Search Results

Search found 3240 results on 130 pages for 'groupwise maximum'.

Page 95/130 | < Previous Page | 91 92 93 94 95 96 97 98 99 100 101 102  | Next Page >

• NetLogo 4.1 - implementation of a motorway ( Problem creating collision of cars )

  - by user206019

  Hi there, I am trying to create a simulation of motorway and the behaviour of the drivers in NetLogo. I have some questions that I m struggling to solve. Here is my code: globals [ selected-car ;; the currently selected car average-speed ;; average speed of all the cars look-ahead ] turtles-own [ speed ;; the current speed of the car speed-limit ;; the maximum speed of the car (different for all cars) lane ;; the current lane of the car target-lane ;; the desired lane of the car change? ;; true if the car wants to change lanes patience ;; the driver's current patience max-patience ;; the driver's maximum patience ] to setup ca import-drawing "my_road3.png" set-default-shape turtles "car" crt number_of_cars [ setup-cars ] end to setup-cars set color blue set size .9 set lane (random 3) set target-lane (lane + 1) setxy round random-xcor (lane + 1) set heading 90 set speed 0.1 + random 9.9 set speed-limit (((random 11) / 10) + 1) set change? false set max-patience ((random 50) + 10) set patience (max-patience - (random 10)) ;; make sure no two cars are on the same patch loop [ ifelse any? other turtles-here [ fd 1 ] [ stop ] ;if count turtles-here > 1 ; fd 0.1 ;if ; ;ifelse (any? turtles-on neighbors) or (count turtles-here > 1) ;[ ; ifelse (count turtles-here = 1) ; [ if any? turtles-on neighbors ; [ ; if distance min-one-of turtles-on neighbors [distance myself] > 0.9 ; [stop] ; ] ; ] ; [ fd 0.1 ] ;] ;[ stop ] ] end to go drive end to drive ;; first determine average speed of the cars set average-speed ((sum [speed] of turtles) / number_of_cars) ;set-current-plot "Car Speeds" ;set-current-plot-pen "average" ;plot average-speed ;set-current-plot-pen "max" ;plot (max [speed] of turtles) ;set-current-plot-pen "min" ;plot (abs (min [speed] of turtles) ) ;set-current-plot-pen "selected-car" ;plot ([speed] of selected-car) ask turtles [ ifelse (any? turtles-at 1 0) [ set speed ([speed] of (one-of (turtles-at 1 0))) decelerate ] [ ifelse (look-ahead = 2) [ ifelse (any? turtles-at 2 0) [ set speed ([speed] of (one-of turtles-at 2 0)) decelerate ] [ accelerate if count turtles-at 0 1 = 0 and ycor < 2.5 [lt 90 fd 1 rt 90] ] ] [accelerate if count turtles-at 0 1 = 0 and ycor < 2.5 [lt 90 fd 1 rt 90] ] ] if (speed < 0.01) [ set speed 0.01 ] if (speed > speed-limit) [ set speed speed-limit ] ifelse (change? = false) [ signal ] [ change-lanes ] ;; Control for making sure no one crashes. ifelse (any? turtles-at 1 0) and (xcor != min-pxcor - .5) [ set speed [speed] of (one-of turtles-at 1 0) ] [ ifelse ((any? turtles-at 2 0) and (speed > 1.0)) [ set speed ([speed] of (one-of turtles-at 2 0)) fd 1 ] [jump speed] ] ] tick end ;; increase speed of cars to accelerate ;; turtle procedure set speed (speed + (speed-up / 1000)) end ;; reduce speed of cars to decelerate ;; turtle procedure set speed (speed - (slow-down / 1000)) end to signal ifelse (any? turtles-at 1 0) [ if ([speed] of (one-of (turtles-at 1 0))) < (speed) [ set change? true ] ] [ set change? false ] end ;; undergoes search algorithms to change-lanes ;; turtle procedure show ycor ifelse (patience <= 0) [ ifelse (max-patience <= 1) [ set max-patience (random 10) + 1 ] [ set max-patience (max-patience - (random 5)) ] set patience max-patience ifelse (target-lane = 0) [ set target-lane 1 set lane 0 ] [ set target-lane 0 set lane 1 ] ] [ set patience (patience - 1) ] ifelse (target-lane = lane) [ ifelse (target-lane = 0) [ set target-lane 1 set change? false ] [ set target-lane 0 set change? false ] ] [ ifelse (target-lane = 1) [ ifelse (pycor = 2) [ set lane 1 set change? false ] [ ifelse (not any? turtles-at 0 1) [ set ycor (ycor + 1) ] [ ifelse (not any? turtles-at 1 0) [ set xcor (xcor + 1) ] [ decelerate if (speed <= 0) [ set speed 0.1 ] ] ] ] ] [ ifelse (pycor = -2) [ set lane 0 set change? false ] [ ifelse (not any? turtles-at 0 -1) [ set ycor (ycor - 1) ] [ ifelse (not any? turtles-at 1 0) [ set xcor (xcor + 1) ] [ decelerate if (speed <= 0) [ set speed 0.1 ] ] ] ] ] ] end I know its a bit messy because I am using code from other models from the library. I want to know how to create the collision of the cars. I can't think of any idea. As you notice my agent has almost the same size as the patch (I set it to 0.9 so that you can distinguish the space between 2 cars when they are set next to each other and I round the coordinates so that they are set to the centre of the patch). In my accelerate procedure I set my agent to turn left, move 1, turn right in a loop. I want to know if there's a command that lets me make the agent jump from one lane to the other (to the patch next to it on its left) without making it turn and move. And last, if you notice the code i created the car checks the patch that is next to it on the lane on its left and the patch in front of it and the back of it. So if the 3 patches on its left are empty then it can change lane. The fuzzy part is that when i run the setup and I press Go sometimes (not always) the car goes out of the 3 basic lanes. To understand this I have 7 lanes. The middle one which I don't use which is lane 0. Then there are 3 lanes on top of lane 0 and 3 below it. So the code I am using refers to the upper 3 lanes where I set the cars but for some reason some of the cars change lane and go to lane -3 then -2 and so forth. If someone can give me a tip I would really appreciate it. Thank you in advance. Tip: if you want to try this code in netlogo keep in mind that on interface tab I have 2 buttons one setup and one go as well as 3 sliders with names: number_of_cars , speed-up , slow-down.

  Read the article

• I am trying to insert value from combo box to database !! but this is not working

  - by user3675488

  At first I have taken some string in which I am trying to save the input values of textboxs and there is a combo box, I am trying to save the input value of the combo box to database, but this following code is unable to do that !!! what is the prob please help me. private void OK_Click(object sender, EventArgs e) { string sTxtcmpnyName = ""; string sTxtcmpnyAdd = ""; string sPhoneno = ""; string sTxtFax = ""; string sPanNo = ""; string sTxtTin = ""; string sTax = ""; string sAccYr = ""; string sComboSt = ""; foreach (Control c in this.Controls) ////*Adding Validation to the textbox.*// // Here the control is entered into GroupBox Grpcmp where c is denoting the name of the control into the groupbox. { // c1 is another control which denotes the textboxes under the GroupBox Grpcmp. foreach (Control c1 in c.Controls) { /////Now this following code snippets reperesents that the name of the company should not be blank. if (c1 is TextBox == true) // simpler that what you've done there { TextBox temp = (TextBox)c1; //The control is entering into Txtcompany. if (temp.Name == "Txtcompanyname") { //Condition checking is the TextBox is empty or Null then the following message will be shown. if ((temp.Text == "") || (temp.Text == "NULL")) { MessageBox.Show("Company Name should not be Blank"); } sTxtcmpnyName = temp.Text; } else if (c1.Name == "TxtcompanyAddress") { sTxtcmpnyAdd = c1.Text; } else if (c1.Name == "Txtphoneno") { sPhoneno = c1.Text; } else if (c1.Name == "TxtFax ") { sTxtFax = c1.Text; } else if (c1.Name == "Txtpanno") { sPanNo = c1.Text; } else if (c1.Name == "TxtTin") { sTxtTin = c1.Text; } else if (c1.Name == "Txtservicetax") { sTax = c1.Text; } //Now I am converting the TxtAcYr into Date format. //For this purpose two conditions are checked first. //First If the TextBox TxtAcYr is Null or empty it will show the message to enter the accountyear!! //Second If the length of the TextBox TxtAcYr is less than 10, it will again generate a message The date format should be in DD/MM/YYYY // Then the value of the use input will be picked using a For loop. if (c1.Name == "TxtAcYr") { sAccYr = c1.Text; //Here a string is taken named as yearlength and the value of the TxtAcYr is assigned to it by using control c1. //Condition Checking If the TextBox TxtAcYr is Null or empty it will show the message to enter the accountyear!! if ((c1.Text == "") || (c1.Text == "NULL")) { MessageBox.Show("Account Year should be entered!!"); } //Condition 2 is checking. Here the length of the string yearlength is whether equals to 10 or not is checked. //Because there are total 10 characters in Date Format along with special character. else // MessageBox.Show(yearlength.Length.ToString()); if (sAccYr.Length != 10) { MessageBox.Show("The Data Format DD-MM-YYYY"); } //Now the value of user will be picked by using the code snippets. else { //A string named as JK is taken for further use. String JK = ""; //This following loop is initiated to pick the user input. //The loop will check wheather the value of i is less than the length of string yearlength or not. //If Yes then it will go further. for (int i = 0; i < sAccYr.Length; i++) { //This condition is checking special characters. //The positions of special characters(Here '-') are placed at 2nd and 5th numbers. //So, the value of i can not be equals to 2 && 5. if ((i != 2) && (i != 5)) { //The new of value of year length i is assinged to the variable JK. JK = JK + sAccYr[i]; } //If the value of i is equals to 1, then enter the following. if (i == 1) { //*Should add the function of TOInt32* // If ToInt32(JK)>= the maximum length of days of a month then the following alert message will be shown. if (Convert.ToInt32(JK) >= 32) { MessageBox.Show("The Data Format DD-MM-YYYY"); } //**Comment should be added.** JK = ""; } else //If the value of i is equals to 4, then enter the following. if (i == 4) { //*Should add the function of TOInt32* // If ToInt32(JK)>= the maximum length of month then the following alert message will be shown. if (Convert.ToInt32(JK) >= 13) { MessageBox.Show("The Data Format DD-MM-YYYY"); } JK = ""; } } } } } else if (c1.Name == "state_cmb") { //sTxttate = c1.Text.ToString(); sComboSt = c1.Text; MessageBox.Show(c1.Text); } } } //////DATABASE CONNECTION///// try { SqlConnection conn = new SqlConnection(); SqlCommand cmd = new SqlCommand(); conn.ConnectionString = ("Data Source =192.168.0.2 ;database= Mee_Company; Persist Security Info =true; User ID =sa;Password = soso654321@"); conn.Open(); cmd.CommandText = ("INSERT INTO CompanyMaster(CompanyName,Address,State,Phone,Fax,PAN,TIN,STAX,AccountsYear)values('" + sTxtcmpnyName + "','" + sTxtcmpnyAdd + "','" + sComboSt + "','" + sPhoneno + "','" + sTxtFax + "','" + sPanNo + "','" + sTxtTin + "','" + sTax + "','" + sAccYr + "')"); //('" + sTxtcmpnyName + "', '" + TxtcompanyAddress.Text + "', '" + Txtphoneno.Text + "', '" + TxtFax.Text + "', '" + Txtservicetax.Text + "','" + TxtAcYr.Text + "')"); cmd.Connection = conn; cmd.ExecuteNonQuery(); conn.Close(); //cmd.Parameters.AddWithValue } catch (Exception ee) { MessageBox.Show(ee.ToString()); } } //An event is created here so that when the user will click on the Cancel Button, the Form will be closed. private void BtmCancle_Click(object sender, EventArgs e) { //this means the form. this.Close(); } //Another Event is created here named as TxtAcYr_KeyPress. //It is for making the TextBox TxtAcYr only allowance of numeric input along with special character '-'. private void TxtAcYr_KeyPress(object sender, KeyPressEventArgs e) { //If the input is number or '-' is checked //And also the backspace and delete option is enabled here. if (char.IsNumber(e.KeyChar) || e.KeyChar == (char)Keys.Back || e.KeyChar == (char)Keys.Delete || e.KeyChar == '-') { e.Handled = false; //ok } else { e.Handled = true; //not ok } }

