SalesOrderID in the OVER clause of the LEAD() function */ LEFT OUTER JOIN s AS sLag ON s.row = sLag.row + s.LagOffset /* Try commenting out this next line when LagOffset != 0 */ AND s.SalesOrderID = sLag.SalesOrderID /* The additional join criteria on SalesOrderID above is equivalent to PARTITION BY SalesOrderID in the OVER clause of the LAG() function */ ORDER BY s.SalesOrderID, s.SalesOrderDetailID, s.OrderQty No Analytic Function and CTE Usage Excellent Solution by Pravin Patel - Winner of SQL Server Interview Questions and Answers (India | USA) --CTE based solution ; WITH cteMain AS ( SELECT SalesOrderID, SalesOrderDetailID, OrderQty, ROW_NUMBER() OVER (ORDER BY SalesOrderDetailID) AS sn FROM Sales.SalesOrderDetail WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ) SELECT m.SalesOrderID, m.SalesOrderDetailID, m.OrderQty, sLead.SalesOrderDetailID AS leadvalue, sLeg.SalesOrderDetailID AS leagvalue FROM cteMain AS m LEFT OUTER JOIN cteMain AS sLead ON sLead.sn = m.sn+1 LEFT OUTER JOIN cteMain AS sLeg ON sLeg.sn = m.sn-1 ORDER BY m.SalesOrderID, m.SalesOrderDetailID, m.OrderQty No Analytic Function and Co-Related Subquery Usage Excellent Solution by Pravin Patel – Winner of SQL Server Interview Questions and Answers (India | USA) -- Co-Related subquery SELECT m.SalesOrderID, m.SalesOrderDetailID, m.OrderQty, ( SELECT MIN(SalesOrderDetailID) FROM Sales.SalesOrderDetail AS l WHERE l.SalesOrderID IN (43670, 43669, 43667, 43663) AND l.SalesOrderID >= m.SalesOrderID AND l.SalesOrderDetailID > m.SalesOrderDetailID ) AS lead, ( SELECT MAX(SalesOrderDetailID) FROM Sales.SalesOrderDetail AS l WHERE l.SalesOrderID IN (43670, 43669, 43667, 43663) AND l.SalesOrderID <= m.SalesOrderID AND l.SalesOrderDetailID < m.SalesOrderDetailID ) AS leag FROM Sales.SalesOrderDetail AS m WHERE m.SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY m.SalesOrderID, m.SalesOrderDetailID, m.OrderQty This was one of the most interesting Puzzle on this blog. Giveaway Winners will get following giveaways. Geri Reshef and Pravin Patel SQL Server Interview Questions and Answers (India | USA) DHall Pluralsight 30 days Subscription Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, Readers Contribution, Readers Question, SQL, SQL Authority, SQL Function, SQL Puzzle, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• Updating the managed debugging API for .NET v4

