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• Lockless queue implementation ends up having a loop under stress

  - by Fozi

  I have lockless queues written in C in form of a linked list that contains requests from several threads posted to and handled in a single thread. After a few hours of stress I end up having the last request's next pointer pointing to itself, which creates an endless loop and locks up the handling thread. The application runs (and fails) on both Linux and Windows. I'm debugging on Windows, where my COMPARE_EXCHANGE_PTR maps to InterlockedCompareExchangePointer. This is the code that pushes a request to the head of the list, and is called from several threads: void push_request(struct request * volatile * root, struct request * request) { assert(request); do { request->next = *root; } while(COMPARE_EXCHANGE_PTR(root, request, request->next) != request->next); } This is the code that gets a request from the end of the list, and is only called by a single thread that is handling them: struct request * pop_request(struct request * volatile * root) { struct request * volatile * p; struct request * request; do { p = root; while(*p && (*p)->next) p = &(*p)->next; // <- loops here request = *p; } while(COMPARE_EXCHANGE_PTR(p, NULL, request) != request); assert(request->next == NULL); return request; } Note that I'm not using a tail pointer because I wanted to avoid the complication of having to deal with the tail pointer in push_request. However I suspect that the problem might be in the way I find the end of the list. There are several places that push a request into the queue, but they all look generaly like this: // device->requests is defined as struct request * volatile requests; struct request * request = malloc(sizeof(struct request)); if(request) { // fill out request fields push_request(&device->requests, request); sem_post(device->request_sem); } The code that handles the request is doing more than that, but in essence does this in a loop: if(sem_wait_timeout(device->request_sem, timeout) == sem_success) { struct request * request = pop_request(&device->requests); // handle request free(request); } I also just added a function that is checking the list for duplicates before and after each operation, but I'm afraid that this check will change the timing so that I will never encounter the point where it fails. (I'm waiting for it to break as I'm writing this.) When I break the hanging program the handler thread loops in pop_request at the marked position. I have a valid list of one or more requests and the last one's next pointer points to itself. The request queues are usually short, I've never seen more then 10, and only 1 and 3 the two times I could take a look at this failure in the debugger. I thought this through as much as I could and I came to the conclusion that I should never be able to end up with a loop in my list unless I push the same request twice. I'm quite sure that this never happens. I'm also fairly sure (although not completely) that it's not the ABA problem. I know that I might pop more than one request at the same time, but I believe this is irrelevant here, and I've never seen it happening. (I'll fix this as well) I thought long and hard about how I can break my function, but I don't see a way to end up with a loop. So the question is: Can someone see a way how this can break? Can someone prove that this can not? Eventually I will solve this (maybe by using a tail pointer or some other solution - locking would be a problem because the threads that post should not be locked, I do have a RW lock at hand though) but I would like to make sure that changing the list actually solves my problem (as opposed to makes it just less likely because of different timing).

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• How best to modernize the 2002-era J2EE app?

  - by user331465

  I have this friend.... I have this friend who works on a java ee application (j2ee) application started in the early 2000's. Currently they add a feature here and there, but have a large codebase. Over the years the team has shrunk by 70%. [Yes, the "i have this friend is". It's me, attempting to humorously inject teenage high-school counselor shame into the mix] Java, Vintage 2002 The application uses EJB 2.1, struts 1.x, DAO's etc with straight jdbc calls (mixture of stored procedures and prepared statements). No ORM. For caching they use a mixture of OpenSymphony OSCache and a home-grown cache layer. Over the last few years, they have spent effort to modernize the UI using ajax techniques and libraries. This largely involves javascript libaries (jquery, yui, etc). Client Side On the client side, the lack of upgrade path from struts1 to struts2 discouraged them from migrating to struts2. Other web frameworks became popular (wicket, spring , jsf). Struts2 was not the "clear winner". Migrating all the existing UI from Struts1 to Struts2/wicket/etc did not seem to present much marginal benefit at a very high cost. They did not want to have a patchwork of technologies-du-jour (subsystem X in Struts2, subsystem Y in Wicket, etc.) so developer write new features using Struts 1. Server Side On the server side, they looked into moving to ejb 3, but never had a big impetus. The developers are all comfortable with ejb-jar.xml, EJBHome, EJBRemote, that "ejb 2.1 as is" represented the path of least resistance. One big complaint about the ejb environment: programmers still pretend "ejb server runs in separate jvm than servlet engine". No app server (jboss/weblogic) has ever enforced this separation. The team has never deployed the ejb server on a separate box then the app server. The ear file contains multiple copies of the same jar file; one for the 'web layer' (foo.war/WEB-INF/lib) and one for the server side (foo.ear/). The app server only loads one jar. The duplications makes for ambiguity. Caching As for caching, they use several cache implementations: OpenSymphony cache and a homegrown cache. Jgroups provides clustering support Now What? The question: The team currently has spare cycles to to invest in modernizing the application? Where would the smart investor spend them? The main criteria: 1) productivity gains. Specifically reducing the time to develope new subsystems features and reduced maintenance. 2) performance/scalability. They do not care about fashion or techno-du-jour street cred. What do you all recommend? On the persistence side Switch everything (or new development only) to JPA/JPA2? Straight hibernate? Wait for Java EE 6? On the client/web-framework side: Migrate (some or all) to struts2? wicket? jsf/jsf2? As for caching: terracotta? ehcache? coherence? stick with what they have? how best to take advantage of the huge heap sizes that the 64-bit jvms offer? Thanks in advance.

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• AES encryption/decryption java bouncy castle explanation?

  - by Programmer0

  Can someone please explain what this program is doing pointing out some of the major points? I'm looking at the code and I'm completely lost. I just need explanation on the encryption/decryption phases. I think it generates an AES 192 key at one point but I'm not 100% sure. I'm not sure what the byte/ivBytes are used for either. import java.security.Key; import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import javax.crypto.spec.IvParameterSpec; public class RandomKey { public static void main(String[] args) throws Exception { byte[] input = new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07 }; byte[] ivBytes = new byte[] { 0x00, 0x00, 0x00, 0x01, 0x04, 0x05, 0x06, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 }; //initializing a new initialization vector IvParameterSpec ivSpec = new IvParameterSpec(ivBytes); //what does this actually do? Cipher cipher = Cipher.getInstance("AES/CTR/NoPadding", "BC"); //what does this do? KeyGenerator generator = KeyGenerator.getInstance("AES","BC"); //I assume this generates a key size of 192 bits generator.init(192); //does this generate a random key? Key encryptKey = generator.generateKey(); System.out.println("input: " +toHex(input)); //encryption phase cipher.init(Cipher.ENCRYPT_MODE, encryptKey, ivSpec); //what is this doing? byte[] cipherText = new byte[cipher.getOutputSize(input.length)]; //what is this doing? int ctLength = cipher.update(input, 0, input.length, cipherText,0); //getting the cipher text length i assume? ctLength += cipher.doFinal (cipherText, ctLength ); System.out.println ("Cipher: " +toHex(cipherText) + " bytes: " + ctLength); //decryption phase cipher.init(Cipher.DECRYPT_MODE, encryptKey, ivSpec); //storing the ciphertext in plaintext i'm assuming? byte[] plainText = new byte[cipher.getOutputSize(ctLength)]; int ptLength = cipher.update(cipherText, 0, ctLength, plainText, 0); //getting plaintextLength i think? ptLength= cipher.doFinal (plainText, ptLength); System.out.println("plain: " + toHex(plainText, ptLength)); } private static String digits = "0123456789abcdef"; public static String toHex(byte[] data, int length) { StringBuffer buf = new StringBuffer(); for (int i=0; i!= length; i++) { int v = data[i] & 0xff; buf.append(digits.charAt(v >>4)); buf.append(digits.charAt(v & 0xf)); } return buf.toString(); } public static String toHex(byte[] data) { return toHex(data, data.length); } }

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• Loading multiple copies of a group of DLLs in the same process

  - by george

  Background I'm maintaining a plugin for an application. I'm Using Visual C++ 2003. The plugin is composed of several DLLs - there's the main DLL, that's the one that the application loads using LoadLibrary, and there are several utility DLLs that are used by the main DLL and by each other. Dependencies generally look like this: plugin.dll - utilA.dll, utilB.dll utilA.dll - utilB.dll utilB.dll - utilA.dll, utilC.dll You get the picture. Some of the dependencies between the DLLs are load-time and some run-time. All the DLL files are stored in the executable's directory (not a requirement, just how it works now). The problem There's a new requirement - running multiple instances of the plugin within the application. The application runs each instance of a plugin in its own thread, i.e. each thread calls The plugin's code, however, is nothing but thread-safe - lots of global variables etc.. Unfortunately, fixing the whole thing isn't currently an option, so I need a way to load multiple (at most 3) copies of the plugin's DLLs in the same process. Option 1: The distinct names approach Creating 3 copies of each DLL file, so that each file has a distinct name. e.g. plugin1.dll, plugin2.dll, plugin3.dll, utilA1.dll, utilA2.dll, utilA3.dll, utilB1.dll, etc.. The application will load plugin1.dll, plugin2.dll and plugin3.dll. The files will be in the executable's directory. For each group of DLLs to know each other by name (so the inter-dependencies work), the names need to be known at compilation time - meaning the DLLs need to be compiled multiple times, only each time with different output file names. Not very complicated, but I'd hate having 3 copies of the VS project files, and don't like having to compile the same files over and over. Option 2: The side-by-side assemblies approach Creating 3 copies of the DLL files, each group in its own directory, and defining each group as an assembly by putting an assembly manifest file in the directory, listing the plugin's DLLs. Each DLL will have an application manifest pointing to the assembly, so that the loader finds the copies of the utility DLLs that reside in the same directory. The manifest needs to be embedded for it to be found when a DLL is loaded using LoadLibrary. I'll use mt.exe from a later VS version for the job, since VS2003 has no built-in manifest embedding support. I've tried this approach with partial success - dependencies are found during load-time of the DLLs, but not when a DLL function is called that loads another DLL. This seems to be the expected behavior according to this article - A DLL's activation context is only used at the DLL's load-time, and afterwards it's deactivated and the process's activation context is used. I haven't yet tried working around this using ISOLATION_AWARE_ENABLED. Questions Got any other options? Any quick & dirty solution will do. :-) Will ISOLATION_AWARE_ENABLED even work with VS2003? Comments will be greatly appreciated. Thanks!

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• C++ Optimize if/else condition

  - by Heye

  I have a single line of code, that consumes 25% - 30% of the runtime of my application. It is a less-than comparator for an std::set (the set is implemented with a Red-Black-Tree). It is called about 180 Million times within 52 seconds. struct Entry { const float _cost; const long _id; // some other vars Entry(float cost, float id) : _cost(cost), _id(id) { } }; template<class T> struct lt_entry: public binary_function <T, T, bool> { bool operator()(const T &l, const T &r) const { // Most readable shape if(l._cost != r._cost) { return r._cost < l._cost; } else { return l._id < r._id; } } }; The entries should be sorted by cost and if the cost is the same by their id. I have many insertions for each extraction of the minimum. I thought about using Fibonacci-Heaps, but I have been told that they are theoretically nice, but suffer from high constants and are pretty complicated to implement. And since insert is in O(log(n)) the runtime increase is nearly constant with large n. So I think its okay to stick to the set. To improve performance I tried to express it in different shapes: return l._cost < r._cost || r._cost > l._cost || l._id < r._id; return l._cost < r._cost || (l._cost == r._cost && l._id < r._id); Even this: typedef union { float _f; int _i; } flint; //... flint diff; diff._f = (l._cost - r._cost); return (diff._i && diff._i >> 31) || l._id < r._id; But the compiler seems to be smart enough already, because I haven't been able to improve the runtime. I also thought about SSE but this problem is really not very applicable for SSE... The assembly looks somewhat like this: movss (%rbx),%xmm1 mov $0x1,%r8d movss 0x20(%rdx),%xmm0 ucomiss %xmm1,%xmm0 ja 0x410600 <_ZNSt8_Rb_tree[..]+96> ucomiss %xmm0,%xmm1 jp 0x4105fd <_ZNSt8_Rb_[..]_+93> jne 0x4105fd <_ZNSt8_Rb_[..]_+93> mov 0x28(%rdx),%rax cmp %rax,0x8(%rbx) jb 0x410600 <_ZNSt8_Rb_[..]_+96> xor %r8d,%r8d I have a very tiny bit experience with assembly language, but not really much. I thought it would be the best (only?) point to squeeze out some performance, but is it really worth the effort? Can you see any shortcuts that could save some cycles? The platform the code will run on is an ubuntu 12 with gcc 4.6 (-stl=c++0x) on a many-core intel machine. Only libraries available are boost, openmp and tbb. I am really stuck on this one, it seems so simple, but takes that much time. I have been crunching my head since days thinking how I could improve this line... Can you give me a suggestion how to improve this part, or is it already at its best?

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• Trying to packetize TCP with non-blocking IO is hard! Am I doing something wrong?

  - by Ricket

  Oh how I wish TCP was packet-based like UDP is! But alas, that's not the case, so I'm trying to implement my own packet layer. Here's the chain of events so far (ignoring writing packets) Oh, and my Packets are very simply structured: two unsigned bytes for length, and then byte[length] data. (I can't imagine if they were any more complex, I'd be up to my ears in if statements!) Server is in an infinite loop, accepting connections and adding them to a list of Connections. PacketGatherer (another thread) uses a Selector to figure out which Connection.SocketChannels are ready for reading. It loops over the results and tells each Connection to read(). Each Connection has a partial IncomingPacket and a list of Packets which have been fully read and are waiting to be processed. On read(): Tell the partial IncomingPacket to read more data. (IncomingPacket.readData below) If it's done reading (IncomingPacket.complete()), make a Packet from it and stick the Packet into the list waiting to be processed and then replace it with a new IncomingPacket. There are a couple problems with this. First, only one packet is being read at a time. If the IncomingPacket needs only one more byte, then only one byte is read this pass. This can of course be fixed with a loop but it starts to get sorta complicated and I wonder if there is a better overall way. Second, the logic in IncomingPacket is a little bit crazy, to be able to read the two bytes for the length and then read the actual data. Here is the code, boiled down for quick & easy reading: int readBytes; // number of total bytes read so far byte length1, length2; // each byte in an unsigned short int (see getLength()) public int getLength() { // will be inaccurate if readBytes < 2 return (int)(length1 << 8 | length2); } public void readData(SocketChannel c) { if (readBytes < 2) { // we don't yet know the length of the actual data ByteBuffer lengthBuffer = ByteBuffer.allocate(2 - readBytes); numBytesRead = c.read(lengthBuffer); if(readBytes == 0) { if(numBytesRead >= 1) length1 = lengthBuffer.get(); if(numBytesRead == 2) length2 = lengthBuffer.get(); } else if(readBytes == 1) { if(numBytesRead == 1) length2 = lengthBuffer.get(); } readBytes += numBytesRead; } if(readBytes >= 2) { // then we know we have the entire length variable // lazily-instantiate data buffers based on getLength() // read into data buffers, increment readBytes // (does not read more than the amount of this packet, so it does not // need to handle overflow into the next packet's data) } } public boolean complete() { return (readBytes > 2 && readBytes == getLength()+2); } Basically I need feedback on my code. Please suggest any improvements. Even overhauling my entire system would be okay, if you have suggestions for how better to implement the whole thing. Book recommendations are welcome too; I love books. I just get the feeling that something isn't quite right.

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• NEED your opinion on .net Profile class VS session vars

  - by Ted

  To save trips to sql db in my older apps, I store *dozens of data points about the current user in an array and then store the array in a session. For example, info that might be used repeatedly during user’s session might be stored… Dim a(7) as string a(0) = “FirstName” a(1) = “LastName” a(2) = “Address” a(3) = “Address2” a(4) = “City” a(5) = “State” a(6) = “Zip” session.add(“s_a”, a) *Some apps have an array 100 in size. That is something I learned in my asp classic days. Referencing the correct index can be laborsome and I find it difficult to go back and add another data point in the array grouped with like data. For example, suppose I need to add Middle Initial to the array as a design alteration. Unless I redo the whole index mapping, I have to stick Middle Initial in the next open slot, which might be in the 50s. NOW, I am considering doing something easier to reference each time (eliminating the need to know the index of the value wanted). So I am looking to do this… session.add(“Firstname”, “FirstName”) session.add(“Lastname”, “LastName”) session.add(“Address”, “Address”) etc. BUT, before I do this, I would like some guidance. I am afraid this might be less efficient, even though easier to use. I don’t know if a new session object is created for each data point or if there is only one session object, and I am adding a name/value pair to that object? If I am adding a name/value pair to a single object, that seems like a good idea. Does anyone know? Or is there a more preferred way? Built-in Profile class? Re: Profile class I have an internal debate about scope. It seems that the .net Profile class is good for storing app-SPECIFIC user settings (i.e. style theme, object display properties, user role, etc.) The examples I give are information whose values are selected/edited by the user to customize the application experience. This information is not typically stored/edited elsewhere in the app db. But when you have data that 1) is stored already in the app db and 2) can be altered by other users (in this case: company reps may update client's status, address, etc.), then the persistence of the Profile data may be an issue. In this case, the Profile would need to be reset at the beginning and dropped like a session.abandon at the end of each user's session to prevent reloading info that had since been edited by someone. I believe this is possible, but not sure Currently, I use the session array to store both scopes, app-specific and user-specific data. If my session plan is good, I think I will create a class to set/get values from the session also. I appreciate your thoughts. I would like to know how others have handled this type of situation. Thanks.

