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• Rendering problem with UITableview

  - by Spider-Paddy

  I have a very strange problem with a UITableview within a navigation controller on the iPhone simulator. Of the cells displayed, only some are correctly rendered. They are all supposed to look the same but the majority are missing the accessory I've set, scrolling the view changes which cell has the accessory so I suspect it's some sort of cell caching happening, although the contents are correct for each cell. I also set an image as the background and that was also only displaying sporadically but I fixed that by changing cell.backgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"yellow-bar_short.png"]]; (which also only rendered a random cell with the background) to cell.backgroundColor = [[UIColor alloc] initWithPatternImage:[UIImage imageNamed:@"yellow-bar_short.png"]]; I now need to fix the problem with the accessory only showing on a random cell. I tried moving the code from cellForRowAtIndex to willDisplayCell but it made no difference. I put in a log command to confirm that it is running through each frame. Basically it's a table view (UITableViewCellStyleSubtitle) that gets its info from a server & is then updated by a delegate method calling reload. Code is: -(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath { NSLog(@"%@", [NSString stringWithFormat:@"Setting colours for cell %i", indexPath.row]); // Set cell background // cell.backgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"yellow-bar_short.png"]]; cell.backgroundColor = [[UIColor alloc] initWithPatternImage:[UIImage imageNamed:@"yellow-bar_short.png"]]; cell.textLabel.backgroundColor = [UIColor clearColor]; cell.detailTextLabel.backgroundColor = [UIColor clearColor]; // detailTableViewAccessory is a view containing an imageview in this view's nib // i.e. nib <- view <- imageview <- image cell.accessoryView = detailTableViewAccessory; } // Called by data fetching object when done -(void)listDataTransferComplete:(ArticleListParser *)articleListParserObject { NSLog(@"Data parsed, reloading detail table"); self.currentTotalResultPages = (((articleListParserObject.currentArticleCount - 1) / 10) + 1); self.detailTableDataSource = [articleListParserObject.returnedArray copy]; // make a local copy of the returned array // Render table again with returned array data (neither of these 2 fixed it) [self.detailTableView performSelectorOnMainThread:@selector(reloadData) withObject:nil waitUntilDone:NO]; // [self.detailTableView reloadData]; // Re-enable necessary buttons (including table cells) letUserSelectRow = TRUE; [btnByName setEnabled:TRUE]; [btnByPrice setEnabled:TRUE]; // Remove please wait message NSLog(@"Removing please wait view"); [pleaseWaitViewControllerObject.view removeFromSuperview]; } I only included code that I thought was relevant, can supply more if needed. I can't test it on an iPhone yet so I don't know if it's maybe just a simulator anomaly or a bug in my code. I've always gotten good feedback from questions, any ideas?

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• ASP.NET MVC Inheriting from ProfileBase

  - by Glen

  I have 2 related issues. I inherited from ProfileBase and I have a couple of properites as such public SomeType PropertyName { get { return (SomeType)base["PropertyName"]; } set { base["PropertyName"] = value; Save(); } } I also have a User class (UserId, UserName, Profile, LastActivityDate) that has 2 additional properties out of the profile that I retrieve in my View to show a list of Users (i.e. @Model.Profile.PropertyName). However, everytime I access a property (from my View) it seems to update the LastActivityDate in the aspnet_Users table because when I show the LastActivityDate as well as the profile properties on my screen the LastActivtyDate is out of sync with the database. Also there is a LastActivityDate property available in my profile which unfortunately is not available and is in fact set to null and throws an exception when accessing it saying the property UserName is null. So the static Create method provided by ProfileBase seems to retrieve the correct profile properties but does not set the base's UserName property even though you pass in a UserName parameter to the Create method. Is this a internal bug? I was kind of hoping if by accessing the property because the LastActivityDate is updated then I could store that value to update my LastActivityDate in my User class before it is rendered to the page. The only way I can think of doing it is: public SomeType PropertyName { get { SomeType result = (SomeType)base["PropertyName"]; OnLastActivityDateChanged(); return result; } set { base["PropertyName"] = value; } } then in my User class: ... public MyProfile() { Profile.LastActivityDateChanged += Profile_LastActivityDateChanged(); } ~MyProfile() { Profile.LastActivityDateChanged -= Profile_LastActivityDateChanged(); } ... void Profile_LastActivityDateChanged(object sender, EventArgs e) { //Run a query to get the latest LastActivityDate this.LastActivityDate = ... } It seems I have to make 1 call to retrieve the full list to my aspnet_Users table then another call for each row just to get the latest activity date. ARGGGGHHH!!! Am I going about this the wrong way! I put an ajax refresh hyperlink next to each User row and when I click it, immediately after loading the page, the value changes. Therefore my suspision is valid that calling a property via the inherited profilebase class updates the value. Is there a workaround? It is a bit miss leading when my page says User Smith has no activity for 4 days then I click my ajax refresh link (or refresh the whole page for that matter) and now it says Smith was active but it was just me meally showing the page that indirectly caused an activity read event.

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• Interconnecting Emulator Instances Android

  - by blah01

  Hi all I want to communicate two emulators via DatagramSocket in Android. Each of them is a Node in a P2P system. Thus each of them has a server Thread and client Thread (created per GUI event). This is how I create server public static final String SERVERIP = "10.0.2.15"; //... run() { InetAddress serverAddr = InetAddress.getByName(SERVERIP); DatagramSocket socket = new DatagramSocket(SERVERPORT,serverAddr); while(true) { byte[] buf = new byte[29]; DatagramPacket packet = new DatagramPacket(buf, buf.length); socket.receive(packet); //... } } The port is given by the user during initializing application. The client part (requesting some data) InetAddress serverAddr = InetAddress.getByName("10.0.2.2"); //... Log.i("Requester", "Trying to connect to device port = "+target); DatagramSocket socketJ = new DatagramSocket(); byte[] bufJ = Adaptor.createStringMsg(Adaptor.createJoingMsg(id, Location.getX(), Location.getY())).getBytes(); DatagramPacket packetJ = new DatagramPacket(bufJ, bufJ.length, serverAddr, target); Log.i("Requester", "Sending: '" + new String(bufJ) + "'"); socketJ.send(packetJ); Log.i("Requester", "Done."); Some additional info. The Node1 (emulatorA) has a server on port 8000 and Node2 (emulatorB) has a server on port 8001. The target port for "client part" is read properly. What tried to do is to set the redirection as such: //emulatorA redir add tcp:8000:8000 //emulatorB redir add tcp:8001:8001 However I can not get any communication beetwen those 2 emulators. As far as I understood the android tutorial about it should work like this redir add tcp:localhostPort:emulatorPort. I'm stuck with it :/. Can anyone point me the mistake or give some good advice. For the record while I was testing communication on a single device (client faking other node) everything worked, so I don't think there is a bug in the code. Btw does any one knows how can I get 2 set of logs for those 2 emulators (logA, logB)? It would help me a lot.

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• iPhone - NSURLConnection does not receive data

  - by Jukurrpa

  Hi, I have a pretty weird problem with NSURLRequest. I'm using them to make an asynchronous image loading in an UITableView. The first time the tableView displays, all connections from NSURLRequests open correctly but receive absolutely no data, regardless of how long I wait. But as soon as I scroll down in the tableView, the newly created requests for the new cells work perfectly! The only way for the images on top of the tableView to load is to make them disappear by scrolling down and then up again, in order to create new requests. Here is what I do in "cellForRowAtIndexPath": UITableViewCell* cell = [tableView dequeueReusableCellWithIdentifier:@"Cell"]; if (cell == nil) { cell = [[UITableViewCell alloc] initWIthFrame:CGRectMake(0, 0, 300, 60)]; AsyncUIImageView imageView = [[AsynUIImageView alloc] initWithFrame:CGRectMake(0, 0, 60, 60)]; imageView.tag = IMG_VIEW // an enum for tags [cell addSubView:imageView]; [imageView release]; } AsyncUIImageView imageView = (AsyncUIImageView*)[cell viewWithTag:IMG_VIEW]; // I do a few cache checks here, but if the image aint cached I do this: [imageView loadImageFromURL:@"http://someurl.com/somepix.jpg"]; // all urls are different, just an example The AsyncUIImageView inherits from UIImageView and contains an NSURLConnection which opens upon calling the loadImageFromURL method: (void) loadImageFromURL:(NSString*)filename { if (self.connection != nil) [self.connection release]; if (self.data != nil) [self.data release]; NSURLRequest* request = [NSURLRequest requestWithURL:[[NSURL alloc] initWithString:fileName] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10.0]; self.connection = [[NSURLConnection alloc] initWithRequest:request delegate:self]; if (self.connection == nil) return; self.data = [[NSMutableData data] retain]; } I've created the delegate methods "connection: didReceiveData", which appends received data to self.data and "connectionDidFinishLoading" which sets the image and closes the connection once the transfer is complete. These work, but are never called for the first requests I create. I suspect this bug to come from the main thread not giving the first requests the control so they can execute themselves, as the same behavior happens if I keep my finger on the screen after a scroll: connections open themselves, but no data is received until I stop touching the screen. What am I doing wrong?

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• dojo dgrid tree, subrows in wrong position

  - by Ventura

  I have a dgrid, working with tree column plugin. Every time that the user click on the tree, I call the server, catch the subrows(json) and bind it. But when it happens, these subrows are show in wrong position, like the image bellow. The most strange is when I change the pagination, after go back to first page, the subrows stay on the correct place. (please, tell me if is possible to understand my english, then I can try to improve the text) My dgrid code: var CustomGrid = declare([OnDemandGrid, Keyboard, Selection, Pagination]); var grid = new CustomGrid({ columns: [ selector({label: "#", disabled: function(object){ return object.type == 'DOCx'; }}, "radio"), {label:'Id', field:'id', sortable: false}, tree({label: "Title", field:"title", sortable: true, indentWidth:20, allowDuplicates:true}), //{label:'Title', field:'title', sortable: false}, {label:'Count', field:'count', sortable: false} ], store: this.memoryStore, collapseOnRefresh:true, pagingLinks: false, pagingTextBox: true, firstLastArrows: true, pageSizeOptions: [10, 15, 25], selectionMode: "single", // for Selection; only select a single row at a time cellNavigation: false // for Keyboard; allow only row-level keyboard navigation }, "grid"); My memory store: loadMemoryStore: function(items){ this.memoryStore = Observable(new Memory({ data: items, getChildren: function(parent, options){ return this.query({parent: parent.id}, options); }, mayHaveChildren: function(parent){ return (parent.count != 0) && (parent.type != 'DOC'); } })); }, This moment I am binding the subrows: success: function(data){ for(var i=0; i<data.report.length; i++){ this.memoryStore.put({id:data.report[i].id, title:data.report[i].created, type:'DOC', parent:this.designId}); } }, I was thinking, maybe every moment that I bind the subrows, I could do like a refresh on the grid, maybe works. I think that the pagination does the same thing. Thanks. edit: I forgot the question. Well, How can I correct this bug? If The refresh in dgrid works. How can I do it? Other thing that I was thinking, maybe my getChildren is wrong, but I could not identify it. thanks again.

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• ie8 playing funny with list-style-position: inside

  - by LeeR

  Ok, So problem here... when using list-style-position:inside in IE8 the first like is indented but every line after that is not. So the new lines appear under the bullet. This is fine, but when I use a list with that css applied with an a tag within the li then the text automatically gets pushed to the second line, and the first line is empty. When I remove the a tag from the li then it jumps back up. Any idea on why this might be or is this a bug in the ie8 world or do I just need to double check my css? Any insights would be much appreciated. As asked here is some code <div id="sub_nav"> <ul> ... <li><a class="active_page" href="#">Liposculpture</a> <ul> <li><a href="#">What is Liposculpture?</a></li> <li><a href="#">About Liposculpture surgery</a></li> <li><a href="#" class="active_sub">After Liposculpture surgery</a></li> <li><a href="#">Post Op Instructions</a></li> <li><a href="#">Liposculpture Side Effects</a></li> <li><a href="#">Liposuction Introduction to</a></li> <li><a href="#">Tumescent Liposculpture</a></li> </ul> </li> ... </ul> </div> For the CSS I will try and show it best I can #sub_nav li { width: 200px; padding:4px 0; border-bottom: 1px #CCC solid; } #sub_nav li a { text-decoration: none; color:#555; padding:7px 15px 7px 15px; display: block; } #sub_nav li ul li { list-style-position: inside; list-style-type: disc; font: 11px Arial; padding-left:15px; color:#FFF; border-bottom: none; } #sub_nav li ul li a { padding:0; margin:0; text-indent: 0; } Hope this helps

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• Unity JS - simple if statements not behaving as expected?

  - by IHazABone

  I have a simple script (please no remarks on the fact that I'm not using a switch statement or better code, this is the earliest version and written this way by a peer, I am improving it) that takes an object and moves it back and forth. For some reason, the variable time gets stuck at 249. It is probably an obvious bug with this inefficient logic, but I cannot seem to find it. var speed = 1; private var time = 0; function Start() { } function Update() { if(condition == true)moveStuff(); } function moveStuff() { var timeSwitch = false; if(time == 0)timeSwitch = false; if(time == timeSet)timeSwitch = true; if(direction == 1) { if(timeSwitch == false) { transform.Translate(Vector3.up * (Time.deltaTime * speed)); time += 1; Debug.Log(time); }else if(timeSwitch == true) { transform.Translate(Vector3.up * ((Time.deltaTime * speed) * -1)); time -= 1; Debug.Log(time); } } else if(direction == 2) { if(timeSwitch == false) { transform.Translate(Vector3.down * (Time.deltaTime * speed)); time += 1; Debug.Log("Moved down. "); }else if(timeSwitch == true){ transform.Translate(Vector3.down * ((Time.deltaTime * speed) * -1)); time -= 1; } } else if(direction == 3) { if(timeSwitch == false) { transform.Translate(Vector3.forward * (Time.deltaTime * speed)); time += 1; Debug.Log("Moved forward. "); }else if(timeSwitch == true){ transform.Translate(Vector3.forward * ((Time.deltaTime * speed) * -1)); time -= 1; } } else if(direction == 4) { if(timeSwitch == false) { transform.Translate(Vector3.back * (Time.deltaTime * speed)); time += 1; Debug.Log("Moved back. "); }else if(timeSwitch == true){ transform.Translate(Vector3.back * ((Time.deltaTime * speed) * -1)); time -= 1; } } else if(direction == 5) { if(timeSwitch == false) { transform.Translate(Vector3.right * (Time.deltaTime * speed)); time += 1; Debug.Log("Moved right. "); }else if(timeSwitch == true){ transform.Translate(Vector3.right * ((Time.deltaTime * speed) * -1)); time -= 1; } } else if(direction == 6) { if(timeSwitch == false) { transform.Translate(Vector3.left * (Time.deltaTime * speed)); time += 1; Debug.Log("Moved left. "); }else if(timeSwitch == true){ transform.Translate(Vector3.left * ((Time.deltaTime * speed) * -1)); time -= 1; } } }

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• Is typeid of type name always evaluated at compile time in c++ ?

  - by cyril42e

  I wanted to check that typeid is evaluated at compile time when used with a type name (ie typeid(int), typeid(std::string)...). To do so, I repeated in a loop the comparison of two typeid calls, and compiled it with optimizations enabled, in order to see if the compiler simplified the loop (by looking at the execution time which is 1us when it simplifies instead of 160ms when it does not). And I get strange results, because sometimes the compiler simplifies the code, and sometimes it does not. I use g++ (I tried different 4.x versions), and here is the program: #include <iostream> #include <typeinfo> #include <time.h> class DisplayData {}; class RobotDisplay: public DisplayData {}; class SensorDisplay: public DisplayData {}; class RobotQt {}; class SensorQt {}; timespec tp1, tp2; const int n = 1000000000; int main() { int avg = 0; clock_gettime(CLOCK_REALTIME, &tp1); for(int i = 0; i < n; ++i) { // if (typeid(RobotQt) == typeid(RobotDisplay)) // (1) compile time // if (typeid(SensorQt) == typeid(SensorDisplay)) // (2) compile time if (typeid(RobotQt) == typeid(RobotDisplay) || typeid(SensorQt) == typeid(SensorDisplay)) // (3) not compile time ???!!! avg++; else avg--; } clock_gettime(CLOCK_REALTIME, &tp2); std::cout << "time (" << avg << "): " << (tp2.tv_sec-tp1.tv_sec)*1000000000+(tp2.tv_nsec-tp1.tv_nsec) << " ns" << std::endl; } The conditions in which this problem appear are not clear, but: - if there is no inheritance involved, no problem (always compile time) - if I do only one comparison, no problem - the problem only appears only with a disjunction of comparisons if all the terms are false So is there something I didn't get with how typeid works (is it always supposed to be evaluated at compilation time when used with type names?) or may this be a gcc bug in evaluation or optimization? About the context, I tracked down the problem to this very simplified example, but my goal is to use typeid with template types (as partial function template specialization is not possible). Thanks for your help!

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• jquery animation problem using stop

  - by Flanders

  Hi! When running a Jquery animation like slideDown(), it looks like a number of element-specific css properties is set to be updated at a specific interval and when the animation is complete these properties are unset and the display property is simply set to auto or whatever. At least in firebug you can't see those temporary properties any more. The problem I've encountered is the scenario where we stop the slide down with stop(). The element is then left with the current temporary css values. Which is fine because it has to, but let us say that I stoped the slidedown because I have decided to slide it back up again a bit prematurely. It would look something like this: $(this).slideDown(2000) //The below events is not in queue but will rather start execute almost simultaneously as the above line. (dont remember the exact syntax) $(this).delay(1000).stop().slideUp(2000) The above code might not make much sense, but the point is: After 1 second of sliding down the animation is stopped and it starts to slide back up. Works like a charm. BUT!!! And here is the problem. Once it it has slid back up the elements css properties are reset to the exact values it had 1000ms into the slideDown() animation (when stop() was called). If we now try to run the following: $(this).slideDown(2000) It will slide down to the very point the prior slideDown was aborted and not further at half the speed (since it uses the same time for approximately half the height). This is because the css properties were saved as I see it. But it is not especially wished for. Of course I want it to slide all the way down this time. Due to UI interaction that is hard to predict everything might soon break. The longer animations we use increases the risk of something like this happening. Is this to be considered a bug, or am I doing something wrong? Or maybe it's just a feature that is not supported? I guess I can use a callback function to reset the css properties, but depending on the animation used, different css properties are used to render it, and covering your back would result in quite a not-so-fancy solution.