  Read the article

• File using .net sockets, transferring problem

  - by Sergei

  I have a client and server, client sending file to server. When i transfer files on my computer(in local) everything is ok(try to sen file over 700mb). When i try to sent file use Internet to my friend in the end of sending appears error on server "Input string is not in correct format".This error appears in this expression fSize = Convert::ToUInt64(tokenes[0]); - and i don't mind wht it's appear. File should be transfered and wait other transferring ps: sorry for too much code, but i want to find solution private: void CreateServer() { try{ IPAddress ^ipAddres = IPAddress::Parse(ipAdress); listener = gcnew System::Net::Sockets::TcpListener(ipAddres, port); listener->Start(); clientsocket =listener->AcceptSocket(); bool keepalive = true; array<wchar_t,1> ^split = gcnew array<wchar_t>(1){ '\0' }; array<wchar_t,1> ^split2 = gcnew array<wchar_t>(1){ '|' }; statusBar1->Text = "Connected" ; // while (keepalive) { array<Byte>^ size1 = gcnew array<Byte>(1024); clientsocket->Receive(size1); System::String ^notSplited = System::Text::Encoding::GetEncoding(1251)->GetString(size1); array<String^> ^ tokenes = notSplited->Split(split2); System::String ^fileName = tokenes[1]->ToString(); statusBar1->Text = "Receiving file" ; unsigned long fSize = 0; //IN THIS EXPRESSIN APPEARS ERROR fSize = Convert::ToUInt64(tokenes[0]); if (!Directory::Exists("Received")) Directory::CreateDirectory("Received"); System::String ^path = "Received\\"+ fileName; while (File::Exists(path)) { int dotPos = path->LastIndexOf('.'); if (dotPos == -1) { path += "[1]"; } else { path = path->Insert(dotPos, "[1]"); } } FileStream ^fs = gcnew FileStream(path, FileMode::CreateNew, FileAccess::Write); BinaryWriter ^f = gcnew BinaryWriter(fs); //bytes received unsigned long processed = 0; pBarFilesTr->Visible = true; pBarFilesTr->Minimum = 0; pBarFilesTr->Maximum = (int)fSize; // Set the initial value of the ProgressBar. pBarFilesTr->Value = 0; pBarFilesTr->Step = 1024; //loop for receive file array<Byte>^ buffer = gcnew array<Byte>(1024); while (processed < fSize) { if ((fSize - processed) < 1024) { int bytes ; array<Byte>^ buf = gcnew array<Byte>(1024); bytes = clientsocket->Receive(buf); if (bytes != 0) { f->Write(buf, 0, bytes); processed = processed + (unsigned long)bytes; pBarFilesTr->PerformStep(); } break; } else { int bytes = clientsocket->Receive(buffer); if (bytes != 0) { f->Write(buffer, 0, 1024); processed = processed + 1024; pBarFilesTr->PerformStep(); } else break; } } statusBar1->Text = "File was received" ; array<Byte>^ buf = gcnew array<Byte>(1); clientsocket->Send(buf,buf->Length,SocketFlags::None); f->Close(); fs->Close(); SystemSounds::Beep->Play(); } }catch(System::Net::Sockets::SocketException ^es) { MessageBox::Show(es->ToString()); } catch(System::Exception ^es) { MessageBox::Show(es->ToString()); } } private: void CreateClient() { clientsock = gcnew System::Net::Sockets::TcpClient(ipAdress, port); ns = clientsock->GetStream(); sr = gcnew StreamReader(ns); statusBar1->Text = "Connected" ; } private:void Send() { try{ OpenFileDialog ^openFileDialog1 = gcnew OpenFileDialog(); System::String ^filePath = ""; System::String ^fileName = ""; //file choose dialog if (openFileDialog1->ShowDialog() == System::Windows::Forms::DialogResult::OK) { filePath = openFileDialog1->FileName; fileName = openFileDialog1->SafeFileName; } else { MessageBox::Show("You must select a file", "Error", MessageBoxButtons::OK, MessageBoxIcon::Exclamation); return; } statusBar1->Text = "Sending file" ; NetworkStream ^writerStream = clientsock->GetStream(); System::Runtime::Serialization::Formatters::Binary::BinaryFormatter ^format = gcnew System::Runtime::Serialization::Formatters::Binary::BinaryFormatter(); array<Byte>^ buffer = gcnew array<Byte>(1024); FileStream ^fs = gcnew FileStream(filePath, FileMode::Open); BinaryReader ^br = gcnew BinaryReader(fs); //file size unsigned long fSize = (unsigned long)fs->Length; //transfer file size + name bFSize = Encoding::GetEncoding(1251)->GetBytes(Convert::ToString(fs->Length+"|"+fileName+"|")); writerStream->Write(bFSize, 0, bFSize->Length); //status bar pBarFilesTr->Visible = true; pBarFilesTr->Minimum = 0; pBarFilesTr->Maximum = (int)fSize; pBarFilesTr->Value = 0; // Set the initial value of the ProgressBar. pBarFilesTr->Step = 1024; //bytes transfered unsigned long processed = 0; int bytes = 1024; //loop for transfer while (processed < fSize) { if ((fSize - processed) < 1024) { bytes = (int)(fSize - processed); array<Byte>^ buf = gcnew array<Byte>(bytes); br->Read(buf, 0, bytes); writerStream->Write(buf, 0, buf->Length); pBarFilesTr->PerformStep(); processed = processed + (unsigned long)bytes; break; } else { br->Read(buffer, 0, 1024); writerStream->Write(buffer, 0, buffer->Length); pBarFilesTr->PerformStep(); processed = processed + 1024; } } array<Byte>^ bufsss = gcnew array<Byte>(100); writerStream->Read(bufsss,0,bufsss->Length); statusBar1->Text = "File was sent" ; btnSend->Enabled = true; fs->Close(); br->Close(); SystemSounds::Beep->Play(); newThread->Abort(); } catch(System::Net::Sockets::SocketException ^es) { MessageBox::Show(es->ToString()); } } UPDATE: ok, i can add checking if clientsocket->Receive(size1); equal zero, but why he begin receiving data again , in the ending of receiving. UPDATE:After adding this checking problem remains. AND WIN RAR SAY TO OPENING ARCHIVE - unexpected end of file! UPDATE:http://img153.imageshack.us/img153/3760/erorr.gif I think it continue receiving some bytes from client(that remains in the stream), but why existes cicle while (processed < fSize)