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• COM port read - Thread remains alive after timeout occurs

  - by Sna

  Hello to all. I have a dll which includes a function called ReadPort that reads data from serial COM port, written in c/c++. This function is called within an extra thread from another WINAPI function using the _beginthreadex. When COM port has data to be read, the worker thread returns the data, ends normaly, the calling thread closes the worker's thread handle and the dll works fine. However, if ReadPort is called without data pending on the COM port, when timeout occurs then WaitForSingleObject returns WAIT_TIMEOUT but the worker thread never ends. As a result, virtual memory grows at about 1 MB every time, physical memory grows some KBs and the application that calls the dll becomes unstable. I also tryied to use TerminateThread() but i got the same results. I have to admit that although i have enough developing experience, i am not familiar with c/c++. I did a lot of research before posting but unfortunately i didn't manage to solve my problem. Does anyone have a clue on how could i solve this problem? However, I really want to stick to this kind of solution. Also, i want to mention that i think i can't use any global variables to use some kind of extra events, because each dll's functions may be called many times for every COM port. I post some parts of my code below: The Worker Thread: unsigned int __stdcall ReadPort(void* readstr){ DWORD dwError; int rres;DWORD dwCommModemStatus, dwBytesTransferred; int ret; char szBuff[64] = ""; ReadParams* params = (ReadParams*)readstr; ret = SetCommMask(params->param2, EV_RXCHAR | EV_CTS | EV_DSR | EV_RLSD | EV_RING); if (ret == 0) { _endthreadex(0); return -1; } ret = WaitCommEvent(params->param2, &dwCommModemStatus, 0); if (ret == 0) { _endthreadex(0); return -2; } ret = SetCommMask(params->param2, EV_RXCHAR | EV_CTS | EV_DSR | EV_RLSD| EV_RING); if (ret == 0) { _endthreadex(0); return -3; } if (dwCommModemStatus & EV_RXCHAR||dwCommModemStatus & EV_RLSD) { rres = ReadFile(params->param2, szBuff, 64, &dwBytesTransferred,NULL); if (rres == 0) { switch (dwError = GetLastError()) { case ERROR_HANDLE_EOF: _endthreadex(0); return -4; } _endthreadex(0); return -5; } else { strcpy(params->param1,szBuff); _endthreadex(0); return 0; } } else { _endthreadex(0); return 0; } _endthreadex(0); return 0;} The Calling Thread: int WINAPI StartReadThread(HANDLE porthandle, HWND windowhandle){ HANDLE hThread; unsigned threadID; ReadParams readstr; DWORD ret, ret2; readstr.param2 = porthandle; hThread = (HANDLE)_beginthreadex( NULL, 0, ReadPort, &readstr, 0, &threadID ); ret = WaitForSingleObject(hThread, 500); if (ret == WAIT_OBJECT_0) { CloseHandle(hThread); if (readstr.param1 != NULL) // Send message to GUI return 0; } else if (ret == WAIT_TIMEOUT) { ret2 = CloseHandle(hThread); return -1; } else { ret2 = CloseHandle(hThread); if (ret2 == 0) return -2; }} Thank you in advance, Sna.

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• Testing for Adjacent Cells In a Multi-level Grid

  - by Steve

  I'm designing an algorithm to test whether cells on a grid are adjacent or not. The catch is that the cells are not on a flat grid. They are on a multi-level grid such as the one drawn below. Level 1 (Top Level) | - - - - - | | A | B | C | | - - - - - | | D | E | F | | - - - - - | | G | H | I | | - - - - - | Level 2 | -Block A- | -Block B- | | 1 | 2 | 3 | 1 | 2 | 3 | | - - - - - | - - - - - | | 4 | 5 | 6 | 4 | 5 | 6 | ... | - - - - - | - - - - - | | 7 | 8 | 9 | 7 | 8 | 9 | | - - - - - | - - - - - | | -Block D- | -Block E- | | 1 | 2 | 3 | 1 | 2 | 3 | | - - - - - | - - - - - | | 4 | 5 | 6 | 4 | 5 | 6 | ... | - - - - - | - - - - - | | 7 | 8 | 9 | 7 | 8 | 9 | | - - - - - | - - - - - | . . . . . . This diagram is simplified from my actual need but the concept is the same. There is a top level block with many cells within it (level 1). Each block is further subdivided into many more cells (level 2). Those cells are further subdivided into level 3, 4 and 5 for my project but let's just stick to two levels for this question. I'm receiving inputs for my function in the form of "A8, A9, B7, D3". That's a list of cell Ids where each cell Id has the format (level 1 id)(level 2 id). Let's start by comparing just 2 cells, A8 and A9. That's easy because they are in the same block. private static RelativePosition getRelativePositionInTheSameBlock(String v1, String v2) { RelativePosition relativePosition; if( v1-v2 == -1 ) { relativePosition = RelativePosition.LEFT_OF; } else if (v1-v2 == 1) { relativePosition = RelativePosition.RIGHT_OF; } else if (v1-v2 == -BLOCK_WIDTH) { relativePosition = RelativePosition.TOP_OF; } else if (v1-v2 == BLOCK_WIDTH) { relativePosition = RelativePosition.BOTTOM_OF; } else { relativePosition = RelativePosition.NOT_ADJACENT; } return relativePosition; } An A9 - B7 comparison could be done by checking if A is a multiple of BLOCK_WIDTH and whether B is (A-BLOCK_WIDTH+1). Either that or just check naively if the A/B pair is 3-1, 6-4 or 9-7 for better readability. For B7 - D3, they are not adjacent but D3 is adjacent to A9 so I can do a similar adjacency test as above. So getting away from the little details and focusing on the big picture. Is this really the best way to do it? Keeping in mind the following points: I actually have 5 levels not 2, so I could potentially get a list like "A8A1A, A8A1B, B1A2A, B1A2B". Adding a new cell to compare still requires me to compare all the other cells before it (seems like the best I could do for this step is O(n)) The cells aren't all 3x3 blocks, they're just that way for my example. They could be MxN blocks with different M and N for different levels. In my current implementation above, I have separate functions to check adjacency if the cells are in the same blocks, if they are in separate horizontally adjacent blocks or if they are in separate vertically adjacent blocks. That means I have to know the position of the two blocks at the current level before I call one of those functions for the layer below. Judging by the complexity of having to deal with mulitple functions for different edge cases at different levels and having 5 levels of nested if statements. I'm wondering if another design is more suitable. Perhaps a more recursive solution, use of other data structures, or perhaps map the entire multi-level grid to a single-level grid (my quick calculations gives me about 700,000+ atomic cell ids). Even if I go that route, mapping from multi-level to single level is a non-trivial task in itself.

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• CodePlex Daily Summary for Wednesday, February 24, 2010

  CodePlex Daily Summary for Wednesday, February 24, 2010New ProjectsADO.Net DataSets to ExtJs.data.Store: A JavaScript (and C#) based project to reduce the amount of client-side code necessary to consume ADO.Net / ASP.Net web services when using ExtJS.AMP.Net Wrapper: AMP is a platform to build on-line marketplaces (http://www.poweredbyamp.com). AMP.Net provided Object-Like interaction with AMP's restful service...ArkSwitch: ArkSwitch is an easy to use, finger-friendly task manager for Windows Mobile 6.5.3 (with a WM6.5 compatibility mode). It is developed mainly in C#,...Biffen: Cinema-booking project in Computer Science at University College Nordjylland, Denmark.Braintree Client Library: Client library for integrating with the Braintree Gateway.Business Framework: A framework which helps building business applications. It provides business rules, validation rules and a text-based language for writing rules. I...Camp Araminta: This project will be used to coordinate development efforts on the Camp Araminta website.ChoServiceHost: Simple and easy way to create and host Windows Service Applications in .NET 3.5/Visual Studio 2008Delta College Game Development Project: Project site for cs 16 game development classDotNetNuke® Labs: DotNetNuke Labs is a collection of "research & development" type projects for the DotNetNuke platform.Generic web part for hosting Silverlight content on SharePoint sites (WSS,MOSS): This is a generic web part for hosting Silverlight content on WSS 30 and MOSS 2007 sites. The objective of this web part was to make it easy for us...GpTiming: GpTiming is a simple "lab" application related to race events, based on a Domain Model.HTML Forms in Windows Forms: As the names suggests this code library is designed to introduce HTML code (primarily form code) into Windows Forms. It was created because standar...imgur uploader - .net open source uploader for image sharing site imgur: Imgur uploader strives to be an easy to use uploader for images you would like to share with friends and family. It is written in c#.kuuy static system: kuuy static system is a full static publish website system!LaTeX Grapher: The goal of this project is to make a tool that facilitates making high quality two dimensional vector graphic function plots with a minimal amount...LightREST: A .NET library to consume REST-based HTTP services.Machiavelli: Machiavelli is Stackoverflow inspired project that I am working on following Andrew Siemer's article on DotNetSlackers. Mover: Mover makes it easier for developers to create programmatic animations in Silverlight. It provides an expressive API to the platform's underlying S...MVC Presenter: ASP.NET MVC 2で作るプレゼンビューアーnHibernate Attribute mapping: How to use Attibute mapping with a ManyToMany Relationship with nHibernateNIPO Data Processing Component Framework: NIPO is a general purpose component framework for data processing applications (that follow the IPO-principle). Its plugin-based architecture makes...PowerShell Remote File Explorer: This project intends to develop a Windows forms based file explorer to browse/transfer files over PowerShell 2.0 remoting channel. 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All notes you have is saved on a server so you ca...kuuy static system: kss_v1.0beta sql: kss_v1.0beta sql scripts sourceMDownloader: MDownloader-0.15.2.55998: Fixed detecting uploading.com dead links; Added hiding rss entries without files;Mover: MoverLib for Silverlight 3: A first version of MoverLib for Silverlight 3.nHibernate Attribute mapping: 1.0: Source CodenHibernate Attribute mapping: Download 1: Zip fileNodeXL: Network Overview, Discovery and Exploration for Excel: NodeXL Class Libraries, version 1.0.1.113: The NodeXL class libraries can be used to display network graphs in .NET applications. To include a NodeXL network graph in a WPF desktop or Windo...NodeXL: Network Overview, Discovery and Exploration for Excel: NodeXL Excel 2007 Template, version 1.0.1.113: The NodeXL Excel 2007 template displays a network graph using edge and vertex lists stored in an Excel 2007 workbook. What's NewThis version inclu...OAuthLib: OAuthLib (1.6.0.0): Difference between previous version is as next. 7079 Make it possible to pass factory method of request in ObtainUnauthorizedRequestToken and Reque...patterns & practices SharePoint Guidance: SPG2010 Drop 5: SharePoint Guidance Drop Notes Microsoft patterns and practices ****************************************** ***************************************...PowerShell Remote File Explorer: PSRemoteExplorer 0.1: This release is the initial release of PowerShell remote file explorer. This enables the basic functionality of a remote file explorer. This also p...Reusable Library: v1.0.3: A collection of reusable abstractions for enterprise application developer.SharePoint Outlook Connector: Version 1.0.2.4: Version 1.0.2.4 Minor bugs have been fixed.Silverlight Server File Manager: First production release: This release is in production. 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This package also registers the policy with Microsoft Visual St...SpecExpress : A Fluent Validation Framework: SpecExpress 1.1: UpdatesAdded Validation Contexts feature Fixed bug with handling for Bool Types and Required MessageStore now allows for overriding individual ...VCC: Latest build, v2.1.30223.0: Automatic drop of latest buildVS2010 Rc1 Fix: RC1Fix01: This is a very simple project implementing a Microsoft Walkthrough at http://msdn.microsoft.com/en-us/library/wdb4eb30%28VS.100%29.aspx and the man...WPF AutoComplete TextBox Control: version 1.0: Initial releaseMost Popular ProjectsASP.NET Ajax LibraryManaged Extensibility FrameworkAccelerators for Microsoft Dynamics CRMWindows 7 USB/DVD Download ToolDotNetZip LibraryMDownloaderVirtual Router - Wifi Hot Spot for Windows 7 / 2008 R2MFCMAPIDroid ExplorerUseful Sharepoint Designer Custom Workflow ActivitiesMost Active ProjectsDinnerNow.netRawrBlogEngine.NETInfoServiceNB_Store - Free DotNetNuke Ecommerce Catalog ModuleRapid Entity Framework. 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• Pluralsight Meet the Author Podcast on Structuring JavaScript Code

  - by dwahlin

  I had the opportunity to talk with Fritz Onion from Pluralsight about one of my recent courses titled Structuring JavaScript Code for one of their Meet the Author podcasts. We talked about why JavaScript patterns are important for building more re-useable and maintainable apps, pros and cons of different patterns, and how to go about picking a pattern as a project is started. The course provides a solid walk-through of converting what I call “Function Spaghetti Code” into more modular code that’s easier to maintain, more re-useable, and less susceptible to naming conflicts. Patterns covered in the course include the Prototype Pattern, Revealing Module Pattern, and Revealing Prototype Pattern along with several other tips and techniques that can be used. Meet the Author:  Dan Wahlin on Structuring JavaScript Code   The transcript from the podcast is shown below: [Fritz]  Hello, this is Fritz Onion with another Pluralsight author interview. Today we’re talking with Dan Wahlin about his new course, Structuring JavaScript Code. Hi, Dan, it’s good to have you with us today. [Dan]  Thanks for having me, Fritz. [Fritz]  So, Dan, your new course, which came out in December of 2011 called Structuring JavaScript Code, goes into several patterns of usage in JavaScript as well as ways of organizing your code and what struck me about it was all the different techniques you described for encapsulating your code. I was wondering if you could give us just a little insight into what your motivation was for creating this course and sort of why you decided to write it and record it. [Dan]  Sure. So, I got started with JavaScript back in the mid 90s. In fact, back in the days when browsers that most people haven’t heard of were out and we had JavaScript but it wasn’t great. I was on a project in the late 90s that was heavy, heavy JavaScript and we pretty much did what I call in the course function spaghetti code where you just have function after function, there’s no rhyme or reason to how those functions are structured, they just kind of flow and it’s a little bit hard to do maintenance on it, you really don’t get a lot of reuse as far as from an object perspective. And so coming from an object-oriented background in JAVA and C#, I wanted to put something together that highlighted kind of the new way if you will of writing JavaScript because most people start out just writing functions and there’s nothing with that, it works, but it’s definitely not a real reusable solution. So the course is really all about how to move from just kind of function after function after function to the world of more encapsulated code and more reusable and hopefully better maintenance in the process. [Fritz]  So I am sure a lot of people have had similar experiences with their JavaScript code and will be looking forward to seeing what types of patterns you’ve put forth. Now, a couple I noticed in your course one is you start off with the prototype pattern. Do you want to describe sort of what problem that solves and how you go about using it within JavaScript? [Dan]  Sure. So, the patterns that are covered such as the prototype pattern and the revealing module pattern just as two examples, you know, show these kind of three things that I harp on throughout the course of encapsulation, better maintenance, reuse, those types of things. The prototype pattern specifically though has a couple kind of pros over some of the other patterns and that is the ability to extend your code without touching source code and what I mean by that is let’s say you’re writing a library that you know either other teammates or other people just out there on the Internet in general are going to be using. With the prototype pattern, you can actually write your code in such a way that we’re leveraging the JavaScript property and by doing that now you can extend my code that I wrote without touching my source code script or you can even override my code and perform some new functionality. Again, without touching my code.  And so you get kind of the benefit of the almost like inheritance or overriding in object oriented languages with this prototype pattern and it makes it kind of attractive that way definitely from a maintenance standpoint because, you know, you don’t want to modify a script I wrote because I might roll out version 2 and now you’d have to track where you change things and it gets a little tricky. So with this you just override those pieces or extend them and get that functionality and that’s kind of some of the benefits that that pattern offers out of the box. [Fritz]  And then the revealing module pattern, how does that differ from the prototype pattern and what problem does that solve differently? [Dan]  Yeah, so the prototype pattern and there’s another one that’s kind of really closely lined with revealing module pattern called the revealing prototype pattern and it also uses the prototype key word but it’s very similar to the one you just asked about the revealing module pattern. [Fritz]  Okay. [Dan]  This is a really popular one out there. In fact, we did a project for Microsoft that was very, very heavy JavaScript. It was an HMTL5 jQuery type app and we use this pattern for most of the structure if you will for the JavaScript code and what it does in a nutshell is allows you to get that encapsulation so you have really a single function wrapper that wraps all your other child functions but it gives you the ability to do public versus private members and this is kind of a sort of debate out there on the web. Some people feel that all JavaScript code should just be directly accessible and others kind of like to be able to hide their, truly their private stuff and a lot of people do that. You just put an underscore in front of your field or your variable name or your function name and that kind of is the defacto way to say hey, this is private. With the revealing module pattern you can do the equivalent of what objective oriented languages do and actually have private members that you literally can’t get to as an external consumer of the JavaScript code and then you can expose only those members that you want to be public. Now, you don’t get the benefit though of the prototype feature, which is I can’t easily extend the revealing module pattern type code if you don’t like something I’m doing, chances are you’re probably going to have to tweak my code to fix that because we’re not leveraging prototyping but in situations where you’re writing apps that are very specific to a given target app, you know, it’s not a library, it’s not going to be used in other apps all over the place, it’s a pattern I actually like a lot, it’s very simple to get going and then if you do like that public/private feature, it’s available to you. [Fritz]  Yeah, that’s interesting. So it’s almost, you can either go private by convention just by using a standard naming convention or you can actually enforce it by using the prototype pattern. [Dan]  Yeah, that’s exactly right. [Fritz]  So one of the things that I know I run across in JavaScript and I’m curious to get your take on is we do have all these different techniques of encapsulation and each one is really quite different when you’re using closures versus simply, you know, referencing member variables and adding them to your objects that the syntax changes with each pattern and the usage changes. So what would you recommend for people starting out in a brand new JavaScript project? Should they all sort of decide beforehand on what patterns they’re going to stick to or do you change it based on what part of the library you’re working on? I know that’s one of the points of confusion in this space. [Dan]  Yeah, it’s a great question. In fact, I just had a company ask me about that. So which one do I pick and, of course, there’s not one answer fits all. [Fritz]  Right. [Dan]  So it really depends what you just said is absolutely in my opinion correct, which is I think as a, especially if you’re on a team or even if you’re just an individual a team of one, you should go through and pick out which pattern for this particular project you think is best. Now if it were me, here’s kind of the way I think of it. If I were writing a let’s say base library that several web apps are going to use or even one, but I know that there’s going to be some pieces that I’m not really sure on right now as I’m writing I and I know people might want to hook in that and have some better extension points, then I would look at either the prototype pattern or the revealing prototype. Now, really just a real quick summation between the two the revealing prototype also gives you that public/private stuff like the revealing module pattern does whereas the prototype pattern does not but both of the prototype patterns do give you the benefit of that extension or that hook capability. So, if I were writing a library that I need people to override things or I’m not even sure what I need them to override, I want them to have that option, I’d probably pick a prototype, one of the prototype patterns. If I’m writing some code that is very unique to the app and it’s kind of a one off for this app which is what I think a lot of people are kind of in that mode as writing custom apps for customers, then my personal preference is the revealing module pattern you could always go with the module pattern as well which is very close but I think the revealing module patterns a little bit cleaner and we go through that in the course and explain kind of the syntax there and the differences. [Fritz]  Great, that makes a lot of sense. [Fritz]  I appreciate you taking the time, Dan, and I hope everyone takes a chance to look at your course and sort of make these decisions for themselves in their next JavaScript project. Dan’s course is, Structuring JavaScript Code and it’s available now in the Pluralsight Library. So, thank you very much, Dan. [Dan]  Thanks for having me again.