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• JPanel's child components paint/layout problem

  - by Tom Brito

  I'm having a problem that when my frame is shown (after a login dialog) the buttons are not on correct position, then in some miliseconds they go to the right position (the center of the panel with border layout). When I make a SSCCE, it works correct, but when I run my whole code I have this fast-miliseconds delay to the buttons to go to the correct place. Unfortunately, I can't post the whole code, but the method that shows the frame is: public void login(JComponent userView) { centerPanel.removeAll(); centerPanel.add(userView); centerPanel.revalidate(); centerPanel.repaint(); frame.setVisible(true); } What would cause this delay to the panel layout? (I'm running everything in the EDT) -- update In my machine, this SSCCE shows the layout problem in 2 of 10 times I run it: import java.awt.BorderLayout; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.SwingUtilities; public class TEST { public static void main(String[] args) throws Exception { SwingUtilities.invokeAndWait(new Runnable() { @Override public void run() { System.out.println("Debug test..."); JPanel btnPnl = new JPanel(); btnPnl.add(new JButton("TEST")); JFrame f = new JFrame("TEST"); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.getContentPane().setLayout(new BorderLayout()); f.getContentPane().add(btnPnl); f.pack(); f.setSize(800, 600); f.setVisible(true); System.out.println("End debug test!"); } }); } } The button first appers in the up-left, and then it goes to the center. Please, note that I'm understand, not just correct. Is it a java bug? --update OK, so the SSCCE don't show the problem with you that tried till now. Maybe it's my computer performance problem. But this don't answer the question, I still think Java Swing is creating new threads for make the layout behind the scenes.

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• onDateSet does not get called from DatePickerDialog on tablet

  - by cit

  I am using a DatePickerDialog to prompt the user for a date. It works fine in the simulator and on my Samsung Galaxy Nexus, but onDateSet does not get called on my Samsung Galaxy Tab 2. I noticed, that the dialog is bigger and shows a calendar besides the normal spin view. Can that be the problem? Here is some code: import java.util.Calendar; import java.util.Date; import android.app.DatePickerDialog; import android.app.Dialog; import android.content.DialogInterface; import android.content.Intent; import android.os.Bundle; import android.support.v4.app.DialogFragment; import android.widget.DatePicker; import com.cbit.gtbetapp.R; import com.cbit.gtbetapp.gui.racedata.MeetingDataActivity; import com.cbit.gtbetapp.gui.racedata.MeetingListFragment; import com.cbit.gtbetapp.logic.Utility; public class DatePickerFragment extends DialogFragment implements DatePickerDialog.OnDateSetListener { protected Date date = null; @Override public Dialog onCreateDialog(Bundle savedInstanceState) { // Use the current date as the default date in the picker final Calendar c = Utility.getToday(); int year = c.get(Calendar.YEAR); int month = c.get(Calendar.MONTH); int day = c.get(Calendar.DAY_OF_MONTH); date = c.getTime(); // Create a new instance of DatePickerDialog and return it DatePickerDialog dialog = new DatePickerDialog(getActivity(), this, year, month, day) { @Override public void onDateChanged(DatePicker view, int year, int month, int day) { super.onDateChanged(view, year, month, day); setTitle(getString(R.string.date_picker_title)); } }; dialog.setTitle(getString(R.string.date_picker_title)); dialog.setButton(DatePickerDialog.BUTTON_POSITIVE, getString(android.R.string.ok), new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.cancel(); Intent intent = new Intent(getActivity(), MeetingDataActivity.class); intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); intent.putExtra(MeetingListFragment.EXTRA_DATE, date.getTime()); startActivity(intent); } }); dialog.setButton(DatePickerDialog.BUTTON_NEGATIVE, getString(R.string.button_cancel), new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.cancel(); } }); return dialog; } public void onDateSet(DatePicker view, int year, int month, int day) { Calendar c = Calendar.getInstance(); c.clear(); c.set(Calendar.YEAR, year); c.set(Calendar.MONTH, month); c.set(Calendar.DAY_OF_MONTH, day); date = c.getTime(); } } What could cause this? A bug in the tablet? Am I missing something? Can anyone think of a workaround? Thanks a lot!

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• C: copying some structs causes strange behavior

  - by Jenny B

  I have an annoying bug in the line rq->tickets[rq->usedContracts] = toAdd; if i do: rq->tickets[0] = toAdd the program crashes if i do rq->tickets[1] = toAdd; it works valgrind says ==19501== Use of uninitialised value of size 8 and ==19501== Invalid write of size 8 for this very line. What is wrong? struct TS_element { int travels; int originalTravels; int cost; char** dates; int moneyLeft; } TicketSet; struct RQ_element { int usedContracts; struct TS_element* tickets; } RabQav; TicketSetStatus tsCreate(TicketSet* t, int n, int c) { if (n <= 0) return TS_ILLEGAL_PARAMETER; TicketSet* myTicketSet = (TicketSet*) malloc(sizeof(TicketSet)); if (myTicketSet == NULL) { return TS_CANNOT_CREATE; } myTicketSet->usedTravels = 0; myTicketSet->originalTravels = n; myTicketSet->cost = c; myTicketSet->moneyLeft = n * c; char** dates = malloc(sizeof(char**)* (n)); //todo maybe c99 allows dynamic arrays? for (int i = 0; i < n; i++) { dates[i] = malloc(sizeof(char)*GOOD_LENGTH+1); if (dates[i] == NULL) { free(dates); free(t); return TS_CANNOT_CREATE; } } myTicketSet->dates = dates; *t = *myTicketSet; return TS_SUCCESS; } static void copyTicketSets(TicketSet* dest, const TicketSet* source) { dest->usedTravels = source->usedTravels; dest->originalTravels = source->originalTravels; dest->cost = source->cost; dest->moneyLeft = source->moneyLeft; for (int i = 0; i < source->originalTravels; i++) { if (NULL != source->dates[i]) { free(dest->dates[i]); dest->dates[i] = malloc(sizeof(char) * GOOD_LENGTH + 1); if (dest->dates[i] == NULL) { free(dest->dates); //todo free dates 0...i-1 free(dest); return; } strcpy(dest->dates[i], source->dates[i]); } } } RabQavStatus rqLoadTS(RabQav* rq, TicketSet t, DateTime dt) { TicketSet toAdd; TicketSetStatus res = tsCreate(&toAdd, t.originalTravels, t.cost); if (res != TS_SUCCESS) { return RQ_FAIL; } copyTicketSets(&toAdd, &t); rq->tickets[rq->usedContracts] = toAdd; rq->usedContracts++; return RQ_SUCCESS; }

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• Detect if class has overloaded function fails on Comeau compiler

  - by Frank

  Hi Everyone, I'm trying to use SFINAE to detect if a class has an overloaded member function that takes a certain type. The code I have seems to work correctly in Visual Studio and GCC, but does not compile using the Comeau online compiler. Here is the code I'm using: #include <stdio.h> //Comeau doesnt' have boost, so define our own enable_if_c template<bool value> struct enable_if_c { typedef void type; }; template<> struct enable_if_c< false > {}; //Class that has the overloaded member function class TestClass { public: void Func(float value) { printf( "%f\n", value ); } void Func(int value) { printf( "%i\n", value ); } }; //Struct to detect if TestClass has an overloaded member function for type T template<typename T> struct HasFunc { template<typename U, void (TestClass::*)( U )> struct SFINAE {}; template<typename U> static char Test(SFINAE<U, &TestClass::Func>*); template<typename U> static int Test(...); static const bool Has = sizeof(Test<T>(0)) == sizeof(char); }; //Use enable_if_c to only allow the function call if TestClass has a valid overload for T template<typename T> typename enable_if_c<HasFunc<T>::Has>::type CallFunc(TestClass &test, T value) { test.Func( value ); } int main() { float value1 = 0.0f; int value2 = 0; TestClass testClass; CallFunc( testClass, value1 ); //Should call TestClass::Func( float ) CallFunc( testClass, value2 ); //Should call TestClass::Func( int ) } The error message is: no instance of function template "CallFunc" matches the argument list. It seems that HasFunc::Has is false for int and float when it should be true. Is this a bug in the Comeau compiler? Am I doing something that's not standard? And if so, what do I need to do to fix it?

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• Android: Stopping method to be called twice if already running.

  - by user285831

  I'm trying to prevent my application to call the same method twice in the event of a double-click, or if the user presses different buttons quickly, almost at the same time. I have clickable Views, acting as buttons, that call the same method but passing different parameters. This is the call: startTheSearch(context, getState(), what, where); Inside this method I'm creating a new Thread, because it queries a web server for the result: new Thread(new Runnable() { public void run() { progDiag = ProgressDialog.show(ctx, null, "Searching", true); getServerXML(context, what, where, searchIsCustom, mOffset); handler.sendEmptyMessage(0); } }).start(); The problem is that upon two quick clicks, the method is fired twice, two threads are created, and consequently two new activities are created. That makes my app crash. When the methods are done, and we have the result from the server, we call the handler: private Handler handler = new Handler() { @Override public void handleMessage(Message msg) { super.handleMessage(msg); try { Intent i = new Intent(Golf.this, Result.class); Bundle b = new Bundle(); b.putString("what", mWhat); b.putString("where", mWhere); b.putInt("offset", mOffset); b.putBoolean("searchIsCustom", searchIsCustom); i.putExtras(b); startActivityForResult(i, Activity.RESULT_OK); progDiag.dismiss(); } catch (Exception e) { Alerts.generalDialogAlert("Error", "settings", ctx); } } }; I tried to have a global boolean variable called "blocked" initially set to false, creating a condition like: if(!blocked){ blocked = true; new Thread(new Runnable() { public void run() { But this only seems to work on slower phones like the G1, I tried on Nexus and before it set blocked = true, the second request has was granted. So is there any way I can block the method being called if it's already running, or if the thread has started so it wont create a new one? Please, I really need to fix this. I've been developing on Android for almost 2 months now, but I'm yet to tackle that bug. Thanks in advance.

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• Javascript .removeChild() only deletes even nodes?

  - by user1476297

  first posting. I am trying dynamically add children DIV under a DIV with ID="prnt". Addition of nodes work fine no problem. However strange enough when it comes to deleted nodes its only deleting the even numbered nodes including 0. Why is this, I could be something stupid but it seem more like a bug. I could be very wrong. Please help Thank you in advance. <script type="text/javascript"> function displayNodes() { var prnt = document.getElementById("prnt"); var chlds = prnt.childNodes; var cont = document.getElementById("content"); for(i = 0; i < chlds.length; i++) { if(chlds[i].nodeType == 1) { cont.innerHTML +="<br />"; cont.innerHTML +="Node # " + (i+1); cont.innerHTML +="<br />"; cont.innerHTML +=chlds[i].nodeName; cont.innerHTML +="<br />"; } } } function deleteENodes() { var prnt = document.getElementById("prnt"); var chlds = prnt.childNodes; for(i = 0; i < chlds.length; i++) { if(!(chlds[i].nodeType == 3)) { prnt.removeChild(chlds[i]); } } } function AddENodes() { var prnt = document.getElementById("prnt"); //Only even nodes are deletable PROBLEM for(i = 0; i < 10; i++) { var newDIV = document.createElement('div'); newDIV.setAttribute("id", "c"+(i)); var text = document.createTextNode("New Inserted Child "+(i)); newDIV.appendChild(text); prnt.appendChild(newDIV); } } </script> <title>Checking Div Nodes</title> </head> <body> <div id="prnt"> Parent 1 </div> <br /> <br /> <br /> <button type="button" onclick="displayNodes()">Show Node Info</button> <button type="button" onclick="deleteENodes()">Remove All Element Nodes Under Parent 1</button> <button type="button" onclick="AddENodes()">Add 5 New DIV Nodes</button> <div id="content"> </div> </body>

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• app-engine-rest-server to raise KeyError("name %s already used" % model_name)

  - by fx

  I'm playing with the project appengine-rest-server to create the REST webservices for all the existing models. I got a strange error, the first time I query the browser: http://localhost:8080/rest/metadata/user, it gives me the result: <xs:schema> - <xs:element name="user"> - <xs:complexType> - <xs:sequence> <xs:element maxOccurs="1" minOccurs="0" name="key" type="xs:normalizedString"/> <xs:element maxOccurs="1" minOccurs="0" name="surname" type="xs:string"/> <xs:element maxOccurs="1" minOccurs="0" name="firstname" type="xs:string"/> <xs:element maxOccurs="1" minOccurs="0" name="ages" type="xs:long"/> <xs:element maxOccurs="1" minOccurs="0" name="sex" type="xs:boolean"/> <xs:element maxOccurs="1" minOccurs="0" name="updatedDate" type="xs:dateTime"/> <xs:element maxOccurs="1" minOccurs="0" name="createdDate" type="xs:dateTime"/> </xs:sequence> </xs:complexType> </xs:element> </xs:schema> But refreshing the page, gives me this error: Traceback (most recent call last): File "/Users/foo/Documents/AppEngine/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/tools/dev_appserver.py", line 3185, in _HandleRequest self._Dispatch(dispatcher, self.rfile, outfile, env_dict) File "/Users/foo/Documents/AppEngine/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/tools/dev_appserver.py", line 3128, in _Dispatch base_env_dict=env_dict) File "/Users/foo/Documents/AppEngine/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/tools/dev_appserver.py", line 515, in Dispatch base_env_dict=base_env_dict) File "/Users/foo/Documents/AppEngine/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/tools/dev_appserver.py", line 2387, in Dispatch self._module_dict) File "/Users/foo/Documents/AppEngine/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/tools/dev_appserver.py", line 2297, in ExecuteCGI reset_modules = exec_script(handler_path, cgi_path, hook) File "/Users/foo/Documents/AppEngine/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/tools/dev_appserver.py", line 2195, in ExecuteOrImportScript script_module.main() File "/Users/foo/Documents/AppEngine/helloworld/main.py", line 48, in main rest.Dispatcher.add_models({"user": UserModel}) File "/Users/foo/Documents/AppEngine/helloworld/rest/__init__.py", line 845, in add_models cls.add_model(model_name, model_type) File "/Users/foo/Documents/AppEngine/helloworld/rest/__init__.py", line 863, in add_model raise KeyError("name %s already used" % model_name) KeyError: 'name user already used' Can someone give me the explanation on why it happens? Restarting the server, run on the browser again I get the xml result, but refreshing causes the error. Is it a bug in the appengine-rest-server application or it is in my code? My helloworld application is available for download here.

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• This task is currently locked by a running workflow and cannot be edited. Limitation to both Nintex and SPD workflow

  - by ybbest

  Note, this post is from Nintex Forum here. These limitations apply to both SharePoint designer Workflow and Nintex Workflow as Nintex using the SharePoint workflow engine. The common cause that I experience is that ‘parent’ workflow is generating more than one task at once. This is common as you can have multiple approvers for certain approval process. You could also have workflow running when the task is created, one of the common scenario is you would like to set a custom column value in your approval task. For me this is huge limitation, as Nintex lover I really hope Nintex could solve this problem with Microsoft going forward. Introduction “This task is currently locked by a running workflow and cannot be edited” is a common message that is seen when an error occurs while the SharePoint workflow engine is processing a task item associated with a workflow. When a workflow processes a task normally, the following sequence of events is expected to occur: 1.       The process begins. 2.       The workflow places a ‘lock’ on the task so nothing else can change the values while the workflow is processing. 3.       The workflow processes the task. 4.       The lock is released when the task processing is finished. When the message is encountered, it usually indicates that an error occurred between step 2 and 4. As a result, the lock is never released. Therefore, the ‘task locked’ message is not an error itself, rather a symptom of another error – the ‘task locked’ message does not indicate what went wrong. In most cases, once this message is encountered, the workflow cannot be made to continue and must be terminated and started again. The following is a guide that can help troubleshoot the cause of these messages.  Some initial observations to narrow down the potential causes are: Is the error consistent or intermittent? When the error is consistent, it will happen every time the workflow is run. When it is intermittent, it may happen regularly, but not every time. Does the error occur the first time the user tries to respond to a task, or do they respond and notice the workflow does not continue, and when they respond again the error occurs? If the message is present when the user first responds to the task, the issue would have occurred when the task was created. Otherwise, it would have occurred when the user attempted to respond to the task. Causes Modifying the task list A cause of this error appearing consistently the first time a user tries to respond to a task is a modification to the default task list schema. For example, changing the ‘Assigned to’ field in a task list to be a multiple selection will cause the behaviour. Deleting the workflow task then restoring it from the Recycle bin If you start a workflow, delete the workflow task then restore it from the Recycle Bin in SharePoint, the workflow will fail with the ‘task locked’ error.  This is confirmed behaviour whether using a SharePoint Designer or a Nintex workflow.  You will need to terminate the workflow and start it again. Parallel simultaneous responses A cause of this error appearing inconsistently is multiple users responding to tasks in parallel at the same time. In this scenario, one task will complete correctly and the other will not process. When the user tries again, the ‘task locked’ message will display. Nintex included a workaround for this issue in build 11000. In build 11000 and later, one of the users will receive a message on the task form when they attempt to respond, stating that they need to try again in a few moments. Additional processing on the task A cause of this error appearing consistently and inconsistently is having an additional system running on the items in the task list. Some examples include: a workflow running on the task list, an event receiver running on the task list or another automated process querying and updating workflow tasks. Note: This Microsoft help article (http://office.microsoft.com/en-us/sharepointdesigner/HA102376561033.aspx#5) explains creating a workflow that runs on the task list to update a field on the task. Our experience shows that this causes the ‘Task Locked’ issues when the ‘parent’ workflow is generating more than one task at once. Isolated system error If the error is a rare event, or a ‘one off’ event, then an isolated system error may have occurred. For example, if there is a database connectivity issue while the workflow is processing the task response, the task will lock. In this case, the user will respond to a task but the workflow will not continue. When they respond again, the ‘task locked’ message will display. In this case, there will be an error in the SharePoint ULS Logs at the time that the user originally responded. Temporary delay while workflow processes If the workflow is taking a long time to process after a user submits a task, they may notice and try to respond to the task again. They will see the task locked error, but after a number of attempts (or after waiting some time) the task response page eventually indicates the task has been responded to. In this case, nothing actually went wrong, and the error message gives an accurate indication of what is happening – the workflow temporarily locked the task while it was processing. This scenario may occur in a very large workflow, or after the SharePoint application pool has just started. Modifying the task via a web service with an invalid url If the Nintex Workflow web service is used to respond to or delegate a task, the site context part of the url must be a valid alternative access mapping url. For example, if you access the web service via the IP address of the SharePoint server, and the IP address is not a valid AAM, the task can become locked. The workflow has become stuck without any apparent errors This behaviour can occur as a result of a bug in the SharePoint 2010 workflow engine.  If you do not have the August 2010 Cumulative Update (or later) for SharePoint, and your workflow uses delays, “Flexi-task”, State machine”, “Task Reminder” actions or variables, you could be affected. Check the SharePoint 2010 Updates site here: http://technet.microsoft.com/en-us/sharepoint/ff800847.  The October CU is recommended http://support.microsoft.com/kb/2553031.   The fix is described as “Consider the following scenario. You add a Delay activity to a workflow. Then, you set the duration for the Delay activity. You deploy the workflow in SharePoint Foundation 2010. In this scenario, the workflow is not resumed after the duration of the Delay activity”. If you find this is occurring in your environment, install the October CU, terminate all the running workflows affected and run them afresh. Investigative steps The first step to isolate the issue is to create a new task list on the site and configure the workflow to use it.  Any customizations that were made to the original task list should not be made to the new task list. If the new task list eliminates the issue, then the cause can be attributed to the original task list or a change that was made to it. To change the task list that the workflow uses: In Workflow Designer select Settings -> Startup Options Then configure the task list as required If any of the scenarios above do not help, check the SharePoint logs for any messages with a category of ‘Workflow Infrastructure’. Conclusion The information in this article has been gathered from observations and investigations by Nintex. The sources of these issues are the underlying SharePoint workflow engine. This article will be updated if further causes are discovered. From <http://connect.nintex.com/forums/thread/6503.aspx>