  Read the article

• File using sockets .net, tranfering problem

  - by Sergei

  I have a client and server, client sending file to server. When i transfer files on my computer(in local) everything is ok(try to sen file over 700mb). When i try to sent file use Internet to my friend in the end of sending appears error on server "Input string is not in correct format".This error appears in this expression fSize = Convert::ToUInt64(tokenes[0]); - and i don't mind wht it's appear. File should be transfered and wait other transferring ps: sorry for too much code, but i want to find solution private: void CreateServer() { try{ IPAddress ^ipAddres = IPAddress::Parse(ipAdress); listener = gcnew System::Net::Sockets::TcpListener(ipAddres, port); listener->Start(); clientsocket =listener->AcceptSocket(); bool keepalive = true; array<wchar_t,1> ^split = gcnew array<wchar_t>(1){ '\0' }; array<wchar_t,1> ^split2 = gcnew array<wchar_t>(1){ '|' }; statusBar1->Text = "Connected" ; // while (keepalive) { array<Byte>^ size1 = gcnew array<Byte>(1024); clientsocket->Receive(size1); System::String ^notSplited = System::Text::Encoding::GetEncoding(1251)->GetString(size1); array<String^> ^ tokenes = notSplited->Split(split2); System::String ^fileName = tokenes[1]->ToString(); statusBar1->Text = "Receiving file" ; unsigned long fSize = 0; //IN THIS EXPRESSIN APPEARS ERROR fSize = Convert::ToUInt64(tokenes[0]); if (!Directory::Exists("Received")) Directory::CreateDirectory("Received"); System::String ^path = "Received\\"+ fileName; while (File::Exists(path)) { int dotPos = path->LastIndexOf('.'); if (dotPos == -1) { path += "[1]"; } else { path = path->Insert(dotPos, "[1]"); } } FileStream ^fs = gcnew FileStream(path, FileMode::CreateNew, FileAccess::Write); BinaryWriter ^f = gcnew BinaryWriter(fs); //bytes received unsigned long processed = 0; pBarFilesTr->Visible = true; pBarFilesTr->Minimum = 0; pBarFilesTr->Maximum = (int)fSize; // Set the initial value of the ProgressBar. pBarFilesTr->Value = 0; pBarFilesTr->Step = 1024; //loop for receive file array<Byte>^ buffer = gcnew array<Byte>(1024); while (processed < fSize) { if ((fSize - processed) < 1024) { int bytes ; array<Byte>^ buf = gcnew array<Byte>(1024); bytes = clientsocket->Receive(buf); if (bytes != 0) { f->Write(buf, 0, bytes); processed = processed + (unsigned long)bytes; pBarFilesTr->PerformStep(); } break; } else { int bytes = clientsocket->Receive(buffer); if (bytes != 0) { f->Write(buffer, 0, 1024); processed = processed + 1024; pBarFilesTr->PerformStep(); } else break; } } statusBar1->Text = "File was received" ; array<Byte>^ buf = gcnew array<Byte>(1); clientsocket->Send(buf,buf->Length,SocketFlags::None); f->Close(); fs->Close(); SystemSounds::Beep->Play(); } }catch(System::Net::Sockets::SocketException ^es) { MessageBox::Show(es->ToString()); } catch(System::Exception ^es) { MessageBox::Show(es->ToString()); } } private: void CreateClient() { clientsock = gcnew System::Net::Sockets::TcpClient(ipAdress, port); ns = clientsock->GetStream(); sr = gcnew StreamReader(ns); statusBar1->Text = "Connected" ; } private:void Send() { try{ OpenFileDialog ^openFileDialog1 = gcnew OpenFileDialog(); System::String ^filePath = ""; System::String ^fileName = ""; //file choose dialog if (openFileDialog1->ShowDialog() == System::Windows::Forms::DialogResult::OK) { filePath = openFileDialog1->FileName; fileName = openFileDialog1->SafeFileName; } else { MessageBox::Show("You must select a file", "Error", MessageBoxButtons::OK, MessageBoxIcon::Exclamation); return; } statusBar1->Text = "Sending file" ; NetworkStream ^writerStream = clientsock->GetStream(); System::Runtime::Serialization::Formatters::Binary::BinaryFormatter ^format = gcnew System::Runtime::Serialization::Formatters::Binary::BinaryFormatter(); array<Byte>^ buffer = gcnew array<Byte>(1024); FileStream ^fs = gcnew FileStream(filePath, FileMode::Open); BinaryReader ^br = gcnew BinaryReader(fs); //file size unsigned long fSize = (unsigned long)fs->Length; //transfer file size + name bFSize = Encoding::GetEncoding(1251)->GetBytes(Convert::ToString(fs->Length+"|"+fileName+"|")); writerStream->Write(bFSize, 0, bFSize->Length); //status bar pBarFilesTr->Visible = true; pBarFilesTr->Minimum = 0; pBarFilesTr->Maximum = (int)fSize; pBarFilesTr->Value = 0; // Set the initial value of the ProgressBar. pBarFilesTr->Step = 1024; //bytes transfered unsigned long processed = 0; int bytes = 1024; //loop for transfer while (processed < fSize) { if ((fSize - processed) < 1024) { bytes = (int)(fSize - processed); array<Byte>^ buf = gcnew array<Byte>(bytes); br->Read(buf, 0, bytes); writerStream->Write(buf, 0, buf->Length); pBarFilesTr->PerformStep(); processed = processed + (unsigned long)bytes; break; } else { br->Read(buffer, 0, 1024); writerStream->Write(buffer, 0, buffer->Length); pBarFilesTr->PerformStep(); processed = processed + 1024; } } array<Byte>^ bufsss = gcnew array<Byte>(100); writerStream->Read(bufsss,0,bufsss->Length); statusBar1->Text = "File was sent" ; btnSend->Enabled = true; fs->Close(); br->Close(); SystemSounds::Beep->Play(); newThread->Abort(); } catch(System::Net::Sockets::SocketException ^es) { MessageBox::Show(es->ToString()); } }

  Read the article

• 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.

  Read the article

• Automatic Properties, Collection Initializers, and Implicit Line Continuation support with VB 2010

  - by ScottGu

  [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] This is the eighteenth in a series of blog posts I’m doing on the upcoming VS 2010 and .NET 4 release. A few days ago I blogged about two new language features coming with C# 4.0: optional parameters and named arguments.  Today I’m going to post about a few of my favorite new features being added to VB with VS 2010: Auto-Implemented Properties, Collection Initializers, and Implicit Line Continuation support. Auto-Implemented Properties Prior to VB 2010, implementing properties within a class using VB required you to explicitly declare the property as well as implement a backing field variable to store its value.  For example, the code below demonstrates how to implement a “Person” class using VB 2008 that exposes two public properties - “Name” and “Age”:   While explicitly declaring properties like above provides maximum flexibility, I’ve always found writing this type of boiler-plate get/set code tedious when you are simply storing/retrieving the value from a field.  You can use VS code snippets to help automate the generation of it – but it still generates a lot of code that feels redundant.  C# 2008 introduced a cool new feature called automatic properties that helps cut down the code quite a bit for the common case where properties are simply backed by a field.  VB 2010 also now supports this same feature.  Using the auto-implemented properties feature of VB 2010 we can now implement our Person class using just the code below: When you declare an auto-implemented property, the VB compiler automatically creates a private field to store the property value as well as generates the associated Get/Set methods for you.  As you can see above – the code is much more concise and easier to read. The syntax supports optionally initializing the properties with default values as well if you want to: You can learn more about VB 2010’s automatic property support from this MSDN page. Collection Initializers VB 2010 also now supports using collection initializers to easily create a collection and populate it with an initial set of values.  You identify a collection initializer by declaring a collection variable and then use the From keyword followed by braces { } that contain the list of initial values to add to the collection.  Below is a code example where I am using the new collection initializer feature to populate a “Friends” list of Person objects with two people, and then bind it to a GridView control to display on a page: You can learn more about VB 2010’s collection initializer support from this MSDN page. Implicit Line Continuation Support Traditionally, when a statement in VB has been split up across multiple lines, you had to use a line-continuation underscore character (_) to indicate that the statement wasn’t complete.  For example, with VB 2008 the below LINQ query needs to append a “_” at the end of each line to indicate that the query is not complete yet: The VB 2010 compiler and code editor now adds support for what is called “implicit line continuation support” – which means that it is smarter about auto-detecting line continuation scenarios, and as a result no longer needs you to explicitly indicate that the statement continues in many, many scenarios.  This means that with VB 2010 we can now write the above code with no “_” at all: The implicit line continuation feature also works well when editing XML Literals within VB (which is pretty cool). You can learn more about VB 2010’s Implicit Line Continuation support and many of the scenarios it supports from this MSDN page (scroll down to the “Implicit Line Continuation” section to find details). Summary The above three VB language features are but a few of the new language and code editor features coming with VB 2010.  Visit this site to learn more about some of the other VB language features coming with the release.  Also subscribe to the VB team’s blog to learn more and stay up-to-date with the posts they the team regularly publishes. Hope this helps, Scott

  Read the article

• The Incremental Architect&rsquo;s Napkin - #5 - Design functions for extensibility and readability