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• How about a new platform for your next API&hellip; a CMS?

  - by Elton Stoneman

  Originally posted on: http://geekswithblogs.net/EltonStoneman/archive/2014/05/22/how-about-a-new-platform-for-your-next-apihellip-a.aspxSay what? I’m seeing a type of API emerge which serves static or long-lived resources, which are mostly read-only and have a controlled process to update the data that gets served. Think of something like an app configuration API, where you want a central location for changeable settings. You could use this server side to store database connection strings and keep all your instances in sync, or it could be used client side to push changes out to all users (and potentially driving A/B or MVT testing). That’s a good candidate for a RESTful API which makes proper use of HTTP expiration and validation caching to minimise traffic, but really you want a front end UI where you can edit the current config that the API returns and publish your changes. Sound like a Content Mangement System would be a good fit? I’ve been looking at that and it’s a great fit for this scenario. You get a lot of what you need out of the box, the amount of custom code you need to write is minimal, and you get a whole lot of extra stuff from using CMS which is very useful, but probably not something you’d build if you had to put together a quick UI over your API content (like a publish workflow, fine-grained security and an audit trail). You typically use a CMS for HTML resources, but it’s simple to expose JSON instead – or to do content negotiation to support both, so you can open a resource in a browser and see a nice visual representation, or request it with: Accept=application/json and get the same content rendered as JSON for the app to use. Enter Umbraco Umbraco is an open source .NET CMS that’s been around for a while. It has very good adoption, a lively community and a good release cycle. It’s easy to use, has all the functionality you need for a CMS-driven API, and it’s scalable (although you won’t necessarily put much scale on the CMS layer). In the rest of this post, I’ll build out a simple app config API using Umbraco. We’ll define the structure of the configuration resource by creating a new Document Type and setting custom properties; then we’ll build a very simple Razor template to return configuration documents as JSON; then create a resource and see how it looks. And we’ll look at how you could build this into a wider solution. If you want to try this for yourself, it’s ultra easy – there’s an Umbraco image in the Azure Website gallery, so all you need to to is create a new Website, select Umbraco from the image and complete the installation. It will create a SQL Azure website to store all the content, as well as a Website instance for editing and accessing content. They’re standard Azure resources, so you can scale them as you need. The default install creates a starter site for some HTML content, which you can use to learn your way around (or just delete). 1. Create Configuration Document Type In Umbraco you manage content by creating and modifying documents, and every document has a known type, defining what properties it holds. We’ll create a new Document Type to describe some basic config settings. In the Settings section from the left navigation (spanner icon), expand Document Types and Master, hit the ellipsis and select to create a new Document Type: This will base your new type off the Master type, which gives you some existing properties that we’ll use – like the Page Title which will be the resource URL. In the Generic Properties tab for the new Document Type, you set the properties you’ll be able to edit and return for the resource: Here I’ve added a text string where I’ll set a default cache lifespan, an image which I can use for a banner display, and a date which could show the user when the next release is due. This is the sort of thing that sits nicely in an app config API. It’s likely to change during the life of the product, but not very often, so it’s good to have a centralised place where you can make and publish changes easily and safely. It also enables A/B and MVT testing, as you can change the response each client gets based on your set logic, and their apps will behave differently without needing a release. 2. Define the response template Now we’ve defined the structure of the resource (as a document), in Umbraco we can define a C# Razor template to say how that resource gets rendered to the client. If you only want to provide JSON, it’s easy to render the content of the document by building each property in the response (Umbraco uses dynamic objects so you can specify document properties as object properties), or you can support content negotiation with very little effort. Here’s a template to render the document as HTML or JSON depending on the Accept header, using JSON.NET for the API rendering: @inherits Umbraco.Web.Mvc.UmbracoTemplatePage @using Newtonsoft.Json @{ Layout = null; } @if(UmbracoContext.HttpContext.Request.Headers["accept"] != null &amp;&amp; UmbracoContext.HttpContext.Request.Headers["accept"] == "application/json") { Response.ContentType = "application/json"; @Html.Raw(JsonConvert.SerializeObject(new { cacheLifespan = CurrentPage.cacheLifespan, bannerImageUrl = CurrentPage.bannerImage, nextReleaseDate = CurrentPage.nextReleaseDate })) } else { <h1>App configuration</h1> <p>Cache lifespan: <b>@CurrentPage.cacheLifespan</b></p> <p>Banner Image: </p> <img src="@CurrentPage.bannerImage"> <p>Next Release Date: <b>@CurrentPage.nextReleaseDate</b></p> } That’s a rough-and ready example of what you can do. You could make it completely generic and just render all the document’s properties as JSON, but having a specific template for each resource gives you control over what gets sent out. And the templates are evaluated at run-time, so if you need to change the output – or extend it, say to add caching response headers – you just edit the template and save, and the next client request gets rendered from the new template. No code to build and ship. 3. Create the content With your document type created, in  the Content pane you can create a new instance of that document, where Umbraco gives you a nice UI to input values for the properties we set up on the Document Type: Here I’ve set the cache lifespan to an xs:duration value, uploaded an image for the banner and specified a release date. Each property gets the appropriate input control – text box, file upload and date picker. At the top of the page is the name of the resource – myapp in this example. That specifies the URL for the resource, so if I had a DNS entry pointing to my Umbraco instance, I could access the config with a URL like http://static.x.y.z.com/config/myapp. The setup is all done now, so when we publish this resource it’ll be available to access.  4. Access the resource Now if you open  that URL in the browser, you’ll see the HTML version rendered: - complete with the  image and formatted date. Umbraco lets you save changes and preview them before publishing, so the HTML view could be a good way of showing editors their changes in a usable view, before they confirm them. If you browse the same URL from a REST client, specifying the Accept=application/json request header, you get this response:   That’s the exact same resource, with a managed UI to publish it, being accessed as HTML or JSON with a tiny amount of effort. 5. The wider landscape If you have fairy stable content to expose as an API, I think  this approach is really worth considering. Umbraco scales very nicely, but in a typical solution you probably wouldn’t need it to. When you have additional requirements, like logging API access requests - but doing it out-of-band so clients aren’t impacted, you can put a very thin API layer on top of Umbraco, and cache the CMS responses in your API layer:   Here the API does a passthrough to CMS, so the CMS still controls the content, but it caches the response. If the response is cached for 1 minute, then Umbraco only needs to handle 1 request per minute (multiplied by the number of API instances), so if you need to support 1000s of request per second, you’re scaling a thin, simple API layer rather than having to scale the more complex CMS infrastructure (including the database). This diagram also shows an approach to logging, by asynchronously publishing a message to a queue (Redis in this case), which can be picked up later and persisted by a different process. Does it work? Beautifully. Using Azure, I spiked the solution above (including the Redis logging framework which I’ll blog about later) in half a day. That included setting up different roles in Umbraco to demonstrate a managed workflow for publishing changes, and a couple of document types representing different resources. Is it maintainable? We have three moving parts, which are all managed resources in Azure –  an Azure Website for Umbraco which may need a couple of instances for HA (or may not, depending on how long the content can be cached), a message queue (Redis is in preview in Azure, but you can easily use Service Bus Queues if performance is less of a concern), and the Web Role for the API. Two of the components are off-the-shelf, from open source projects, and the only custom code is the API which is very simple. Does it scale? Pretty nicely. With a single Umbraco instance running as an Azure Website, and with 4x instances for my API layer (Standard sized Web Roles), I got just under 4,000 requests per second served reliably, with a Worker Role in the background saving the access logs. So we had a nice UI to publish app config changes, with a friendly Web preview and a publishing workflow, capable of supporting 14 million requests in an hour, with less than a day’s effort. Worth considering if you’re publishing long-lived resources through your API.

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• Option Trading: Getting the most out of the event session options

  - by extended_events

  You can control different aspects of how an event session behaves by setting the event session options as part of the CREATE EVENT SESSION DDL. The default settings for the event session options are designed to handle most of the common event collection situations so I generally recommend that you just use the defaults. Like everything in the real world though, there are going to be a handful of “special cases” that require something different. This post focuses on identifying the special cases and the correct use of the options to accommodate those cases. There is a reason it’s called Default The default session options specify a total event buffer size of 4 MB with a 30 second latency. Translating this into human terms; this means that our default behavior is that the system will start processing events from the event buffer when we reach about 1.3 MB of events or after 30 seconds, which ever comes first. Aside: What’s up with the 1.3 MB, I thought you said the buffer was 4 MB?The Extended Events engine takes the total buffer size specified by MAX_MEMORY (4MB by default) and divides it into 3 equally sized buffers. This is done so that a session can be publishing events to one buffer while other buffers are being processed. There are always at least three buffers; how to get more than three is covered later. Using this configuration, the Extended Events engine can “keep up” with most event sessions on standard workloads. Why is this? The fact is that most events are small, really small; on the order of a couple hundred bytes. Even when you start considering events that carry dynamically sized data (eg. binary, text, etc.) or adding actions that collect additional data, the total size of the event is still likely to be pretty small. This means that each buffer can likely hold thousands of events before it has to be processed. When the event buffers are finally processed there is an economy of scale achieved since most targets support bulk processing of the events so they are processed at the buffer level rather than the individual event level. When all this is working together it’s more likely that a full buffer will be processed and put back into the ready queue before the remaining buffers (remember, there are at least three) are full. I know what you’re going to say: “My server is exceptional! My workload is so massive it defies categorization!” OK, maybe you weren’t going to say that exactly, but you were probably thinking it. The point is that there are situations that won’t be covered by the Default, but that’s a good place to start and this post assumes you’ve started there so that you have something to look at in order to determine if you do have a special case that needs different settings. So let’s get to the special cases… What event just fired?! How about now?! Now?! If you believe the commercial adage from Heinz Ketchup (Heinz Slow Good Ketchup ad on You Tube), some things are worth the wait. This is not a belief held by most DBAs, particularly DBAs who are looking for an answer to a troubleshooting question fast. If you’re one of these anxious DBAs, or maybe just a Program Manager doing a demo, then 30 seconds might be longer than you’re comfortable waiting. If you find yourself in this situation then consider changing the MAX_DISPATCH_LATENCY option for your event session. This option will force the event buffers to be processed based on your time schedule. This option only makes sense for the asynchronous targets since those are the ones where we allow events to build up in the event buffer – if you’re using one of the synchronous targets this option isn’t relevant. Avoid forgotten events by increasing your memory Have you ever had one of those days where you keep forgetting things? That can happen in Extended Events too; we call it dropped events. In order to optimizes for server performance and help ensure that the Extended Events doesn’t block the server if to drop events that can’t be published to a buffer because the buffer is full. You can determine if events are being dropped from a session by querying the dm_xe_sessions DMV and looking at the dropped_event_count field. Aside: Should you care if you’re dropping events?Maybe not – think about why you’re collecting data in the first place and whether you’re really going to miss a few dropped events. For example, if you’re collecting query duration stats over thousands of executions of a query it won’t make a huge difference to miss a couple executions. Use your best judgment. If you find that your session is dropping events it means that the event buffer is not large enough to handle the volume of events that are being published. There are two ways to address this problem. First, you could collect fewer events – examine you session to see if you are over collecting. Do you need all the actions you’ve specified? Could you apply a predicate to be more specific about when you fire the event? Assuming the session is defined correctly, the next option is to change the MAX_MEMORY option to a larger number. Picking the right event buffer size might take some trial and error, but a good place to start is with the number of dropped events compared to the number you’ve collected. Aside: There are three different behaviors for dropping events that you specify using the EVENT_RETENTION_MODE option. The default is to allow single event loss and you should stick with this setting since it is the best choice for keeping the impact on server performance low.You’ll be tempted to use the setting to not lose any events (NO_EVENT_LOSS) – resist this urge since it can result in blocking on the server. If you’re worried that you’re losing events you should be increasing your event buffer memory as described in this section. Some events are too big to fail A less common reason for dropping an event is when an event is so large that it can’t fit into the event buffer. Even though most events are going to be small, you might find a condition that occasionally generates a very large event. You can determine if your session is dropping large events by looking at the dm_xe_sessions DMV once again, this time check the largest_event_dropped_size. If this value is larger than the size of your event buffer [remember, the size of your event buffer, by default, is max_memory / 3] then you need a large event buffer. To specify a large event buffer you set the MAX_EVENT_SIZE option to a value large enough to fit the largest event dropped based on data from the DMV. When you set this option the Extended Events engine will create two buffers of this size to accommodate these large events. As an added bonus (no extra charge) the large event buffer will also be used to store normal events in the cases where the normal event buffers are all full and waiting to be processed. (Note: This is just a side-effect, not the intended use. If you’re dropping many normal events then you should increase your normal event buffer size.) Partitioning: moving your events to a sub-division Earlier I alluded to the fact that you can configure your event session to use more than the standard three event buffers – this is called partitioning and is controlled by the MEMORY_PARTITION_MODE option. The result of setting this option is fairly easy to explain, but knowing when to use it is a bit more art than science. First the science… You can configure partitioning in three ways: None, Per NUMA Node & Per CPU. This specifies the location where sets of event buffers are created with fairly obvious implication. There are rules we follow for sub-dividing the total memory (specified by MAX_MEMORY) between all the event buffers that are specific to the mode used: None: 3 buffers (fixed)Node: 3 * number_of_nodesCPU: 2.5 * number_of_cpus Here are some examples of what this means for different Node/CPU counts: Configuration None Node CPU 2 CPUs, 1 Node 3 buffers 3 buffers 5 buffers 6 CPUs, 2 Node 3 buffers 6 buffers 15 buffers 40 CPUs, 5 Nodes 3 buffers 15 buffers 100 buffers   Aside: Buffer size on multi-processor computersAs the number of Nodes or CPUs increases, the size of the event buffer gets smaller because the total memory is sub-divided into more pieces. The defaults will hold up to this for a while since each buffer set is holding events only from the Node or CPU that it is associated with, but at some point the buffers will get too small and you’ll either see events being dropped or you’ll get an error when you create your session because you’re below the minimum buffer size. Increase the MAX_MEMORY setting to an appropriate number for the configuration. The most likely reason to start partitioning is going to be related to performance. If you notice that running an event session is impacting the performance of your server beyond a reasonably expected level [Yes, there is a reasonably expected level of work required to collect events.] then partitioning might be an answer. Before you partition you might want to check a few other things: Is your event retention set to NO_EVENT_LOSS and causing blocking? (I told you not to do this.) Consider changing your event loss mode or increasing memory. Are you over collecting and causing more work than necessary? Consider adding predicates to events or removing unnecessary events and actions from your session. Are you writing the file target to the same slow disk that you use for TempDB and your other high activity databases? <kidding> <not really> It’s always worth considering the end to end picture – if you’re writing events to a file you can be impacted by I/O, network; all the usual stuff. Assuming you’ve ruled out the obvious (and not so obvious) issues, there are performance conditions that will be addressed by partitioning. For example, it’s possible to have a successful event session (eg. no dropped events) but still see a performance impact because you have many CPUs all attempting to write to the same free buffer and having to wait in line to finish their work. This is a case where partitioning would relieve the contention between the different CPUs and likely reduce the performance impact cause by the event session. There is no DMV you can check to find these conditions – sorry – that’s where the art comes in. This is  largely a matter of experimentation. On the bright side you probably won’t need to to worry about this level of detail all that often. The performance impact of Extended Events is significantly lower than what you may be used to with SQL Trace. You will likely only care about the impact if you are trying to set up a long running event session that will be part of your everyday workload – sessions used for short term troubleshooting will likely fall into the “reasonably expected impact” category. Hey buddy – I think you forgot something OK, there are two options I didn’t cover: STARTUP_STATE & TRACK_CAUSALITY. If you want your event sessions to start automatically when the server starts, set the STARTUP_STATE option to ON. (Now there is only one option I didn’t cover.) I’m going to leave causality for another post since it’s not really related to session behavior, it’s more about event analysis. - Mike Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• Translating with Google Translate without API and C# Code