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• sudo apt-get update errors

  - by Adrian Begi

  Here is what I get on my terminal when running sudo apt-get update errors. I dont know if the issue is from my sources.list or my proxy setup(have not made any changes to proxies). Thank you for any help in advanced. Ign http://security.ubuntu.com oneiric-security Release.gpg Ign http://security.ubuntu.com oneiric-security Release Ign http://security.ubuntu.com oneiric-security/main Sources/DiffIndex Ign http://security.ubuntu.com oneiric-security/restricted Sources/DiffIndex Ign http://security.ubuntu.com oneiric-security/universe Sources/DiffIndex Ign http://security.ubuntu.com oneiric-security/multiverse Sources/DiffIndex Ign http://security.ubuntu.com oneiric-security/main amd64 Packages/DiffIndex Ign http://security.ubuntu.com oneiric-security/restricted amd64 Packages/DiffIndex Ign http://security.ubuntu.com oneiric-security/universe amd64 Packages/DiffIndex Ign http://security.ubuntu.com oneiric-security/multiverse amd64 Packages/DiffIndex Ign http://security.ubuntu.com oneiric-security/main i386 Packages/DiffIndex Ign http://security.ubuntu.com oneiric-security/restricted i386 Packages/DiffIndex Ign http://security.ubuntu.com oneiric-security/universe i386 Packages/DiffIndex Ign http://security.ubuntu.com oneiric-security/multiverse i386 Packages/DiffIndex Ign http://security.ubuntu.com oneiric-security/main TranslationIndex Ign http://security.ubuntu.com oneiric-security/multiverse TranslationIndex Ign http://security.ubuntu.com oneiric-security/restricted TranslationIndex Ign http://security.ubuntu.com oneiric-security/universe TranslationIndex Err http://security.ubuntu.com oneiric-security/main Sources 404 Not Found [IP: 91.189.91.15 80] Err http://security.ubuntu.com oneiric-security/restricted Sources 404 Not Found [IP: 91.189.91.15 80] Err http://security.ubuntu.com oneiric-security/universe Sources 404 Not Found [IP: 91.189.91.15 80] Err http://security.ubuntu.com oneiric-security/multiverse Sources 404 Not Found [IP: 91.189.91.15 80] Err http://security.ubuntu.com oneiric-security/main amd64 Packages 404 Not Found [IP: 91.189.91.15 80] Err http://security.ubuntu.com oneiric-security/restricted amd64 Packages 404 Not Found [IP: 91.189.91.15 80] Err http://security.ubuntu.com oneiric-security/universe amd64 Packages 404 Not Found [IP: 91.189.91.15 80] Err http://security.ubuntu.com oneiric-security/multiverse amd64 Packages 404 Not Found [IP: 91.189.91.15 80] Err http://security.ubuntu.com oneiric-security/main i386 Packages 404 Not Found [IP: 91.189.91.15 80] Err http://security.ubuntu.com oneiric-security/restricted i386 Packages 404 Not Found [IP: 91.189.91.15 80] Err http://security.ubuntu.com oneiric-security/universe i386 Packages 404 Not Found [IP: 91.189.91.15 80] Err http://security.ubuntu.com oneiric-security/multiverse i386 Packages 404 Not Found [IP: 91.189.91.15 80] Ign http://security.ubuntu.com oneiric-security/main Translation-en_US Ign http://security.ubuntu.com oneiric-security/main Translation-en Ign http://security.ubuntu.com oneiric-security/multiverse Translation-en_US Ign http://security.ubuntu.com oneiric-security/multiverse Translation-en Ign http://security.ubuntu.com oneiric-security/restricted Translation-en_US Ign http://security.ubuntu.com oneiric-security/restricted Translation-en Ign http://security.ubuntu.com oneiric-security/universe Translation-en_US Ign http://security.ubuntu.com oneiric-security/universe Translation-en W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/main/source/Sources 404 Not Found [IP: 91.189.91.15 80] W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/restricted/source/Sources 404 Not Found [IP: 91.189.91.15 80] W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/universe/source/Sources 404 Not Found [IP: 91.189.91.15 80] W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/multiverse/source/Sources 404 Not Found [IP: 91.189.91.15 80] W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/main/binary-amd64/Packages 404 Not Found [IP: 91.189.91.15 80] W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/restricted/binary-amd64/Packages 404 Not Found [IP: 91.189.91.15 80] W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/universe/binary-amd64/Packages 404 Not Found [IP: 91.189.91.15 80] W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/multiverse/binary-amd64/Packages 404 Not Found [IP: 91.189.91.15 80] W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/main/binary-i386/Packages 404 Not Found [IP: 91.189.91.15 80] W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/restricted/binary-i386/Packages 404 Not Found [IP: 91.189.91.15 80] W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/universe/binary-i386/Packages 404 Not Found [IP: 91.189.91.15 80] W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/multiverse/binary-i386/Packages 404 Not Found [IP: 91.189.91.15 80] E: Some index files failed to download. They have been ignored, or old ones used instead. HERE IS MY SOURCES.LIST # # deb cdrom:[Ubuntu-Server 11.10 _Oneiric Ocelot_ - Release amd64 (20111011)]/ dists/oneiric/main/binary-i386/ # deb cdrom:[Ubuntu-Server 11.10 _Oneiric Ocelot_ - Release amd64 (20111011)]/ dists/oneiric/restricted/binary-i386/ # deb cdrom:[Ubuntu-Server 11.10 _Oneiric Ocelot_ - Release amd64 (20111011)]/ oneiric main restricted #deb cdrom:[Ubuntu-Server 11.10 _Oneiric Ocelot_ - Release amd64 (20111011)]/ dists/oneiric/main/binary-i386/ #deb cdrom:[Ubuntu-Server 11.10 _Oneiric Ocelot_ - Release amd64 (20111011)]/ dists/oneiric/restricted/binary-i386/ #deb cdrom:[Ubuntu-Server 11.10 _Oneiric Ocelot_ - Release amd64 (20111011)]/ oneiric main restricted # See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to # newer versions of the distribution. deb http://us.archive.ubuntu.com/ubuntu/ oneiric main restricted deb-src http://us.archive.ubuntu.com/ubuntu/ oneiric main restricted ## Major bug fix updates produced after the final release of the ## distribution. deb http://us.archive.ubuntu.com/ubuntu/ oneiric-updates main restricted deb-src http://us.archive.ubuntu.com/ubuntu/ oneiric-updates main restricted ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team. Also, please note that software in universe WILL NOT receive any ## review or updates from the Ubuntu security team. deb http://us.archive.ubuntu.com/ubuntu/ oneiric universe deb-src http://us.archive.ubuntu.com/ubuntu/ oneiric universe deb http://us.archive.ubuntu.com/ubuntu/ oneiric-updates universe deb-src http://us.archive.ubuntu.com/ubuntu/ oneiric-updates universe ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team, and may not be under a free licence. Please satisfy yourself as to ## your rights to use the software. Also, please note that software in ## multiverse WILL NOT receive any review or updates from the Ubuntu ## security team. deb http://us.archive.ubuntu.com/ubuntu/ oneiric multiverse deb-src http://us.archive.ubuntu.com/ubuntu/ oneiric multiverse deb http://us.archive.ubuntu.com/ubuntu/ oneiric-updates multiverse deb-src http://us.archive.ubuntu.com/ubuntu/ oneiric-updates multiverse ## N.B. software from this repository may not have been tested as ## extensively as that contained in the main release, although it includes ## newer versions of some applications which may provide useful features. ## Also, please note that software in backports WILL NOT receive any review ## or updates from the Ubuntu security team. deb http://us.archive.ubuntu.com/ubuntu/ oneiric-backports main restricted universe multiverse deb-src http://us.archive.ubuntu.com/ubuntu/ oneiric-backports main restricted universe multiverse deb http://security.ubuntu.com/ubuntu oneiric-security main restricted deb-src http://security.ubuntu.com/ubuntu oneiric-security main restricted deb http://security.ubuntu.com/ubuntu oneiric-security universe deb-src http://security.ubuntu.com/ubuntu oneiric-security universe deb http://security.ubuntu.com/ubuntu oneiric-security multiverse deb-src http://security.ubuntu.com/ubuntu oneiric-security multiverse ## Uncomment the following two lines to add software from Canonical's ## 'partner' repository. ## This software is not part of Ubuntu, but is offered by Canonical and the ## respective vendors as a service to Ubuntu users. # deb http://archive.canonical.com/ubuntu oneiric partner # deb-src http://archive.canonical.com/ubuntu oneiric partner ## Uncomment the following two lines to add software from Ubuntu's ## 'extras' repository. ## This software is not part of Ubuntu, but is offered by third-party ## developers who want to ship their latest software. # deb http://extras.ubuntu.com/ubuntu oneiric main # deb-src http://extras.ubuntu.com/ubuntu oneiric main

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• Week in Geek: 4chan Falls Victim to DDoS Attack Edition

  - by Asian Angel

  This week we learned how to tweak the low battery action on a Windows 7 laptop, access an eBook collection anywhere in the world, “extend iPad battery life, batch resize photos, & sync massive music collections”, went on a reign of destruction with Snow Crusher, and had fun decorating our desktops with abstract icon collections. Photo by pasukaru76. Random Geek Links We have included extra news article goodness to help you catch up on any developments that you may have missed during the holiday break this past week. Note: The three 27C3 articles listed here represent three different presentations at the 27th Chaos Communication Congress hacker conference. 4chan victim of DDoS as FBI investigates role in PayPal attack Users of 4chan may have gotten a taste of their own medicine after the site was knocked offline by a DDoS attack from an unknown origin early Thursday morning. Report: FBI seizes server in probe of WikiLeaks attacks The FBI has seized a server in Texas as part of its hunt for the groups behind the pro-WikiLeaks denial-of-service attacks launched in December against PayPal, Visa, MasterCard, and others. Mozilla exposes older user-account database Mozilla has disabled 44,000 older user accounts for its Firefox add-ons site after a security researcher found part of a database of the account information on a publicly available server. Data breach affects 4.9 million Honda customers Japanese automaker Honda has put some 2.2 million customers in the United States on a security breach alert after a database containing information on the owners and their cars was hacked. Chinese Trojan discovered in Android games An Android-based Trojan called “Geinimi” has been discovered in the wild and the Trojan is capable of sending personal information to remote servers and exhibits botnet-like behavior. 27C3 presentation claims many mobiles vulnerable to SMS attacks According to security experts, an ‘SMS of death’ threatens to disable many current Sony Ericsson, Samsung, Motorola, Micromax and LG mobiles. 27C3: GSM cell phones even easier to tap Security researchers have demonstrated how open source software on a number of revamped, entry-level cell phones can decrypt and record mobile phone calls in the GSM network. 27C3: danger lurks in PDF documents Security researcher Julia Wolf has pointed out numerous, previously hardly known, security problems in connection with Adobe’s PDF standard. Critical update for WordPress A critical update has been made available for WordPress in the form of version 3.0.4. The update fixes a security bug in WordPress’s KSES library. McAfee Labs Predicts Geolocation, Mobile Devices and Apple Will Top the List of Targets for Emerging Threats in 2011 The list comprises 2010’s most buzzed about platforms and services, including Google’s Android, Apple’s iPhone, foursquare, Google TV and the Mac OS X platform, which are all expected to become major targets for cybercriminals. McAfee Labs also predicts that politically motivated attacks will be on the rise. Windows Phone 7 piracy materializes with FreeMarketplace A proof-of-concept application, FreeMarketplace, that allows any Windows Phone 7 application to be downloaded and installed free of charge has been developed. Empty email accounts, and some bad buzz for Hotmail In the past few days, a number of Hotmail users have been complaining about a rather disconcerting issue: their Hotmail accounts, some up to 10 years old, appear completely empty.  No emails, no folders, nothing, just what appears to be a new account. Reports: Nintendo warns of 3DS risk for kids Nintendo has reportedly issued a warning that the 3DS, its eagerly awaited glasses-free 3D portable gaming device, should not be used by children under 6 when the gadget is in 3D-viewing mode. Google eyes ‘cloaking’ as next antispam target Google plans to take a closer look at the practice of “cloaking,” or presenting one look to a Googlebot crawling one’s site while presenting another look to users. Facebook, Twitter stock trading drawing SEC eye? The high degree of investor interest in shares of hot Silicon Valley companies that aren’t yet publicly traded–like Facebook, Twitter, LinkedIn, and Zynga–may be leading to scrutiny from the U.S. Securities and Exchange Commission (SEC). Random TinyHacker Links Photo by jcraveiro. Exciting Software Set for Release in 2011 A few bloggers from great websites such as How-To Geek, Guiding Tech and 7 Tutorials took the time to sit down and talk about their software wishes for 2011. Take the time to read it and share… Wikileaks Infopr0n An infographic detailing the quest to plug WikiLeaks. The New York Times Guide to Mobile Apps A growing collection of all mobile app coverage by the New York Times as well as lists of favorite apps from Times writers. 7,000,000,000 (Video) A fascinating look at the world’s population via National Geographic Magazine. Super User Questions Check out the great answers to these hot questions from Super User. How to use a Personal computer as a Linux web server for development purposes? How to link processing power of old computers together? Free virtualization tool for testing suspicious files? Why do some actions not work with Remote Desktop? What is the simplest way to send a large batch of pictures to a distant friend or colleague? How-To Geek Weekly Article Recap Had a busy week and need to get caught up on your HTG reading? Then sit back and relax while enjoying these hot posts full of how-to roundup goodness. The 50 Best How-To Geek Windows Articles of 2010 The 20 Best How-To Geek Explainer Topics for 2010 The 20 Best How-To Geek Linux Articles of 2010 How to Search Just the Site You’re Viewing Using Google Search Ask the Readers: Backing Your Files Up – Local Storage versus the Cloud One Year Ago on How-To Geek Need more how-to geekiness for your weekend? Then look through this great batch of articles from one year ago that focus on dual-booting and O.S. installation goodness. Dual Boot Your Pre-Installed Windows 7 Computer with Vista Dual Boot Your Pre-Installed Windows 7 Computer with XP How To Setup a USB Flash Drive to Install Windows 7 Dual Boot Your Pre-Installed Windows 7 Computer with Ubuntu Easily Install Ubuntu Linux with Windows Using the Wubi Installer The Geek Note We hope that you and your families have had a terrific holiday break as everyone prepares to return to work and school this week. Remember to keep those great tips coming in to us at [email protected]! Photo by pjbeardsley. Latest Features How-To Geek ETC The 20 Best How-To Geek Linux Articles of 2010 The 50 Best How-To Geek Windows Articles of 2010 The 20 Best How-To Geek Explainer Topics for 2010 How to Disable Caps Lock Key in Windows 7 or Vista How to Use the Avira Rescue CD to Clean Your Infected PC The Complete List of iPad Tips, Tricks, and Tutorials Tune Pop Enhances Android Music Notifications Another Busy Night in Gotham City Wallpaper Classic Super Mario Brothers Theme for Chrome and Iron Experimental Firefox Builds Put Tabs on the Title Bar (Available for Download) Android Trojan Found in the Wild Chaos, Panic, and Disorder Wallpaper

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• Using the West Wind Web Toolkit to set up AJAX and REST Services