  - by Brian Donahue

  In any successful investigation, the right tools play a big part in collecting evidence about the state of the "crime scene" as it was before the detectives arrived. Unfortunately for the Crash Scene Investigator, we don't have the budget to fly out to the customer's site, chalk the outline, and eat their doughnuts. We have to rely on the end-user to collect the evidence for us, which means giving them the fingerprint dust and the evidence baggies and leaving them to it. With that in mind, the Red Gate support team have been writing tools that can collect vital clues with a minimum of fuss. Years ago we would have asked for a memory dump, where we used to get the customer to run CDB.exe and produce dumps that we could analyze in-house, but those dumps were pretty unwieldy (500MB files) and the debugger often didn't dump exactly where we wanted, or made five or more dumps. What we wanted was just the minimum state information from the program at the time of failure, so we produced a managed debugger that captured every first and second-chance exception and logged the stack and a minimal amount of variables from the memory of the application, which could all be exported as XML. This caused less inconvenience to the end-user because it is much easier to send a 65KB XML file in an email than a 500MB file containing all of the application's memory. We don't need to have the entire victim shipped out to us when we just want to know what was under the fingernails. The thing that made creating a managed debugging tool possible was the MDbg Engine example written by Microsoft as part of the Debugging Tools for Windows distribution. Since the ICorDebug interface is a bit difficult to understand, they had kindly created some wrappers that provided an event-driven debugging model that was perfect for our needs, but .NET 4 applications under debugging started complaining that "The debugger's protocol is incompatible with the debuggee". The introduction of .NET Framework v4 had changed the managed debugging API significantly, however, without an update for the MDbg Engine code! After a few hours of research, I had finally worked out that most of the version 4 ICorDebug interface still works much the same way in "legacy" v2 mode and there was a relatively easy fix for the problem in that you can still get a reference to legacy ICorDebug by changing the way the interface is created. In .NET v2, the interface was acquired using the CreateDebuggingInterfaceFromVersion method in mscoree.dll. In v4, you must first create IClrMetaHost, enumerate the runtimes, get an ICLRRuntimeInfo interface to the .NET 4 runtime from that, and use the GetInterface method in mscoree.dll to return a "legacy" ICorDebug interface. The rest of the MDbg Engine will continue working the old way. Here is how I had changed the MDbg Engine code to support .NET v4: private void InitFromVersion(string debuggerVersion){if( debuggerVersion.StartsWith("v1") ){throw new ArgumentException( "Can't debug a version 1 CLR process (\"" + debuggerVersion + "\"). Run application in a version 2 CLR, or use a version 1 debugger instead." );} ICorDebug rawDebuggingAPI=null;if (debuggerVersion.StartsWith("v4")){Guid CLSID_MetaHost = new Guid("9280188D-0E8E-4867-B30C-7FA83884E8DE"); Guid IID_MetaHost = new Guid("D332DB9E-B9B3-4125-8207-A14884F53216"); ICLRMetaHost metahost = (ICLRMetaHost)NativeMethods.ClrCreateInterface(CLSID_MetaHost, IID_MetaHost); IEnumUnknown runtimes = metahost.EnumerateInstalledRuntimes(); ICLRRuntimeInfo runtime = GetRuntime(runtimes, debuggerVersion); //Defined in metahost.hGuid CLSID_CLRDebuggingLegacy = new Guid(0xDF8395B5, 0xA4BA, 0x450b, 0xA7, 0x7C, 0xA9, 0xA4, 0x77, 0x62, 0xC5, 0x20);Guid IID_ICorDebug = new Guid("3D6F5F61-7538-11D3-8D5B-00104B35E7EF"); Object res;runtime.GetInterface(ref CLSID_CLRDebuggingLegacy, ref IID_ICorDebug, out res); rawDebuggingAPI = (ICorDebug)res; }elserawDebuggingAPI = NativeMethods.CreateDebuggingInterfaceFromVersion((int)CorDebuggerVersion.Whidbey,debuggerVersion);if (rawDebuggingAPI != null)InitFromICorDebug(rawDebuggingAPI);elsethrow new ArgumentException("Support for debugging version " + debuggerVersion + " is not yet implemented");} The changes above will ensure that the debugger can support .NET Framework v2 and v4 applications with the same codebase, but we do compile two different applications: one targeting v2 and the other v4. As a footnote I need to add that some missing native methods and wrappers, along with the EnumerateRuntimes method code, came from the Mindbg project on Codeplex. Another change is that when using the MDbgEngine.CreateProcess to launch a process in the debugger, do not supply a null as the final argument. This does not work any more because GetCORVersion always returns "v2.0.50727" as the function has been deprecated in .NET v4. What's worse is that on a system with only .NET 4, the user will be prompted to download and install .NET v2! Not nice! This works much better: proc = m_Debugger.CreateProcess(ProcessName, ProcessArgs, DebugModeFlag.Default,String.Format("v{0}.{1}.{2}",System.Environment.Version.Major,System.Environment.Version.Minor,System.Environment.Version.Build)); Microsoft "unofficially" plan on updating the MDbg samples soon, but if you have an MDbg-based application, you can get it working right now by changing one method a bit and adding a few new interfaces (ICLRMetaHost, IEnumUnknown, and ICLRRuntimeInfo). The new, non-legacy implementation of MDbg Engine will add new, interesting features like dump-file support and by association I assume garbage-collection/managed object stats, so it will be well worth looking into if you want to extend the functionality of a managed debugger going forward.