  - by Rick Strahl

  Some time back I created a data base driven ASP.NET Resource Provider along with some tools that make it easy to edit ASP.NET resources interactively in a Web application. One of the small helper features of the interactive resource admin tool is the ability to do simple translations using both Google Translate and Babelfish. Here's what this looks like in the resource administration form: When a resource is displayed, the user can click a Translate button and it will show the current resource text and then lets you set the source and target languages to translate. The Go button fires the translation for both Google and Babelfish and displays them - pressing use then changes the language of the resource to the target language and sets the resource value to the newly translated value. It's a nice and quick way to get a quick translation going. Ch… Ch… Changes Originally, both implementations basically did some screen scraping of the interactive Web sites and retrieved translated text out of result HTML. Screen scraping is always kind of an iffy proposition as content can be changed easily, but surprisingly that code worked for many years without fail. Recently however, Google at least changed their input pages to use AJAX callbacks and the page updates no longer worked the same way. End result: The Google translate code was broken. Now, Google does have an official API that you can access, but the API is being deprecated and you actually need to have an API key. Since I have public samples that people can download the API key is an issue if I want people to have the samples work out of the box - the only way I could even do this is by sharing my API key (not allowed).   However, after a bit of spelunking and playing around with the public site however I found that Google's interactive translate page actually makes callbacks using plain public access without an API key. By intercepting some of those AJAX calls and calling them directly from code I was able to get translation back up and working with minimal fuss, by parsing out the JSON these AJAX calls return. I don't think this particular Warning: This is hacky code, but after a fair bit of testing I found this to work very well with all sorts of languages and accented and escaped text etc. as long as you stick to small blocks of translated text. I thought I'd share it in case anybody else had been relying on a screen scraping mechanism like I did and needed a non-API based replacement. Here's the code: /// <summary> /// Translates a string into another language using Google's translate API JSON calls. /// <seealso>Class TranslationServices</seealso> /// </summary> /// <param name="Text">Text to translate. Should be a single word or sentence.</param> /// <param name="FromCulture"> /// Two letter culture (en of en-us, fr of fr-ca, de of de-ch) /// </param> /// <param name="ToCulture"> /// Two letter culture (as for FromCulture) /// </param> public string TranslateGoogle(string text, string fromCulture, string toCulture) { fromCulture = fromCulture.ToLower(); toCulture = toCulture.ToLower(); // normalize the culture in case something like en-us was passed // retrieve only en since Google doesn't support sub-locales string[] tokens = fromCulture.Split('-'); if (tokens.Length > 1) fromCulture = tokens[0]; // normalize ToCulture tokens = toCulture.Split('-'); if (tokens.Length > 1) toCulture = tokens[0]; string url = string.Format(@"http://translate.google.com/translate_a/t?client=j&text={0}&hl=en&sl={1}&tl={2}", HttpUtility.UrlEncode(text),fromCulture,toCulture); // Retrieve Translation with HTTP GET call string html = null; try { WebClient web = new WebClient(); // MUST add a known browser user agent or else response encoding doen't return UTF-8 (WTF Google?) web.Headers.Add(HttpRequestHeader.UserAgent, "Mozilla/5.0"); web.Headers.Add(HttpRequestHeader.AcceptCharset, "UTF-8"); // Make sure we have response encoding to UTF-8 web.Encoding = Encoding.UTF8; html = web.DownloadString(url); } catch (Exception ex) { this.ErrorMessage = Westwind.Globalization.Resources.Resources.ConnectionFailed + ": " + ex.GetBaseException().Message; return null; } // Extract out trans":"...[Extracted]...","from the JSON string string result = Regex.Match(html, "trans\":(\".*?\"),\"", RegexOptions.IgnoreCase).Groups[1].Value; if (string.IsNullOrEmpty(result)) { this.ErrorMessage = Westwind.Globalization.Resources.Resources.InvalidSearchResult; return null; } //return WebUtils.DecodeJsString(result); // Result is a JavaScript string so we need to deserialize it properly JavaScriptSerializer ser = new JavaScriptSerializer(); return ser.Deserialize(result, typeof(string)) as string; } To use the code is straightforward enough - simply provide a string to translate and a pair of two letter source and target languages: string result = service.TranslateGoogle("Life is great and one is spoiled when it goes on and on and on", "en", "de"); TestContext.WriteLine(result); How it works The code to translate is fairly straightforward. It basically uses the URL I snagged from the Google Translate Web Page slightly changed to return a JSON result (&client=j) instead of the funky nested PHP style JSON array that the default returns. The JSON result returned looks like this: {"sentences":[{"trans":"Das Leben ist großartig und man wird verwöhnt, wenn es weiter und weiter und weiter geht","orig":"Life is great and one is spoiled when it goes on and on and on","translit":"","src_translit":""}],"src":"en","server_time":24} I use WebClient to make an HTTP GET call to retrieve the JSON data and strip out part of the full JSON response that contains the actual translated text. Since this is a JSON response I need to deserialize the JSON string in case it's encoded (for upper/lower ASCII chars or quotes etc.). Couple of odd things to note in this code: First note that a valid user agent string must be passed (or at least one starting with a common browser identification - I use Mozilla/5.0). Without this Google doesn't encode the result with UTF-8, but instead uses a ISO encoding that .NET can't easily decode. Google seems to ignore the character set header and use the user agent instead which is - odd to say the least. The other is that the code returns a full JSON response. Rather than use the full response and decode it into a custom type that matches Google's result object, I just strip out the translated text. Yeah I know that's hacky but avoids an extra type and firing up the JavaScript deserializer. My internal version uses a small DecodeJsString() method to decode Javascript without the overhead of a full JSON parser. It's obviously not rocket science but as mentioned above what's nice about it is that it works without an Google API key. I can't vouch on how many translates you can do before there are cut offs but in my limited testing running a few stress tests on a Web server under load I didn't run into any problems. Limitations There are some restrictions with this: It only works on single words or single sentences - multiple sentences (delimited by .) are cut off at the ".". There is also a length limitation which appears to happen at around 220 characters or so. While that may not sound  like much for typical word or phrase translations this this is plenty of length. Use with a grain of salt - Google seems to be trying to limit their exposure to usage of the Translate APIs so this code might break in the future, but for now at least it works. FWIW, I also found that Google's translation is not as good as Babelfish, especially for contextual content like sentences. Google is faster, but Babelfish tends to give better translations. This is why in my translation tool I show both Google and Babelfish values retrieved. You can check out the code for this in the West Wind West Wind Web Toolkit's TranslationService.cs file which contains both the Google and Babelfish translation code pieces. Ironically the Babelfish code has been working forever using screen scraping and continues to work just fine today. I think it's a good idea to have multiple translation providers in case one is down or changes its format, hence the dual display in my translation form above. I hope this has been helpful to some of you - I've actually had many small uses for this code in a number of applications and it's sweet to have a simple routine that performs these operations for me easily. Resources Live Localization Sample Localization Resource Provider Administration form that includes options to translate text using Google and Babelfish interactively. TranslationService.cs The full source code in the West Wind West Wind Web Toolkit's Globalization library that contains the translation code. © Rick Strahl, West Wind Technologies, 2005-2011Posted in CSharp  HTTP   Tweet (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• Simple Branching and Merging with SVN

  Its a good idea not to do too much work without checking something into source control.  By too much work I mean typically on the order of a couple of hours at most, and certainly its a good practice to check in anything you have before you leave the office for the day.  But what if your changes break the build (on the build server you do have a build server dont you?) or would cause problems for others on your team if they get the latest code?  The solution with Subversion is branching and merging (incidentally, if youre using Microsoft Visual Studio Team System, you can shelve your changes and share shelvesets with others, which accomplishes many of the same things as branching and merging, but is a bit simpler to do). Getting Started Im going to assume you have Subversion installed along with the nearly ubiquitous client, TortoiseSVN.  See my previous post on installing SVN server if you want to get it set up real quick (you can put it on your workstation/laptop just to learn how it works easily enough). Overview When you know you are going to be working on something that you wont be able to check in quickly, its a good idea to start a branch.  Its also perfectly fine to create the branch after-the-fact (have you ever started something thinking it would be an hour and 4 hours later realized you were nowhere near done?).  In any event, the first thing you need to do is create a branch.  A branch is simply a copy of the current trunk (a typical subversion setup has root directories called trunk, tags, and branches its a good idea to keep this and to put your branches in the branches folder).  Once you have a new branch, you need to switch your working copy so that it is bound to your branch.  As you work,  you may want to merge in changes that are happening in the trunk to your branch, and ultimately when you are done youll want to merge your branch back into the trunk.  When done, you can delete your branch (or not, but it may add clutter).  To sum up: Create a new branch Switch your local working copy to the new branch Develop in the branch (commit changes, etc.) Merge changes from trunk into your branch Merge changes from branch into trunk Delete the branch Create a new branch From the root of your repository, right-click and select TortoiseSVN > Branch/tag as shown at right (click to enlarge).  This will bring up the Copy (Branch / Tag) interface.  By default the From WC at URL: should be pointing at the trunk of your repository.  I recommend (after ensuring that you have the latest version) that you choose to make the copy from the HEAD revision in the repository (the first radio button).  In the To URL: textbox, you should change the URL from /trunk to /branches/NAME_OF_BRANCH.  You can name the branch anything you like, but its often useful to give it your name (if its just for your use) or some useful information (such as a datestamp or a bug/issue ID from that it relates to, or perhaps just the name of the feature you are adding. When youre done with that, enter in a log message for your new branch.  If you want to immediately switch your local working copy to the new branch/tag, check the box at the bottom of the dialog (Switch working copy to new branch/tag).  You can see an example at right. Assuming everything works, you should very quickly see a window telling you the Copy finished, like the one shown below: Switch Local Working Copy to New Branch If you followed the instructions above and checked the box when you created your branch, you dont need to do this step.  However, if you have a branch that already exists and you would like to switch over to working on it, you can do so by using the Switch command.  Youll find it in the explorer context menu under TortoiseSVN > Switch: This brings up a dialog that shows you your current binding, and lets you enter in a new URL to switch to: In the screenshot above, you can see that Im currently bound to a branch, and so I could switch back to the trunk or to another branch.  If youre not sure what to enter here, you can click the [] next to the URL textbox to explore your repository and find the appropriate root URL to use.  Also, the dropdown will show you URLs that might be a good fit (such as the trunk of the current repository). Develop in the Branch Once you have created a branch and switched your working copy to use it,  you can make changes and Commit them as usual.  Your commits are now going into the branch, so they wont impact other users or the build server that are working off of the trunk (or their own branches).  In theory you can keep on doing this forever, but practically its a good idea to periodically merge the trunk into your branch, and/or keep your branches short-lived and merge them back into the trunk before they get too far out of sync. Merge Changes from Trunk into your Branch Once you have been working in a branch for a little while, change to the trunk will have occurred that youll want to merge into your branch.  Its much safer and easier to integrate changes in small increments than to wait for weeks or months and then try to merge in two very different codebases.  To perform the merge, simply go to the root of your branch working copy and right click, select TortoiseSVN->Merge.  Youll be presented with this dialog: In this case you want to leave the default setting, Merge a range of revisions.  Click Next.  Now choose the URL to merge from.  You should select the trunk of your current repository (which should be in the dropdownlist, or you can click the [] to browse your repository for the correct URL).  You can leave everything else blank since you want to merge everything: Click Next.  Again you can leave the default settings.  If you want to do something more granular than everything in the trunk, you can select a different Merge depth, to include merging just one item in the tree.  You can also perform a Test merge to see what changes will take place before you click Merge (which is often a good idea).  Heres what the dialog should look like before you click Merge: After clicking Merge (or Test merge) you should see a confirmation like this (it will say Test Only in the title if you click Test merge): Now you should build your solution, run all of your tests, and verify that your branch still works the way it should, given the updates that youve just integrated from the trunk.  Once everything works, Commit your changes, and then continue with your work on the branch.  Note that until you commit, nothing has actually changed in your branch on the server.  Other team members who may also be working in this branch wont be impacted, etc.  The Merge is purely a client-side operation until you perform a Commit. In a more real-world scenario, you may have conflicts.  When you do, youll be presented with a dialog like this one: Its up to you which option you want to go with.  The more frequently you Merge, the fewer of these youll have to deal with.  Also, be very sure that youre merging the right folders together.  If you try and merge your trunk with some subfolder in your branchs structure, youll end up with all kinds of conflicts and problems.  Fortunately, theyre only on your working copy (unless you commit them!) but if you see something like that, be sure to doublecheck your URL and your local file location. Merge Your Branch Back Into Trunk When youre done working in your branch, its time to pull it back into the trunk.  The first thing you should do is follow the previous steps instructions for merging the latest from the trunk into your branch.  This lets you ensure that what you have in your branch works correctly with the current trunk.  Once youve done that and committed your changes to your branch, youre ready to proceed with this step. Once youre confident your branch is good to go, you should go to its root folder and select TortoiseSVN->Merge (as above) from the explorer right-click menu.  This time, select Reintegrate a branch as shown below: Click Next.  Youll want it to merge with the trunk, which should be the default: Click Next. Leave the default settings: Click Test merge to see a test, and then if all looks good, click Merge.  Note that if you havent checked in your working copy changes, youll see something like this: If on the other hand things are successful: After this step, its likely you are finished working in your branch.  Dont forget to use the ToroiseSVN->Switch command to change your working copy back to the trunk. Delete the Branch You dont have to delete the branch, but over time your branches area of your repository will get cluttered, and in any event if theyre not actively being worked on the branches are just taking up space and adding to later confusion.  Keeping your branches limited to things youre actively working on is simply a good habit to get into, just like making sure your codebase itself remains tidy and not filled with old commented out bits of code. To delete the branch after youre finished with it, the simplest thing to do is choose TortoiseSVN->Repo Browser.  From there, assuming you did this from your branch, it should already be highlighted.  In any event, navigate to your branch in the treeview on the left, and then right-click and select Delete.  Enter a log message if youd like: Click OK, and its gone.  Dont be too afraid of this, though.  You can still get to the files by viewing the log for branches, and selecting a previous revision (anything before the delete action): If for some reason you needed something that was previously in this branch, you could easily get back to any changeset you checked in, so you should have absolutely no fear when it comes to deleting branches youre done with.   Resources If youre using Eclipse, theres a nice write-up of the steps required by Zach Cox that I found helpful here. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Migrating from SQL Trace to Extended Events

  - by extended_events

  In SQL Server codenamed “Denali” we are moving our diagnostic tracing capabilities forward by building a system on top of Extended Events. With every new system you face the specter of migration which is always a bit of a hassle. I’m obviously motivated to see everyone move their diagnostic tracing systems over to the new extended events based system, so I wanted to make sure we lowered the bar for the migration process to help ease your trials. In my initial post on Denali CTP 1 I described a couple tables that we created that will help map the existing SQL Trace Event Classes to the equivalent Extended Events events. In this post I’ll describe the tables in a bit more details, explain the relationship between the SQL Trace objects (Event Class & Column) and Extended Event objects (Events & Actions) and at the end provide some sample code for a managed stored procedure that will take an existing SQL Trace session (eg. a trace that you can see in sys.Traces) and converts it into event session DDL. Can you relate? In some ways, SQL Trace and Extended Events is kind of like the Standard and Metric measuring systems in the United States. If you spend too much time trying to figure out how to convert between the two it will probably make your head hurt. It’s often better to just use the new system without trying to translate between the two. That said, people like to relate new things to the things they’re comfortable with, so, with some trepidation, I will now explain how these two systems are related to each other. First, some terms… SQL Trace is made up of Event Classes and Columns. The Event Class occurs as the result of some activity in the database engine, for example, SQL:Batch Completed fires when a batch has completed executing on the server. Each Event Class can have any number of Columns associated with it and those Columns contain the data that is interesting about the Event Class, such as the duration or database name. In Extended Events we have objects named Events, EventData field and Actions. The Event (some people call this an xEvent but I’ll stick with Event) is equivalent to the Event Class in SQL Trace since it is the thing that occurs as the result of some activity taking place in the server. An  EventData field (from now on I’ll just refer to these as fields) is a piece of information that is highly correlated with the event and is always included as part of the schema of an Event. An Action is something that can be associated with any Event and it will cause some additional “action” to occur when ever the parent Event occurs. Actions can do a number of different things for example, there are Actions that collect additional data and, take memory dumps. When mapping SQL Trace onto Extended Events, Columns are covered by a combination of both fields and Actions. Knowing exactly where a Column is covered by a field and where it is covered by an Action is a bit of an art, so we created the mapping tables to make you an Artist without the years of practice. Let me draw you a map. Event Mapping The table dbo.trace_xe_event_map exists in the master database with the following structure: Column_name Type trace_event_id smallint package_name nvarchar xe_event_name nvarchar By joining this table sys.trace_events using trace_event_id and to the sys.dm_xe_objects using xe_event_name you can get a fair amount of information about how Event Classes are related to Events. The most basic query this lends itself to is to match an Event Class with the corresponding Event. SELECT     t.trace_event_id,     t.name [event_class],     e.package_name,     e.xe_event_name FROM sys.trace_events t INNER JOIN dbo.trace_xe_event_map e     ON t.trace_event_id = e.trace_event_id There are a couple things you’ll notice as you peruse the output of this query: For the most part, the names of Events are fairly close to the original Event Class; eg. SP:CacheMiss == sp_cache_miss, and so on. We’ve mostly stuck to a one to one mapping between Event Classes and Events, but there are a few cases where we have combined when it made sense. For example, Data File Auto Grow, Log File Auto Grow, Data File Auto Shrink & Log File Auto Shrink are now all covered by a single event named database_file_size_change. This just seemed like a “smarter” implementation for this type of event, you can get all the same information from this single event (grow/shrink, Data/Log, Auto/Manual growth) without having multiple different events. You can use Predicates if you want to limit the output to just one of the original Event Class measures. There are some Event Classes that did not make the cut and were not migrated. These fall into two categories; there were a few Event Classes that had been deprecated, or that just did not make sense, so we didn’t migrate them. (You won’t find an Event related to mounting a tape – sorry.) The second class is bigger; with rare exception, we did not migrate any of the Event Classes that were related to Security Auditing using SQL Trace. We introduced the SQL Audit feature in SQL Server 2008 and that will be the compliance and auditing feature going forward. Doing this is a very deliberate decision to support separation of duties for DBAs. There are separate permissions required for SQL Audit and Extended Events tracing so you can assign these tasks to different people if you choose. (If you’re wondering, the permission for Extended Events is ALTER ANY EVENT SESSION, which is covered by CONTROL SERVER.) Action Mapping The table dbo.trace_xe_action_map exists in the master database with the following structure: Column_name Type trace_column_id smallint package_name nvarchar xe_action_name nvarchar You can find more details by joining this to sys.trace_columns on the trace_column_id field. SELECT     c.trace_column_id,     c.name [column_name],     a.package_name,     a.xe_action_name FROM sys.trace_columns c INNER JOIN    dbo.trace_xe_action_map a     ON c.trace_column_id = a.trace_column_id If you examine this list, you’ll notice that there are relatively few Actions that map to SQL Trace Columns given the number of Columns that exist. This is not because we forgot to migrate all the Columns, but because much of the data for individual Event Classes is included as part of the EventData fields of the equivalent Events so there is no need to specify them as Actions. Putting it all together If you’ve spent a bunch of time figuring out the inner workings of SQL Trace, and who hasn’t, then you probably know that the typically set of Columns you find associated with any given Event Class in SQL Profiler is not fix, but is determine by the contents of the table sys.trace_event_bindings. We’ve used this table along with the mapping tables to produce a list of Event + Action combinations that duplicate the SQL Profiler Event Class definitions using the following query, which you can also find in the Books Online topic How To: View the Extended Events Equivalents to SQL Trace Event Classes. USE MASTER; GO SELECT DISTINCT    tb.trace_event_id,    te.name AS 'Event Class',    em.package_name AS 'Package',    em.xe_event_name AS 'XEvent Name',    tb.trace_column_id,    tc.name AS 'SQL Trace Column',    am.xe_action_name as 'Extended Events action' FROM (sys.trace_events te LEFT OUTER JOIN dbo.trace_xe_event_map em    ON te.trace_event_id = em.trace_event_id) LEFT OUTER JOIN sys.trace_event_bindings tb    ON em.trace_event_id = tb.trace_event_id LEFT OUTER JOIN sys.trace_columns tc    ON tb.trace_column_id = tc.trace_column_id LEFT OUTER JOIN dbo.trace_xe_action_map am    ON tc.trace_column_id = am.trace_column_id ORDER BY te.name, tc.name As you might imagine, it’s also possible to map an existing trace definition to the equivalent event session by judicious use of fn_trace_geteventinfo joined with the two mapping tables. This query extracts the list of Events and Actions equivalent to the trace with ID = 1, which is most likely the Default Trace. You can find this query, along with a set of other queries and steps required to migrate your existing traces over to Extended Events in the Books Online topic How to: Convert an Existing SQL Trace Script to an Extended Events Session. USE MASTER; GO DECLARE @trace_id int SET @trace_id = 1 SELECT DISTINCT el.eventid, em.package_name, em.xe_event_name AS 'event'    , el.columnid, ec.xe_action_name AS 'action' FROM (sys.fn_trace_geteventinfo(@trace_id) AS el    LEFT OUTER JOIN dbo.trace_xe_event_map AS em       ON el.eventid = em.trace_event_id) LEFT OUTER JOIN dbo.trace_xe_action_map AS ec    ON el.columnid = ec.trace_column_id WHERE em.xe_event_name IS NOT NULL AND ec.xe_action_name IS NOT NULL You’ll notice in the output that the list doesn’t include any of the security audit Event Classes, as I wrote earlier, those were not migrated. But wait…there’s more! If this were an infomercial there’d by some obnoxious guy next to me blogging “Well Mike…that’s pretty neat, but I’m sure you can do more. Can’t you make it even easier to migrate from SQL Trace?”  Needless to say, I’d blog back, in an overly excited way, “You bet I can' obnoxious blogger side-kick!” What I’ve got for you here is a Extended Events Team Blog only special – this tool will not be sold in any store; it’s a special offer for those of you reading the blog. I’ve wrapped all the logic of pulling the configuration information out of an existing trace and and building the Extended Events DDL statement into a handy, dandy CLR stored procedure. Once you load the assembly and register the procedure you just supply the trace id (from sys.traces) and provide a name for the event session. Run the procedure and out pops the DDL required to create an equivalent session. Any aspects of the trace that could not be duplicated are included in comments within the DDL output. This procedure does not actually create the event session – you need to copy the DDL out of the message tab and put it into a new query window to do that. It also requires an existing trace (but it doesn’t have to be running) to evaluate; there is no functionality to parse t-sql scripts. I’m not going to spend a bunch of time explaining the code here – the code is pretty well commented and hopefully easy to follow. If not, you can always post comments or hit the feedback button to send us some mail. Sample code: TraceToExtendedEventDDL   Installing the procedure Just in case you’re not familiar with installing CLR procedures…once you’ve compile the assembly you can load it using a script like this: -- Context to master USE master GO -- Create the assembly from a shared location. CREATE ASSEMBLY TraceToXESessionConverter FROM 'C:\Temp\TraceToXEventSessionConverter.dll' WITH PERMISSION_SET = SAFE GO -- Create a stored procedure from the assembly. CREATE PROCEDURE CreateEventSessionFromTrace @trace_id int, @session_name nvarchar(max) AS EXTERNAL NAME TraceToXESessionConverter.StoredProcedures.ConvertTraceToExtendedEvent GO Enjoy! -Mike