  - by Rick Strahl

  I frequently get questions about which option to use for creating AJAX and REST backends for ASP.NET applications. There are many solutions out there to do this actually, but when I have a choice - not surprisingly - I fall back to my own tools in the West Wind West Wind Web Toolkit. I've talked a bunch about the 'in-the-box' solutions in the past so for a change in this post I'll talk about the tools that I use in my own and customer applications to handle AJAX and REST based access to service resources using the West Wind West Wind Web Toolkit. Let me preface this by saying that I like things to be easy. Yes flexible is very important as well but not at the expense of over-complexity. The goal I've had with my tools is make it drop dead easy, with good performance while providing the core features that I'm after, which are: Easy AJAX/JSON Callbacks Ability to return any kind of non JSON content (string, stream, byte[], images) Ability to work with both XML and JSON interchangeably for input/output Access endpoints via POST data, RPC JSON calls, GET QueryString values or Routing interface Easy to use generic JavaScript client to make RPC calls (same syntax, just what you need) Ability to create clean URLS with Routing Ability to use standard ASP.NET HTTP Stack for HTTP semantics It's all about options! In this post I'll demonstrate most of these features (except XML) in a few simple and short samples which you can download. So let's take a look and see how you can build an AJAX callback solution with the West Wind Web Toolkit. Installing the Toolkit Assemblies The easiest and leanest way of using the Toolkit in your Web project is to grab it via NuGet: West Wind Web and AJAX Utilities (Westwind.Web) and drop it into the project by right clicking in your Project and choosing Manage NuGet Packages from anywhere in the Project.   When done you end up with your project looking like this: What just happened? Nuget added two assemblies - Westwind.Web and Westwind.Utilities and the client ww.jquery.js library. It also added a couple of references into web.config: The default namespaces so they can be accessed in pages/views and a ScriptCompressionModule that the toolkit optionally uses to compress script resources served from within the assembly (namely ww.jquery.js and optionally jquery.js). Creating a new Service The West Wind Web Toolkit supports several ways of creating and accessing AJAX services, but for this post I'll stick to the lower level approach that works from any plain HTML page or of course MVC, WebForms, WebPages. There's also a WebForms specific control that makes this even easier but I'll leave that for another post. So, to create a new standalone AJAX/REST service we can create a new HttpHandler in the new project either as a pure class based handler or as a generic .ASHX handler. Both work equally well, but generic handlers don't require any web.config configuration so I'll use that here. In the root of the project add a Generic Handler. I'm going to call this one StockService.ashx. Once the handler has been created, edit the code and remove all of the handler body code. Then change the base class to CallbackHandler and add methods that have a [CallbackMethod] attribute. Here's the modified base handler implementation now looks like with an added HelloWorld method: using System; using Westwind.Web; namespace WestWindWebAjax { /// <summary> /// Handler implements CallbackHandler to provide REST/AJAX services /// </summary> public class SampleService : CallbackHandler { [CallbackMethod] public string HelloWorld(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } } } Notice that the class inherits from CallbackHandler and that the HelloWorld service method is marked up with [CallbackMethod]. We're done here. Services Urlbased Syntax Once you compile, the 'service' is live can respond to requests. All CallbackHandlers support input in GET and POST formats, and can return results as JSON or XML. To check our fancy HelloWorld method we can now access the service like this: http://localhost/WestWindWebAjax/StockService.ashx?Method=HelloWorld&name=Rick which produces a default JSON response - in this case a string (wrapped in quotes as it's JSON): (note by default JSON will be downloaded by most browsers not displayed - various options are available to view JSON right in the browser) If I want to return the same data as XML I can tack on a &format=xml at the end of the querystring which produces: <string>Hello Rick. Time is: 11/1/2011 12:11:13 PM</string> Cleaner URLs with Routing Syntax If you want cleaner URLs for each operation you can also configure custom routes on a per URL basis similar to the way that WCF REST does. To do this you need to add a new RouteHandler to your application's startup code in global.asax.cs one for each CallbackHandler based service you create: protected void Application_Start(object sender, EventArgs e) { CallbackHandlerRouteHandler.RegisterRoutes<StockService>(RouteTable.Routes); } With this code in place you can now add RouteUrl properties to any of your service methods. For the HelloWorld method that doesn't make a ton of sense but here is what a routed clean URL might look like in definition: [CallbackMethod(RouteUrl="stocks/HelloWorld/{name}")] public string HelloWorld(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } The same URL I previously used now becomes a bit shorter and more readable with: http://localhost/WestWindWebAjax/HelloWorld/Rick It's an easy way to create cleaner URLs and still get the same functionality. Calling the Service with $.getJSON() Since the result produced is JSON you can now easily consume this data using jQuery's getJSON method. First we need a couple of scripts - jquery.js and ww.jquery.js in the page: <!DOCTYPE html> <html> <head> <link href="Css/Westwind.css" rel="stylesheet" type="text/css" /> <script src="scripts/jquery.min.js" type="text/javascript"></script> <script src="scripts/ww.jquery.min.js" type="text/javascript"></script> </head> <body> Next let's add a small HelloWorld example form (what else) that has a single textbox to type a name, a button and a div tag to receive the result: <fieldset> <legend>Hello World</legend> Please enter a name: <input type="text" name="txtHello" id="txtHello" value="" /> <input type="button" id="btnSayHello" value="Say Hello (POST)" /> <input type="button" id="btnSayHelloGet" value="Say Hello (GET)" /> <div id="divHelloMessage" class="errordisplay" style="display:none;width: 450px;" > </div> </fieldset> Then to call the HelloWorld method a little jQuery is used to hook the document startup and the button click followed by the $.getJSON call to retrieve the data from the server. <script type="text/javascript"> $(document).ready(function () { $("#btnSayHelloGet").click(function () { $.getJSON("SampleService.ashx", { Method: "HelloWorld", name: $("#txtHello").val() }, function (result) { $("#divHelloMessage") .text(result) .fadeIn(1000); }); });</script> .getJSON() expects a full URL to the endpoint of our service, which is the ASHX file. We can either provide a full URL (SampleService.ashx?Method=HelloWorld&name=Rick) or we can just provide the base URL and an object that encodes the query string parameters for us using an object map that has a property that matches each parameter for the server method. We can also use the clean URL routing syntax, but using the object parameter encoding actually is safer as the parameters will get properly encoded by jQuery. The result returned is whatever the result on the server method is - in this case a string. The string is applied to the divHelloMessage element and we're done. Obviously this is a trivial example, but it demonstrates the basics of getting a JSON response back to the browser. AJAX Post Syntax - using ajaxCallMethod() The previous example allows you basic control over the data that you send to the server via querystring parameters. This works OK for simple values like short strings, numbers and boolean values, but doesn't really work if you need to pass something more complex like an object or an array back up to the server. To handle traditional RPC type messaging where the idea is to map server side functions and results to a client side invokation, POST operations can be used. The easiest way to use this functionality is to use ww.jquery.js and the ajaxCallMethod() function. ww.jquery wraps jQuery's AJAX functions and knows implicitly how to call a CallbackServer method with parameters and parse the result. Let's look at another simple example that posts a simple value but returns something more interesting. Let's start with the service method: [CallbackMethod(RouteUrl="stocks/{symbol}")] public StockQuote GetStockQuote(string symbol) { Response.Cache.SetExpires(DateTime.UtcNow.Add(new TimeSpan(0, 2, 0))); StockServer server = new StockServer(); var quote = server.GetStockQuote(symbol); if (quote == null) throw new ApplicationException("Invalid Symbol passed."); return quote; } This sample utilizes a small StockServer helper class (included in the sample) that downloads a stock quote from Yahoo's financial site via plain HTTP GET requests and formats it into a StockQuote object. Lets create a small HTML block that lets us query for the quote and display it: <fieldset> <legend>Single Stock Quote</legend> Please enter a stock symbol: <input type="text" name="txtSymbol" id="txtSymbol" value="msft" /> <input type="button" id="btnStockQuote" value="Get Quote" /> <div id="divStockDisplay" class="errordisplay" style="display:none; width: 450px;"> <div class="label-left">Company:</div> <div id="stockCompany"></div> <div class="label-left">Last Price:</div> <div id="stockLastPrice"></div> <div class="label-left">Quote Time:</div> <div id="stockQuoteTime"></div> </div> </fieldset> The final result looks something like this:   Let's hook up the button handler to fire the request and fill in the data as shown: $("#btnStockQuote").click(function () { ajaxCallMethod("SampleService.ashx", "GetStockQuote", [$("#txtSymbol").val()], function (quote) { $("#divStockDisplay").show().fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, HH:mm EST")); }, onPageError); }); So we point at SampleService.ashx and the GetStockQuote method, passing a single parameter of the input symbol value. Then there are two handlers for success and failure callbacks.  The success handler is the interesting part - it receives the stock quote as a result and assigns its values to various 'holes' in the stock display elements. The data that comes back over the wire is JSON and it looks like this: { "Symbol":"MSFT", "Company":"Microsoft Corpora", "OpenPrice":26.11, "LastPrice":26.01, "NetChange":0.02, "LastQuoteTime":"2011-11-03T02:00:00Z", "LastQuoteTimeString":"Nov. 11, 2011 4:20pm" } which is an object representation of the data. JavaScript can evaluate this JSON string back into an object easily and that's the reslut that gets passed to the success function. The quote data is then applied to existing page content by manually selecting items and applying them. There are other ways to do this more elegantly like using templates, but here we're only interested in seeing how the data is returned. The data in the object is typed - LastPrice is a number and QuoteTime is a date. Note about the date value: JavaScript doesn't have a date literal although the JSON embedded ISO string format used above  ("2011-11-03T02:00:00Z") is becoming fairly standard for JSON serializers. However, JSON parsers don't deserialize dates by default and return them by string. This is why the StockQuote actually returns a string value of LastQuoteTimeString for the same date. ajaxMethodCallback always converts dates properly into 'real' dates and the example above uses the real date value along with a .formatDate() data extension (also in ww.jquery.js) to display the raw date properly. Errors and Exceptions So what happens if your code fails? For example if I pass an invalid stock symbol to the GetStockQuote() method you notice that the code does this: if (quote == null) throw new ApplicationException("Invalid Symbol passed."); CallbackHandler automatically pushes the exception message back to the client so it's easy to pick up the error message. Regardless of what kind of error occurs: Server side, client side, protocol errors - any error will fire the failure handler with an error object parameter. The error is returned to the client via a JSON response in the error callback. In the previous examples I called onPageError which is a generic routine in ww.jquery that displays a status message on the bottom of the screen. But of course you can also take over the error handling yourself: $("#btnStockQuote").click(function () { ajaxCallMethod("SampleService.ashx", "GetStockQuote", [$("#txtSymbol").val()], function (quote) { $("#divStockDisplay").fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, hh:mmt")); }, function (error, xhr) { $("#divErrorDisplay").text(error.message).fadeIn(1000); }); }); The error object has a isCallbackError, message and  stackTrace properties, the latter of which is only populated when running in Debug mode, and this object is returned for all errors: Client side, transport and server side errors. Regardless of which type of error you get the same object passed (as well as the XHR instance optionally) which makes for a consistent error retrieval mechanism. Specifying HttpVerbs You can also specify HTTP Verbs that are allowed using the AllowedHttpVerbs option on the CallbackMethod attribute: [CallbackMethod(AllowedHttpVerbs=HttpVerbs.GET | HttpVerbs.POST)] public string HelloWorld(string name) { … } If you're building REST style API's this might be useful to force certain request semantics onto the client calling. For the above if call with a non-allowed HttpVerb the request returns a 405 error response along with a JSON (or XML) error object result. The default behavior is to allow all verbs access (HttpVerbs.All). Passing in object Parameters Up to now the parameters I passed were very simple. But what if you need to send something more complex like an object or an array? Let's look at another example now that passes an object from the client to the server. Keeping with the Stock theme here lets add a method called BuyOrder that lets us buy some shares for a stock. Consider the following service method that receives an StockBuyOrder object as a parameter: [CallbackMethod] public string BuyStock(StockBuyOrder buyOrder) { var server = new StockServer(); var quote = server.GetStockQuote(buyOrder.Symbol); if (quote == null) throw new ApplicationException("Invalid or missing stock symbol."); return string.Format("You're buying {0} shares of {1} ({2}) stock at {3} for a total of {4} on {5}.", buyOrder.Quantity, quote.Company, quote.Symbol, quote.LastPrice.ToString("c"), (quote.LastPrice * buyOrder.Quantity).ToString("c"), buyOrder.BuyOn.ToString("MMM d")); } public class StockBuyOrder { public string Symbol { get; set; } public int Quantity { get; set; } public DateTime BuyOn { get; set; } public StockBuyOrder() { BuyOn = DateTime.Now; } } This is a contrived do-nothing example that simply echoes back what was passed in, but it demonstrates how you can pass complex data to a callback method. On the client side we now have a very simple form that captures the three values on a form: <fieldset> <legend>Post a Stock Buy Order</legend> Enter a symbol: <input type="text" name="txtBuySymbol" id="txtBuySymbol" value="GLD" />&nbsp;&nbsp; Qty: <input type="text" name="txtBuyQty" id="txtBuyQty" value="10" style="width: 50px" />&nbsp;&nbsp; Buy on: <input type="text" name="txtBuyOn" id="txtBuyOn" value="<%= DateTime.Now.ToString("d") %>" style="width: 70px;" /> <input type="button" id="btnBuyStock" value="Buy Stock" /> <div id="divStockBuyMessage" class="errordisplay" style="display:none"></div> </fieldset> The completed form and demo then looks something like this:   The client side code that picks up the input values and assigns them to object properties and sends the AJAX request looks like this: $("#btnBuyStock").click(function () { // create an object map that matches StockBuyOrder signature var buyOrder = { Symbol: $("#txtBuySymbol").val(), Quantity: $("#txtBuyQty").val() * 1, // number Entered: new Date() } ajaxCallMethod("SampleService.ashx", "BuyStock", [buyOrder], function (result) { $("#divStockBuyMessage").text(result).fadeIn(1000); }, onPageError); }); The code creates an object and attaches the properties that match the server side object passed to the BuyStock method. Each property that you want to update needs to be included and the type must match (ie. string, number, date in this case). Any missing properties will not be set but also not cause any errors. Pass POST data instead of Objects In the last example I collected a bunch of values from form variables and stuffed them into object variables in JavaScript code. While that works, often times this isn't really helping - I end up converting my types on the client and then doing another conversion on the server. If lots of input controls are on a page and you just want to pick up the values on the server via plain POST variables - that can be done too - and it makes sense especially if you're creating and filling the client side object only to push data to the server. Let's add another method to the server that once again lets us buy a stock. But this time let's not accept a parameter but rather send POST data to the server. Here's the server method receiving POST data: [CallbackMethod] public string BuyStockPost() { StockBuyOrder buyOrder = new StockBuyOrder(); buyOrder.Symbol = Request.Form["txtBuySymbol"]; ; int qty; int.TryParse(Request.Form["txtBuyQuantity"], out qty); buyOrder.Quantity = qty; DateTime time; DateTime.TryParse(Request.Form["txtBuyBuyOn"], out time); buyOrder.BuyOn = time; // Or easier way yet //FormVariableBinder.Unbind(buyOrder,null,"txtBuy"); var server = new StockServer(); var quote = server.GetStockQuote(buyOrder.Symbol); if (quote == null) throw new ApplicationException("Invalid or missing stock symbol."); return string.Format("You're buying {0} shares of {1} ({2}) stock at {3} for a total of {4} on {5}.", buyOrder.Quantity, quote.Company, quote.Symbol, quote.LastPrice.ToString("c"), (quote.LastPrice * buyOrder.Quantity).ToString("c"), buyOrder.BuyOn.ToString("MMM d")); } Clearly we've made this server method take more code than it did with the object parameter. We've basically moved the parameter assignment logic from the client to the server. As a result the client code to call this method is now a bit shorter since there's no client side shuffling of values from the controls to an object. $("#btnBuyStockPost").click(function () { ajaxCallMethod("SampleService.ashx", "BuyStockPost", [], // Note: No parameters - function (result) { $("#divStockBuyMessage").text(result).fadeIn(1000); }, onPageError, // Force all page Form Variables to be posted { postbackMode: "Post" }); }); The client simply calls the BuyStockQuote method and pushes all the form variables from the page up to the server which parses them instead. The feature that makes this work is one of the options you can pass to the ajaxCallMethod() function: { postbackMode: "Post" }); which directs the function to include form variable POST data when making the service call. Other options include PostNoViewState (for WebForms to strip out WebForms crap vars), PostParametersOnly (default), None. If you pass parameters those are always posted to the server except when None is set. The above code can be simplified a bit by using the FormVariableBinder helper, which can unbind form variables directly into an object: FormVariableBinder.Unbind(buyOrder,null,"txtBuy"); which replaces the manual Request.Form[] reading code. It receives the object to unbind into, a string of properties to skip, and an optional prefix which is stripped off form variables to match property names. The component is similar to the MVC model binder but it's independent of MVC. Returning non-JSON Data CallbackHandler also supports returning non-JSON/XML data via special return types. You can return raw non-JSON encoded strings like this: [CallbackMethod(ReturnAsRawString=true,ContentType="text/plain")] public string HelloWorldNoJSON(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } Calling this method results in just a plain string - no JSON encoding with quotes around the result. This can be useful if your server handling code needs to return a string or HTML result that doesn't fit well for a page or other UI component. Any string output can be returned. You can also return binary data. Stream, byte[] and Bitmap/Image results are automatically streamed back to the client. Notice that you should set the ContentType of the request either on the CallbackMethod attribute or using Response.ContentType. This ensures the Web Server knows how to display your binary response. Using a stream response makes it possible to return any of data. Streamed data can be pretty handy to return bitmap data from a method. The following is a method that returns a stock history graph for a particular stock over a provided number of years: [CallbackMethod(ContentType="image/png",RouteUrl="stocks/history/graph/{symbol}/{years}")] public Stream GetStockHistoryGraph(string symbol, int years = 2,int width = 500, int height=350) { if (width == 0) width = 500; if (height == 0) height = 350; StockServer server = new StockServer(); return server.GetStockHistoryGraph(symbol,"Stock History for " + symbol,width,height,years); } I can now hook this up into the JavaScript code when I get a stock quote. At the end of the process I can assign the URL to the service that returns the image into the src property and so force the image to display. Here's the changed code: $("#btnStockQuote").click(function () { var symbol = $("#txtSymbol").val(); ajaxCallMethod("SampleService.ashx", "GetStockQuote", [symbol], function (quote) { $("#divStockDisplay").fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, hh:mmt")); // display a stock chart $("#imgStockHistory").attr("src", "stocks/history/graph/" + symbol + "/2"); },onPageError); }); The resulting output then looks like this: The charting code uses the new ASP.NET 4.0 Chart components via code to display a bar chart of the 2 year stock data as part of the StockServer class which you can find in the sample download. The ability to return arbitrary data from a service is useful as you can see - in this case the chart is clearly associated with the service and it's nice that the graph generation can happen off a handler rather than through a page. Images are common resources, but output can also be PDF reports, zip files for downloads etc. which is becoming increasingly more common to be returned from REST endpoints and other applications. Why reinvent? Obviously the examples I've shown here are pretty basic in terms of functionality. But I hope they demonstrate the core features of AJAX callbacks that you need to work through in most applications which is simple: return data, send back data and potentially retrieve data in various formats. While there are other solutions when it comes down to making AJAX callbacks and servicing REST like requests, I like the flexibility my home grown solution provides. Simply put it's still the easiest solution that I've found that addresses my common use cases: AJAX JSON RPC style callbacks Url based access XML and JSON Output from single method endpoint XML and JSON POST support, querystring input, routing parameter mapping UrlEncoded POST data support on callbacks Ability to return stream/raw string data Essentially ability to return ANYTHING from Service and pass anything All these features are available in various solutions but not together in one place. I've been using this code base for over 4 years now in a number of projects both for myself and commercial work and it's served me extremely well. Besides the AJAX functionality CallbackHandler provides, it's also an easy way to create any kind of output endpoint I need to create. Need to create a few simple routines that spit back some data, but don't want to create a Page or View or full blown handler for it? Create a CallbackHandler and add a method or multiple methods and you have your generic endpoints.  It's a quick and easy way to add small code pieces that are pretty efficient as they're running through a pretty small handler implementation. I can have this up and running in a couple of minutes literally without any setup and returning just about any kind of data. Resources Download the Sample NuGet: Westwind Web and AJAX Utilities (Westwind.Web) ajaxCallMethod() Documentation Using the AjaxMethodCallback WebForms Control West Wind Web Toolkit Home Page West Wind Web Toolkit Source Code © Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  jQuery  AJAX   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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• HttpContext.Items and Server.Transfer/Execute