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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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• C# 4.0: Named And Optional Arguments

  - by Paulo Morgado

  As part of the co-evolution effort of C# and Visual Basic, C# 4.0 introduces Named and Optional Arguments. First of all, let’s clarify what are arguments and parameters: Method definition parameters are the input variables of the method. Method call arguments are the values provided to the method parameters. In fact, the C# Language Specification states the following on §7.5: The argument list (§7.5.1) of a function member invocation provides actual values or variable references for the parameters of the function member. Given the above definitions, we can state that: Parameters have always been named and still are. Parameters have never been optional and still aren’t. Named Arguments Until now, the way the C# compiler matched method call definition arguments with method parameters was by position. The first argument provides the value for the first parameter, the second argument provides the value for the second parameter, and so on and so on, regardless of the name of the parameters. If a parameter was missing a corresponding argument to provide its value, the compiler would emit a compilation error. For this call: Greeting("Mr.", "Morgado", 42); this method: public void Greeting(string title, string name, int age) will receive as parameters: title: “Mr.” name: “Morgado” age: 42 What this new feature allows is to use the names of the parameters to identify the corresponding arguments in the form: name:value Not all arguments in the argument list must be named. However, all named arguments must be at the end of the argument list. The matching between arguments (and the evaluation of its value) and parameters will be done first by name for the named arguments and than by position for the unnamed arguments. This means that, for this method definition: public static void Method(int first, int second, int third) this call declaration: int i = 0; Method(i, third: i++, second: ++i); will have this code generated by the compiler: int i = 0; int CS$0$0000 = i++; int CS$0$0001 = ++i; Method(i, CS$0$0001, CS$0$0000); which will give the method the following parameter values: first: 2 second: 2 third: 0 Notice the variable names. Although invalid being invalid C# identifiers, they are valid .NET identifiers and thus avoiding collision between user written and compiler generated code. Besides allowing to re-order of the argument list, this feature is very useful for auto-documenting the code, for example, when the argument list is very long or not clear, from the call site, what the arguments are. Optional Arguments Parameters can now have default values: public static void Method(int first, int second = 2, int third = 3) Parameters with default values must be the last in the parameter list and its value is used as the value of the parameter if the corresponding argument is missing from the method call declaration. For this call declaration: int i = 0; Method(i, third: ++i); will have this code generated by the compiler: int i = 0; int CS$0$0000 = ++i; Method(i, 2, CS$0$0000); which will give the method the following parameter values: first: 1 second: 2 third: 1 Because, when method parameters have default values, arguments can be omitted from the call declaration, this might seem like method overloading or a good replacement for it, but it isn’t. Although methods like this: public static StreamReader OpenTextFile( string path, Encoding encoding = null, bool detectEncoding = true, int bufferSize = 1024) allow to have its calls written like this: OpenTextFile("foo.txt", Encoding.UTF8); OpenTextFile("foo.txt", Encoding.UTF8, bufferSize: 4096); OpenTextFile( bufferSize: 4096, path: "foo.txt", detectEncoding: false); The complier handles default values like constant fields taking the value and useing it instead of a reference to the value. So, like with constant fields, methods with parameters with default values are exposed publicly (and remember that internal members might be publicly accessible – InternalsVisibleToAttribute). If such methods are publicly accessible and used by another assembly, those values will be hard coded in the calling code and, if the called assembly has its default values changed, they won’t be assumed by already compiled code. At the first glance, I though that using optional arguments for “bad” written code was great, but the ability to write code like that was just pure evil. But than I realized that, since I use private constant fields, it’s OK to use default parameter values on privately accessed methods.

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• ASP.NET MVC HandleError Attribute