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• Quick guide to Oracle IRM 11g: Server installation

  - by Simon Thorpe

  Quick guide to Oracle IRM 11g index This is the first of a set of articles designed to assist with the successful installation, configuration and deployment of a document security solution using Oracle IRM. This article goes through a set of simple instructions which detail how to download, install and configure the IRM server, the starting point for building a document security solution. This article contains a subset of information from the official documentation and is focused on installing the server on Oracle Enterprise Linux. If you are planning to deploy on a non-Linux platform, you will need to reference the documentation for platform specific information. Contents Introduction Downloading the software Preparing a database Creating the schema WebLogic Server installation Installing Oracle IRM Introduction Because we are using Oracle Enterprise Linux in this guide, and before we get into the detail of IRM, i'd like to share some tips with Linux to make life a bit easier.Use a 64bit platform, IRM 11g runs just fine on a 32bit server but with 64bit you will build a more future proof service. Download and install the latest Java JDK package. Make sure you get the 64bit version if you are on a 64bit server. Configure Linux to use a good Yum server to simplify installing packages. For Oracle Enterprise Linux we maintain a great public Yum here. Have at least 20GB of free disk space on the partition you intend to install the IRM server. The downloads are big, then you extract them and then install. This quickly consumes disk space which you can easily recover by deleting the downloaded and extracted files after wards. But it's nice to have the disk space spare to keep these around in case you need to restart any part of the installation process again. Downloading the software OK, so before you can do anything, you need the software install kits. Luckily Oracle allows you to freely download every technology we create. You'll need to get the following; Oracle WebLogic Server Oracle Database Oracle Repository Creation Utility (rcu) Oracle IRM server You can use Microsoft SQL server 2005 or 2008, in this guide i've used Oracle RDBMS 11gR2 for Linux. Preparing the database I'm not going to go through the finer points of installing the database. There are many very good guides on installing the Oracle Database. However one thing I would suggest you think about is enabling TDE, network encryption and using Database Vault. These Oracle database security technologies are excellent for creating a complete end to end security solution. No point in going to all the effort to secure document access with IRM when someone can go directly to the database and assign themselves rights to documents. To understand this further, you can see a video of the IRM service using these database security technologies here. With a database up and running we need to create a schema to hold the IRM data. This schema contains the rights model, cryptographic keys, user account id's and associated rights etc. Creating the IRM database schema Oracle uses the Repository Creation Tool which builds your schema, extract the files from the rcu zip. Then in a terminal window; cd /oracle/install/rcu/bin ./rcu This will launch the Repository Creation Tool and you will be presented with the image to the right. Hit next and continue onto the next dialog. You are asked if you are going to be creating a new schema or wish to drop an existing one, you obviously just need to click next at this point to create a new schema. The RCU next needs to know where your database is so you'll need the following details of your database instance. Below, for reference, is the information for my installation. Hostname: irm.oracle.demo Port: 1521 (This is the default TCP port for the Oracle Database) Service Name: irm.oracle.demo. Note this is not the SID, but the service name. Username: sys Password: ******** Role: SYSDBA And then select next. Because the RCU contains schemas for many of the Oracle Technologies, you now need to select to just deploy the Oracle IRM schema. Open the section under "Enterprise Content Management" and tick the "Oracle Information Rights Management" component. Note that you also get the chance to select a prefix which defaults to "DEV" (for development). I usually change this to something that reflects my own install. PROD for a production system, INT for internal only etc. The next step asks for the passwords for the schema users. We are only creating one schema here so you just enter one password. Some brave souls store this password in an Excel spreadsheet which is then secure against the IRM server you're about to install in this guide. Nearing the end of the schema creation is the mapping of the tablespaces to the schema. Note I had setup a table space already that was encrypted using TDE and at this point I was able to select that tablespace by clicking in the "Default Tablespace" column. The next dialog confirms your actions and clicking on next causes it to create the schema and default data. After this you are presented with the completion summary. WebLogic Server installation The database is now ready and the next step is to install the application server. Oracle IRM 11g is a JEE application and currently only supported in Oracle WebLogic Server. So the next step is get WebLogic Server installed, which is pretty easy. Depending on the version you download, you either run the binary or for a 64 bit platform (like mine) run the following command. java -d64 -jar wls1033_generic.jar And in the resulting dialog hit next to start walking through the install. Next choose a directory into which you will install WebLogic Server. I like to change from the default and install into /oracle/. Then all my software goes into this one folder, all owned by the "oracle" user. The next dialog asks for your Oracle support information to ensure you are kept up to date. If you have an Oracle support account, enter your details but for most evaluation systems I leave these fields blank. Again, for evaluation or development systems, I usually stick with the "Typical" install type which you are next asked for. Next you are asked for the JDK which will be used for the server. When installing from the generic jar on a 64bit platform like in this guide, no JDK is bundled with the installer. But as you can see in the image on the right, that it does a good job of detecting the one you've got installed. Defaults for the install directories are usually taken, no changes here, just click next. And finally we are ready to install, hit next, sit back and relax. Typically this takes about 10 minutes. After the install, do not run the quick start, we need to deploy the IRM install itself from which we will create a new WebLogic domain. For now just hit done and lets move to the final step of the installation process. Installing Oracle IRM The last piece of the puzzle to getting your environment ready is to deploy the IRM files themselves. Unzip the Oracle Enterprise Content Management 11g zip file and it will create a Disk1 directory. Switch to this folder and in the console run ./runInstaller. This will launch the installer which will also ask for the location of the JDK. Look at the image on the right for the detail. You should now see the first stage of the IRM installation. The dialog warns you need to have a WebLogic server installed and have created the schema's, but you've just done all that above (I hope) so we are ready to go. The installer now checks that you have all the required libraries installed and other system parameters are correct. Because nearly all of my development and evaluation installations have the database server on the same system, the installer passes these checks without issue... Next... Now chose where to install the IRM files, you must install into the same Middleware Home as the WebLogic Server installation you just performed. Usually the installer already defaults to this location anyway. I also tend to change the Oracle Home Directory to Oracle_IRM so it's clear this is just an IRM install. The summary page tells you about space needed to deploy the files. Unfortunately the IRM install comes with all of the other Oracle ECM software, you can't just select the IRM files, everything gets deployed to disk and uses 1.6GB of space! Not fun, but Oracle has to package up similar technologies otherwise we would have a very large number of installers to QA and manage, again, not fun. Hit Install, time for another drink, maybe a piece of cake or a donut... on a half decent system this part of the install took under 10 minutes. Finally the installation of your IRM server is complete, click on finish and the next phase is to create the WebLogic domain and start configuring your server. Now move onto the next article in this guide... configuring your IRM server ready to seal your first document.

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• CodePlex Daily Summary for Monday, April 19, 2010

  CodePlex Daily Summary for Monday, April 19, 2010New Projects8085 Microprocessor simulator: This program allows you to write 8085 programs in assembly and run those programs on your PC. It comes with lots of help, plus you can put breakpo...Additional.NET framework: The Additional.Net framework extends the functionality of the .NET framework for easier application development. It is developed in C#.Astoria Contrib: A contrib project for filling the gaps in WCF Data Services, providing missing functionality or augmenting with T4 templates, helpers, etc.ClipoWeb: ClipoWeb is a web clipboard that allows you to copy text and files between computers. Users access a web page on the source and destination compute...elearning Center: Đây là một ứng dụng web viết hoàn toàn bằng Sliverlight. Ứng dụng này là một dạng elearning với đầy đủ chức năng và có khả năng tương tác tối đa v...Excel VSTO SQL Server Browser: Get Data from SQL Server and put it in Excel directly. The objective is to get more control about what do you need to pull and create automatic pro...Generic Tree Structure: Generic Base Classes that helps you to create complex tree structures without writing it again and again. Simply to use Like "var Node<Folder> fold...LAN Lordz LAN Party System: The LAN Lordz LAN Party System makes it easier for medium and large size events to track their attendance, sponsors, door prizes, tournaments, and...LiteFx: O LiteFx é um framework que ajuda na implementação de DDD (anêmico ou rico) ele foi desenvolvido por Douglas Aguiar (http://twitter.com/DouglasAgui...Managed UI Flow for ASP.NET MVC Framework: If your web application getting more complex, understanding and managing of complex UI flows(pageflow of application) getting harder and harder, If...Meus Exemplos: Meus ExemplosOrchard Blueprint Theme: Orchard BluePrint is a project that provides a WYSIWYG reference implementation of a Orchard theme to help designers get started with theme design....Outlook Social Network Connector - Avatar: Avatar 是一个开源的MS Outlook的插件，豆瓣用户可以在Outlook 2010中使用豆瓣。查看一封邮件中相关的收件人、发件人的用户广播、同城活动以及豆邮。不用上豆瓣也能方便了解好友动态。这个插件使用C#， .NET 4.0 开发。API 请求认证使用OAuth 认证。 (Avat...Quadro Tree: This is Quadri tree library.Sharepoint 2010 Alert Controller: In MOSS 2007 or Sharepoint Server 2010 if you want to see your alerts by list name you should use this tool.SharePoint Web Parts: The goal of this project is to develop a set of web parts for SharePoint.Silverlight Image Cropper: This is a silverlight 4 util that makes it easy to crop out a number images of a specific resolution screen or screens. ie. an easy way to crop ...SilverlightFTP: Silverlight ftp clientsplibex: libraries for sharepoint lists manipulationStardustExtensions: Official Extensions for StardustSwim Team Manager: Swim Team Manager is designed for managing and tracking administrative and performance information for your club, school, or swim team. Swim Tea...ToDoListWpf: A To Do List, I used it to manage my work items. I am sorry for my poor English.Trance Layer: TranceLayer is a fast and flexible logging or diagnostics framework for .Net. It allows you to plug it into an existing or new application with m...Unoficcial NeoFM.hu NowPlaying: A little windows tray program. Shows what's on neofm.hu right now.WabbitStudio Z80 Software Tools: The software suite provides all of the tools you need to create high quality Z80 software in Z80 assembly language, with a focus on TI calculators....WinToolbar: Windows.Toolbar is Silverlight library that implements common widgets that allows us to build a rich toolbar control in our applications, it incor...XP-More: XP-More is a tool that helps manage Windows 7 Virtual Machines (XP Mode and any other). Specifically, it makes duplication of VMs a no brainer - no...Yodelay .NET Framework Extensions: The Yodelay .NET Framework Extensions project provides a library of components that make many kinds of programming tasks simpler. These include bas...New ReleasesClipoWeb: ClipoWeb 1.0: First Beta release of the ClipoWeb web applicationDDDSample.Net: 0.8: This release contains all four versions of DDDSample.Net available in previous, 0.7 and a brand new one: Layered Model version. Layered Model demon...DotNetNuke Blueprint: 00.00.02: Added to this version CSS Reset Skin version including Grids This version will soon be updated with corresponding HTML version and DNN templateEsferatec.Text.RegularExpressions: 3.5.1003.1001: first stable release of the class; the assembly file is ready to use, the documentation is complete;Excel VSTO SQL Server Browser: Sample Only: Sample without Ribbon UI, if you close the TaskPane you will no longer able to open it without restart ExcelFolder Bookmarks: Folder Bookmarks 1.5.5: This is the latest version of Folder Bookmarks (1.5.5), with the new Archive Manager and Archive Viewer. It has an installer - it will create a dir...Gardens Point LEX: Gardens Point LEX, Version 1.1.3: The main distribution is a zip file. This contains the binary executable, documentation, source code and the examples. ChangesVersion 1.1.3 corre...Gardens Point Parser Generator: Gardens Point Parser Generator V1.4.0: The distribution is a zip archive which contains the binary executables, documentation, source code and examples. ChangesVersion 1.4.0 of GPPG has...HKGolden Express: HKGoldenExpress (Build 201004181455): New features: Added rating of each topic. (Note: This feature is availabe since Build 201004172120) Bug fix: Handle invalid XML character in XML...Home Access Plus+: v4.0.0.0 Beta: v4.0.0.0 Beta Change Log: Moved to using .net 4.0 New Silverlight Uploader Various .net 4 fixes and tweaks File Changes: All fixes have changedHTML Ruby: 6.21.6: Reduced performance hit on pages with heavy DOM manipulations Fixed issue where empty tags caused it to apply invalid spacing values Stop spaci...LINQ to VFP: LinqToVfp (v1.0.17.2): Modified to allow using RecNo as a primary key. This build requires IQToolkit v0.17b.Managed UI Flow for ASP.NET MVC Framework: Preview 1: The source available on this site, does not reflect the final state of the project, it is a preview of what will be shipping in the framework in th...MVVM Light Toolkit: MVVM Light Toolkit V3 SP1 (2): Super minor update to accommodate the new Blend 4 RC. Only changes: The path to the Blend 4 templates changed to be "My Documents\Expression\Blend...N2 CMS: 2.0 rc: N2 is a lightweight CMS framework for ASP.NET. It helps you build great web sites that anyone can update. Major Changes (1.5 -> 2.0 release candid...OpenGL ES 2.0 Compact Framework Wrapper: Sample application CAB with texturing: This took some time as it was pretty hard to get the texture loaded and setup so that it would bind to the sampler2D in the fragment shader. Featu...Orchard Blueprint Theme: 00.00.01: This is the first release of this project, still in a very alpha version. Very soon this release is to be updated with the HTML version of the them...RoughJs: RoughJsSL: This is Silverlight library's CompilerSharepoint 2010 Alert Controller: Sharepoint 2010 Alert Controller: After you download WSP file you can get help from Home PageSharePoint LogViewer: SharePoint LogViewer 2.5: Minimize log viewer to tray Get popup notification of SharePoint log events from tray Redirect log entries to event log Send email notifications on...Site Directory for SharePoint 2010 (from Microsoft Consulting Services, UK): v1.1: This is a minor update which includes the following changes: Code consolidation across the whole project Additional site data captured. See solut...Stardust: Stardust 1.0: First stable version of Stardust (Build 172)StardustExtensions: Facebook Extension: Extension for stardust to upload and post images on Facebook.StardustExtensions: Facebook Extension (Source): The source code of an extension for Stardust used to post images on facebook.StardustExtensions: WPF Example: This is an example extension. Uses WPF to create a Window and say "Hello World!" Is a perfect download if want to start writing Stardust ExtensionsStardustExtensions: WPF Example Source: This is the source code of an extension that creates a Window using WPF & displays a simple text. Is great as an example of creating Stardust Exten...TFTP Server: TFTP Server 1.1 Beta installer: New MSI based installer Installs a TFTP service Supports multiple servers on different endpoints, with every server pointing to its own root di...TiledLib: TiledLib 1.1: This download is for prebuilt DLLs and a demo project. For the full source code, use the Source Code tab. Changes: Bug fixes in a few methods Ad...Trance Layer: TranceLayer Digger: Digger version is a beta. It is intended to be used as a demonstration of muscles while lacking a set of features that are in the docs. The set of ...uManage - Active Directory Self-Service Portal: uManage v1.2 (.NET 4.0 RTM): New Releasev1.2 Adds the Administrative Portal as well as the requirement of a MSSQL database (2005+). The Setup Wizard has also been updated to i...Unoficcial NeoFM.hu NowPlaying: NeoNotifier: First release. Aplha, but usable.VidCoder: 0.2.1: Changes: Added 2-pass encoding Fixed x264 options getting mangled during p-invoke Fixed intermittent crash with logging window open due to thre...WCF RIA Services Contrib: WCF RIA Services Contrib RC2 Release: This version is for the WCF RIA Services RC2 (SL4 RTM) release. The ApplyState has been modifed in this version to disable validation during proces...WiiCIS.NET: WiiCIS.NET v0.2: Changes... - Removal of WiimoteManager, connection must be done manually - Accelerometer orientation was originally in degrees, is now in radians -...WinToolbar: WinToolbar Source code plus sample: This zip file contains the current version source code and libraries plus a testrunner (sample app).XP-More: 0.9 (Beta): Most of the functionality is in place, final polishing will be done soon.Most Popular ProjectsFacebook Developer ToolkitWSPBuilder (SharePoint WSP tool)QuickGraph, Graph Data Structures And Algorithms for .NetPerformance Analysis of Logs (PAL) Toolpatterns & practices: Team Development with Visual Studio Team Foundation ServerTFS Integration Platformpatterns & practices: Performance Testing Guidance for Web Applicationspatterns & practices: Enterprise Library ContribJSON ViewerManaged Wifi APIMost Active ProjectsRawrpatterns & practices – Enterprise LibraryIndustrial DashboardIonics Isapi Rewrite FilterFarseer Physics EngineMVVM Light ToolkitjQuery Library for SharePoint Web ServicesN2 CMSCaliburn: An Application Framework for WPF and SilverlightBlogEngine.NET