  - by Rick Strahl

  A few days ago my buddy Ben Jones pointed out that he ran into a bug in the ScriptContainer control in the West Wind Web and Ajax Toolkit. The problem was basically that when a Server.Transfer call was applied the script container (and also various ClientScriptProxy script embedding routines) would potentially fail to load up the specified scripts. It turns out the problem is due to the fact that the various components in the toolkit use request specific singletons via a Current property. I use a static Current property tied to a Context.Items[] entry to handle this type of operation which looks something like this: /// <summary> /// Current instance of this class which should always be used to /// access this object. There are no public constructors to /// ensure the reference is used as a Singleton to further /// ensure that all scripts are written to the same clientscript /// manager. /// </summary> public static ClientScriptProxy Current { get { if (HttpContext.Current == null) return new ClientScriptProxy(); ClientScriptProxy proxy = null; if (HttpContext.Current.Items.Contains(STR_CONTEXTID)) proxy = HttpContext.Current.Items[STR_CONTEXTID] as ClientScriptProxy; else { proxy = new ClientScriptProxy(); HttpContext.Current.Items[STR_CONTEXTID] = proxy; } return proxy; } } The proxy is attached to a Context.Items[] item which makes the instance Request specific. This works perfectly fine in most situations EXCEPT when you’re dealing with Server.Transfer/Execute requests. Server.Transfer doesn’t cause Context.Items to be cleared so both the current transferred request and the original request’s Context.Items collection apply. For the ClientScriptProxy this causes a problem because script references are tracked on a per request basis in Context.Items to check for script duplication. Once a script is rendered an ID is written into the Context collection and so considered ‘rendered’: // No dupes - ref script include only once if (HttpContext.Current.Items.Contains( STR_SCRIPTITEM_IDENTITIFIER + fileId ) ) return; HttpContext.Current.Items.Add(STR_SCRIPTITEM_IDENTITIFIER + fileId, string.Empty); where the fileId is the script name or unique identifier. The problem is on the Transferred page the item will already exist in Context and so fail to render because it thinks the script has already rendered based on the Context item. Bummer. The workaround for this is simple once you know what’s going on, but in this case it was a bitch to track down because the context items are used in many places throughout this class. The trick is to determine when a request is transferred and then removing the specific keys. The first issue is to determine if a script is in a Trransfer or Execute call: if (HttpContext.Current.CurrentHandler != HttpContext.Current.Handler) Context.Handler is the original handler and CurrentHandler is the actual currently executing handler that is running when a Transfer/Execute is active. You can also use Context.PreviousHandler to get the last handler and chain through the whole list of handlers applied if Transfer calls are nested (dog help us all for the person debugging that). For the ClientScriptProxy the full logic to check for a transfer and remove the code looks like this: /// <summary> /// Clears all the request specific context items which are script references /// and the script placement index. /// </summary> public void ClearContextItemsOnTransfer() { if (HttpContext.Current != null) { // Check for Server.Transfer/Execute calls - we need to clear out Context.Items if (HttpContext.Current.CurrentHandler != HttpContext.Current.Handler) { List<string> Keys = HttpContext.Current.Items.Keys.Cast<string>().Where(s => s.StartsWith(STR_SCRIPTITEM_IDENTITIFIER) || s == STR_ScriptResourceIndex).ToList(); foreach (string key in Keys) { HttpContext.Current.Items.Remove(key); } } } } along with a small update to the Current property getter that sets a global flag to indicate whether the request was transferred: if (!proxy.IsTransferred && HttpContext.Current.Handler != HttpContext.Current.CurrentHandler) { proxy.ClearContextItemsOnTransfer(); proxy.IsTransferred = true; } return proxy; I know this is pretty ugly, but it works and it’s actually minimal fuss without affecting the behavior of the rest of the class. Ben had a different solution that involved explicitly clearing out the Context items and replacing the collection with a manually maintained list of items which also works, but required changes through the code to make this work. In hindsight, it would have been better to use a single object that encapsulates all the ‘persisted’ values and store that object in Context instead of all these individual small morsels. Hindsight is always 20/20 though :-}. If possible use Page.Items ClientScriptProxy is a generic component that can be used from anywhere in ASP.NET, so there are various methods that are not Page specific on this component which is why I used Context.Items, rather than the Page.Items collection.Page.Items would be a better choice since it will sidestep the above Server.Transfer nightmares as the Page is reloaded completely and so any new Page gets a new Items collection. No fuss there. So for the ScriptContainer control, which has to live on the page the behavior is a little different. It is attached to Page.Items (since it’s a control): /// <summary> /// Returns a current instance of this control if an instance /// is already loaded on the page. Otherwise a new instance is /// created, added to the Form and returned. /// /// It's important this function is not called too early in the /// page cycle - it should not be called before Page.OnInit(). /// /// This property is the preferred way to get a reference to a /// ScriptContainer control that is either already on a page /// or needs to be created. Controls in particular should always /// use this property. /// </summary> public static ScriptContainer Current { get { // We need a context for this to work! if (HttpContext.Current == null) return null; Page page = HttpContext.Current.CurrentHandler as Page; if (page == null) throw new InvalidOperationException(Resources.ERROR_ScriptContainer_OnlyWorks_With_PageBasedHandlers); ScriptContainer ctl = null; // Retrieve the current instance ctl = page.Items[STR_CONTEXTID] as ScriptContainer; if (ctl != null) return ctl; ctl = new ScriptContainer(); page.Form.Controls.Add(ctl); return ctl; } } The biggest issue with this approach is that you have to explicitly retrieve the page in the static Current property. Notice again the use of CurrentHandler (rather than Handler which was my original implementation) to ensure you get the latest page including the one that Server.Transfer fired. Server.Transfer and Server.Execute are Evil All that said – this fix is probably for the 2 people who are crazy enough to rely on Server.Transfer/Execute. :-} There are so many weird behavior problems with these commands that I avoid them at all costs. I don’t think I have a single application that uses either of these commands… Related Resources Full source of ClientScriptProxy.cs (repository) Part of the West Wind Web Toolkit Static Singletons for ASP.NET Controls Post © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  

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• WatiN screenshot saver

  - by Brian Schroer

  In addition to my automated unit, system and integration tests for ASP.NET projects, I like to give my customers something pretty that they can look at and visually see that the web site is behaving properly. I use the Gallio test runner to produce a pretty HTML report, and WatiN (Web Application Testing In .NET) to test the UI and create screenshots. I have a couple of issues with WatiN’s “CaptureWebPageToFile” method, though: It blew up the first (and only) time I tried it, possibly because… It scrolls down to capture the entire web page (I tried it on a very long page), and I usually don’t need that Also, sometimes I don’t need a picture of the whole browser window - I just want a picture of the element that I'm testing (for example, proving that a button has the correct caption). I wrote a WatiN screenshot saver helper class with these methods: SaveBrowserWindowScreenshot(Watin.Core.IE ie)  / SaveBrowserWindowScreenshot(Watin.Core.Element element) saves a screenshot of the browser window SaveBrowserWindowScreenshotWithHighlight(Watin.Core.Element element) saves a screenshot of the browser window, with the specified element scrolled into view and highlighted SaveElementScreenshot(Watin.Core.Element element) saves a picture of only the specified element The element highlighting improves on the built-in WatiN method (which just gives the element a yellow background, and makes the element pretty much unreadable when you have a light foreground color) by adding the ability to specify a HighlightCssClassName that points to a style in your site’s stylesheet. This code is specifically for testing with Internet Explorer (‘cause that’s what I have to test with at work), but you’re welcome to take it and do with it what you want… using System; using System.Drawing; using System.Drawing.Imaging; using System.IO; using System.Reflection; using System.Runtime.InteropServices; using System.Text; using System.Threading; using SHDocVw; using WatiN.Core; using mshtml; namespace BrianSchroer.TestHelpers { public static class WatinScreenshotSaver { public static void SaveBrowserWindowScreenshotWithHighlight (Element element, string screenshotName) { HighlightElement(element, true); SaveBrowserWindowScreenshot(element, screenshotName); HighlightElement(element, false); } public static void SaveBrowserWindowScreenshotWithHighlight(Element element) { HighlightElement(element, true); SaveBrowserWindowScreenshot(element); HighlightElement(element, false); } public static void SaveBrowserWindowScreenshot(Element element, string screenshotName) { SaveScreenshot(GetIe(element), screenshotName, SaveBitmapForCallbackArgs); } public static void SaveBrowserWindowScreenshot(Element element) { SaveScreenshot(GetIe(element), null, SaveBitmapForCallbackArgs); } public static void SaveBrowserWindowScreenshot(IE ie, string screenshotName) { SaveScreenshot(ie, screenshotName, SaveBitmapForCallbackArgs); } public static void SaveBrowserWindowScreenshot(IE ie) { SaveScreenshot(ie, null, SaveBitmapForCallbackArgs); } public static void SaveElementScreenshot(Element element, string screenshotName) { // TODO: Figure out how to get browser window "chrome" size and not have to go to full screen: var iex = (InternetExplorerClass) GetIe(element).InternetExplorer; bool fullScreen = iex.FullScreen; if (!fullScreen) iex.FullScreen = true; ScrollIntoView(element); SaveScreenshot(GetIe(element), screenshotName, args => SaveElementBitmapForCallbackArgs(element, args)); iex.FullScreen = fullScreen; } public static void SaveElementScreenshot(Element element) { SaveElementScreenshot(element, null); } private static void SaveScreenshot(IE browser, string screenshotName, Action<ScreenshotCallbackArgs> screenshotCallback) { string fileName = string.Format("{0:000}{1}{2}.jpg", ++_screenshotCount, (string.IsNullOrEmpty(screenshotName)) ? "" : " ", screenshotName); string path = Path.Combine(ScreenshotDirectoryName, fileName); Console.WriteLine(); // Gallio HTML-encodes the following display, but I have a utility program to // remove the "HTML===" and "===HTML" and un-encode the rest to show images in the Gallio report: Console.WriteLine("HTML===<div><b>{0}:</br></b><img src=\"{1}\" /></div>===HTML", screenshotName, new Uri(path).AbsoluteUri); MakeBrowserWindowTopmost(browser); try { var args = new ScreenshotCallbackArgs { InternetExplorerClass = (InternetExplorerClass)browser.InternetExplorer, ScreenshotPath = path }; Thread.Sleep(100); screenshotCallback(args); } catch (Exception ex) { Console.WriteLine(ex.Message); } } public static void HighlightElement(Element element, bool doHighlight) { if (!element.Exists) return; if (string.IsNullOrEmpty(HighlightCssClassName)) { element.Highlight(doHighlight); return; } string jsRef = element.GetJavascriptElementReference(); if (string.IsNullOrEmpty(jsRef)) return; var sb = new StringBuilder("try { "); sb.AppendFormat(" {0}.scrollIntoView(false);", jsRef); string format = (doHighlight) ? "{0}.className += ' {1}'" : "{0}.className = {0}.className.replace(' {1}', '')"; sb.AppendFormat(" " + format + ";", jsRef, HighlightCssClassName); sb.Append("} catch(e) {}"); string script = sb.ToString(); GetIe(element).RunScript(script); } public static void ScrollIntoView(Element element) { string jsRef = element.GetJavascriptElementReference(); if (string.IsNullOrEmpty(jsRef)) return; var sb = new StringBuilder("try { "); sb.AppendFormat(" {0}.scrollIntoView(false);", jsRef); sb.Append("} catch(e) {}"); string script = sb.ToString(); GetIe(element).RunScript(script); } public static void MakeBrowserWindowTopmost(IE ie) { ie.BringToFront(); SetWindowPos(ie.hWnd, HWND_TOPMOST, 0, 0, 0, 0, TOPMOST_FLAGS); } public static string HighlightCssClassName { get; set; } private static int _screenshotCount; private static string _screenshotDirectoryName; public static string ScreenshotDirectoryName { get { if (_screenshotDirectoryName == null) { var asm = Assembly.GetAssembly(typeof(WatinScreenshotSaver)); var uri = new Uri(asm.CodeBase); var fileInfo = new FileInfo(uri.LocalPath); string directoryName = fileInfo.DirectoryName; _screenshotDirectoryName = Path.Combine( directoryName, string.Format("Screenshots_{0:yyyyMMddHHmm}", DateTime.Now)); Console.WriteLine("Screenshot folder: {0}", _screenshotDirectoryName); Directory.CreateDirectory(_screenshotDirectoryName); } return _screenshotDirectoryName; } set { _screenshotDirectoryName = value; _screenshotCount = 0; } } [DllImport("user32.dll")] [return: MarshalAs(UnmanagedType.Bool)] private static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, uint uFlags); private static readonly IntPtr HWND_TOPMOST = new IntPtr(-1); private const UInt32 SWP_NOSIZE = 0x0001; private const UInt32 SWP_NOMOVE = 0x0002; private const UInt32 TOPMOST_FLAGS = SWP_NOMOVE | SWP_NOSIZE; private static IE GetIe(Element element) { if (element == null) return null; var container = element.DomContainer; while (container as IE == null) container = container.DomContainer; return (IE)container; } private static void SaveBitmapForCallbackArgs(ScreenshotCallbackArgs args) { InternetExplorerClass iex = args.InternetExplorerClass; SaveBitmap(args.ScreenshotPath, iex.Left, iex.Top, iex.Width, iex.Height); } private static void SaveElementBitmapForCallbackArgs(Element element, ScreenshotCallbackArgs args) { InternetExplorerClass iex = args.InternetExplorerClass; Rectangle bounds = GetElementBounds(element); SaveBitmap(args.ScreenshotPath, iex.Left + bounds.Left, iex.Top + bounds.Top, bounds.Width, bounds.Height); } /// <summary> /// This method is used instead of element.NativeElement.GetElementBounds because that /// method has a bug (http://sourceforge.net/tracker/?func=detail&aid=2994660&group_id=167632&atid=843727). /// </summary> private static Rectangle GetElementBounds(Element element) { var ieElem = element.NativeElement as WatiN.Core.Native.InternetExplorer.IEElement; IHTMLElement elem = ieElem.AsHtmlElement; int left = elem.offsetLeft; int top = elem.offsetTop; for (IHTMLElement parent = elem.offsetParent; parent != null; parent = parent.offsetParent) { left += parent.offsetLeft; top += parent.offsetTop; } return new Rectangle(left, top, elem.offsetWidth, elem.offsetHeight); } private static void SaveBitmap(string path, int left, int top, int width, int height) { using (var bitmap = new Bitmap(width, height)) { using (Graphics g = Graphics.FromImage(bitmap)) { g.CopyFromScreen( new Point(left, top), Point.Empty, new Size(width, height) ); } bitmap.Save(path, ImageFormat.Jpeg); } } private class ScreenshotCallbackArgs { public InternetExplorerClass InternetExplorerClass { get; set; } public string ScreenshotPath { get; set; } } } }

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• Adding DTrace Probes to PHP Extensions