  - by Ben Griswold

  Last Wednesday, I took a whopping 15 minutes out of my day and added ELMAH (Error Logging Modules and Handlers) to my ASP.NET MVC application.  If you haven’t heard the news (I hadn’t until recently), ELMAH does a killer job of logging and reporting nearly all unhandled exceptions.  As for handled exceptions, I’ve been using NLog but since I was already playing with the ELMAH bits I thought I’d see if I couldn’t replace it. Atif Aziz provided a quick solution in his answer to a Stack Overflow question.  I’ll let you consult his answer to see how one can subclass the HandleErrorAttribute and override the OnException method in order to get the bits working.  I pretty much took rolled the recommended logic into my application and it worked like a charm.  Along the way, I did uncover a few HandleError fact to which I wasn’t already privy.  Most of my learning came from Steven Sanderson’s book, Pro ASP.NET MVC Framework.  I’ve flipped through a bunch of the book and spent time on specific sections.  It’s a really good read if you’re looking to pick up an ASP.NET MVC reference. Anyway, my notes are found a comments in the following code snippet.  I hope my notes clarify a few things for you too. public class LogAndHandleErrorAttribute : HandleErrorAttribute {     public override void OnException(ExceptionContext context)     {         // A word from our sponsors:         //      http://stackoverflow.com/questions/766610/how-to-get-elmah-to-work-with-asp-net-mvc-handleerror-attribute         //      and Pro ASP.NET MVC Framework by Steven Sanderson         //         // Invoke the base implementation first. This should mark context.ExceptionHandled = true         // which stops ASP.NET from producing a "yellow screen of death." This also sets the         // Http StatusCode to 500 (internal server error.)         //         // Assuming Custom Errors aren't off, the base implementation will trigger the application         // to ultimately render the "Error" view from one of the following locations:         //         //      1. ~/Views/Controller/Error.aspx         //      2. ~/Views/Controller/Error.ascx         //      3. ~/Views/Shared/Error.aspx         //      4. ~/Views/Shared/Error.ascx         //         // "Error" is the default view, however, a specific view may be provided as an Attribute property.         // A notable point is the Custom Errors defaultRedirect is not considered in the redirection plan.         base.OnException(context);           var e = context.Exception;                  // If the exception is unhandled, simply return and let Elmah handle the unhandled exception.         // Otherwise, try to use error signaling which involves the fully configured pipeline like logging,         // mailing, filtering and what have you). Failing that, see if the error should be filtered.         // If not, the error simply logged the exception.         if (!context.ExceptionHandled                || RaiseErrorSignal(e)                   || IsFiltered(context))                  return;           LogException(e); // FYI. Simple Elmah logging doesn't handle mail notifications.     }

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• SQL SERVER – Service Broker and CAP_CPU_PERCENT – Limiting SQL Server Instances to CPU Usage

  - by pinaldave

  I have mentioned several times on this blog that the best part of blogging is the questions I receive from readers. They are often very interesting. The questions from readers give me a good idea what other readers might be thinking as well. After reading my earlier article Simple Example to Configure Resource Governor – Introduction to Resource Governor – I received an email from a reader and we exchanged a few emails. After exchanging emails we both figured out what is going on. It was indeed interesting and reader suggested to that I should blog about it.  I asked for permission to publish his name but he does not like the attention so we will just call him Jeff. I have converted our emails into chat for easy consumption. Jeff: Your script does not work at all. I think either there is a bug in SQL Server. Pinal: Would you please explain in detail? Jeff: Your code does not limit the CPU usage? Pinal: How did you measure it? Jeff: Well, we have third party tools for it but let us say I have limited the resources for Reporting Services and used your script described in your blog. After that I ran only reporting service workload the CPU is still used more than 100% and it is not limited to 30% as described in your script. Clearly something is wrong somewhere. Pinal: Did you say you ONLY ran reporting server load? Jeff: Yeah, to validate I ran ONLY reporting server load and CPU did not throttle at 30% as per your script. Pinal: Oh! I get it here is the answer - CAP_CPU_PERCENT = 30. Use it. Jeff: What is that, I think your earlier script says it will throttle the Reporting Service workload and Application/OLTP workload and balance it. Pinal: Exactly, that is correct. Jeff: You need to write more in email buddy! Just like your blogs, your answers do not make sense! No Offense! Pinal: Hmm…feedback well taken. Let me try again. In SQL Server 2012 there are a few enhancements with regards to SQL Server Resource Governor. One of the enhancement is how the resources are allocated. Let me explain you with examples. Configuration: [Read Earlier Post] Reporting Workload: MIN_CPU_PERCENT=0, MAX_CPU_PERCENT=30 Application/OLTP Workload: MIN_CPU_PERCENT=50, MAX_CPU_PERCENT=100 Example 1: If there is only Reporting Workload on the server: SQL Server will not limit usage of CPU to only 30% workload but SQL Server instance will use all available CPU (if needed). In another word in this scenario it will use more than 30% CPU. Example 2: If there is Reproting Workload and heavy Application/OLTP workload: SQL Server will allocate a maximum of 30% CPU resources to Reporting Workload and allocate remaining resources to heavy application/OLTP workload. The reason for this enhancement is for better utilization of the resources. Let us think, if there is only single workload, which we have limited to max CPU usage to 30%. The other unused available CPU resources is now wasted. In this situation SQL Server allows the workload to use more than 30% resources leading to overall improved/optimized performance. However, in the case of multiple workload where lots of resources are needed the limits specified in MAX_CPU_PERCENT are acknowledged. Example 3: If there is a situation where the max CPU workload has to be enforced: This is a very interesting scenario, in the case when the max CPU workload has to be enforced irrespective of the workload and enhanced algorithm, the keyword CAP_CPU_PERCENT is essential. It specifies a hard cap on the CPU bandwidth that all requests in the resource pool will receive. It will never let CPU usage for reporting workload to go over 30% in our case. You can use the key word as follows: -- Creating Resource Pool for Report Server CREATE RESOURCE POOL ReportServerPool WITH ( MIN_CPU_PERCENT=0, MAX_CPU_PERCENT=30, CAP_CPU_PERCENT=40, MIN_MEMORY_PERCENT=0, MAX_MEMORY_PERCENT=30) GO Notice that there is MAX_CPU_PERCENT=30 and CAP_CPU_PERCENT=40, what it means is that when SQL Server Instance is under heavy load under different workload it will use the maximum CPU at 30%. However, when the SQL Server instance is not under workload it will go over the 30% limit. However, as CAP_CPU_PERCENT is set to 40, it will not go over 40% in any case by limiting the usage of CPU. CAP_CPU_PERCENT puts a hard limit on the resources usage by workload. Jeff: Nice Pinal, you should blog about it. [A day passes by] Pinal: Jeff, it is done! Click here to read it. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Service Broker