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• Option Trading: Getting the most out of the event session options

  - by extended_events

  You can control different aspects of how an event session behaves by setting the event session options as part of the CREATE EVENT SESSION DDL. The default settings for the event session options are designed to handle most of the common event collection situations so I generally recommend that you just use the defaults. Like everything in the real world though, there are going to be a handful of “special cases” that require something different. This post focuses on identifying the special cases and the correct use of the options to accommodate those cases. There is a reason it’s called Default The default session options specify a total event buffer size of 4 MB with a 30 second latency. Translating this into human terms; this means that our default behavior is that the system will start processing events from the event buffer when we reach about 1.3 MB of events or after 30 seconds, which ever comes first. Aside: What’s up with the 1.3 MB, I thought you said the buffer was 4 MB?The Extended Events engine takes the total buffer size specified by MAX_MEMORY (4MB by default) and divides it into 3 equally sized buffers. This is done so that a session can be publishing events to one buffer while other buffers are being processed. There are always at least three buffers; how to get more than three is covered later. Using this configuration, the Extended Events engine can “keep up” with most event sessions on standard workloads. Why is this? The fact is that most events are small, really small; on the order of a couple hundred bytes. Even when you start considering events that carry dynamically sized data (eg. binary, text, etc.) or adding actions that collect additional data, the total size of the event is still likely to be pretty small. This means that each buffer can likely hold thousands of events before it has to be processed. When the event buffers are finally processed there is an economy of scale achieved since most targets support bulk processing of the events so they are processed at the buffer level rather than the individual event level. When all this is working together it’s more likely that a full buffer will be processed and put back into the ready queue before the remaining buffers (remember, there are at least three) are full. I know what you’re going to say: “My server is exceptional! My workload is so massive it defies categorization!” OK, maybe you weren’t going to say that exactly, but you were probably thinking it. The point is that there are situations that won’t be covered by the Default, but that’s a good place to start and this post assumes you’ve started there so that you have something to look at in order to determine if you do have a special case that needs different settings. So let’s get to the special cases… What event just fired?! How about now?! Now?! If you believe the commercial adage from Heinz Ketchup (Heinz Slow Good Ketchup ad on You Tube), some things are worth the wait. This is not a belief held by most DBAs, particularly DBAs who are looking for an answer to a troubleshooting question fast. If you’re one of these anxious DBAs, or maybe just a Program Manager doing a demo, then 30 seconds might be longer than you’re comfortable waiting. If you find yourself in this situation then consider changing the MAX_DISPATCH_LATENCY option for your event session. This option will force the event buffers to be processed based on your time schedule. This option only makes sense for the asynchronous targets since those are the ones where we allow events to build up in the event buffer – if you’re using one of the synchronous targets this option isn’t relevant. Avoid forgotten events by increasing your memory Have you ever had one of those days where you keep forgetting things? That can happen in Extended Events too; we call it dropped events. In order to optimizes for server performance and help ensure that the Extended Events doesn’t block the server if to drop events that can’t be published to a buffer because the buffer is full. You can determine if events are being dropped from a session by querying the dm_xe_sessions DMV and looking at the dropped_event_count field. Aside: Should you care if you’re dropping events?Maybe not – think about why you’re collecting data in the first place and whether you’re really going to miss a few dropped events. For example, if you’re collecting query duration stats over thousands of executions of a query it won’t make a huge difference to miss a couple executions. Use your best judgment. If you find that your session is dropping events it means that the event buffer is not large enough to handle the volume of events that are being published. There are two ways to address this problem. First, you could collect fewer events – examine you session to see if you are over collecting. Do you need all the actions you’ve specified? Could you apply a predicate to be more specific about when you fire the event? Assuming the session is defined correctly, the next option is to change the MAX_MEMORY option to a larger number. Picking the right event buffer size might take some trial and error, but a good place to start is with the number of dropped events compared to the number you’ve collected. Aside: There are three different behaviors for dropping events that you specify using the EVENT_RETENTION_MODE option. The default is to allow single event loss and you should stick with this setting since it is the best choice for keeping the impact on server performance low.You’ll be tempted to use the setting to not lose any events (NO_EVENT_LOSS) – resist this urge since it can result in blocking on the server. If you’re worried that you’re losing events you should be increasing your event buffer memory as described in this section. Some events are too big to fail A less common reason for dropping an event is when an event is so large that it can’t fit into the event buffer. Even though most events are going to be small, you might find a condition that occasionally generates a very large event. You can determine if your session is dropping large events by looking at the dm_xe_sessions DMV once again, this time check the largest_event_dropped_size. If this value is larger than the size of your event buffer [remember, the size of your event buffer, by default, is max_memory / 3] then you need a large event buffer. To specify a large event buffer you set the MAX_EVENT_SIZE option to a value large enough to fit the largest event dropped based on data from the DMV. When you set this option the Extended Events engine will create two buffers of this size to accommodate these large events. As an added bonus (no extra charge) the large event buffer will also be used to store normal events in the cases where the normal event buffers are all full and waiting to be processed. (Note: This is just a side-effect, not the intended use. If you’re dropping many normal events then you should increase your normal event buffer size.) Partitioning: moving your events to a sub-division Earlier I alluded to the fact that you can configure your event session to use more than the standard three event buffers – this is called partitioning and is controlled by the MEMORY_PARTITION_MODE option. The result of setting this option is fairly easy to explain, but knowing when to use it is a bit more art than science. First the science… You can configure partitioning in three ways: None, Per NUMA Node & Per CPU. This specifies the location where sets of event buffers are created with fairly obvious implication. There are rules we follow for sub-dividing the total memory (specified by MAX_MEMORY) between all the event buffers that are specific to the mode used: None: 3 buffers (fixed)Node: 3 * number_of_nodesCPU: 2.5 * number_of_cpus Here are some examples of what this means for different Node/CPU counts: Configuration None Node CPU 2 CPUs, 1 Node 3 buffers 3 buffers 5 buffers 6 CPUs, 2 Node 3 buffers 6 buffers 15 buffers 40 CPUs, 5 Nodes 3 buffers 15 buffers 100 buffers   Aside: Buffer size on multi-processor computersAs the number of Nodes or CPUs increases, the size of the event buffer gets smaller because the total memory is sub-divided into more pieces. The defaults will hold up to this for a while since each buffer set is holding events only from the Node or CPU that it is associated with, but at some point the buffers will get too small and you’ll either see events being dropped or you’ll get an error when you create your session because you’re below the minimum buffer size. Increase the MAX_MEMORY setting to an appropriate number for the configuration. The most likely reason to start partitioning is going to be related to performance. If you notice that running an event session is impacting the performance of your server beyond a reasonably expected level [Yes, there is a reasonably expected level of work required to collect events.] then partitioning might be an answer. Before you partition you might want to check a few other things: Is your event retention set to NO_EVENT_LOSS and causing blocking? (I told you not to do this.) Consider changing your event loss mode or increasing memory. Are you over collecting and causing more work than necessary? Consider adding predicates to events or removing unnecessary events and actions from your session. Are you writing the file target to the same slow disk that you use for TempDB and your other high activity databases? <kidding> <not really> It’s always worth considering the end to end picture – if you’re writing events to a file you can be impacted by I/O, network; all the usual stuff. Assuming you’ve ruled out the obvious (and not so obvious) issues, there are performance conditions that will be addressed by partitioning. For example, it’s possible to have a successful event session (eg. no dropped events) but still see a performance impact because you have many CPUs all attempting to write to the same free buffer and having to wait in line to finish their work. This is a case where partitioning would relieve the contention between the different CPUs and likely reduce the performance impact cause by the event session. There is no DMV you can check to find these conditions – sorry – that’s where the art comes in. This is  largely a matter of experimentation. On the bright side you probably won’t need to to worry about this level of detail all that often. The performance impact of Extended Events is significantly lower than what you may be used to with SQL Trace. You will likely only care about the impact if you are trying to set up a long running event session that will be part of your everyday workload – sessions used for short term troubleshooting will likely fall into the “reasonably expected impact” category. Hey buddy – I think you forgot something OK, there are two options I didn’t cover: STARTUP_STATE & TRACK_CAUSALITY. If you want your event sessions to start automatically when the server starts, set the STARTUP_STATE option to ON. (Now there is only one option I didn’t cover.) I’m going to leave causality for another post since it’s not really related to session behavior, it’s more about event analysis. - Mike Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• Lightning talk: Coderetreat

  - by Michael Williamson

  In the spirit of trying to encourage more deliberate practice amongst coders in Red Gate, Lauri Pesonen had the idea of running a coderetreat in Red Gate. Lauri and I ran the first one a few weeks ago: given that neither of us hadn’t even been to a coderetreat before, let alone run one, I think it turned out quite well. The participants gave positive feedback, saying that they enjoyed the day, wrote some thought-provoking code and would do it again. Sam Blackburn was one of the attendees, and gave a lightning talk to the other developers in one of our regular lightning talk sessions: In case you can’t watch the video, I’ve transcribed the talk below, although I’d recommend watching the video if you can — I didn’t have much time to do the transcribing! So, what is a coderetreat? So it’s not just something in Red Gate, there’s a website and everything, although it’s not a very big website. It calls itself a community network. The basic ideas behind coderetreat are: you’ve got one day, and you split it into one hour sections. You spend three quarters of that coding, and do a little retrospective at the end. You’re supposed to start fresh each, we were told to delete our code after every session. We were in pairs, swapping after each session, and we did the same task every time. In fact, Conway’s Game of Life is the only task mentioned anywhere that I find for coderetreat. So I don’t know what we’ll do next time, or if we’re meant to do the same thing again. There are some guiding principles which felt to us like restrictions, that you have to code in crazy ways to encourage better code. Final thing is that it’s supposed to be free for outsiders to join. It’s meant to be a kind of networking thing, where you link up with people from other companies. We had a pilot day with Michael and Lauri. Since it was basically the first time any of us had done anything like this, everybody was from Red Gate. We didn’t chat to anybody else for the initial one. The task was Conway’s Game of Life, which most of you have probably heard of it, all but one of us knew about it when did the coderetreat. I won’t got into the details of what it is, but it felt like the right size of task, basically one or two groups actually produced something working by the end of the day, and of course that doesn’t mean it’s necessarily a day’s work to produce that because we were starting again every hour. The task really drives you more than trying to create good code, I found. It was really tempting to try and get it working rather than stick to the rules. But it’s really good to stop and try again because there are so many what-ifs when you’ve finished writing something, “what if I’d done it this way?”. You can answer all those questions at a coderetreat because it’s not about getting a product out the door, it’s about learning and playing with ideas. So we had all these different practices we were trying. I’ll try and go through most of these. Single responsibility is this idea that everything should do just one thing. It was the very first session, we were still trying to figure out how do you go about the Game of Life? So by the end of forty-five minutes hadn’t produced very much for that first session. We were still thinking, “Do we start with a board, how do we represent all these squares? It can be infinitely big, help, this is getting really difficult!”. So, most of us didn’t really get anywhere on the first one. Although it was interesting that some people started with the board, one group started with the FateDecider class that decides whether things live or die. A sort of god class, but in a good way. They managed to implement all of the rules without even defining how the squares were arranged or anything like that. Another thing we tried was TDD (test-driven development). I’m sure most of you know what TDD is: Watch a test, watch it fail for the right reason Write code to pass the test, watch it pass Refactor, check the test still passes Repeat! It basically worked, we were able to produce code, but we often found the tests defined the direction that code went, which is obviously the idea of TDD. But you tend to find that by the time you’ve even written your first assertion, which is supposed to be the very first thing you write, because you write your tests backwards from the assertions back to the initial conditions, you’ve already constrained the logic of the code in some way by the time you’ve done that. You then get to this situation of, “Well, we actually want to go in a slightly different direction. Can we do this?”. Can we write tests that don’t constrain the architecture? Wrapping up all primitives: it’s kind of turtles all the way down. We had a Size, which has a Width and Height, which both derive from Dimension. You’ve got pages of code before you’ve even done anything. No getters and setters (use tell don’t ask instead): mocks and stubs for tests are required if you want to assert that your results are what you think they should be. You can’t just check the internal state of the code. And people found that really challenging and it made them think in a different way which I think is really good. Not having mutable state: that was kind of confusing because we weren’t quite sure what fitted within that rule and what didn’t, and I think we were trying too hard to follow the rule rather than the guideline. No if-statements: supposed to use polymorphism instead, but polymorphism still requires a factory with conditional behaviour. We did something really crazy to get around this: public T If(bool condition, Func<T> left, Func<T> right) { var dict = new Dictionary<bool, Func<T>> {{true, left}, {false, right}}; return dict[condition].Invoke(); } That is not really polymorphism, is it? For-loops: you can always replace a for-loop with recursion, but it doesn’t tend to make it any more readable unless it’s the kind of task that really lends itself to that. So it was interesting, it was good practice, but it wouldn’t make it easier it’s the kind of tree-structure algorithm where that would help. Having a limit on the number of levels of indentation: again, I think it does produce very nice, clean code, but it wasn’t actually a challenge because you just extract methods. That’s quite a useful thing because you can apply that to real code and say, “Okay, should this method really be going crazy like this?” No talking: we hated that. It’s like there’s two of you at a computer, and one of you is doing the typing, what does the other guy do if they’re not allowed to talk. The answer is TDD ping-pong – one person writes the tests, and then the other person writes the code to pass the test. And that creates communication without actually having to have discussion about things which is kind of cool. No code comments: just makes no difference to anything. It’s a forty-five minute exercise, so what are you going to put comments in code for? Finally, this is my fault. I discovered an entertaining way of doing the calculation that was kind of cool (using convolutions over the state of the board). Unfortunately, it turns out to be really hard to implement in C#, so didn’t even manage to work out how to do that convolution in C#. It’s trivial in some high-level languages, but you need something matrix-orientated for it to really work. That’s most of it, really. The thoughts that people went away with: we put down our answers to questions like “What have you learnt?” and “What surprised you?”, “How are you going to do things differently?”, and most people said redoing the problem is really, really good for understanding it properly. People hate having a massive legacy codebase that they can’t change, so being able to attack something three different ways in an environment where the end-product isn’t important: that’s something people really enjoyed. Pair-programming: also people said that they wanted to do more of that, especially with TDD ping-pong, where you write the test and somebody else writes the code. Various people thought different things about immutables, but most people thought they were good, they promote functional programming. And TDD people found really hard. “Tell, don’t ask” people found really, really hard and really, really, really hard to do well. And the recursion just made things trickier to debug. But most people agreed that coderetreats are really cool, and we should do more of them.