  - by cj

  The powerful DTrace tracing facility has some PHP-specific probes that can be enabled with --enable-dtrace. DTrace for Linux is being created by Oracle and is currently in tech preview. Currently it doesn't support userspace tracing so, in the meantime, Systemtap can be used to monitor the probes implemented in PHP. This was recently outlined in David Soria Parra's post Probing PHP with Systemtap on Linux. My post shows how DTrace probes can be added to PHP extensions and traced on Linux. I was using Oracle Linux 6.3. Not all Linux kernels are built with Systemtap, since this can impact stability. Check whether your running kernel (or others installed) have Systemtap enabled, and reboot with such a kernel: # grep CONFIG_UTRACE /boot/config-`uname -r` # grep CONFIG_UTRACE /boot/config-* When you install Systemtap itself, the package systemtap-sdt-devel is needed since it provides the sdt.h header file: # yum install systemtap-sdt-devel You can now install and build PHP as shown in David's article. Basically the build is with: $ cd ~/php-src $ ./configure --disable-all --enable-dtrace $ make (For me, running 'make' a second time failed with an error. The workaround is to do 'git checkout Zend/zend_dtrace.d' and then rerun 'make'. See PHP Bug 63704) David's article shows how to trace the probes already implemented in PHP. You can also use Systemtap to trace things like userspace PHP function calls. For example, create test.php: <?php $c = oci_connect('hr', 'welcome', 'localhost/orcl'); $s = oci_parse($c, "select dbms_xmlgen.getxml('select * from dual') xml from dual"); $r = oci_execute($s); $row = oci_fetch_array($s, OCI_NUM); $x = $row[0]->load(); $row[0]->free(); echo $x; ?> The normal output of this file is the XML form of Oracle's DUAL table: $ ./sapi/cli/php ~/test.php <?xml version="1.0"?> <ROWSET> <ROW> <DUMMY>X</DUMMY> </ROW> </ROWSET> To trace the PHP function calls, create the tracing file functrace.stp: probe process("sapi/cli/php").function("zif_*") { printf("Started function %s\n", probefunc()); } probe process("sapi/cli/php").function("zif_*").return { printf("Ended function %s\n", probefunc()); } This makes use of the way PHP userspace functions (not builtins) like oci_connect() map to C functions with a "zif_" prefix. Login as root, and run System tap on the PHP script: # cd ~cjones/php-src # stap -c 'sapi/cli/php ~cjones/test.php' ~cjones/functrace.stp Started function zif_oci_connect Ended function zif_oci_connect Started function zif_oci_parse Ended function zif_oci_parse Started function zif_oci_execute Ended function zif_oci_execute Started function zif_oci_fetch_array Ended function zif_oci_fetch_array Started function zif_oci_lob_load <?xml version="1.0"?> <ROWSET> <ROW> <DUMMY>X</DUMMY> </ROW> </ROWSET> Ended function zif_oci_lob_load Started function zif_oci_free_descriptor Ended function zif_oci_free_descriptor Each call and return is logged. The Systemtap scripting language allows complex scripts to be built. There are many examples on the web. To augment this generic capability and the PHP probes in PHP, other extensions can have probes too. Below are the steps I used to add probes to OCI8: I created a provider file ext/oci8/oci8_dtrace.d, enabling three probes. The first one will accept a parameter that runtime tracing can later display: provider php { probe oci8__connect(char *username); probe oci8__nls_start(); probe oci8__nls_done(); }; I updated ext/oci8/config.m4 with the PHP_INIT_DTRACE macro. The patch is at the end of config.m4. The macro takes the provider prototype file, a name of the header file that 'dtrace' will generate, and a list of sources files with probes. When --enable-dtrace is used during PHP configuration, then the outer $PHP_DTRACE check is true and my new probes will be enabled. I've chosen to define an OCI8 specific macro, HAVE_OCI8_DTRACE, which can be used in the OCI8 source code: diff --git a/ext/oci8/config.m4 b/ext/oci8/config.m4 index 34ae76c..f3e583d 100644 --- a/ext/oci8/config.m4 +++ b/ext/oci8/config.m4 @@ -341,4 +341,17 @@ if test "$PHP_OCI8" != "no"; then PHP_SUBST_OLD(OCI8_ORACLE_VERSION) fi + + if test "$PHP_DTRACE" = "yes"; then + AC_CHECK_HEADERS([sys/sdt.h], [ + PHP_INIT_DTRACE([ext/oci8/oci8_dtrace.d], + [ext/oci8/oci8_dtrace_gen.h],[ext/oci8/oci8.c]) + AC_DEFINE(HAVE_OCI8_DTRACE,1, + [Whether to enable DTrace support for OCI8 ]) + ], [ + AC_MSG_ERROR( + [Cannot find sys/sdt.h which is required for DTrace support]) + ]) + fi + fi In ext/oci8/oci8.c, I added the probes at, for this example, semi-arbitrary places: diff --git a/ext/oci8/oci8.c b/ext/oci8/oci8.c index e2241cf..ffa0168 100644 --- a/ext/oci8/oci8.c +++ b/ext/oci8/oci8.c @@ -1811,6 +1811,12 @@ php_oci_connection *php_oci_do_connect_ex(char *username, int username_len, char } } +#ifdef HAVE_OCI8_DTRACE + if (DTRACE_OCI8_CONNECT_ENABLED()) { + DTRACE_OCI8_CONNECT(username); + } +#endif + /* Initialize global handles if they weren't initialized before */ if (OCI_G(env) == NULL) { php_oci_init_global_handles(TSRMLS_C); @@ -1870,11 +1876,22 @@ php_oci_connection *php_oci_do_connect_ex(char *username, int username_len, char size_t rsize = 0; sword result; +#ifdef HAVE_OCI8_DTRACE + if (DTRACE_OCI8_NLS_START_ENABLED()) { + DTRACE_OCI8_NLS_START(); + } +#endif PHP_OCI_CALL_RETURN(result, OCINlsEnvironmentVariableGet, (&charsetid_nls_lang, 0, OCI_NLS_CHARSET_ID, 0, &rsize)); if (result != OCI_SUCCESS) { charsetid_nls_lang = 0; } smart_str_append_unsigned_ex(&hashed_details, charsetid_nls_lang, 0); + +#ifdef HAVE_OCI8_DTRACE + if (DTRACE_OCI8_NLS_DONE_ENABLED()) { + DTRACE_OCI8_NLS_DONE(); + } +#endif } timestamp = time(NULL); The oci_connect(), oci_pconnect() and oci_new_connect() calls all use php_oci_do_connect_ex() internally. The first probe simply records that the PHP application made a connection call. I already showed a way to do this without needing a probe, but adding a specific probe lets me record the username. The other two probes can be used to time how long the globalization initialization takes. The relationships between the oci8_dtrace.d names like oci8__connect, the probe guards like DTRACE_OCI8_CONNECT_ENABLED() and probe names like DTRACE_OCI8_CONNECT() are obvious after seeing the pattern of all three probes. I included the new header that will be automatically created by the dtrace tool when PHP is built. I did this in ext/oci8/php_oci8_int.h: diff --git a/ext/oci8/php_oci8_int.h b/ext/oci8/php_oci8_int.h index b0d6516..c81fc5a 100644 --- a/ext/oci8/php_oci8_int.h +++ b/ext/oci8/php_oci8_int.h @@ -44,6 +44,10 @@ # endif # endif /* osf alpha */ +#ifdef HAVE_OCI8_DTRACE +#include "oci8_dtrace_gen.h" +#endif + #if defined(min) #undef min #endif Now PHP can be rebuilt: $ cd ~/php-src $ rm configure && ./buildconf --force $ ./configure --disable-all --enable-dtrace \ --with-oci8=instantclient,/home/cjones/instantclient $ make If 'make' fails, do the 'git checkout Zend/zend_dtrace.d' trick I mentioned. The new probes can be seen by logging in as root and running: # stap -l 'process.provider("php").mark("oci8*")' -c 'sapi/cli/php -i' process("sapi/cli/php").provider("php").mark("oci8__connect") process("sapi/cli/php").provider("php").mark("oci8__nls_done") process("sapi/cli/php").provider("php").mark("oci8__nls_start") To test them out, create a new trace file, oci.stp: global numconnects; global start; global numcharlookups = 0; global tottime = 0; probe process.provider("php").mark("oci8-connect") { printf("Connected as %s\n", user_string($arg1)); numconnects += 1; } probe process.provider("php").mark("oci8-nls_start") { start = gettimeofday_us(); numcharlookups++; } probe process.provider("php").mark("oci8-nls_done") { tottime += gettimeofday_us() - start; } probe end { printf("Connects: %d, Charset lookups: %ld\n", numconnects, numcharlookups); printf("Total NLS charset initalization time: %ld usecs/connect\n", (numcharlookups 0 ? tottime/numcharlookups : 0)); } This calculates the average time that the NLS character set lookup takes. It also prints out the username of each connection, as an example of using parameters. Login as root and run Systemtap over the PHP script: # cd ~cjones/php-src # stap -c 'sapi/cli/php ~cjones/test.php' ~cjones/oci.stp Connected as cj <?xml version="1.0"?> <ROWSET> <ROW> <DUMMY>X</DUMMY> </ROW> </ROWSET> Connects: 1, Charset lookups: 1 Total NLS charset initalization time: 164 usecs/connect This shows the time penalty of making OCI8 look up the default character set. This time would be zero if a character set had been passed as the fourth argument to oci_connect() in test.php.

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• Problems with Update Manager

  - by user65965

  Whenever I try to update with update manager I get the following errors: W:Failed to fetch http://archive.ubuntu.com/ubuntu/dists/precise/Release Unable to find expected entry 'commercial/source/Sources' in Release file (Wrong sources.list entry or malformed file) W:Failed to fetch http://archive.ubuntu.com/ubuntu/dists/precise-updates/Release Unable to find expected entry 'commercial/source/Sources' in Release file (Wrong sources.list entry or malformed file) W:Failed to fetch http://archive.ubuntu.com/ubuntu/dists/precise-backports/Release Unable to find expected entry 'commercial/source/Sources' in Release file (Wrong sources.list entry or malformed file) W:Failed to fetch http://archive.ubuntu.com/ubuntu/dists/precise-security/Release Unable to find expected entry 'commercial/source/Sources' in Release file (Wrong sources.list entry or malformed file) W:Failed to fetch http://ppa.launchpad.net/iefremov/ppa/ubuntu/dists/precise/main/source/Sources 404 Not Found W:Failed to fetch http://ppa.launchpad.net/iefremov/ppa/ubuntu/dists/precise/main/binary-amd64/Packages 404 Not Found W:Failed to fetch http://ppa.launchpad.net/iefremov/ppa/ubuntu/dists/precise/main/binary-i386/Packages 404 Not Found E:Some index files failed to download. They have been ignored, or old ones used instead. Any help would be much appreciated, thank you. Thank you very much Eliah. I'm still pretty new to Ubuntu. Here's the output I got from the terminal: No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 12.04 LTS Release: 12.04 Codename: precise # See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to # newer versions of the distribution. deb http://archive.ubuntu.com/ubuntu precise main restricted commercial deb-src http://archive.ubuntu.com/ubuntu precise restricted main commercial multiverse universe #Added by software-properties ## Major bug fix updates produced after the final release of the ## distribution. deb http://archive.ubuntu.com/ubuntu precise-updates main restricted commercial deb-src http://archive.ubuntu.com/ubuntu precise-updates restricted main commercial multiverse universe #Added by software-properties ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team. Also, please note that software in universe WILL NOT receive any ## review or updates from the Ubuntu security team. deb http://archive.ubuntu.com/ubuntu precise universe deb http://archive.ubuntu.com/ubuntu precise-updates universe ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team, and may not be under a free licence. Please satisfy yourself as to ## your rights to use the software. Also, please note that software in ## multiverse WILL NOT receive any review or updates from the Ubuntu ## security team. deb http://archive.ubuntu.com/ubuntu precise multiverse deb http://archive.ubuntu.com/ubuntu precise-updates multiverse ## N.B. software from this repository may not have been tested as ## extensively as that contained in the main release, although it includes ## newer versions of some applications which may provide useful features. ## Also, please note that software in backports WILL NOT receive any review ## or updates from the Ubuntu security team. deb http://archive.ubuntu.com/ubuntu precise-backports main restricted universe multiverse commercial deb-src http://archive.ubuntu.com/ubuntu precise-backports main restricted universe multiverse commercial #Added by software-properties deb http://archive.ubuntu.com/ubuntu precise-security main restricted commercial deb-src http://archive.ubuntu.com/ubuntu precise-security restricted main commercial multiverse universe #Added by software-properties deb http://archive.ubuntu.com/ubuntu precise-security universe deb http://archive.ubuntu.com/ubuntu precise-security multiverse ## Uncomment the following two lines to add software from Canonical's ## 'partner' repository. ## This software is not part of Ubuntu, but is offered by Canonical and the ## respective vendors as a service to Ubuntu users. deb http://archive.canonical.com/ubuntu oneiric partner deb-src http://archive.canonical.com/ubuntu precise partner ## This software is not part of Ubuntu, but is offered by third-party ## developers who want to ship their latest software. deb http://extras.ubuntu.com/ubuntu precise main deb-src http://extras.ubuntu.com/ubuntu precise main ## This is a 3rd party script to install and update Oracle Java deb http://www.duinsoft.nl/pkg debs all ## Sun-Java6-JRE deb http://security.ubuntu.com/ubuntu hardy-security main multiverse ** /etc/apt/sources.list.d/askubuntu-tools-ppa-precise.list: deb http://ppa.launchpad.net/askubuntu-tools/ppa/ubuntu precise main deb-src http://ppa.launchpad.net/askubuntu-tools/ppa/ubuntu precise main ** /etc/apt/sources.list.d/askubuntu-tools-ppa-precise.list.save: deb http://ppa.launchpad.net/askubuntu-tools/ppa/ubuntu precise main deb-src http://ppa.launchpad.net/askubuntu-tools/ppa/ubuntu precise main ** /etc/apt/sources.list.d/effie-jayx-turpial-oneiric.list: deb http://ppa.launchpad.net/effie-jayx/turpial/ubuntu precise main # disabled on upgrade to precise deb-src http://ppa.launchpad.net/effie-jayx/turpial/ubuntu precise main # disabled on upgrade to precise ** /etc/apt/sources.list.d/effie-jayx-turpial-oneiric.list.distUpgrade: deb http://ppa.launchpad.net/effie-jayx/turpial/ubuntu oneiric main deb-src http://ppa.launchpad.net/effie-jayx/turpial/ubuntu oneiric main ** /etc/apt/sources.list.d/effie-jayx-turpial-oneiric.list.save: deb http://ppa.launchpad.net/effie-jayx/turpial/ubuntu precise main # disabled on upgrade to precise deb-src http://ppa.launchpad.net/effie-jayx/turpial/ubuntu precise main # disabled on upgrade to precise ** /etc/apt/sources.list.d/getdeb.list: # deb http://archive.getdeb.net/ubuntu oneiric-getdeb apps # disabled on upgrade to precise ** /etc/apt/sources.list.d/getdeb.list.distUpgrade: deb http://archive.getdeb.net/ubuntu oneiric-getdeb apps ** /etc/apt/sources.list.d/getdeb.list.save: # deb http://archive.getdeb.net/ubuntu oneiric-getdeb apps # disabled on upgrade to precise ** /etc/apt/sources.list.d/hotot-team-ppa-oneiric.list: deb http://ppa.launchpad.net/hotot-team/ppa/ubuntu precise main # disabled on upgrade to precise deb-src http://ppa.launchpad.net/hotot-team/ppa/ubuntu precise main # disabled on upgrade to precise ** /etc/apt/sources.list.d/hotot-team-ppa-oneiric.list.distUpgrade: deb http://ppa.launchpad.net/hotot-team/ppa/ubuntu oneiric main deb-src http://ppa.launchpad.net/hotot-team/ppa/ubuntu oneiric main ** /etc/apt/sources.list.d/hotot-team-ppa-oneiric.list.save: deb http://ppa.launchpad.net/hotot-team/ppa/ubuntu precise main # disabled on upgrade to precise deb-src http://ppa.launchpad.net/hotot-team/ppa/ubuntu precise main # disabled on upgrade to precise ** /etc/apt/sources.list.d/iefremov-ppa-precise.list: deb http://ppa.launchpad.net/iefremov/ppa/ubuntu precise main deb-src http://ppa.launchpad.net/iefremov/ppa/ubuntu precise main ** /etc/apt/sources.list.d/iefremov-ppa-precise.list.save: deb http://ppa.launchpad.net/iefremov/ppa/ubuntu precise main deb-src http://ppa.launchpad.net/iefremov/ppa/ubuntu precise main ** /etc/apt/sources.list.d/jockey.list: deb http://www.openprinting.org/download/printdriver/debian/ lsb3.2 main-nonfree # disabled on upgrade to precise ** /etc/apt/sources.list.d/jockey.list.distUpgrade: deb http://www.openprinting.org/download/printdriver/debian/ lsb3.2 main-nonfree ** /etc/apt/sources.list.d/jockey.list.save: deb http://www.openprinting.org/download/printdriver/debian/ lsb3.2 main-nonfree # disabled on upgrade to precise ** /etc/apt/sources.list.d/plexydesk-plexydesk-dailybuild-precise.list: deb http://ppa.launchpad.net/plexydesk/plexydesk-dailybuild/ubuntu precise main deb-src http://ppa.launchpad.net/plexydesk/plexydesk-dailybuild/ubuntu precise main ** /etc/apt/sources.list.d/plexydesk-plexydesk-dailybuild-precise.list.save: deb http://ppa.launchpad.net/plexydesk/plexydesk-dailybuild/ubuntu precise main deb-src http://ppa.launchpad.net/plexydesk/plexydesk-dailybuild/ubuntu precise main ** /etc/apt/sources.list.d/precise-partner.list: deb http://archive.canonical.com/ubuntu precise partner #Added by software-center ** /etc/apt/sources.list.d/precise-partner.list.save: deb http://archive.canonical.com/ubuntu precise partner #Added by software-center ** /etc/apt/sources.list.d/private-ppa.launchpad.net_commercial-ppa-uploaders_crossover-pro_ubuntu.list: # deb https://justin-dormandy:[email protected]/commercial-ppa-uploaders/crossover-pro/ubuntu precise main #Added by software-center disabled on upgrade to precise ** /etc/apt/sources.list.d/private-ppa.launchpad.net_commercial-ppa-uploaders_crossover-pro_ubuntu.list.distUpgrade: cat: /etc/apt/sources.list.d/private-ppa.launchpad.net_commercial-ppa-uploaders_crossover-pro_ubuntu.list.distUpgrade: Permission denied ** /etc/apt/sources.list.d/private-ppa.launchpad.net_commercial-ppa-uploaders_crossover-pro_ubuntu.list.save: cat: /etc/apt/sources.list.d/private-ppa.launchpad.net_commercial-ppa-uploaders_crossover-pro_ubuntu.list.save: Permission denied ** /etc/apt/sources.list.d/screenlets-ppa-precise.list: deb http://ppa.launchpad.net/screenlets/ppa/ubuntu precise main deb-src http://ppa.launchpad.net/screenlets/ppa/ubuntu precise main ** /etc/apt/sources.list.d/screenlets-ppa-precise.list.save: deb http://ppa.launchpad.net/screenlets/ppa/ubuntu precise main deb-src http://ppa.launchpad.net/screenlets/ppa/ubuntu precise main ** /etc/apt/sources.list.d/webupd8team-java-precise.list: deb http://ppa.launchpad.net/webupd8team/java/ubuntu precise main deb-src http://ppa.launchpad.net/webupd8team/java/ubuntu precise main ** /etc/apt/sources.list.d/webupd8team-java-precise.list.save: deb http://ppa.launchpad.net/webupd8team/java/ubuntu precise main deb-src http://ppa.launchpad.net/webupd8team/java/ubuntu precise main

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• SQL Server 2012 - AlwaysOn