  - by Ralf Westphal

  Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/08/24/the-incremental-architectrsquos-napkin---5---design-functions-for.aspx The functionality of programs is entered via Entry Points. So what we´re talking about when designing software is a bunch of functions handling the requests represented by and flowing in through those Entry Points. Designing software thus consists of at least three phases: Analyzing the requirements to find the Entry Points and their signatures Designing the functionality to be executed when those Entry Points get triggered Implementing the functionality according to the design aka coding I presume, you´re familiar with phase 1 in some way. And I guess you´re proficient in implementing functionality in some programming language. But in my experience developers in general are not experienced in going through an explicit phase 2. “Designing functionality? What´s that supposed to mean?” you might already have thought. Here´s my definition: To design functionality (or functional design for short) means thinking about… well, functions. You find a solution for what´s supposed to happen when an Entry Point gets triggered in terms of functions. A conceptual solution that is, because those functions only exist in your head (or on paper) during this phase. But you may have guess that, because it´s “design” not “coding”. And here is, what functional design is not: It´s not about logic. Logic is expressions (e.g. +, -, && etc.) and control statements (e.g. if, switch, for, while etc.). Also I consider calling external APIs as logic. It´s equally basic. It´s what code needs to do in order to deliver some functionality or quality. Logic is what´s doing that needs to be done by software. Transformations are either done through expressions or API-calls. And then there is alternative control flow depending on the result of some expression. Basically it´s just jumps in Assembler, sometimes to go forward (if, switch), sometimes to go backward (for, while, do). But calling your own function is not logic. It´s not necessary to produce any outcome. Functionality is not enhanced by adding functions (subroutine calls) to your code. Nor is quality increased by adding functions. No performance gain, no higher scalability etc. through functions. Functions are not relevant to functionality. Strange, isn´t it. What they are important for is security of investment. By introducing functions into our code we can become more productive (re-use) and can increase evolvability (higher unterstandability, easier to keep code consistent). That´s no small feat, however. Evolvable code can hardly be overestimated. That´s why to me functional design is so important. It´s at the core of software development. To sum this up: Functional design is on a level of abstraction above (!) logical design or algorithmic design. Functional design is only done until you get to a point where each function is so simple you are very confident you can easily code it. Functional design an logical design (which mostly is coding, but can also be done using pseudo code or flow charts) are complementary. Software needs both. If you start coding right away you end up in a tangled mess very quickly. Then you need back out through refactoring. Functional design on the other hand is bloodless without actual code. It´s just a theory with no experiments to prove it. But how to do functional design? An example of functional design Let´s assume a program to de-duplicate strings. The user enters a number of strings separated by commas, e.g. a, b, a, c, d, b, e, c, a. And the program is supposed to clear this list of all doubles, e.g. a, b, c, d, e. There is only one Entry Point to this program: the user triggers the de-duplication by starting the program with the string list on the command line C:\>deduplicate "a, b, a, c, d, b, e, c, a" a, b, c, d, e …or by clicking on a GUI button. This leads to the Entry Point function to get called. It´s the program´s main function in case of the batch version or a button click event handler in the GUI version. That´s the physical Entry Point so to speak. It´s inevitable. What then happens is a three step process: Transform the input data from the user into a request. Call the request handler. Transform the output of the request handler into a tangible result for the user. Or to phrase it a bit more generally: Accept input. Transform input into output. Present output. This does not mean any of these steps requires a lot of effort. Maybe it´s just one line of code to accomplish it. Nevertheless it´s a distinct step in doing the processing behind an Entry Point. Call it an aspect or a responsibility - and you will realize it most likely deserves a function of its own to satisfy the Single Responsibility Principle (SRP). Interestingly the above list of steps is already functional design. There is no logic, but nevertheless the solution is described - albeit on a higher level of abstraction than you might have done yourself. But it´s still on a meta-level. The application to the domain at hand is easy, though: Accept string list from command line De-duplicate Present de-duplicated strings on standard output And this concrete list of processing steps can easily be transformed into code:static void Main(string[] args) { var input = Accept_string_list(args); var output = Deduplicate(input); Present_deduplicated_string_list(output); } Instead of a big problem there are three much smaller problems now. If you think each of those is trivial to implement, then go for it. You can stop the functional design at this point. But maybe, just maybe, you´re not so sure how to go about with the de-duplication for example. Then just implement what´s easy right now, e.g.private static string Accept_string_list(string[] args) { return args[0]; } private static void Present_deduplicated_string_list( string[] output) { var line = string.Join(", ", output); Console.WriteLine(line); } Accept_string_list() contains logic in the form of an API-call. Present_deduplicated_string_list() contains logic in the form of an expression and an API-call. And then repeat the functional design for the remaining processing step. What´s left is the domain logic: de-duplicating a list of strings. How should that be done? Without any logic at our disposal during functional design you´re left with just functions. So which functions could make up the de-duplication? Here´s a suggestion: De-duplicate Parse the input string into a true list of strings. Register each string in a dictionary/map/set. That way duplicates get cast away. Transform the data structure into a list of unique strings. Processing step 2 obviously was the core of the solution. That´s where real creativity was needed. That´s the core of the domain. But now after this refinement the implementation of each step is easy again:private static string[] Parse_string_list(string input) { return input.Split(',') .Select(s => s.Trim()) .ToArray(); } private static Dictionary<string,object> Compile_unique_strings(string[] strings) { return strings.Aggregate( new Dictionary<string, object>(), (agg, s) => { agg[s] = null; return agg; }); } private static string[] Serialize_unique_strings( Dictionary<string,object> dict) { return dict.Keys.ToArray(); } With these three additional functions Main() now looks like this:static void Main(string[] args) { var input = Accept_string_list(args); var strings = Parse_string_list(input); var dict = Compile_unique_strings(strings); var output = Serialize_unique_strings(dict); Present_deduplicated_string_list(output); } I think that´s very understandable code: just read it from top to bottom and you know how the solution to the problem works. It´s a mirror image of the initial design: Accept string list from command line Parse the input string into a true list of strings. Register each string in a dictionary/map/set. That way duplicates get cast away. Transform the data structure into a list of unique strings. Present de-duplicated strings on standard output You can even re-generate the design by just looking at the code. Code and functional design thus are always in sync - if you follow some simple rules. But about that later. And as a bonus: all the functions making up the process are small - which means easy to understand, too. So much for an initial concrete example. Now it´s time for some theory. Because there is method to this madness ;-) The above has only scratched the surface. Introducing Flow Design Functional design starts with a given function, the Entry Point. Its goal is to describe the behavior of the program when the Entry Point is triggered using a process, not an algorithm. An algorithm consists of logic, a process on the other hand consists just of steps or stages. Each processing step transforms input into output or a side effect. Also it might access resources, e.g. a printer, a database, or just memory. Processing steps thus can rely on state of some sort. This is different from Functional Programming, where functions are supposed to not be stateful and not cause side effects.[1] In its simplest form a process can be written as a bullet point list of steps, e.g. Get data from user Output result to user Transform data Parse data Map result for output Such a compilation of steps - possibly on different levels of abstraction - often is the first artifact of functional design. It can be generated by a team in an initial design brainstorming. Next comes ordering the steps. What should happen first, what next etc.? Get data from user Parse data Transform data Map result for output Output result to user That´s great for a start into functional design. It´s better than starting to code right away on a given function using TDD. Please get me right: TDD is a valuable practice. But it can be unnecessarily hard if the scope of a functionn is too large. But how do you know beforehand without investing some thinking? And how to do this thinking in a systematic fashion? My recommendation: For any given function you´re supposed to implement first do a functional design. Then, once you´re confident you know the processing steps - which are pretty small - refine and code them using TDD. You´ll see that´s much, much easier - and leads to cleaner code right away. For more information on this approach I call “Informed TDD” read my book of the same title. Thinking before coding is smart. And writing down the solution as a bunch of functions possibly is the simplest thing you can do, I´d say. It´s more according to the KISS (Keep It Simple, Stupid) principle than returning constants or other trivial stuff TDD development often is started with. So far so good. A simple ordered list of processing steps will do to start with functional design. As shown in the above example such steps can easily be translated into functions. Moving from design to coding thus is simple. However, such a list does not scale. Processing is not always that simple to be captured in a list. And then the list is just text. Again. Like code. That means the design is lacking visuality. Textual representations need more parsing by your brain than visual representations. Plus they are limited in their “dimensionality”: text just has one dimension, it´s sequential. Alternatives and parallelism are hard to encode in text. In addition the functional design using numbered lists lacks data. It´s not visible what´s the input, output, and state of the processing steps. That´s why functional design should be done using a lightweight visual notation. No tool is necessary to draw such designs. Use pen and paper; a flipchart, a whiteboard, or even a napkin is sufficient. Visualizing processes The building block of the functional design notation is a functional unit. I mostly draw it like this: Something is done, it´s clear what goes in, it´s clear what comes out, and it´s clear what the processing step requires in terms of state or hardware. Whenever input flows into a functional unit it gets processed and output is produced and/or a side effect occurs. Flowing data is the driver of something happening. That´s why I call this approach to functional design Flow Design. It´s about data flow instead of control flow. Control flow like in algorithms is of no concern to functional design. Thinking about control flow simply is too low level. Once you start with control flow you easily get bogged down by tons of details. That´s what you want to avoid during design. Design is supposed to be quick, broad brush, abstract. It should give overview. But what about all the details? As Robert C. Martin rightly said: “Programming is abot detail”. Detail is a matter of code. Once you start coding the processing steps you designed you can worry about all the detail you want. Functional design does not eliminate all the nitty gritty. It just postpones tackling them. To me that´s also an example of the SRP. Function design has the responsibility to come up with a solution to a problem posed by a single function (Entry Point). And later coding has the responsibility to implement the solution down to the last detail (i.e. statement, API-call). TDD unfortunately mixes both responsibilities. It´s just coding - and thereby trying to find detailed implementations (green phase) plus getting the design right (refactoring). To me that´s one reason why TDD has failed to deliver on its promise for many developers. Using functional units as building blocks of functional design processes can be depicted very easily. Here´s the initial process for the example problem: For each processing step draw a functional unit and label it. Choose a verb or an “action phrase” as a label, not a noun. Functional design is about activities, not state or structure. Then make the output of an upstream step the input of a downstream step. Finally think about the data that should flow between the functional units. Write the data above the arrows connecting the functional units in the direction of the data flow. Enclose the data description in brackets. That way you can clearly see if all flows have already been specified. Empty brackets mean “no data is flowing”, but nevertheless a signal is sent. A name like “list” or “strings” in brackets describes the data content. Use lower case labels for that purpose. A name starting with an upper case letter like “String” or “Customer” on the other hand signifies a data type. If you like, you also can combine descriptions with data types by separating them with a colon, e.g. (list:string) or (strings:string[]). But these are just suggestions from my practice with Flow Design. You can do it differently, if you like. Just be sure to be consistent. Flows wired-up in this manner I call one-dimensional (1D). Each functional unit just has one input and/or one output. A functional unit without an output is possible. It´s like a black hole sucking up input without producing any output. Instead it produces side effects. A functional unit without an input, though, does make much sense. When should it start to work? What´s the trigger? That´s why in the above process even the first processing step has an input. If you like, view such 1D-flows as pipelines. Data is flowing through them from left to right. But as you can see, it´s not always the same data. It get´s transformed along its passage: (args) becomes a (list) which is turned into (strings). The