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• SQL SERVER – LCK_M_XXX – Wait Type – Day 15 of 28

  - by pinaldave

  Locking is a mechanism used by the SQL Server Database Engine to synchronize access by multiple users to the same piece of data, at the same time. In simpler words, it maintains the integrity of data by protecting (or preventing) access to the database object. From Book On-Line: LCK_M_BU Occurs when a task is waiting to acquire a Bulk Update (BU) lock. LCK_M_IS Occurs when a task is waiting to acquire an Intent Shared (IS) lock. LCK_M_IU Occurs when a task is waiting to acquire an Intent Update (IU) lock. LCK_M_IX Occurs when a task is waiting to acquire an Intent Exclusive (IX) lock. LCK_M_S Occurs when a task is waiting to acquire a Shared lock. LCK_M_SCH_M Occurs when a task is waiting to acquire a Schema Modify lock. LCK_M_SCH_S Occurs when a task is waiting to acquire a Schema Share lock. LCK_M_SIU Occurs when a task is waiting to acquire a Shared With Intent Update lock. LCK_M_SIX Occurs when a task is waiting to acquire a Shared With Intent Exclusive lock. LCK_M_U Occurs when a task is waiting to acquire an Update lock. LCK_M_UIX Occurs when a task is waiting to acquire an Update With Intent Exclusive lock. LCK_M_X Occurs when a task is waiting to acquire an Exclusive lock. LCK_M_XXX Explanation: I think the explanation of this wait type is the simplest. When any task is waiting to acquire lock on any resource, this particular wait type occurs. The common reason for the task to be waiting to put lock on the resource is that the resource is already locked and some other operations may be going on within it. This wait also indicates that resources are not available or are occupied at the moment due to some reasons. There is a good chance that the waiting queries start to time out if this wait type is very high. Client application may degrade the performance as well. You can use various methods to find blocking queries: EXEC sp_who2 SQL SERVER – Quickest Way to Identify Blocking Query and Resolution – Dirty Solution DMV – sys.dm_tran_locks DMV – sys.dm_os_waiting_tasks Reducing LCK_M_XXX wait: Check the Explicit Transactions. If transactions are very long, this wait type can start building up because of other waiting transactions. Keep the transactions small. Serialization Isolation can build up this wait type. If that is an acceptable isolation for your business, this wait type may be natural. The default isolation of SQL Server is ‘Read Committed’. One of my clients has changed their isolation to “Read Uncommitted”. I strongly discourage the use of this because this will probably lead to having lots of dirty data in the database. Identify blocking queries mentioned using various methods described above, and then optimize them. Partition can be one of the options to consider because this will allow transactions to execute concurrently on different partitions. If there are runaway queries, use timeout. (Please discuss this solution with your database architect first as timeout can work against you). Check if there is no memory and IO-related issue using the following counters: 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) Read all the post in the Wait Types and Queue series. 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 the discussion 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 Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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• SQL SERVER – Beginning of SQL Server Architecture – Terminology – Guest Post