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• Following the Thread in OSB

  - by Antony Reynolds

  Threading in OSB The Scenario I recently led an OSB POC where we needed to get high throughput from an OSB pipeline that had the following logic: 1. Receive Request 2. Send Request to External System 3. If Response has a particular value   3.1 Modify Request   3.2 Resend Request to External System 4. Send Response back to Requestor All looks very straightforward and no nasty wrinkles along the way.  The flow was implemented in OSB as follows (see diagram for more details): Proxy Service to Receive Request and Send Response Request Pipeline   Copies Original Request for use in step 3 Route Node   Sends Request to External System exposed as a Business Service Response Pipeline   Checks Response to Check If Request Needs to Be Resubmitted Modify Request Callout to External System (same Business Service as Route Node) The Proxy and the Business Service were each assigned their own Work Manager, effectively giving each of them their own thread pool. The Surprise Imagine our surprise when, on stressing the system we saw it lock up, with large numbers of blocked threads.  The reason for the lock up is due to some subtleties in the OSB thread model which is the topic of this post.   Basic Thread Model OSB goes to great lengths to avoid holding on to threads.  Lets start by looking at how how OSB deals with a simple request/response routing to a business service in a route node. Most Business Services are implemented by OSB in two parts.  The first part uses the request thread to send the request to the target.  In the diagram this is represented by the thread T1.  After sending the request to the target (the Business Service in our diagram) the request thread is released back to whatever pool it came from.  A multiplexor (muxer) is used to wait for the response.  When the response is received the muxer hands off the response to a new thread that is used to execute the response pipeline, this is represented in the diagram by T2. OSB allows you to assign different Work Managers and hence different thread pools to each Proxy Service and Business Service.  In out example we have the “Proxy Service Work Manager” assigned to the Proxy Service and the “Business Service Work Manager” assigned to the Business Service.  Note that the Business Service Work Manager is only used to assign the thread to process the response, it is never used to process the request. This architecture means that while waiting for a response from a business service there are no threads in use, which makes for better scalability in terms of thread usage. First Wrinkle Note that if the Proxy and the Business Service both use the same Work Manager then there is potential for starvation.  For example: Request Pipeline makes a blocking callout, say to perform a database read. Business Service response tries to allocate a thread from thread pool but all threads are blocked in the database read. New requests arrive and contend with responses arriving for the available threads. Similar problems can occur if the response pipeline blocks for some reason, maybe a database update for example. Solution The solution to this is to make sure that the Proxy and Business Service use different Work Managers so that they do not contend with each other for threads. Do Nothing Route Thread Model So what happens if there is no route node?  In this case OSB just echoes the Request message as a Response message, but what happens to the threads?  OSB still uses a separate thread for the response, but in this case the Work Manager used is the Default Work Manager. So this is really a special case of the Basic Thread Model discussed above, except that the response pipeline will always execute on the Default Work Manager.   Proxy Chaining Thread Model So what happens when the route node is actually calling a Proxy Service rather than a Business Service, does the second Proxy Service use its own Thread or does it re-use the thread of the original Request Pipeline? Well as you can see from the diagram when a route node calls another proxy service then the original Work Manager is used for both request pipelines.  Similarly the response pipeline uses the Work Manager associated with the ultimate Business Service invoked via a Route Node.  This actually fits in with the earlier description I gave about Business Services and by extension Route Nodes they “… uses the request thread to send the request to the target”. Call Out Threading Model So what happens when you make a Service Callout to a Business Service from within a pipeline.  The documentation says that “The pipeline processor will block the thread until the response arrives asynchronously” when using a Service Callout.  What this means is that the target Business Service is called using the pipeline thread but the response is also handled by the pipeline thread.  This implies that the pipeline thread blocks waiting for a response.  It is the handling of this response that behaves in an unexpected way. When a Business Service is called via a Service Callout, the calling thread is suspended after sending the request, but unlike the Route Node case the thread is not released, it waits for the response.  The muxer uses the Business Service Work Manager to allocate a thread to process the response, but in this case processing the response means getting the response and notifying the blocked pipeline thread that the response is available.  The original pipeline thread can then continue to process the response. Second Wrinkle This leads to an unfortunate wrinkle.  If the Business Service is using the same Work Manager as the Pipeline then it is possible for starvation or a deadlock to occur.  The scenario is as follows: Pipeline makes a Callout and the thread is suspended but still allocated Multiple Pipeline instances using the same Work Manager are in this state (common for a system under load) Response comes back but all Work Manager threads are allocated to blocked pipelines. Response cannot be processed and so pipeline threads never unblock – deadlock! Solution The solution to this is to make sure that any Business Services used by a Callout in a pipeline use a different Work Manager to the pipeline itself. The Solution to My Problem Looking back at my original workflow we see that the same Business Service is called twice, once in a Routing Node and once in a Response Pipeline Callout.  This was what was causing my problem because the response pipeline was using the Business Service Work Manager, but the Service Callout wanted to use the same Work Manager to handle the responses and so eventually my Response Pipeline hogged all the available threads so no responses could be processed. The solution was to create a second Business Service pointing to the same location as the original Business Service, the only difference was to assign a different Work Manager to this Business Service.  This ensured that when the Service Callout completed there were always threads available to process the response because the response processing from the Service Callout had its own dedicated Work Manager. Summary Request Pipeline Executes on Proxy Work Manager (WM) Thread so limited by setting of that WM.  If no WM specified then uses WLS default WM. Route Node Request sent using Proxy WM Thread Proxy WM Thread is released before getting response Muxer is used to handle response Muxer hands off response to Business Service (BS) WM Response Pipeline Executes on Routed Business Service WM Thread so limited by setting of that WM.  If no WM specified then uses WLS default WM. No Route Node (Echo functionality) Proxy WM thread released New thread from the default WM used for response pipeline Service Callout Request sent using proxy pipeline thread Proxy thread is suspended (not released) until the response comes back Notification of response handled by BS WM thread so limited by setting of that WM.  If no WM specified then uses WLS default WM. Note this is a very short lived use of the thread After notification by callout BS WM thread that thread is released and execution continues on the original pipeline thread. Route/Callout to Proxy Service Request Pipeline of callee executes on requestor thread Response Pipeline of caller executes on response thread of requested proxy Throttling Request message may be queued if limit reached. Requesting thread is released (route node) or suspended (callout) So what this means is that you may get deadlocks caused by thread starvation if you use the same thread pool for the business service in a route node and the business service in a callout from the response pipeline because the callout will need a notification thread from the same thread pool as the response pipeline.  This was the problem we were having. You get a similar problem if you use the same work manager for the proxy request pipeline and a business service callout from that request pipeline. It also means you may want to have different work managers for the proxy and business service in the route node. Basically you need to think carefully about how threading impacts your proxy services. References Thanks to Jay Kasi, Gerald Nunn and Deb Ayers for helping to explain this to me.  Any errors are my own and not theirs.  Also thanks to my colleagues Milind Pandit and Prasad Bopardikar who travelled this road with me. OSB Thread Model Great Blog Post on Thread Usage in OSB

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• First toe in the water with Object Databases : DB4O

  - by REA_ANDREW

  I have been wanting to have a play with Object Databases for a while now, and today I have done just that.  One of the obvious choices I had to make was which one to use.  My criteria for choosing one today was simple, I wanted one which I could literally wack in and start using, which means I wanted one which either had a .NET API or was designed/ported to .NET.  My decision was between two being: db4o MongoDb I went for db4o for the single reason that it looked like I could get it running and integrated the quickest.  I am making a Blogging application and front end as a project with which I can test and learn with these object databases.  Another requirement which I thought I would mention is that I also want to be able to use the said database in a shared hosting environment where I cannot install, run and maintain a server instance of said object database.  I can do exactly this with db4o. I have not tried to do this with MongoDb at time of writing.  There are quite a few in the industry now and you read an interesting post about different ones and how they are used with some of the heavy weights in the industry here : http://blog.marcua.net/post/442594842/notes-from-nosql-live-boston-2010 In the example which I am building I am using StructureMap as my IOC.  To inject the object for db4o I went with a Singleton instance scope as I am using a single file and I need this to be available to any thread on in the process as opposed to using the server implementation where I could open and close client connections with the server handling each one respectively.  Again I want to point out that I have chosen to stick with the non server implementation of db4o as I wanted to use this in a shared hosting environment where I cannot have such servers installed and run.     public static class Bootstrapper    {        public static void ConfigureStructureMap()        {            ObjectFactory.Initialize(x => x.AddRegistry(new MyApplicationRegistry()));        }    }    public class MyApplicationRegistry : Registry    {        public const string DB4O_FILENAME = "blog123";        public string DbPath        {            get            {                return Path.Combine(Path.GetDirectoryName(Assembly.GetAssembly(typeof(IBlogRepository)).Location), DB4O_FILENAME);            }        }        public MyApplicationRegistry()        {            For<IObjectContainer>().Singleton().Use(                () => Db4oEmbedded.OpenFile(Db4oEmbedded.NewConfiguration(), DbPath));            Scan(assemblyScanner =>            {                assemblyScanner.TheCallingAssembly();                assemblyScanner.WithDefaultConventions();            });        }    } So my code above is the structure map plumbing which I use for the application.  I am doing this simply as a quick scratch pad to play around with different things so I am simply segregating logical layers with folder structure as opposed to different assemblies.  It will be easy if I want to do this with any segment but for the purposes of example I have literally just wacked everything in the one assembly.  You can see an example file structure I have on the right.  I am planning on testing out a few implementations of the object databases out there so I can program to an interface of IBlogRepository One of the things which I was unsure about was how it performed under a multi threaded environment which it will undoubtedly be used 9 times out of 10, and for the reason that I am using the db context as a singleton, I assumed that the library was of course thread safe but I did not know as I have not read any where in the documentation, again this is probably me not reading things correctly.  In short though I threw together a simple test where I simply iterate to a limit each time kicking a common task off with a thread from a thread pool.  This task simply created and added an random Post and added it to the storage. The execution of the threads I put inside the Setup of the Test and then simply ensure the number of posts committed to the database is equal to the number of iterations I made; here is the code I used to do the multi thread jobs: [TestInitialize] public void Setup() { var sw = new System.Diagnostics.Stopwatch(); sw.Start(); var resetEvent = new ManualResetEvent(false); ThreadPool.SetMaxThreads(20, 20); for (var i = 0; i < MAX_ITERATIONS; i++) { ThreadPool.QueueUserWorkItem(delegate(object state) { var eventToReset = (ManualResetEvent)state; var post = new Post { Author = MockUser, Content = "Mock Content", Title = "Title" }; Repository.Put(post); var counter = Interlocked.Decrement(ref _threadCounter); if (counter == 0) eventToReset.Set(); }, resetEvent); } WaitHandle.WaitAll(new[] { resetEvent }); sw.Stop(); Console.WriteLine("{0:00}.{1:00} seconds", sw.Elapsed.Seconds, sw.Elapsed.Milliseconds); }   I was not doing this to test out the speed performance of db4o but while I was doing this I could not help but put in a StopWatch and see out of sheer interest how fast it would take to insert a number of Posts.  I tested it out in this case with 10000 inserts of a small, simple POCO and it resulted in an average of:  899.36 object inserts / second.  Again this is just  simple crude test which came out of my curiosity at how it performed under many threads when using the non server implementation of db4o. The spec summary of the computer I used is as follows: With regards to the actual Repository implementation itself, it really is quite straight forward and I have to say I am very surprised at how easy it was to integrate and get up and running.  One thing I have noticed in the exposure I have had so far is that the Query returns IList<T> as opposed to IQueryable<T> but again I have not looked into this in depth and this could be there already and if not they have provided everything one needs to make there own repository.  An example of a couple of methods from by db4o implementation of the BlogRepository is below: public class BlogRepository : IBlogRepository { private readonly IObjectContainer _db; public BlogRepository(IObjectContainer db) { _db = db; } public void Put(DomainObject obj) { _db.Store(obj); } public void Delete(DomainObject obj) { _db.Delete(obj); } public Post GetByKey(object key) { return _db.Query<Post>(post => post.Key == key).FirstOrDefault(); } … Anyways I hope to get a few more implementations going of the object databases and literally just get familiarized with them and the concept of no sql databases. Cheers for now, Andrew

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• Clustering Basics and Challenges

  - by Karoly Vegh

  For upcoming posts it seemed to be a good idea to dedicate some time for cluster basic concepts and theory. This post misses a lot of details that would explode the articlesize, should you have questions, do not hesitate to ask them in the comments.  The goal here is to get some concepts straight. I can't promise to give you an overall complete definitions of cluster, cluster agent, quorum, voting, fencing, split brain condition, so the following is more of an explanation. Here we go. -------- Cluster, HA, failover, switchover, scalability -------- An attempted definition of a Cluster: A cluster is a set (2+) server nodes dedicated to keep application services alive, communicating through the cluster software/framework with eachother, test and probe health status of servernodes/services and with quorum based decisions and with switchover/failover techniques keep the application services running on them available. That is, should a node that runs a service unexpectedly lose functionality/connection, the other ones would take over the and run the services, so that availability is guaranteed. To provide availability while strictly sticking to a consistent clusterconfiguration is the main goal of a cluster.  At this point we have to add that this defines a HA-cluster, a High-Availability cluster, where the clusternodes are planned to run the services in an active-standby, or failover fashion. An example could be a single instance database. Some applications can be run in a distributed or scalable fashion. In the latter case instances of the application run actively on separate clusternodes serving servicerequests simultaneously. An example for this version could be a webserver that forwards connection requests to many backend servers in a round-robin way. Or a database running in active-active RAC setup.  -------- Cluster arhitecture, interconnect, topologies -------- Now, what is a cluster made of? Servers, right. These servers (the clusternodes) need to communicate. This of course happens over the network, usually over dedicated network interfaces interconnecting all the clusternodes. These connection are called interconnects.How many clusternodes are in a cluster? There are different cluster topologies. The most simple one is a clustered pair topology, involving only two clusternodes:  There are several more topologies, clicking the image above will take you to the relevant documentation. Also, to answer the question Solaris Cluster allows you to run up to 16 servers in a cluster. Where shall these clusternodes be placed? A very important question. The right answer is: It depends on what you plan to achieve with the cluster. Do you plan to avoid only a server outage? Then you can place them right next to eachother in the datacenter. Do you need to avoid DataCenter outage? In that case of course you should place them at least in different fire zones. Or in two geographically distant DataCenters to avoid disasters like floods, large-scale fires or power outages. We call this a stretched- or campus cluster, the clusternodes being several kilometers away from eachother. To cover really large distances, you probably need to move to a GeoCluster, which is a different kind of animal.  What is a geocluster? A Geographic Cluster in Solaris Cluster terms is actually a metacluster between two, separate (locally-HA) clusters.  -------- Cluster resource types, agents, resources, resource groups -------- So how does the cluster manage my applications? The cluster needs to start, stop and probe your applications. If you application runs, the cluster needs to check regularly if the application state is healthy, does it respond over the network, does it have all the processes running, etc. This is called probing. If the cluster deems the application is in a faulty state, then it can try to restart it locally or decide to switch (stop on node A, start on node B) the service. Starting, stopping and probing are the three actions that a cluster agent does. There are many different kinds of agents included in Solaris Cluster, but you can build your own too. Examples are an agent that manages (mounts, moves) ZFS filesystems, or the Oracle DB HA agent that cares about the database, or an agent that moves a floating IP address between nodes. There are lots of other agents included for Apache, Tomcat, MySQL, Oracle DB, Oracle Weblogic, Zones, LDoms, NFS, DNS, etc.We also need to clarify the difference between a cluster resource and the cluster resource group.A cluster resource is something that is managed by a cluster agent. Cluster resource types are included in Solaris cluster (see above, e.g. HAStoragePlus, HA-Oracle, LogicalHost). You can group cluster resources into cluster resourcegroups, and switch these groups together from one node to another. To stick to the example above, to move an Oracle DB service from one node to another, you have to switch the group between nodes, and the agents of the cluster resources in the group will do the following:  On node A Shut down the DB Unconfigure the LogicalHost IP the DB Listener listens on unmount the filesystem   Then, on node B: mount the FS configure the IP  startup the DB -------- Voting, Quorum, Split Brain Condition, Fencing, Amnesia -------- How do the clusternodes agree upon their action? How do they decide which node runs what services? Another important question. Running a cluster is a strictly democratic thing.Every node has votes, and you need the majority of votes to have the deciding power. Now, this is usually no problem, clusternodes think very much all alike. Still, every action needs to be governed upon in a productive system, and has to be agreed upon. Agreeing is easy as long as the clusternodes all behave and talk to eachother over the interconnect. But if the interconnect is gone/down, this all gets tricky and confusing. Clusternodes think like this: "My job is to run these services. The other node does not answer my interconnect communication, it must be down. I'd better take control and run the services!". The problem is, as I have already mentioned, clusternodes very much think alike. If the interconnect is gone, they all assume the other node is down, and they all want to mount the data backend, enable the IP and run the database. Double IPs, double mounts, double DB instances - now that is trouble. Also, in a 2-node cluster they both have only 50% of the votes, that is, they themselves alone are not allowed to run a cluster.  This is where you need a quorum device. According to Wikipedia, the "requirement for a quorum is protection against totally unrepresentative action in the name of the body by an unduly small number of persons.". They need additional votes to run the cluster. For this requirement a 2-node cluster needs a quorum device or a quorum server. If the interconnect is gone, (this is what we call a split brain condition) both nodes start to race and try to reserve the quorum device to themselves. They do this, because the quorum device bears an additional vote, that could ensure majority (50% +1). The one that manages to lock the quorum device (e.g. if it's an FC LUN, it SCSI reserves it) wins the right to build/run a cluster, the other one - realizing he was late - panics/reboots to ensure the cluster config stays consistent.  Losing the interconnect isn't only endangering the availability of services, but it also endangers the cluster configuration consistence. Just imagine node A being down and during that the cluster configuration changes. Now node B goes down, and node A comes up. It isn't uptodate about the cluster configuration's changes so it will refuse to start a cluster, since that would lead to cluster amnesia, that is the cluster had some changes, but now runs with an older cluster configuration repository state, that is it's like it forgot about the changes.  Also, to ensure application data consistence, the clusternode that wins the race makes sure that a server that isn't part of or can't currently join the cluster can access the devices. This procedure is called fencing. This usually happens to storage LUNs via SCSI reservation.  Now, another important question: Where do I place the quorum disk?  Imagine having two sites, two separate datacenters, one in the north of the city and the other one in the south part of it. You run a stretched cluster in the clustered pair topology. Where do you place the quorum disk/server? If you put it into the north DC, and that gets hit by a meteor, you lose one clusternode, which isn't a problem, but you also lose your quorum, and the south clusternode can't keep the cluster running lacking the votes. This problem can't be solved with two sites and a campus cluster. You will need a third site to either place the quorum server to, or a third clusternode. Otherwise, lacking majority, if you lose the site that had your quorum, you lose the cluster. Okay, we covered the very basics. We haven't talked about virtualization support, CCR, ClusterFilesystems, DID devices, affinities, storage-replication, management tools, upgrade procedures - should those be interesting for you, let me know in the comments, along with any other questions. Given enough demand I'd be glad to write a followup post too. Now I really want to move on to the second part in the series: ClusterInstallation.  Oh, as for additional source of information, I recommend the documentation: http://docs.oracle.com/cd/E23623_01/index.html, and the OTN Oracle Solaris Cluster site: http://www.oracle.com/technetwork/server-storage/solaris-cluster/index.html