Principle of Mutual Oblivion A very characteristic trait of flows put together from function units is: no functional units knows another one. They are all completely independent of each other. Functional units don´t know where their input is coming from (or even when it´s gonna arrive). They just specify a range of values they can process. And they promise a certain behavior upon input arriving. Also they don´t know where their output is going. They just produce it in their own time independent of other functional units. That means at least conceptually all functional units work in parallel. Functional units don´t know their “deployment context”. They now nothing about the overall flow they are place in. They are just consuming input from some upstream, and producing output for some downstream. That makes functional units very easy to test. At least as long as they don´t depend on state or resources. I call this the Principle of Mutual Oblivion (PoMO). Functional units are oblivious of others as well as an overall context/purpose. They are just parts of a whole focused on a single responsibility. How the whole is built, how a larger goal is achieved, is of no concern to the single functional units. By building software in such a manner, functional design interestingly follows nature. Nature´s building blocks for organisms also follow the PoMO. The cells forming your body do not know each other. Take a nerve cell “controlling” a muscle cell for example:[2] The nerve cell does not know anything about muscle cells, let alone the specific muscel cell it is “attached to”. Likewise the muscle cell does not know anything about nerve cells, let a lone a specific nerve cell “attached to” it. Saying “the nerve cell is controlling the muscle cell” thus only makes sense when viewing both from the outside. “Control” is a concept of the whole, not of its parts. Control is created by wiring-up parts in a certain way. Both cells are mutually oblivious. Both just follow a contract. One produces Acetylcholine (ACh) as output, the other consumes ACh as input. Where the ACh is going, where it´s coming from neither cell cares about. Million years of evolution have led to this kind of division of labor. And million years of evolution have produced organism designs (DNA) which lead to the production of these different cell types (and many others) and also to their co-location. The result: the overall behavior of an organism. How and why this happened in nature is a mystery. For our software, though, it´s clear: functional and quality requirements needs to be fulfilled. So we as developers have to become “intelligent designers” of “software cells” which we put together to form a “software organism” which responds in satisfying ways to triggers from it´s environment. My bet is: If nature gets complex organisms working by following the PoMO, who are we to not apply this recipe for success to our much simpler “machines”? So my rule is: Wherever there is functionality to be delivered, because there is a clear Entry Point into software, design the functionality like nature would do it. Build it from mutually oblivious functional units. That´s what Flow Design is about. In that way it´s even universal, I´d say. Its notation can also be applied to biology: Never mind labeling the functional units with nouns. That´s ok in Flow Design. You´ll do that occassionally for functional units on a higher level of abstraction or when their purpose is close to hardware. Getting a cockroach to roam your bedroom takes 1,000,000 nerve cells (neurons). Getting the de-duplication program to do its job just takes 5 “software cells” (functional units). Both, though, follow the same basic principle. Translating functional units into code Moving from functional design to code is no rocket science. In fact it´s straightforward. There are two simple rules: Translate an input port to a function. Translate an output port either to a return statement in that function or to a function pointer visible to that function. The simplest translation of a functional unit is a function. That´s what you saw in the above example. Functions are mutually oblivious. That why Functional Programming likes them so much. It makes them composable. Which is the reason, nature works according to the PoMO. Let´s be clear about one thing: There is no dependency injection in nature. For all of an organism´s complexity no DI container is used. Behavior is the result of smooth cooperation between mutually oblivious building blocks. Functions will often be the adequate translation for the functional units in your designs. But not always. Take for example the case, where a processing step should not always produce an output. Maybe the purpose is to filter input. Here the functional unit consumes words and produces words. But it does not pass along every word flowing in. Some words are swallowed. Think of a spell checker. It probably should not check acronyms for correctness. There are too many of them. Or words with no more than two letters. Such words are called “stop words”. In the above picture the optionality of the output is signified by the astrisk outside the brackets. It means: Any number of (word) data items can flow from the functional unit for each input data item. It might be none or one or even more. This I call a stream of data. Such behavior cannot be translated into a function where output is generated with return. Because a function always needs to return a value. So the output port is translated into a function pointer or continuation which gets passed to the subroutine when called:[3]void filter_stop_words( string word, Action<string> onNoStopWord) { if (...check if not a stop word...) onNoStopWord(word); } If you want to be nitpicky you might call such a function pointer parameter an injection. And technically you´re right. Conceptually, though, it´s not an injection. Because the subroutine is not functionally dependent on the continuation. Firstly continuations are procedures, i.e. subroutines without a return type. Remember: Flow Design is about unidirectional data flow. Secondly the name of the formal parameter is chosen in a way as to not assume anything about downstream processing steps. onNoStopWord describes a situation (or event) within the functional unit only. Translating output ports into function pointers helps keeping functional units mutually oblivious in cases where output is optional or produced asynchronically. Either pass the function pointer to the function upon call. Or make it global by putting it on the encompassing class. Then it´s called an event. In C# that´s even an explicit feature.class Filter { public void filter_stop_words( string word) { if (...check if not a stop word...) onNoStopWord(word); } public event Action<string> onNoStopWord; } When to use a continuation and when to use an event dependens on how a functional unit is used in flows and how it´s packed together with others into classes. You´ll see examples further down the Flow Design road. Another example of 1D functional design Let´s see Flow Design once more in action using the visual notation. How about the famous word wrap kata? Robert C. Martin has posted a much cited solution including an extensive reasoning behind his TDD approach. So maybe you want to compare it to Flow Design. The function signature given is:string WordWrap(string text, int maxLineLength) {...} That´s not an Entry Point since we don´t see an application with an environment and users. Nevertheless it´s a function which is supposed to provide a certain functionality. The text passed in has to be reformatted. The input is a single line of arbitrary length consisting of words separated by spaces. The output should consist of one or more lines of a maximum length specified. If a word is longer than a the maximum line length it can be split in multiple parts each fitting in a line. Flow Design Let´s start by brainstorming the process to accomplish the feat of reformatting the text. What´s needed? Words need to be assembled into lines Words need to be extracted from the input text The resulting lines need to be assembled into the output text Words too long to fit in a line need to be split Does sound about right? I guess so. And it shows a kind of priority. Long words are a special case. So maybe there is a hint for an incremental design here. First let´s tackle “average words” (words not longer than a line). Here´s the Flow Design for this increment: The the first three bullet points turned into functional units with explicit data added. As the signature requires a text is transformed into another text. See the input of the first functional unit and the output of the last functional unit. In between no text flows, but words and lines. That´s good to see because thereby the domain is clearly represented in the design. The requirements are talking about words and lines and here they are. But note the asterisk! It´s not outside the brackets but inside. That means it´s not a stream of words or lines, but lists or sequences. For each text a sequence of words is output. For each sequence of words a sequence of lines is produced. The asterisk is used to abstract from the concrete implementation. Like with streams. Whether the list of words gets implemented as an array or an IEnumerable is not important during design. It´s an implementation detail. Does any processing step require further refinement? I don´t think so. They all look pretty “atomic” to me. And if not… I can always backtrack and refine a process step using functional design later once I´ve gained more insight into a sub-problem. Implementation The implementation is straightforward as you can imagine. The processing steps can all be translated into functions. Each can be tested easily and separately. Each has a focused responsibility. And the process flow becomes just a sequence of function calls: Easy to understand. It clearly states how word wrapping works - on a high level of abstraction. And it´s easy to evolve as you´ll see. Flow Design - Increment 2 So far only texts consisting of “average words” are wrapped correctly. Words not fitting in a line will result in lines too long. Wrapping long words is a feature of the requested functionality. Whether it´s there or not makes a difference to the user. To quickly get feedback I decided to first implement a solution without this feature. But now it´s time to add it to deliver the full scope. Fortunately Flow Design automatically leads to code following the Open Closed Principle (OCP). It´s easy to extend it - instead of changing well tested code. How´s that possible? Flow Design allows for extension of functionality by inserting functional units into the flow. That way existing functional units need not be changed. The data flow arrow between functional units is a natural extension point. No need to resort to the Strategy Pattern. No need to think ahead where extions might need to be made in the future. I just “phase in” the remaining processing step: Since neither Extract words nor Reformat know of their environment neither needs to be touched due to the “detour”. The new processing step accepts the output of the existing upstream step and produces data compatible with the existing downstream step. Implementation - Increment 2 A trivial implementation checking the assumption if this works does not do anything to split long words. The input is just passed on: Note how clean WordWrap() stays. The solution is easy to understand. A developer looking at this code sometime in the future, when a new feature needs to be build in, quickly sees how long words are dealt with. Compare this to Robert C. Martin´s solution:[4] How does this solution handle long words? Long words are not even part of the domain language present in the code. At least I need considerable time to understand the approach. Admittedly the Flow Design solution with the full implementation of long word splitting is longer than Robert C. Martin´s. At least it seems. Because his solution does not cover all the “word wrap situations” the Flow Design solution handles. Some lines would need to be added to be on par, I guess. But even then… Is a difference in LOC that important as long as it´s in the same ball park? I value understandability and openness for extension higher than saving on the last line of code. Simplicity is not just less code, it´s also clarity in design. But don´t take my word for it. Try Flow Design on larger problems and compare for yourself. What´s the easier, more straightforward way to clean code? And keep in mind: You ain´t seen all yet ;-) There´s more to Flow Design than described in this chapter. In closing I hope I was able to give you a impression of functional design that makes you hungry for more. To me it´s an inevitable step in software development. Jumping from requirements to code does not scale. And it leads to dirty code all to quickly. Some thought should be invested first. Where there is a clear Entry Point visible, it´s functionality should be designed using data flows. Because with data flows abstraction is possible. For more background on why that´s necessary read my blog article here. For now let me point out to you - if you haven´t already noticed - that Flow Design is a general purpose declarative language. It´s “programming by intention” (Shalloway et al.). Just write down how you think the solution should work on a high level of abstraction. This breaks down a large problem in smaller problems. And by following the PoMO the solutions to those smaller problems are independent of each other. So they are easy to test. Or you could even think about getting them implemented in parallel by different team members. Flow Design not only increases evolvability, but also helps becoming more productive. All team members can participate in functional design. This goes beyon collective code ownership. We´re talking collective design/architecture ownership. Because with Flow Design there is a common visual language to talk about functional design - which is the foundation for all other design activities.   PS: If you like what you read, consider getting my ebook “The Incremental Architekt´s Napkin”. It´s where I compile all the articles in this series for easier reading. I like the strictness of Function Programming - but I also find it quite hard to live by. And it certainly is not what millions of programmers are used to. Also to me it seems, the real world is full of state and side effects. So why give them such a bad image? That´s why functional design takes a more pragmatic approach. State and side effects are ok for processing steps - but be sure to follow the SRP. Don´t put too much of it into a single processing step. ? Image taken from www.physioweb.org ? My code samples are written in C#. C# sports typed function pointers called delegates. Action is such a function pointer type matching functions with signature void someName(T t). Other languages provide similar ways to work with functions as first class citizens - even Java now in version 8. I trust you find a way to map this detail of my translation to your favorite programming language. I know it works for Java, C++, Ruby, JavaScript, Python, Go. And if you´re using a Functional Programming language it´s of course a no brainer. ? Taken from his blog post “The Craftsman 62, The Dark Path”. ?