  - by pinaldave

  SQL Server Architecture is a very deep subject. Covering it in a single post is an almost impossible task. However, this subject is very popular topic among beginners and advanced users.  I have requested my friend Anil Kumar who is expert in SQL Domain to help me write  a simple post about Beginning SQL Server Architecture. As stated earlier this subject is very deep subject and in this first article series he has covered basic terminologies. In future article he will explore the subject further down. Anil Kumar Yadav is Trainer, SQL Domain, Koenig Solutions. Koenig is a premier IT training firm that provides several IT certifications, such as Oracle 11g, Server+, RHCA, SQL Server Training, Prince2 Foundation etc. In this Article we will discuss about MS SQL Server architecture. The major components of SQL Server are: Relational Engine Storage Engine SQL OS Now we will discuss and understand each one of them. 1) Relational Engine: Also called as the query processor, Relational Engine includes the components of SQL Server that determine what your query exactly needs to do and the best way to do it. It manages the execution of queries as it requests data from the storage engine and processes the results returned. Different Tasks of Relational Engine: Query Processing Memory Management Thread and Task Management Buffer Management Distributed Query Processing 2) Storage Engine: Storage Engine is responsible for storage and retrieval of the data on to the storage system (Disk, SAN etc.). to understand more, let’s focus on the following diagram. When we talk about any database in SQL server, there are 2 types of files that are created at the disk level – Data file and Log file. Data file physically stores the data in data pages. Log files that are also known as write ahead logs, are used for storing transactions performed on the database. Let’s understand data file and log file in more details: Data File: Data File stores data in the form of Data Page (8KB) and these data pages are logically organized in extents. Extents: Extents are logical units in the database. They are a combination of 8 data pages i.e. 64 KB forms an extent. Extents can be of two types, Mixed and Uniform. Mixed extents hold different types of pages like index, System, Object data etc. On the other hand, Uniform extents are dedicated to only one type. Pages: As we should know what type of data pages can be stored in SQL Server, below mentioned are some of them: Data Page: It holds the data entered by the user but not the data which is of type text, ntext, nvarchar(max), varchar(max), varbinary(max), image and xml data. Index: It stores the index entries. Text/Image: It stores LOB ( Large Object data) like text, ntext, varchar(max), nvarchar(max),  varbinary(max), image and xml data. GAM & SGAM (Global Allocation Map & Shared Global Allocation Map): They are used for saving information related to the allocation of extents. PFS (Page Free Space): Information related to page allocation and unused space available on pages. IAM (Index Allocation Map): Information pertaining to extents that are used by a table or index per allocation unit. BCM (Bulk Changed Map): Keeps information about the extents changed in a Bulk Operation. DCM (Differential Change Map): This is the information of extents that have modified since the last BACKUP DATABASE statement as per allocation unit. Log File: It also known as write ahead log. It stores modification to the database (DML and DDL). Sufficient information is logged to be able to: Roll back transactions if requested Recover the database in case of failure Write Ahead Logging is used to create log entries Transaction logs are written in chronological order in a circular way Truncation policy for logs is based on the recovery model SQL OS: This lies between the host machine (Windows OS) and SQL Server. All the activities performed on database engine are taken care of by SQL OS. It is a highly configurable operating system with powerful API (application programming interface), enabling automatic locality and advanced parallelism. SQL OS provides various operating system services, such as memory management deals with buffer pool, log buffer and deadlock detection using the blocking and locking structure. Other services include exception handling, hosting for external components like Common Language Runtime, CLR etc. I guess this brief article gives you an idea about the various terminologies used related to SQL Server Architecture. In future articles we will explore them further. Guest Author  The author of the article is Anil Kumar Yadav is Trainer, SQL Domain, Koenig Solutions. Koenig is a premier IT training firm that provides several IT certifications, such as Oracle 11g, Server+, RHCA, SQL Server Training, Prince2 Foundation etc. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Security, SQL Server, SQL Tips and Tricks, SQL Training, T SQL, Technology

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