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• CodePlex Daily Summary for Saturday, October 13, 2012

  CodePlex Daily Summary for Saturday, October 13, 2012Popular ReleasesArduino Installer For Atmel Studio 6: Arduino Installer - Version 1.01 Beta2: Bug Fixes - Handling spaces in avrdude path - Handling spaces in avrdude config path - Handling spaces in project names - Handling spaces in project path - hard coded directories pointing to my space has been removed New Features - Total of 7 project templates included - C program - C library - C++ program - C++ library - Arduino Unit Tests - Arduino library - Arduino program (sketch) - Group all supporting scripts under a script directory in the solution - Support for calling multiple pre-...AcDown????? - AcDown Downloader Framework: AcDown????? v4.2: ??●AcDown??????????、??、??、???????。????，????，?????????????????????????。???????????Acfun、????(Bilibili)、??、??、YouTube、??、???、??????、SF????、????????????。 ●??????AcPlay?????，??????、????????????????。 ● AcDown??????????????????，????????????????????????????。 ● AcDown???????C#??，????.NET Framework 2.0??。?????"Acfun?????"。 ????32??64? Windows XP/Vista/7/8 ???? 32??64? ???Linux ????(1)????????Windows XP???，????????.NET Framework 2.0???(x86)，?????"?????????"??? (2)???????????Linux???，????????Mono?? ??2...PHPExcel: PHPExcel 1.7.8: See Change Log for details of the new features and bugfixes included in this release, and methods that are now deprecated. Note changes to the PDF Writer: tcPDF is no longer bundled with PHPExcel, but should be installed separately if you wish to use that 3rd-Party library with PHPExcel. Alternatively, you can choose to use mPDF or DomPDF as PDF Rendering libraries instead: PHPExcel now provides a configurable wrapper allowing you a choice of PDF renderer. See the documentation, or the PDF s...DirectX Tool Kit: October 12, 2012: October 12, 2012 Added PrimitiveBatch for drawing user primitives Debug object names for all D3D resources (for PIX and debug layer leak reporting)Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.70: Fixed issue described in discussion #399087: variable references within case values weren't getting resolved.GoogleMap Control: GoogleMap Control 6.1: Some important bug fixes and couple of new features were added. There are no major changes to the sample website. Source code could be downloaded from the Source Code section selecting branch release-6.1. Thus just builds of GoogleMap Control are issued here in this release. NuGet Package GoogleMap Control 6.1 NuGet Package FeaturesBounds property to provide ability to create a map by center and bounds as well; Setting in markup <artem:GoogleMap ID="GoogleMap1" runat="server" MapType="HY...mojoPortal: 2.3.9.3: see release notes on mojoportal.com http://www.mojoportal.com/mojoportal-2393-released Note that we have separate deployment packages for .NET 3.5 and .NET 4.0, but we recommend you to use .NET 4, we will probably drop support for .NET 3.5 once .NET 4.5 is available The deployment package downloads on this page are pre-compiled and ready for production deployment, they contain no C# source code and are not intended for use in Visual Studio. To download the source code see getting the lates...OstrivDB: OstrivDB 0.1: - Storage configuration: objects serialization (Xml, Json), storage file compressing, data block size. - Caching for Select queries. - Indexing. - Batch of queries. - No special query language (LINQ used). - Integrated sorting and paging. - Multithreaded data processing.D3 Loot Tracker: 1.5.4: Fixed a bug where the server ip was not logged properly in the stats file.Captcha MVC: Captcha Mvc 2.1.2: v 2.1.2: Fixed problem with serialization. Made all classes from a namespace Jetbrains.Annotaions as the internal. Added autocomplete attribute and autocorrect attribute for captcha input element. Minor changes. v 2.1.1: Fixed problem with serialization. Minor changes. v 2.1: Added support for storing captcha in the session or cookie. See the updated example. Updated example. Minor changes. v 2.0.1: Added support for a partial captcha. Now you can easily customize the layout, s...DotNetNuke® Community Edition CMS: 06.02.04: Major Highlights Fixed issue where the module printing function was only visible to administrators Fixed issue where pane level skinning was being assigned to a default container for any content pane Fixed issue when using password aging and FB / Google authentication Fixed issue that was causing the DateEditControl to not load the assigned value Fixed issue that stopped additional profile properties to be displayed in the member directory after modifying the template Fixed er...Advanced DataGridView with Excel-like auto filter: 1.0.0.0: ?????? ??????WinRT XAML Toolkit: WinRT XAML Toolkit - 1.3.3: WinRT XAML Toolkit based on the Windows 8 RTM SDK. Download the latest source from the SOURCE CODE page. For compiled version use NuGet. You can add it to your project in Visual Studio by going to View/Other Windows/Package Manager Console and entering: PM> Install-Package winrtxamltoolkit Features Attachable Behaviors AwaitableUI extensions Controls Converters Debugging helpers Extension methods Imaging helpers IO helpers VisualTree helpers Samples Recent changes NOTE:...VidCoder: 1.4.4 Beta: Fixed inability to create new presets with "Save As".MCEBuddy 2.x: MCEBuddy 2.3.2: Changelog for 2.3.2 (32bit and 64bit) 1. Added support for generating XBMC XML NFO files for files in the conversion queue (store it along with the source video with source video name.nfo). Right click on the file in queue and select generate XML 2. UI bugifx, start and end trim box locations interchanged 3. Added support for removing commercials from non DVRMS/WTV files (MP4, AVI etc) 4. Now checking for Firewall port status before enabling (might help with some firewall problems) 5. User In...Sandcastle Help File Builder: SHFB v1.9.5.0 with Visual Studio Package: General InformationIMPORTANT: On some systems, the content of the ZIP file is blocked and the installer may fail to run. Before extracting it, right click on the ZIP file, select Properties, and click on the Unblock button if it is present in the lower right corner of the General tab in the properties dialog. This release supports the Sandcastle October 2012 Release (v2.7.1.0). It includes full support for generating, installing, and removing MS Help Viewer files. This new release suppor...The GLMET Project: Shutdown Manager: Shutdown, Log off and Restart Timer Set time for shutdown, log off and restartClosedXML - The easy way to OpenXML: ClosedXML 0.68.0: ClosedXML now resolves formulas! Yes it finally happened. If you call cell.Value and it has a formula the library will try to evaluate the formula and give you the result. For example: var wb = new XLWorkbook(); var ws = wb.AddWorksheet("Sheet1"); ws.Cell("A1").SetValue(1).CellBelow().SetValue(1); ws.Cell("B1").SetValue(1).CellBelow().SetValue(1); ws.Cell("C1").FormulaA1 = "\"The total value is: \" & SUM(A1:B2)"; var...Json.NET: Json.NET 4.5 Release 10: New feature - Added Portable build to NuGet package New feature - Added GetValue and TryGetValue with StringComparison to JObject Change - Improved duplicate object reference id error message Fix - Fixed error when comparing empty JObjects Fix - Fixed SecAnnotate warnings Fix - Fixed error when comparing DateTime JValue with a DateTimeOffset JValue Fix - Fixed serializer sometimes not using DateParseHandling setting Fix - Fixed error in JsonWriter.WriteToken when writing a DateT...Readable Passphrase Generator: KeePass Plugin 0.7.2: Changes: Tested against KeePass 2.20.1 Tested under Ubuntu 12.10 (and KeePass 2.20) Added GenerateAsUtf8 method returning the encrypted passphrase as a UTF8 byte array.New ProjectsAaron.Core: It's a special core be used to help your project become standardization. It provides the standard platform, including core systems, data flows,...AFSSignarlRServer: Server ready tryAgileFramework: Agile Framework in order to build easily application based on WCF, NHibernate , WPF, and multithreadingala, A Programming Language: ala, A Programming LanguageBaseSRS (Basic Service Request System): BaseSRS is a basic "Service Request System" or "SRS" which can be adapted and used by anyone. ContainerVariations: ContainerVariations is a collection of similar unit tests projects, each applied to a different Inversion of Control container. If successful, it will provide a consistent and comprehensive set of examples for popular .NET IoC containers. It is developed in C#.COST Policies - ART Work: COST Policies: ART Work ? ??????? ?????? ?? ??????? ?? ??????????: -baceCP -guideCPCS Script Runner: Provide users an easy way of executing C# programs (scripts) that are compiled on the fly.DbUtility: DbUtility is a free utility to display databases info like, size, backup date, instance name, database name, last backup log date, with export to excel feature.EchoLink Monitor: EchoLink Monitor is a management tool for EchoLink sysops maintaining remote EchoLink nodes.NextUI: We are on the way...Notas Alexandre: Apenas teste ainda...será modificado depois...Orchard CMS Amba.HtmlBlocks: Amba.HtmlBlocks module for Orchard CMS 1.5.1Portable Basemap Server: multiple map data source<--PBS-->multiple map apiRonYee: ??????????????。 ????（viewer）???????????????????，???????????????。 ????（customer）?????????????????，???????，?????????????????。 ??????（user）??????????????????。ShangWu: ????，???StoreIpAddress: Examine different means to store IP addressesSummon for Umbraco: Summon for Umbraco is a .NET solution for Summon API, provided by Serials Solutions.teasingg: this is for testing code plexWeb Scripting and Content Creation assignment: A stub project.WriteableBitmapEx for Windows Embedded: WriteableBitmapEx for Windows Embedded Compact 7 and Silverlight for Windows Embedded. Requires XAML In The Hand for managed code development.X.Web.Sitemap: X.Web.Sitemap is a part of X-Framework library. X.Web.Sitemap allows quickly and easily generate a Google-compatible filesZeropaste: A pastebin with minimal features.??: ?????EPUB????。

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• Software Engineering Practices &ndash; Different Projects should have different maturity levels

  - by Dylan Smith

  I’ve had a lot of discussions at the office lately about the drastically different sets of software engineering practices used on our various projects, if what we are doing is appropriate, and what factors should you be considering when determining what practices are most appropriate in a given context. I wanted to write up my thoughts in a little more detail on this subject, so here we go: If you compare any two software projects (specifically comparing their codebases) you’ll often see very different levels of maturity in the software engineering practices employed. By software engineering practices, I’m specifically referring to the quality of the code and the amount of technical debt present in the project. Things such as Test Driven Development, Domain Driven Design, Behavior Driven Development, proper adherence to the SOLID principles, etc. are all practices that you would expect at the mature end of the spectrum. At the other end of the spectrum would be the quick-and-dirty solutions that are done using something like an Access Database, Excel Spreadsheet, or maybe some quick “drag-and-drop coding”. For this blog post I’m going to refer to this as the Software Engineering Maturity Spectrum (SEMS). I believe there is a time and a place for projects at every part of that SEMS. The risks and costs associated with under-engineering solutions have been written about a million times over so I won’t bother going into them again here, but there are also (unnecessary) costs with over-engineering a solution. Sometimes putting multiple layers, and IoC containers, and abstracting out the persistence, etc is complete overkill if a one-time use Access database could solve the problem perfectly well. A lot of software developers I talk to seem to automatically jump to the very right-hand side of this SEMS in everything they do. A common rationalization I hear is that it may seem like a small trivial application today, but these things always grow and stick around for many years, then you’re stuck maintaining a big ball of mud. I think this is a cop-out. Sure you can’t always anticipate how an application will be used or grow over its lifetime (can you ever??), but that doesn’t mean you can’t manage it and evolve the underlying software architecture as necessary (even if that means having to toss the code out and re-write it at some point…maybe even multiple times). My thoughts are that we should be making a conscious decision around the start of each project approximately where on the SEMS we want the project to exist. I believe this decision should be based on 3 factors: 1. Importance - How important to the business is this application? What is the impact if the application were to suddenly stop working? 2. Complexity - How complex is the application functionality? 3. Life-Expectancy - How long is this application expected to be in use? Is this a one-time use application, does it fill a short-term need, or is it more strategic and is expected to be in-use for many years to come? Of course this isn’t an exact science. You can’t say that Project X should be at the 73% mark on the SEMS and expect that to be helpful. My point is not that you need to precisely figure out what point on the SEMS the project should be at then translate that into some prescriptive set of practices and techniques you should be using. Rather my point is that we need to be aware that there is a spectrum, and that not everything is going to be (or should be) at the edges of that spectrum, indeed a large number of projects should probably fall somewhere within the middle; and different projects should adopt a different level of software engineering practices and maturity levels based on the needs of that project. To give an example of this way of thinking from my day job: Every couple of years my company plans and hosts a large event where ~400 of our customers all fly in to one location for a multi-day event with various activities. We have some staff whose job it is to organize the logistics of this event, which includes tracking which flights everybody is booked on, arranging for transportation to/from airports, arranging for hotel rooms, name tags, etc The last time we arranged this event all these various pieces of data were tracked in separate spreadsheets and reconciliation and cross-referencing of all the data was literally done by hand using printed copies of the spreadsheets and several people sitting around a table going down each list row by row. Obviously there is some room for improvement in how we are using software to manage the event’s logistics. The next time this event occurs we plan to provide the event planning staff with a more intelligent tool (either an Excel spreadsheet or probably an Access database) that can track all the information in one location and make sure that the various pieces of data are properly linked together (so for example if a person cancels you only need to delete them from one place, and not a dozen separate lists). This solution would fall at or near the very left end of the SEMS meaning that we will just quickly create something with very little attention paid to using mature software engineering practices. If we examine this project against the 3 criteria I listed above for determining it’s place within the SEMS we can see why: Importance – If this application were to stop working the business doesn’t grind to a halt, revenue doesn’t stop, and in fact our customers wouldn’t even notice since it isn’t a customer facing application. The impact would simply be more work for our event planning staff as they revert back to the previous way of doing things (assuming we don’t have any data loss). Complexity – The use cases for this project are pretty straightforward. It simply needs to manage several lists of data, and link them together appropriately. Precisely the task that access (and/or Excel) can do with minimal custom development required. Life-Expectancy – For this specific project we’re only planning to create something to be used for the one event (we only hold these events every 2 years). If it works well this may change (see below). Let’s assume we hack something out quickly and it works great when we plan the next event. We may decide that we want to make some tweaks to the tool and adopt it for planning all future events of this nature. In that case we should examine where the current application is on the SEMS, and make a conscious decision whether something needs to be done to move it further to the right based on the new objectives and goals for this application. This may mean scrapping the access database and re-writing it as an actual web or windows application. In this case, the life-expectancy changed, but let’s assume the importance and complexity didn’t change all that much. We can still probably get away with not adopting a lot of the so-called “best practices”. For example, we can probably still use some of the RAD tooling available and might have an Autonomous View style design that connects directly to the database and binds to typed datasets (we might even choose to simply leave it as an access database and continue using it; this is a decision that needs to be made on a case-by-case basis). At Anvil Digital we have aspirations to become a primarily product-based company. So let’s say we use this tool to plan a handful of events internally, and everybody loves it. Maybe a couple years down the road we decide we want to package the tool up and sell it as a product to some of our customers. In this case the project objectives/goals change quite drastically. Now the tool becomes a source of revenue, and the impact of it suddenly stopping working is significantly less acceptable. Also as we hold focus groups, and gather feedback from customers and potential customers there’s a pretty good chance the feature-set and complexity will have to grow considerably from when we were using it only internally for planning a small handful of events for one company. In this fictional scenario I would expect the target on the SEMS to jump to the far right. Depending on how we implemented the previous release we may be able to refactor and evolve the existing codebase to introduce a more layered architecture, a robust set of automated tests, introduce a proper ORM and IoC container, etc. More likely in this example the jump along the SEMS would be so large we’d probably end up scrapping the current code and re-writing. Although, if it was a slow phased roll-out to only a handful of customers, where we collected feedback, made some tweaks, and then rolled out to a couple more customers, we may be able to slowly refactor and evolve the code over time rather than tossing it out and starting from scratch. The key point I’m trying to get across is not that you should be throwing out your code and starting from scratch all the time. But rather that you should be aware of when and how the context and objectives around a project changes and periodically re-assess where the project currently falls on the SEMS and whether that needs to be adjusted based on changing needs. Note: There is also the idea of “spectrum decay”. Since our industry is rapidly evolving, what we currently accept as mature software engineering practices (the right end of the SEMS) probably won’t be the same 3 years from now. If you have a project that you were to assess at somewhere around the 80% mark on the SEMS today, but don’t touch the code for 3 years and come back and re-assess its position, it will almost certainly have changed since the right end of the SEMS will have moved farther out (maybe the project is now only around 60% due to decay). Developer Skills Another important aspect to this whole discussion is around the skill sets of your architects and lead developers. When talking about the progression of a developers skills from junior->intermediate->senior->… they generally start by only being able to write code that belongs on the left side of the SEMS and as they gain more knowledge and skill they become capable of working at a higher and higher level along the SEMS. We all realize that the learning never stops, but eventually you’ll get to the point where you can comfortably develop at the right-end of the SEMS (the exact practices and techniques that translates to is constantly changing, but that’s not the point here). A critical skill that I’d love to see more evidence of in our industry is the most senior guys not only being able to work at the right-end of the SEMS, but more importantly be able to consciously work at any point along the SEMS as project needs dictate. An even more valuable skill would be if you could make the conscious decision to move a projects code further right on the SEMS (based on changing needs) and do so in an incremental manner without having to start from scratch. An exercise that I’m planning to go through with all of our projects here at Anvil in the near future is to map out where I believe each project currently falls within this SEMS, where I believe the project *should* be on the SEMS based on the business needs, and for those that don’t match up (i.e. most of them) come up with a plan to improve the situation.

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