  Read the article

• Apply Skins to Add Some Flair to Windows Media Player 12

  - by DigitalGeekery

  Tired of the same look and feel of Windows Media Player in Windows 7? We’ll show you how to inject new life into your media experience by applying skins in WMP 12. Adding Skins In Library view, click on View from the Menu and select Skin Chooser. By default, WMP 12 comes with only a couple of modest skins. When you select a skin from the left pane, a preview will be displayed to the right. To apply one of the skins, simply select it from the pane on the left and click Apply Skin.   You can also switch to the currently selected skin in the Skin chooser by selecting Skin from the View menu, or by pressing Crtl + 2. Media Player will open in Now Playing mode. Click on the Switch to Library button at the top left to return to Library view.     Ok, so the included skins are a little boring. You can find additional skins by selecting Tools > Download > Skins.   Or, by clicking on More Skins from within the Skin chooser.   You will be taken the the Microsoft website where you can choose from dozens of skins to download and install. Select a skin you’d like to try and click the link to download.   If prompted with a warning message about files containing scripts that access your library, click Yes. Note: These warning boxes may look a bit different depending on your browser. We are using Chrome for this example.   Click on View Now.   Your new skin will be on display. To get back to the Library mode, find and click the Return to Full Mode button.    Some skins may launch video in a separate window.   If you want to delete one of the skins, select it from the list within the Skin chooser and click the red “X.” You can also press the delete key on your keyboard.   Then click Yes to confirm.   Conclusion Using skins is a quick and easy way to add some style to Windows Media Player and switching back and forth between skins is a breeze. Regardless of your interests, you are sure to find a skin that fits your tastes. You may find WMP skins on other sites, but sticking with Microsoft’s website will ensure maximum compatibility. Skins for Windows Media Player Similar Articles Productive Geek Tips Make VLC Player Look like Windows Media Player 10Make VLC Player Look like Windows Media Player 11Make VLC Player Look like Winamp 5 (Kinda)Fixing When Windows Media Player Library Won’t Let You Add FilesInstall and Use the VLC Media Player on Ubuntu Linux TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips VMware Workstation 7 Acronis Online Backup DVDFab 6 Revo Uninstaller Pro Use Flixtime To Create Video Slideshows Creating a Password Reset Disk in Windows Bypass Waiting Time On Customer Service Calls With Lucyphone MELTUP – "The Beginning Of US Currency Crisis And Hyperinflation" Enable or Disable the Task Manager Using TaskMgrED Explorer++ is a Worthy Windows Explorer Alternative

  Read the article

• Adatbázis szerver konszolidáció Oracle technológiákkal - eroforrás allokálás

  - by Lajos Sárecz

  Szerver konszolidációnál alapmegoldás a virtualizáció, pedig az Oracle Database rendelkezik olyan képességekkel, melyekkel a virtualizáció elonyeit élvezhetjük, ám teljesítményben felülmúljuk azt. Több adatbázis konszolidációját meg lehet oldani egy nagy szerveren, vagy egy több szerverbol álló klaszteren. Bármelyik megoldást is választjuk (ezek elonyeivel és hátrányaival most nem foglalkozok), az egyik legfontosabb megoldandó probléma, hogy biztonsággal el tudjuk oket szeparálni akár adatbiztonsági, akár eroforrás kezelési szempontból. A szoftveres és hardveres virtualizációk lehetové teszik, hogy a szerver eroforrásait több virtuális szerver között felosszuk, ezáltal elszeparálhatók a párhuzamosan futó adatbázis példányok. Ezek a megoldások általában költségesek, plusz adminisztrációt jelentenek és teljesítmény csökkenést okoznak. Az alábbiakban röviden összeszedem, hogy az Oracle Database milyen eroforrás szeparációs technológiákkal rendelkezik, melyek jól használhatók adatbázis konszolidáció esetén: Adatbázis szolgáltatások: Azt talán minden Oracle adatbázis-kezelovel foglalkozó szakérto tudja, hogy akliensek az adatbázist az adatbázis szolgáltatás nevével érik el. Alapértelmezetten minden adatbázis egyetlen szolgáltatással rendelkezik, mely automatikusan a 'global database name' paraméterrel megegyezo nevet kapja az adatbázis létrehozásakor. Ugyanakkor egy adatbázishoz több szolgáltatás név is rendelheto. A szolgáltatásokkal csoportosíthatók a különbözo feladatokat végrehajtó kliensek, és a szolgáltatásokhoz rendelhetjük hogy melyik kliens csoportnak mennyi rendszer eroforrást allokálunk. Klaszteres adatbázisok (RAC) esetén egy szolgáltatás több adatbázis példányhoz (szerverhez) kapcsolódhat, amivel valós terheléstol függo terhelés elosztás valósítható meg (itt már szerepet kap egyébként a Resource Manager is, lásd késobb). Az alkalmazás számára irrelevánssá válik, hogy az adott szolgáltatást mely szerver szolgálja ki. A szolgáltatásokhoz kapcsolódó eroforrások menet közben dinamikusan bovíthetok, de kezelik a kieso eroforrások hiányát is (failover). Database Resource Manager: Az Oracle Database Resource Manager az adatbázis szintjén kezeli az eroforrásokat, a CPU használatot szabályozza az adatbázis terhelés kontrolljával. A Resource Manager egy CPU-n adott pillanatban csak egyetlen Oracle processz futtatását engedélyezi, miközben a többit várakoztatja (ahogy az egy operációs rendszer ütemezojében is muködik). A Resource Manager csak akkor lép muködésbe, amikor a CPU terhelése eléri a 100%-ot. Ekkor a Resource Plan-nek megfeleloen korlátozhatja az egyes eroforrás csoportok számára elérheto eroforrás (CPU) mennyiségét. Instance Caging: A Resource Manager részeként az Oracle Database 11gR2-tol elérheto Instance Caging technológiával virtualizáció és operációs rendszer szintu eroforrás felosztás nélkül az adatbázis példány szintjén lehet szabályozni az allokált CPU számot. Erre akkor lehet szükség, ha egy szerveren több példány futtatására van szükség. A Resource Manager bekapcsolásával és a cpu_count paraméter beállításával lehet adatbázis példányonként aktiválni az Instance Caging funkcionalitást. A cpu_count egy dinamikus paraméter, célszeru arra az értékre állítani, ahány CPU-t az adott adatbázis példány maximálisan igényelhet. Lehetoség van túlméretezni a példányok számára rendelkezésre álló processzorok számát. Például egy 4 CPUs- szerver esetében ha van 3 példányunk, mindháromnak adhatunk 3 CPU-t. Azonban ha mindegyik terhelés alatt van, akkor a példány számára maximum allokált CPU szám osztva összes allokált CPU számmal arányban részesül a processzorból, ami a példában 33,33%, azaz 1,33 CPU. Input Output Resource Manager (IORM):Nem csak a processzorok használatát szabályozhatjuk, lehetoség van a megosztott storage eroforrásainak felosztására is. Az Input Output Resorce Manager (IORM) alkalmazásával storage szinten tudjuk szabályozni az adatbázisok közötti és azokon belüli minimális I/O szinteket. Database Vault: Ugyanazon adatbázisba konszolidált alkalmazások esetén a rendszergazda szerepkörök szeparálása lehetséges az Oracle Database Vault technológiával. Ezzel elérheto az, hogy biztonságosan konszolidáljuk adatbázisainkat úgy, hogy minden adminisztrátor csak a hozzá tartozó adatokat, objektumokat lássa, módosíthassa.