  - by Claus Jandausch

  Ich war nicht nur irritiert, ich war sogar regelrecht schockiert - und für einen kurzen Moment sprachlos (was nur selten der Fall ist). Gerade eben hatte mich jemand gefragt "Wann Oracle denn etwas Vergleichbares wie AlwaysOn bieten würde - und ob überhaupt?" War ich hier im falschen Film gelandet? Ich konnte nicht anders, als meinen Unmut kundzutun und zu erklären, dass die Fragestellung normalerweise anders herum läuft. Zugegeben - es mag vielleicht strittige Punkte geben im Vergleich zwischen Oracle und SQL Server - bei denen nicht unbedingt immer Oracle die Nase vorn haben muss - aber das Thema Clustering für Hochverfügbarkeit (HA), Disaster Recovery (DR) und Skalierbarkeit gehört mit Sicherheit nicht dazu. Dieses Erlebnis hakte ich am Nachgang als Einzelfall ab, der so nie wieder vorkommen würde. Bis ich kurz darauf eines Besseren belehrt wurde und genau die selbe Frage erneut zu hören bekam. Diesmal sogar im Exadata-Umfeld und einem Oracle Stretch Cluster. Einmal ist keinmal, doch zweimal ist einmal zu viel... Getreu diesem alten Motto war mir klar, dass man das so nicht länger stehen lassen konnte. Ich habe keine Ahnung, wie die Microsoft Marketing Abteilung es geschafft hat, unter dem AlwaysOn Brading eine innovative Technologie vermuten zu lassen - aber sie hat ihren Job scheinbar gut gemacht. Doch abgesehen von einem guten Marketing, stellt sich natürlich die Frage, was wirklich dahinter steckt und wie sich das Ganze mit Oracle vergleichen lässt - und ob überhaupt? Damit wären wir wieder bei der ursprünglichen Frage angelangt.  So viel zum Hintergrund dieses Blogbeitrags - von meiner Antwort handelt der restliche Blog. "Windows was the God ..." Um den wahren Unterschied zwischen Oracle und Microsoft verstehen zu können, muss man zunächst das bedeutendste Microsoft Dogma kennen. Es lässt sich schlicht und einfach auf den Punkt bringen: "Alles muss auf Windows basieren." Die Überschrift dieses Absatzes ist kein von mir erfundener Ausspruch, sondern ein Zitat. Konkret stammt es aus einem längeren Artikel von Kurt Eichenwald in der Vanity Fair aus dem August 2012. Er lautet Microsoft's Lost Decade und sei jedem ans Herz gelegt, der die "Microsoft-Maschinerie" unter Steve Ballmer und einige ihrer Kuriositäten besser verstehen möchte. "YOU TALKING TO ME?" Microsoft C.E.O. Steve Ballmer bei seiner Keynote auf der 2012 International Consumer Electronics Show in Las Vegas am 9. Januar   Manche Dinge in diesem Artikel mögen überspitzt dargestellt erscheinen - sind sie aber nicht. Vieles davon kannte ich bereits aus eigener Erfahrung und kann es nur bestätigen. Anderes hat sich mir erst so richtig erschlossen. Insbesondere die folgenden Passagen führten zum Aha-Erlebnis: “Windows was the god—everything had to work with Windows,” said Stone... “Every little thing you want to write has to build off of Windows (or other existing roducts),” one software engineer said. “It can be very confusing, …” Ich habe immer schon darauf hingewiesen, dass in einem SQL Server Failover Cluster die Microsoft Datenbank eigentlich nichts Nenneswertes zum Geschehen beiträgt, sondern sich voll und ganz auf das Windows Betriebssystem verlässt. Deshalb muss man auch die Windows Server Enterprise Edition installieren, soll ein Failover Cluster für den SQL Server eingerichtet werden. Denn hier werden die Cluster Services geliefert - nicht mit dem SQL Server. Er ist nur lediglich ein weiteres Server Produkt, für das Windows in Ausfallszenarien genutzt werden kann - so wie Microsoft Exchange beispielsweise, oder Microsoft SharePoint, oder irgendein anderes Server Produkt das auf Windows gehostet wird. Auch Oracle kann damit genutzt werden. Das Stichwort lautet hier: Oracle Failsafe. Nur - warum sollte man das tun, wenn gleichzeitig eine überlegene Technologie wie die Oracle Real Application Clusters (RAC) zur Verfügung steht, die dann auch keine Windows Enterprise Edition voraussetzen, da Oracle die eigene Clusterware liefert. Welche darüber hinaus für kürzere Failover-Zeiten sorgt, da diese Cluster-Technologie Datenbank-integriert ist und sich nicht auf "Dritte" verlässt. Wenn man sich also schon keine technischen Vorteile mit einem SQL Server Failover Cluster erkauft, sondern zusätzlich noch versteckte Lizenzkosten durch die Lizenzierung der Windows Server Enterprise Edition einhandelt, warum hat Microsoft dann in den vergangenen Jahren seit SQL Server 2000 nicht ebenfalls an einer neuen und innovativen Lösung gearbeitet, die mit Oracle RAC mithalten kann? Entwickler hat Microsoft genügend? Am Geld kann es auch nicht liegen? Lesen Sie einfach noch einmal die beiden obenstehenden Zitate und sie werden den Grund verstehen. Anders lässt es sich ja auch gar nicht mehr erklären, dass AlwaysOn aus zwei unterschiedlichen Technologien besteht, die beide jedoch wiederum auf dem Windows Server Failover Clustering (WSFC) basieren. Denn daraus ergeben sich klare Nachteile - aber dazu später mehr. Um AlwaysOn zu verstehen, sollte man sich zunächst kurz in Erinnerung rufen, was Microsoft bisher an HA/DR (High Availability/Desaster Recovery) Lösungen für SQL Server zur Verfügung gestellt hat. Replikation Basiert auf logischer Replikation und Pubisher/Subscriber Architektur Transactional Replication Merge Replication Snapshot Replication Microsoft's Replikation ist vergleichbar mit Oracle GoldenGate. Oracle GoldenGate stellt jedoch die umfassendere Technologie dar und bietet High Performance. Log Shipping Microsoft's Log Shipping stellt eine einfache Technologie dar, die vergleichbar ist mit Oracle Managed Recovery in Oracle Version 7. Das Log Shipping besitzt folgende Merkmale: Transaction Log Backups werden von Primary nach Secondary/ies geschickt Einarbeitung (z.B. Restore) auf jedem Secondary individuell Optionale dritte Server Instanz (Monitor Server) für Überwachung und Alarm Log Restore Unterbrechung möglich für Read-Only Modus (Secondary) Keine Unterstützung von Automatic Failover Database Mirroring Microsoft's Database Mirroring wurde verfügbar mit SQL Server 2005, sah aus wie Oracle Data Guard in Oracle 9i, war funktional jedoch nicht so umfassend. Für ein HA/DR Paar besteht eine 1:1 Beziehung, um die produktive Datenbank (Principle DB) abzusichern. Auf der Standby Datenbank (Mirrored DB) werden alle Insert-, Update- und Delete-Operationen nachgezogen. Modi Synchron (High-Safety Modus) Asynchron (High-Performance Modus) Automatic Failover Unterstützt im High-Safety Modus (synchron) Witness Server vorausgesetzt     Zur Frage der Kontinuität Es stellt sich die Frage, wie es um diesen Technologien nun im Zusammenhang mit SQL Server 2012 bestellt ist. Unter Fanfaren seinerzeit eingeführt, war Database Mirroring das erklärte Mittel der Wahl. Ich bin kein Produkt Manager bei Microsoft und kann hierzu nur meine Meinung äußern, aber zieht man den SQL AlwaysOn Team Blog heran, so sieht es nicht gut aus für das Database Mirroring - zumindest nicht langfristig. "Does AlwaysOn Availability Group replace Database Mirroring going forward?” “The short answer is we recommend that you migrate from the mirroring configuration or even mirroring and log shipping configuration to using Availability Group. Database Mirroring will still be available in the Denali release but will be phased out over subsequent releases. Log Shipping will continue to be available in future releases.” Damit wären wir endlich beim eigentlichen Thema angelangt. Was ist eine sogenannte Availability Group und was genau hat es mit der vielversprechend klingenden Bezeichnung AlwaysOn auf sich?   SQL Server 2012 - AlwaysOn Zwei HA-Features verstekcne sich hinter dem “AlwaysOn”-Branding. Einmal das AlwaysOn Failover Clustering aka SQL Server Failover Cluster Instances (FCI) - zum Anderen die AlwaysOn Availability Groups. Failover Cluster Instances (FCI) Entspricht ungefähr dem Stretch Cluster Konzept von Oracle Setzt auf Windows Server Failover Clustering (WSFC) auf Bietet HA auf Instanz-Ebene AlwaysOn Availability Groups (Verfügbarkeitsgruppen) Ähnlich der Idee von Consistency Groups, wie in Storage-Level Replikations-Software von z.B. EMC SRDF Abhängigkeiten zu Windows Server Failover Clustering (WSFC) Bietet HA auf Datenbank-Ebene   Hinweis: Verwechseln Sie nicht eine SQL Server Datenbank mit einer Oracle Datenbank. Und auch nicht eine Oracle Instanz mit einer SQL Server Instanz. Die gleichen Begriffe haben hier eine andere Bedeutung - nicht selten ein Grund, weshalb Oracle- und Microsoft DBAs schnell aneinander vorbei reden. Denken Sie bei einer SQL Server Datenbank eher an ein Oracle Schema, das kommt der Sache näher. So etwas wie die SQL Server Northwind Datenbank ist vergleichbar mit dem Oracle Scott Schema. Wenn Sie die genauen Unterschiede kennen möchten, finden Sie eine detaillierte Beschreibung in meinem Buch "Oracle10g Release 2 für Windows und .NET", erhältich bei Lehmanns, Amazon, etc.   Windows Server Failover Clustering (WSFC) Wie man sieht, basieren beide AlwaysOn Technologien wiederum auf dem Windows Server Failover Clustering (WSFC), um einerseits Hochverfügbarkeit auf Ebene der Instanz zu gewährleisten und andererseits auf der Datenbank-Ebene. Deshalb nun eine kurze Beschreibung der WSFC. Die WSFC sind ein mit dem Windows Betriebssystem geliefertes Infrastruktur-Feature, um HA für Server Anwendungen, wie Microsoft Exchange, SharePoint, SQL Server, etc. zu bieten. So wie jeder andere Cluster, besteht ein WSFC Cluster aus einer Gruppe unabhängiger Server, die zusammenarbeiten, um die Verfügbarkeit einer Applikation oder eines Service zu erhöhen. Falls ein Cluster-Knoten oder -Service ausfällt, kann der auf diesem Knoten bisher gehostete Service automatisch oder manuell auf einen anderen im Cluster verfügbaren Knoten transferriert werden - was allgemein als Failover bekannt ist. Unter SQL Server 2012 verwenden sowohl die AlwaysOn Avalability Groups, als auch die AlwaysOn Failover Cluster Instances die WSFC als Plattformtechnologie, um Komponenten als WSFC Cluster-Ressourcen zu registrieren. Verwandte Ressourcen werden in eine Ressource Group zusammengefasst, die in Abhängigkeit zu anderen WSFC Cluster-Ressourcen gebracht werden kann. Der WSFC Cluster Service kann jetzt die Notwendigkeit zum Neustart der SQL Server Instanz erfassen oder einen automatischen Failover zu einem anderen Server-Knoten im WSFC Cluster auslösen.   Failover Cluster Instances (FCI) Eine SQL Server Failover Cluster Instanz (FCI) ist eine einzelne SQL Server Instanz, die in einem Failover Cluster betrieben wird, der aus mehreren Windows Server Failover Clustering (WSFC) Knoten besteht und so HA (High Availability) auf Ebene der Instanz bietet. Unter Verwendung von Multi-Subnet FCI kann auch Remote DR (Disaster Recovery) unterstützt werden. Eine weitere Option für Remote DR besteht darin, eine unter FCI gehostete Datenbank in einer Availability Group zu betreiben. Hierzu später mehr. FCI und WSFC Basis FCI, das für lokale Hochverfügbarkeit der Instanzen genutzt wird, ähnelt der veralteten Architektur eines kalten Cluster (Aktiv-Passiv). Unter SQL Server 2008 wurde diese Technologie SQL Server 2008 Failover Clustering genannt. Sie nutzte den Windows Server Failover Cluster. In SQL Server 2012 hat Microsoft diese Basistechnologie unter der Bezeichnung AlwaysOn zusammengefasst. Es handelt sich aber nach wie vor um die klassische Aktiv-Passiv-Konfiguration. Der Ablauf im Failover-Fall ist wie folgt: Solange kein Hardware-oder System-Fehler auftritt, werden alle Dirty Pages im Buffer Cache auf Platte geschrieben Alle entsprechenden SQL Server Services (Dienste) in der Ressource Gruppe werden auf dem aktiven Knoten gestoppt Die Ownership der Ressource Gruppe wird auf einen anderen Knoten der FCI transferriert Der neue Owner (Besitzer) der Ressource Gruppe startet seine SQL Server Services (Dienste) Die Connection-Anforderungen einer Client-Applikation werden automatisch auf den neuen aktiven Knoten mit dem selben Virtuellen Network Namen (VNN) umgeleitet Abhängig vom Zeitpunkt des letzten Checkpoints, kann die Anzahl der Dirty Pages im Buffer Cache, die noch auf Platte geschrieben werden müssen, zu unvorhersehbar langen Failover-Zeiten führen. Um diese Anzahl zu drosseln, besitzt der SQL Server 2012 eine neue Fähigkeit, die Indirect Checkpoints genannt wird. Indirect Checkpoints ähnelt dem Fast-Start MTTR Target Feature der Oracle Datenbank, das bereits mit Oracle9i verfügbar war.   SQL Server Multi-Subnet Clustering Ein SQL Server Multi-Subnet Failover Cluster entspricht vom Konzept her einem Oracle RAC Stretch Cluster. Doch dies ist nur auf den ersten Blick der Fall. Im Gegensatz zu RAC ist in einem lokalen SQL Server Failover Cluster jeweils nur ein Knoten aktiv für eine Datenbank. Für die Datenreplikation zwischen geografisch entfernten Sites verlässt sich Microsoft auf 3rd Party Lösungen für das Storage Mirroring.     Die Verbesserung dieses Szenario mit einer SQL Server 2012 Implementierung besteht schlicht darin, dass eine VLAN-Konfiguration (Virtual Local Area Network) nun nicht mehr benötigt wird, so wie dies bisher der Fall war. Das folgende Diagramm stellt dar, wie der Ablauf mit SQL Server 2012 gehandhabt wird. In Site A und Site B wird HA jeweils durch einen lokalen Aktiv-Passiv-Cluster sichergestellt.     Besondere Aufmerksamkeit muss hier der Konfiguration und dem Tuning geschenkt werden, da ansonsten völlig inakzeptable Failover-Zeiten resultieren. Dies liegt darin begründet, weil die Downtime auf Client-Seite nun nicht mehr nur von der reinen Failover-Zeit abhängt, sondern zusätzlich von der Dauer der DNS Replikation zwischen den DNS Servern. (Rufen Sie sich in Erinnerung, dass wir gerade von Multi-Subnet Clustering sprechen). Außerdem ist zu berücksichtigen, wie schnell die Clients die aktualisierten DNS Informationen abfragen. Spezielle Konfigurationen für Node Heartbeat, HostRecordTTL (Host Record Time-to-Live) und Intersite Replication Frequeny für Active Directory Sites und Services werden notwendig. Default TTL für Windows Server 2008 R2: 20 Minuten Empfohlene Einstellung: 1 Minute DNS Update Replication Frequency in Windows Umgebung: 180 Minuten Empfohlene Einstellung: 15 Minuten (minimaler Wert)   Betrachtet man diese Werte, muss man feststellen, dass selbst eine optimale Konfiguration die rigiden SLAs (Service Level Agreements) heutiger geschäftskritischer Anwendungen für HA und DR nicht erfüllen kann. Denn dies impliziert eine auf der Client-Seite erlebte Failover-Zeit von insgesamt 16 Minuten. Hierzu ein Auszug aus der SQL Server 2012 Online Dokumentation: Cons: If a cross-subnet failover occurs, the client recovery time could be 15 minutes or longer, depending on your HostRecordTTL setting and the setting of your cross-site DNS/AD replication schedule.    Wir sind hier an einem Punkt unserer Überlegungen angelangt, an dem sich erklärt, weshalb ich zuvor das "Windows was the God ..." Zitat verwendet habe. Die unbedingte Abhängigkeit zu Windows wird zunehmend zum Problem, da sie die Komplexität einer Microsoft-basierenden Lösung erhöht, anstelle sie zu reduzieren. Und Komplexität ist das Letzte, was sich CIOs heutzutage wünschen.  Zur Ehrenrettung des SQL Server 2012 und AlwaysOn muss man sagen, dass derart lange Failover-Zeiten kein unbedingtes "Muss" darstellen, sondern ein "Kann". Doch auch ein "Kann" kann im unpassenden Moment unvorhersehbare und kostspielige Folgen haben. Die Unabsehbarkeit ist wiederum Ursache vieler an der Implementierung beteiligten Komponenten und deren Abhängigkeiten, wie beispielsweise drei Cluster-Lösungen (zwei von Microsoft, eine 3rd Party Lösung). Wie man die Sache auch dreht und wendet, kommt man an diesem Fakt also nicht vorbei - ganz unabhängig von der Dauer einer Downtime oder Failover-Zeiten. Im Gegensatz zu AlwaysOn und der hier vorgestellten Version eines Stretch-Clusters, vermeidet eine entsprechende Oracle Implementierung eine derartige Komplexität, hervorgerufen duch multiple Abhängigkeiten. Den Unterschied machen Datenbank-integrierte Mechanismen, wie Fast Application Notification (FAN) und Fast Connection Failover (FCF). Für Oracle MAA Konfigurationen (Maximum Availability Architecture) sind Inter-Site Failover-Zeiten im Bereich von Sekunden keine Seltenheit. Wenn Sie dem Link zur Oracle MAA folgen, finden Sie außerdem eine Reihe an Customer Case Studies. Auch dies ist ein wichtiges Unterscheidungsmerkmal zu AlwaysOn, denn die Oracle Technologie hat sich bereits zigfach in höchst kritischen Umgebungen bewährt.   Availability Groups (Verfügbarkeitsgruppen) Die sogenannten Availability Groups (Verfügbarkeitsgruppen) sind - neben FCI - der weitere Baustein von AlwaysOn.   Hinweis: Bevor wir uns näher damit beschäftigen, sollten Sie sich noch einmal ins Gedächtnis rufen, dass eine SQL Server Datenbank nicht die gleiche Bedeutung besitzt, wie eine Oracle Datenbank, sondern eher einem Oracle Schema entspricht. So etwas wie die SQL Server Northwind Datenbank ist vergleichbar mit dem Oracle Scott Schema.   Eine Verfügbarkeitsgruppe setzt sich zusammen aus einem Set mehrerer Benutzer-Datenbanken, die im Falle eines Failover gemeinsam als Gruppe behandelt werden. Eine Verfügbarkeitsgruppe unterstützt ein Set an primären Datenbanken (primäres Replikat) und einem bis vier Sets von entsprechenden sekundären Datenbanken (sekundäre Replikate).       