  Read the article

• Clean Code: A Handbook of Agile Software Craftsmanship – book review

  - by DigiMortal

     Writing code that is easy read and test is not something that is easy to achieve. Unfortunately there are still way too much programming students who write awful spaghetti after graduating. But there is one really good book that helps you raise your code to new level – your code will be also communication tool for you and your fellow programmers. “Clean Code: A Handbook of Agile Software Craftsmanship” by Robert C. Martin is excellent book that helps you start writing the easily readable code. Of course, you are the one who has to learn and practice but using this book you have very good guide that keeps you going to right direction. You can start writing better code while you read this book and you can do it right in your current projects – you don’t have to create new guestbook or some other simple application to start practicing. Take the project you are working on and start making it better! My special thanks to Robert C. Martin I want to say my special thanks to Robert C. Martin for this book. There are many books that teach you different stuff and usually you have markable learning curve to go before you start getting results. There are many books that show you the direction to go and then leave you alone figuring out how to achieve all that stuff you just read about. Clean Code gives you a lot more – the mental tools to use so you can go your way to clean code being sure you will be soon there. I am reading books as much as I have time for it. Clean Code is top-level book for developers who have to write working code. Before anything else take Clean Code and read it. You will never regret your decision. I promise. Fragment of editorial review “Even bad code can function. But if code isn’t clean, it can bring a development organization to its knees. Every year, countless hours and significant resources are lost because of poorly written code. But it doesn’t have to be that way. What kind of work will you be doing? You’ll be reading code—lots of code. And you will be challenged to think about what’s right about that code, and what’s wrong with it. More importantly, you will be challenged to reassess your professional values and your commitment to your craft. Readers will come away from this book understanding How to tell the difference between good and bad code How to write good code and how to transform bad code into good code How to create good names, good functions, good objects, and good classes How to format code for maximum readability How to implement complete error handling without obscuring code logic How to unit test and practice test-driven development This book is a must for any developer, software engineer, project manager, team lead, or systems analyst with an interest in producing better code.” Table of contents Clean code Meaningful names Functions Comments Formatting Objects and data structures Error handling Boundaries Unit tests Classes Systems Emergence Concurrency Successive refinement JUnit internals Refactoring SerialDate Smells and heuristics A Concurrency II org.jfree.date.SerialDate Cross references of heuristics Epilogue Index

  Read the article

• Oracle’s New Memory-Optimized x86 Servers: Getting the Most Out of Oracle Database In-Memory

  - by Josh Rosen, x86 Product Manager-Oracle

  With the launch of Oracle Database In-Memory, it is now possible to perform real-time analytics operations on your business data as it exists at that moment – in the DRAM of the server – and immediately return completely current and consistent data. The Oracle Database In-Memory option dramatically accelerates the performance of analytics queries by storing data in a highly optimized columnar in-memory format.  This is a truly exciting advance in database technology.As Larry Ellison mentioned in his recent webcast about Oracle Database In-Memory, queries run 100 times faster simply by throwing a switch.  But in order to get the most from the Oracle Database In-Memory option, the underlying server must also be memory-optimized. This week Oracle announced new 4-socket and 8-socket x86 servers, the Sun Server X4-4 and Sun Server X4-8, both of which have been designed specifically for Oracle Database In-Memory.  These new servers use the fastest Intel® Xeon® E7 v2 processors and each subsystem has been designed to be the best for Oracle Database, from the memory, I/O and flash technologies right down to the system firmware.Amongst these subsystems, one of the most important aspects we have optimized with the Sun Server X4-4 and Sun Server X4-8 are their memory subsystems.  The new In-Memory option makes it possible to select which parts of the database should be memory optimized.  You can choose to put a single column or table in memory or, if you can, put the whole database in memory.  The more, the better.  With 3 TB and 6 TB total memory capacity on the Sun Server X4-4 and Sun Server X4-8, respectively, you can memory-optimize more, if not your entire database.   Sun Server X4-8 CMOD with 24 DIMM slots per socket (up to 192 DIMM slots per server) But memory capacity is not the only important factor in selecting the best server platform for Oracle Database In-Memory.  As you put more of your database in memory, a critical performance metric known as memory bandwidth comes into play.  The total memory bandwidth for the server will dictate the rate in which data can be stored and retrieved from memory.  In order to achieve real-time analysis of your data using Oracle Database In-Memory, even under heavy load, the server must be able to handle extreme memory workloads.  With that in mind, the Sun Server X4-8 was designed with the maximum possible memory bandwidth, providing over a terabyte per second of total memory bandwidth.  Likewise, the Sun Server X4-4 also provides extreme memory bandwidth in an even more compact form factor with over half a terabyte per second, providing customers with scalability and choice depending on the size of the database.Beyond the memory subsystem, Oracle’s Sun Server X4-4 and Sun Server X4-8 systems provide other key technologies that enable Oracle Database to run at its best.  The Sun Server X4-4 allows for up 4.8 TB of internal, write-optimized PCIe flash while the Sun Server X4-8 allows for up to 6.4 TB of PCIe flash.  This enables dramatic acceleration of data inserts and updates to Oracle Database.  And with the new elastic computing capability of Oracle’s new x86 servers, server performance can be adapted to your specific Oracle Database workload to ensure that every last bit of processing power is utilized.Because Oracle designs and tests its x86 servers specifically for Oracle workloads, we provide the highest possible performance and reliability when running Oracle Database.  To learn more about Sun Server X4-4 and Sun Server X4-8, you can find more details including data sheets and white papers here. Josh Rosen is a Principal Product Manager for Oracle’s x86 servers, focusing on Oracle’s operating systems and software.  He previously spent more than a decade as a developer and architect of system management software. Josh has worked on system management for many of Oracle's hardware products ranging from the earliest blade systems to the latest Oracle x86 servers. 

  Read the article

• What's new in ASP.Net 4.5 and VS 2012 - part 2

  - by nikolaosk

  This is the second post in a series of posts titled "What's new in ASP.Net 4.5 and VS 2012".You can have a look at the first post in this series, here. Please find all my posts regarding VS 2012, here. In this post I will be looking into the various new features available in ASP.Net 4.5 and VS 2012.I will be looking into the enhancements in the HTML Editor,CSS Editor and Javascript Editor.In order to follow along this post you must have Visual Studio 2012 and .Net Framework 4.5 installed in your machine.Download and install VS 2012 using this link.My machine runs on Windows 8 and Visual Studio 2012 works just fine.I will work fine in Windows 7 as well so do not worry if you do not have the latest Microsoft operating system.1) Launch VS 2012 and create a new Web Forms application by going to File - >New Web Site - > ASP.Net Web Forms Site.2) Choose an appropriate name for your web site.3) I would like to point out the new enhancements in the CSS editor in VS 2012. In the Solution Explorer in the Content folder and open the Site.cssThen when I try to change the background-color property of the html element, I get a brand new handy color-picker. Have a look at the picture below  Please note that the color-picker shows all the colors that have been used in this website. Then you can expand the color-picker by clicking on the arrows. Opacity is also supported. Have a look at the picture below4) There are also mobile styles in the Site.css .These are based on media queries.Please have a look at another post of mine on CSS3 media queries. Have a look at the picture below In this case when the maximum width of the screen is less than 850px there will be a new layout that will be dictated by these new rules. Also CSS snippets are supported. Have a look at the picture below I am writing a new CSS rule for an image element. I write the property transform and hit tab and then I have cross-browser CSS handling all of the major vendors.Then I simply add the value rotate and it is applied to all the cross browser options.Have a look at the picture below.  I am sure you realise how productive you can become with all these CSS snippets. 5) Now let's have a look at the new HTML editor enhancements in VS 2012You can drag and drop a GridView web server control from the Toolbox in the Site.master file.You will see a smart tag (that was only available in the Design View) that you can expand and add fields, format the web server control.Have a look at the picture below 6) We also have available code snippets. I type <video and then press tab twice.By doing that I have the rest of the HTML 5 markup completed.Have a look at the picture below 7) I have new support for the input tag including all the HTML 5 types and all the new accessibility features.Have a look at the picture below   8) Another interesting feature is the new Intellisense capabilities. When I change the DocType to 4.01 and the type <audio>,<video> HTML 5 tags, Intellisense does not recognise them and add squiggly lines.Have a look at the picture below All these features support ASP.Net Web forms, ASP.Net MVC applications and Web Pages. 9) Finally I would like to show you the enhanced support that we have for Javascript in VS 2012. I have full Intellisense support and code snippets support.I create a sample javascript file. I type If and press tab. I type while and press tab.I type for and press tab.In all three cases code snippet support kicks in and completes the code stack. Have a look at the picture below We also have full Intellisense support.Have a look at the picture below I am creating a simple function and then type some sort of XML like comments for the input parameters. Have a look at the picture below. Then when I call this function, Intellisense has picked up the XML comments and shows the variables data types.Have a look at the picture below Hope it helps!!!

  Read the article

• SQL SERVER – DMV – sys.dm_os_wait_stats Explanation – Wait Type – Day 3 of 28

  - by pinaldave

  The key Dynamic Management View (DMV) that helps us to understand wait stats is sys.dm_os_wait_stats; this DMV gives us all the information that we need to know regarding wait stats. However, the interpretation is left to us. This is a challenge as understanding wait stats can often be quite tricky. Anyway, we will cover few wait stats in one of the future articles. Today we will go over the basic understanding of the DMV. The Official Book OnLine Reference for DMV is over here: sys.dm_os_wait_stats. I suggest you all to refer this for all the accuracy. Following is a statement from the online book: “Specific types of wait times during query execution can indicate bottlenecks or stall points within the query. Similarly, high wait times, or wait counts server wide can indicate bottlenecks or hot spots in interaction query interactions within the server instance.” This is the statement which has inspired me to write this series. Let us first run the following statement from DMV. SELECT * FROM sys.dm_os_wait_stats ORDER BY wait_time_ms DESC GO Above statement will show us few of the columns. Here it is quick explanation of each of the column. wait_type – this is the name of the wait type. There can be three different kinds of wait types – resource, queue and external. waiting_tasks_count – this incremental counter is a good indication of frequent the wait is happening. If this number is very high, it is good indication for us to investigate that particular wait type. It is quite possible that the wait time is considerably low, but the frequency of the wait is much high. wait_time_ms – this is total wait accumulated for any type of wait. This is the total wait time and includes singal_wait_time_ms. max_wait_time_ms – this indicates the maximum wait type ever occurred for that particular wait type. Using this, one can estimate the intensity of the wait type in past. Again, it is not necessary that this max wait time will occur every time; so do not over invest yourself here. signal_wait_time_ms – this is the wait time when thread is marked as runnable and it gets to the running state. If the runnable queue is very long, you will find that this wait time becomes high. Additionally, please note that this DMV does not show current wait type or wait stats. This is cumulative view of the all the wait stats since server (instance) restarted or wait stats have been cleared. In future blog post, we will also cover two more DMVs which can be helpful to identify wait-related issues. ?sys.dm_os_waiting_tasks sys.dm_exec_requests Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL DMV, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

  Read the article

• How do I fix my resolution after Directx install through Steam?