Es können jedoch nicht alle SQL Server Datenbanken einer AlwaysOn Verfügbarkeitsgruppe zugeordnet werden. Der SQL Server Spezialist Michael Otey zählt in seinem SQL Server Pro Artikel folgende Anforderungen auf: Verfügbarkeitsgruppen müssen mit Benutzer-Datenbanken erstellt werden. System-Datenbanken können nicht verwendet werden Die Datenbanken müssen sich im Read-Write Modus befinden. Read-Only Datenbanken werden nicht unterstützt Die Datenbanken in einer Verfügbarkeitsgruppe müssen Multiuser Datenbanken sein Sie dürfen nicht das AUTO_CLOSE Feature verwenden Sie müssen das Full Recovery Modell nutzen und es muss ein vollständiges Backup vorhanden sein Eine gegebene Datenbank kann sich nur in einer einzigen Verfügbarkeitsgruppe befinden und diese Datenbank düerfen nicht für Database Mirroring konfiguriert sein Microsoft empfiehl außerdem, dass der Verzeichnispfad einer Datenbank auf dem primären und sekundären Server identisch sein sollte Wie man sieht, eignen sich Verfügbarkeitsgruppen nicht, um HA und DR vollständig abzubilden. Die Unterscheidung zwischen der Instanzen-Ebene (FCI) und Datenbank-Ebene (Availability Groups) ist von hoher Bedeutung. Vor kurzem wurde mir gesagt, dass man mit den Verfügbarkeitsgruppen auf Shared Storage verzichten könne und dadurch Kosten spart. So weit so gut ... Man kann natürlich eine Installation rein mit Verfügbarkeitsgruppen und ohne FCI durchführen - aber man sollte sich dann darüber bewusst sein, was man dadurch alles nicht abgesichert hat - und dies wiederum für Desaster Recovery (DR) und SLAs (Service Level Agreements) bedeutet. Kurzum, um die Kombination aus beiden AlwaysOn Produkten und der damit verbundene Komplexität kommt man wohl in der Praxis nicht herum.    Availability Groups und WSFC AlwaysOn hängt von Windows Server Failover Clustering (WSFC) ab, um die aktuellen Rollen der Verfügbarkeitsreplikate einer Verfügbarkeitsgruppe zu überwachen und zu verwalten, und darüber zu entscheiden, wie ein Failover-Ereignis die Verfügbarkeitsreplikate betrifft. Das folgende Diagramm zeigt de Beziehung zwischen Verfügbarkeitsgruppen und WSFC:   Der Verfügbarkeitsmodus ist eine Eigenschaft jedes Verfügbarkeitsreplikats. Synychron und Asynchron können also gemischt werden: Availability Modus (Verfügbarkeitsmodus) Asynchroner Commit-Modus Primäres replikat schließt Transaktionen ohne Warten auf Sekundäres Synchroner Commit-Modus Primäres Replikat wartet auf Commit von sekundärem Replikat Failover Typen Automatic Manual Forced (mit möglichem Datenverlust) Synchroner Commit-Modus Geplanter, manueller Failover ohne Datenverlust Automatischer Failover ohne Datenverlust Asynchroner Commit-Modus Nur Forced, manueller Failover mit möglichem Datenverlust   Der SQL Server kennt keinen separaten Switchover Begriff wie in Oracle Data Guard. Für SQL Server werden alle Role Transitions als Failover bezeichnet. Tatsächlich unterstützt der SQL Server keinen Switchover für asynchrone Verbindungen. Es gibt nur die Form des Forced Failover mit möglichem Datenverlust. Eine ähnliche Fähigkeit wie der Switchover unter Oracle Data Guard ist so nicht gegeben.   SQL Sever FCI mit Availability Groups (Verfügbarkeitsgruppen) Neben den Verfügbarkeitsgruppen kann eine zweite Failover-Ebene eingerichtet werden, indem SQL Server FCI (auf Shared Storage) mit WSFC implementiert wird. Ein Verfügbarkeitesreplikat kann dann auf einer Standalone Instanz gehostet werden, oder einer FCI Instanz. Zum Verständnis: Die Verfügbarkeitsgruppen selbst benötigen kein Shared Storage. Diese Kombination kann verwendet werden für lokale HA auf Ebene der Instanz und DR auf Datenbank-Ebene durch Verfügbarkeitsgruppen. Das folgende Diagramm zeigt dieses Szenario:   Achtung! Hier handelt es sich nicht um ein Pendant zu Oracle RAC plus Data Guard, auch wenn das Bild diesen Eindruck vielleicht vermitteln mag - denn alle sekundären Knoten im FCI sind rein passiv. Es existiert außerdem eine weitere und ernsthafte Einschränkung: SQL Server Failover Cluster Instanzen (FCI) unterstützen nicht das automatische AlwaysOn Failover für Verfügbarkeitsgruppen. Jedes unter FCI gehostete Verfügbarkeitsreplikat kann nur für manuelles Failover konfiguriert werden.   Lesbare Sekundäre Replikate Ein oder mehrere Verfügbarkeitsreplikate in einer Verfügbarkeitsgruppe können für den lesenden Zugriff konfiguriert werden, wenn sie als sekundäres Replikat laufen. Dies ähnelt Oracle Active Data Guard, jedoch gibt es Einschränkungen. Alle Abfragen gegen die sekundäre Datenbank werden automatisch auf das Snapshot Isolation Level abgebildet. Es handelt sich dabei um eine Versionierung der Rows. Microsoft versuchte hiermit die Oracle MVRC (Multi Version Read Consistency) nachzustellen. Tatsächlich muss man die SQL Server Snapshot Isolation eher mit Oracle Flashback vergleichen. Bei der Implementierung des Snapshot Isolation Levels handelt sich um ein nachträglich aufgesetztes Feature und nicht um einen inhärenten Teil des Datenbank-Kernels, wie im Falle Oracle. (Ich werde hierzu in Kürze einen weiteren Blogbeitrag verfassen, wenn ich mich mit der neuen SQL Server 2012 Core Lizenzierung beschäftige.) Für die Praxis entstehen aus der Abbildung auf das Snapshot Isolation Level ernsthafte Restriktionen, derer man sich für den Betrieb in der Praxis bereits vorab bewusst sein sollte: Sollte auf der primären Datenbank eine aktive Transaktion zu dem Zeitpunkt existieren, wenn ein lesbares sekundäres Replikat in die Verfügbarkeitsgruppe aufgenommen wird, werden die Row-Versionen auf der korrespondierenden sekundären Datenbank nicht sofort vollständig verfügbar sein. Eine aktive Transaktion auf dem primären Replikat muss zuerst abgeschlossen (Commit oder Rollback) und dieser Transaktions-Record auf dem sekundären Replikat verarbeitet werden. Bis dahin ist das Isolation Level Mapping auf der sekundären Datenbank unvollständig und Abfragen sind temporär geblockt. Microsoft sagt dazu: "This is needed to guarantee that row versions are available on the secondary replica before executing the query under snapshot isolation as all isolation levels are implicitly mapped to snapshot isolation." (SQL Storage Engine Blog: AlwaysOn: I just enabled Readable Secondary but my query is blocked?)  Grundlegend bedeutet dies, dass ein aktives lesbares Replikat nicht in die Verfügbarkeitsgruppe aufgenommen werden kann, ohne das primäre Replikat vorübergehend stillzulegen. Da Leseoperationen auf das Snapshot Isolation Transaction Level abgebildet werden, kann die Bereinigung von Ghost Records auf dem primären Replikat durch Transaktionen auf einem oder mehreren sekundären Replikaten geblockt werden - z.B. durch eine lang laufende Abfrage auf dem sekundären Replikat. Diese Bereinigung wird auch blockiert, wenn die Verbindung zum sekundären Replikat abbricht oder der Datenaustausch unterbrochen wird. Auch die Log Truncation wird in diesem Zustant verhindert. Wenn dieser Zustand längere Zeit anhält, empfiehlt Microsoft das sekundäre Replikat aus der Verfügbarkeitsgruppe herauszunehmen - was ein ernsthaftes Downtime-Problem darstellt. Die Read-Only Workload auf den sekundären Replikaten kann eingehende DDL Änderungen blockieren. Obwohl die Leseoperationen aufgrund der Row-Versionierung keine Shared Locks halten, führen diese Operatioen zu Sch-S Locks (Schemastabilitätssperren). DDL-Änderungen durch Redo-Operationen können dadurch blockiert werden. Falls DDL aufgrund konkurrierender Lese-Workload blockiert wird und der Schwellenwert für 'Recovery Interval' (eine SQL Server Konfigurationsoption) überschritten wird, generiert der SQL Server das Ereignis sqlserver.lock_redo_blocked, welches Microsoft zum Kill der blockierenden Leser empfiehlt. Auf die Verfügbarkeit der Anwendung wird hierbei keinerlei Rücksicht genommen.   Keine dieser Einschränkungen existiert mit Oracle Active Data Guard.   Backups auf sekundären Replikaten  Über die sekundären Replikate können Backups (BACKUP DATABASE via Transact-SQL) nur als copy-only Backups einer vollständigen Datenbank, Dateien und Dateigruppen erstellt werden. Das Erstellen inkrementeller Backups ist nicht unterstützt, was ein ernsthafter Rückstand ist gegenüber der Backup-Unterstützung physikalischer Standbys unter Oracle Data Guard. Hinweis: Ein möglicher Workaround via Snapshots, bleibt ein Workaround. Eine weitere Einschränkung dieses Features gegenüber Oracle Data Guard besteht darin, dass das Backup eines sekundären Replikats nicht ausgeführt werden kann, wenn es nicht mit dem primären Replikat kommunizieren kann. Darüber hinaus muss das sekundäre Replikat synchronisiert sein oder sich in der Synchronisation befinden, um das Beackup auf dem sekundären Replikat erstellen zu können.   Vergleich von Microsoft AlwaysOn mit der Oracle MAA Ich komme wieder zurück auf die Eingangs erwähnte, mehrfach an mich gestellte Frage "Wann denn - und ob überhaupt - Oracle etwas Vergleichbares wie AlwaysOn bieten würde?" und meine damit verbundene (kurze) Irritation. Wenn Sie diesen Blogbeitrag bis hierher gelesen haben, dann kennen Sie jetzt meine darauf gegebene Antwort. Der eine oder andere Punkt traf dabei nicht immer auf Jeden zu, was auch nicht der tiefere Sinn und Zweck meiner Antwort war. Wenn beispielsweise kein Multi-Subnet mit im Spiel ist, sind alle diesbezüglichen Kritikpunkte zunächst obsolet. Was aber nicht bedeutet, dass sie nicht bereits morgen schon wieder zum Thema werden könnten (Sag niemals "Nie"). In manch anderes Fettnäpfchen tritt man wiederum nicht unbedingt in einer Testumgebung, sondern erst im laufenden Betrieb. Erst recht nicht dann, wenn man sich potenzieller Probleme nicht bewusst ist und keine dedizierten Tests startet. Und wer AlwaysOn erfolgreich positionieren möchte, wird auch gar kein Interesse daran haben, auf mögliche Schwachstellen und den besagten Teufel im Detail aufmerksam zu machen. Das ist keine Unterstellung - es ist nur menschlich. Außerdem ist es verständlich, dass man sich in erster Linie darauf konzentriert "was geht" und "was gut läuft", anstelle auf das "was zu Problemen führen kann" oder "nicht funktioniert". Wer will schon der Miesepeter sein? Für mich selbst gesprochen, kann ich nur sagen, dass ich lieber vorab von allen möglichen Einschränkungen wissen möchte, anstelle sie dann nach einer kurzen Zeit der heilen Welt schmerzhaft am eigenen Leib erfahren zu müssen. Ich bin davon überzeugt, dass es Ihnen nicht anders geht. Nachfolgend deshalb eine Zusammenfassung all jener Punkte, die ich im Vergleich zur Oracle MAA (Maximum Availability Architecture) als unbedingt Erwähnenswert betrachte, falls man eine Evaluierung von Microsoft AlwaysOn in Betracht zieht. 1. AlwaysOn ist eine komplexe Technologie Der SQL Server AlwaysOn Stack ist zusammengesetzt aus drei verschiedenen Technlogien: Windows Server Failover Clustering (WSFC) SQL Server Failover Cluster Instances (FCI) SQL Server Availability Groups (Verfügbarkeitsgruppen) Man kann eine derartige Lösung nicht als nahtlos bezeichnen, wofür auch die vielen von Microsoft dargestellten Einschränkungen sprechen. Während sich frühere SQL Server Versionen in Richtung eigener HA/DR Technologien entwickelten (wie Database Mirroring), empfiehlt Microsoft nun die Migration. Doch weshalb dieser Schwenk? Er führt nicht zu einem konsisten und robusten Angebot an HA/DR Technologie für geschäftskritische Umgebungen.  Liegt die Antwort in meiner These begründet, nach der "Windows was the God ..." noch immer gilt und man die Nachteile der allzu engen Kopplung mit Windows nicht sehen möchte? Entscheiden Sie selbst ... 2. Failover Cluster Instanzen - Kein RAC-Pendant Die SQL Server und Windows Server Clustering Technologie basiert noch immer auf dem veralteten Aktiv-Passiv Modell und führt zu einer Verschwendung von Systemressourcen. In einer Betrachtung von lediglich zwei Knoten erschließt sich auf Anhieb noch nicht der volle Mehrwert eines Aktiv-Aktiv Clusters (wie den Real Application Clusters), wie er von Oracle bereits vor zehn Jahren entwickelt wurde. Doch kennt man die Vorzüge der Skalierbarkeit durch einfaches Hinzufügen weiterer Cluster-Knoten, die dann alle gemeinsam als ein einziges logisches System zusammenarbeiten, versteht man was hinter dem Motto "Pay-as-you-Grow" steckt. In einem Aktiv-Aktiv Cluster geht es zwar auch um Hochverfügbarkeit - und ein Failover erfolgt zudem schneller, als in einem Aktiv-Passiv Modell - aber es geht eben nicht nur darum. An dieser Stelle sei darauf hingewiesen, dass die Oracle 11g Standard Edition bereits die Nutzung von Oracle RAC bis zu vier Sockets kostenfrei beinhaltet. Möchten Sie dazu Windows nutzen, benötigen Sie keine Windows Server Enterprise Edition, da Oracle 11g die eigene Clusterware liefert. Sie kommen in den Genuss von Hochverfügbarkeit und Skalierbarkeit und können dazu die günstigere Windows Server Standard Edition nutzen. 3. SQL Server Multi-Subnet Clustering - Abhängigkeit zu 3rd Party Storage Mirroring  Die SQL Server Multi-Subnet Clustering Architektur unterstützt den Aufbau eines Stretch Clusters, basiert dabei aber auf dem Aktiv-Passiv Modell. Das eigentlich Problematische ist jedoch, dass man sich zur Absicherung der Datenbank auf 3rd Party Storage Mirroring Technologie verlässt, ohne Integration zwischen dem Windows Server Failover Clustering (WSFC) und der darunterliegenden Mirroring Technologie. Wenn nun im Cluster ein Failover auf Instanzen-Ebene erfolgt, existiert keine Koordination mit einem möglichen Failover auf Ebene des Storage-Array. 4. Availability Groups (Verfügbarkeitsgruppen) - Vier, oder doch nur Zwei? Ein primäres Replikat erlaubt bis zu vier sekundäre Replikate innerhalb einer Verfügbarkeitsgruppe, jedoch nur zwei im Synchronen Commit Modus. Während dies zwar einen Vorteil gegenüber dem stringenten 1:1 Modell unter Database Mirroring darstellt, fällt der SQL Server 2012 damit immer noch weiter zurück hinter Oracle Data Guard mit bis zu 30 direkten Stanbdy Zielen - und vielen weiteren durch kaskadierende Ziele möglichen. Damit eignet sich Oracle Active Data Guard auch für die Bereitstellung einer Reader-Farm Skalierbarkeit für Internet-basierende Unternehmen. Mit AwaysOn Verfügbarkeitsgruppen ist dies nicht möglich. 5. Availability Groups (Verfügbarkeitsgruppen) - kein asynchrones Switchover  Die Technologie der Verfügbarkeitsgruppen wird auch als geeignetes Mittel für administrative Aufgaben positioniert - wie Upgrades oder Wartungsarbeiten. Man muss sich jedoch einem gravierendem Defizit bewusst sein: Im asynchronen Verfügbarkeitsmodus besteht die einzige Möglichkeit für Role Transition im Forced Failover mit Datenverlust! Um den Verlust von Daten durch geplante Wartungsarbeiten zu vermeiden, muss man den synchronen Verfügbarkeitsmodus konfigurieren, was jedoch ernstzunehmende Auswirkungen auf WAN Deployments nach sich zieht. Spinnt man diesen Gedanken zu Ende, kommt man zu dem Schluss, dass die Technologie der Verfügbarkeitsgruppen für geplante Wartungsarbeiten in einem derartigen Umfeld nicht effektiv genutzt werden kann. 6. Automatisches Failover - Nicht immer möglich Sowohl die SQL Server FCI, als auch Verfügbarkeitsgruppen unterstützen automatisches Failover. Möchte man diese jedoch kombinieren, wird das Ergebnis kein automatisches Failover sein. Denn ihr Zusammentreffen im Failover-Fall führt zu Race Conditions (Wettlaufsituationen), weshalb diese Konfiguration nicht länger das automatische Failover zu einem Replikat in einer Verfügbarkeitsgruppe erlaubt. Auch hier bestätigt sich wieder die tiefere Problematik von AlwaysOn, mit einer Zusammensetzung aus unterschiedlichen Technologien und der Abhängigkeit zu Windows. 7. Problematische RTO (Recovery Time Objective) Microsoft postioniert die SQL Server Multi-Subnet Clustering Architektur als brauchbare HA/DR Architektur. Bedenkt man jedoch die Problematik im Zusammenhang mit DNS Replikation und den möglichen langen Wartezeiten auf Client-Seite von bis zu 16 Minuten, sind strenge RTO Anforderungen (Recovery Time Objectives) nicht erfüllbar. Im Gegensatz zu Oracle besitzt der SQL Server keine Datenbank-integrierten Technologien, wie Oracle Fast Application Notification (FAN) oder Oracle Fast Connection Failover (FCF). 8. Problematische RPO (Recovery Point Objective) SQL Server ermöglicht Forced Failover (erzwungenes Failover), bietet jedoch keine Möglichkeit zur automatischen Übertragung der letzten Datenbits von einem alten zu einem neuen primären Replikat, wenn der Verfügbarkeitsmodus asynchron war. Oracle Data Guard hingegen bietet diese Unterstützung durch das Flush Redo Feature. Dies sichert "Zero Data Loss" und beste RPO auch in erzwungenen Failover-Situationen. 9. Lesbare Sekundäre Replikate mit Einschränkungen Aufgrund des Snapshot Isolation Transaction Level für lesbare sekundäre Replikate, besitzen diese Einschränkungen mit Auswirkung auf die primäre Datenbank. Die Bereinigung von Ghost Records auf der primären Datenbank, wird beeinflusst von lang laufenden Abfragen auf der lesabaren sekundären Datenbank. Die lesbare sekundäre Datenbank kann nicht in die Verfügbarkeitsgruppe aufgenommen werden, wenn es aktive Transaktionen auf der primären Datenbank gibt. Zusätzlich können DLL Änderungen auf der primären Datenbank durch Abfragen auf der sekundären blockiert werden. Und imkrementelle Backups werden hier nicht unterstützt.   Keine dieser Restriktionen existiert unter Oracle Data Guard.

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