  - by Justin

  I'm a bit long-winded so see bottom for quick version and specs. Friendly Hello: Hello all on these askUbuntu pages, I just recently built my own computer and decided to switch to Ubuntu for the extra coolness. I've been learning a lot through all this, and mostly been trying to figure out issues on my own (read: Google searches). However, I couldn't seem to find others with this problem so I've come here for help. Detailed Recount: So I just used WINE and WINETRICKS to install Steam. All went well and it worked. Then I went to trying a game out. I remembered that Orcs Must Die! worked from http://www.steamgamesonlinux.com/ so I tried that out. After selecting to download it, that's when the problem occurred. The screen suddenly zoomed in!!! I think it's the resolution right? Half the screen is cut off and I can't see parts of the right side of windows. My theory is that this is due to Direct X being installed through Steam, as Steam automatically installed it as I chose to download the game. It didn't even ask me to install Direct X or not ): It all happened so fast. This all being said, the game works fine! It looks a little strange, as if the resolution was off, but it plays just fine. What I did so far: Restarted my computer. Didn't work -_- Researched Steam installing DirectX on Ubuntu then messing up resolution and couldn't really find anything. Researched uninstalling DirectX from Ubuntu but only found uninstalling DirectX after having been installed with Wine, not through Steam. Got mad and ate my feelings. Tried "xrandr -s 0" but it didn't do anything. Ran xrandr alone and terminal showed this: Screen 0: minimum 8 x 8, current 640 x 480, maximum 16384 x 16384 DVI-I-0 connected 640x480+0+0 (normal left inverted right x axis y axis) 0mm x 0mm 640x480 59.9*+ 320x240 120.1 DVI-I-1 disconnected (normal left inverted right x axis y axis) HDMI-0 disconnected (normal left inverted right x axis y axis) DP-0 disconnected (normal left inverted right x axis y axis) DVI-D-0 disconnected (normal left inverted right x axis y axis) DP-1 disconnected (normal left inverted right x axis y axis) About now I was mad so I played Odin's Sphere then took a nap. Back to it! I entered the following: xrandr --output DVI-I-0 --mode 1024x768 But I was met with this message: xrandr: cannot find mode 1024x768 I get the same messages for 800x600, 1400x1050, and seemingly any other combination of numbers. I then tried Going into System Settings then Displays, then playing around in there. My Resolution is set to 640x480 and there are no other options for me to choose from. Rotation has Normal, Clockwise, Counter Clockwise, and 180 Degrees. It's set to Normal and I haven't messed with that. Launcher Placement has Unknown and All Displays as its two options. It's set to Unknown, but moving it to All Displays doesn't seem to do anything. Finally, when I click Detect Displays, nothing seems to happen. Quick Version: Linux noob. Steam installed with Wine and Winetricks. Steam downloaded and installed game + DirectX. Resolution messed up now (I think; pretty sure), can't fix it, very annoying, no idea what's going on, halp! Specs: Ubuntu Version 12.04 Wine Version 1.4.1 Have not changed any settings in Wine Using Winetricks Graphics Card: http://www.gigabyte.com/products/pro...px?pid=4361#sp Drivers: Proprietary (Installing those were a LOT of fun) Also let it be known that I have a DVI to VGA cord running from my Graphics card to my monitor. If any more information is needed I am ready to report. Thank You: Thanks a lot for your help and all the work you do to support noob ubuntuers like me (:

  Read the article

• Book &ldquo;Team Foundation Server 2012 Starter&rdquo; published!

  - by Jakob Ehn

  During the summer and fall this year, me and my colleague Terje Sandstrøm has worked together on a book project that has now finally hit the stores! The title of the book is Team Foundation Server 2012 Starter and is published by Packt Publishing. You can find it at http://www.packtpub.com/team-foundation-server-2012-starter/book or from Amazon http://www.amazon.com/dp/1849688389                          The book is part of a concept that Packt have with starter-books, intended for people new to Team Foundation Server 2012 and who want a quick guideline to get it up and working. It covers the fundamentals, from installing and configuring it, and how to use it with source control, work items and builds. It is done as a step-by-step guide, but also includes best practices advice in the different areas. It covers the use of both the on-premises and the TFS Services version. It also has a list of links and references in the end to the most relevant Visual Studio 2012 ALM sites. Our good friend and fellow ALM MVP Mathias Olausson have done the review of the book, thanks again Mathias! We hope the book fills the gap between the different online guide sites and the more advanced books that are out. Check it out and please let us know what you think of the book! Book Description Your quick start guide to TFS 2012, top features, and best practices with hands on examples Overview Install TFS 2012 from scratch Get up and running with your first project Streamline release cycles for maximum productivity In Detail Team Foundation Server 2012 is Microsoft's leading ALM tool, integrating source control, work item and process handling, build automation, and testing. This practical "Team Foundation Server 2012 Starter Guide" will provide you with clear step-by-step exercises covering all major aspects of the product. This is essential reading for anyone wishing to set up, organize, and use TFS server. This hands-on guide looks at the top features in Team Foundation Server 2012, starting with a quick installation guide and then moving into using it for your software development projects. Manage your team projects with Team Explorer, one of the many new features for 2012. Covering all the main features in source control to help you work more efficiently, including tools for branching and merging, we will delve into the Agile Planning Tools for planning your product and sprint backlogs. Learn to set up build automation, allowing your team to become faster, more streamlined, and ultimately more productive with this "Team Foundation Server 2012 Starter Guide". What you will learn from this book Install TFS 2012 on premise Access TFS Services in the cloud Quickly get started with a new project with product backlogs, source control, and build automation Work efficiently with source control using the top features Understand how the tools for branching and merging in TFS 2012 help you isolate work and teams Learn about the existing process templates, such as Visual Studio Scrum 2.0 Manage your product and sprint backlogs using the Agile planning tools Approach This Starter guide is a short, sharp introduction to Team Foundation Server 2012, covering everything you need to get up and running. Who this book is written for If you are a developer, project lead, tester, or IT administrator working with Team Foundation Server 2012 this guide will get you up to speed quickly and with minimal effort.

  Read the article

• Installing SharePoint 2010 in one machine with built in database

  - by sreejukg

  It is very easy to deploy SharePoint 2010 in a single server using the built-in database. Normally one need to choose such installation for evaluation purposes. When installing with default settings, setup installs Microsoft SQL server 2008 express database along with SharePoint. After installing SharePoint, you need to run SharePoint products and technology configuration wizard which will install central admin website and creates the configuration database and content database for SharePoint sites. Limitations 1. You can not perform this installation on a domain controller 2. The maximum size for express edition database is 4 GB SharePoint 2010 only supports 64 bit operating systems. The installation steps are for windows server r2 64 bit enterprise edition. Installation steps The first screen for the installation is as follows As a first step you need to install the s/w prerequisites. Click on the corresponding link Click next, here you have to agree on the license terms. Select the checkbox and then click next. The installation will starts. The progress will be updated in the screen. This may take some time as during this process, there are some components needs to be downloaded from internet. Make sure you are connected to the internet, then only the installation will become a success. If any error occurs, it will display the error, you need to configure in order to continue. If everything ok you will receive the following success page. Click finish to exit the installation window. Now from the first screen, select Install SharePoint server. This will install SharePoint and SQL server 2008 express edition. First you need to enter the product key for SharePoint. Enter the product key and clicks continue. Now you need to accept the license agreement. Select the checkbox and click on continue. Select the installation type you want.   Now click on the standalone button. In production scenario, you need to select the server farm installation. This article only cover the first option, installing server farm is not in the scope of this article. Once you click on the standalone, the installation starts and you can view the progress as below. If any error occurred during installation, you will get the details and link to the log file. Refer log file and fix the corresponding issue and then start the installation again. If installation completes without any error, you will see the below screen. Make sure you selected the check box “Run the SharePoint products Configuration Wizard now” and click close. The SharePoint products configuration wizard starts. Click next; you will get the following warning Click yes and the configuration steps starts. You can view the progress for each step. Once completed the below screen appears to the user. Click finish to complete the installation. Now SharePoint installation is completed. You can navigate to SharePoint central administration website from the administrative tools and start building your portal. Good luck

  Read the article

• Tuple in C# 4.0

  - by Jalpesh P. Vadgama

  C# 4.0 language includes a new feature called Tuple. Tuple provides us a way of grouping elements of different data type. That enables us to use it a lots places at practical world like we can store a coordinates of graphs etc. In C# 4.0 we can create Tuple with Create method. This Create method offer 8 overload like following. So you can group maximum 8 data types with a Tuple. Followings are overloads of a data type. Create(T1)- Which represents a tuple of size 1 Create(T1,T2)- Which represents a tuple of size 2 Create(T1,T2,T3) – Which represents a tuple of size 3 Create(T1,T2,T3,T4) – Which represents a tuple of size 4 Create(T1,T2,T3,T4,T5) – Which represents a tuple of size 5 Create(T1,T2,T3,T4,T5,T6) – Which represents a tuple of size 6 Create(T1,T2,T3,T4,T5,T6,T7) – Which represents a tuple of size 7 Create(T1,T2,T3,T4,T5,T6,T7,T8) – Which represents a tuple of size 8 Following are some example code for tuple. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace TupleExample { class Program { static void Main(string[] args) { var tuple = System.Tuple.Create<string, string, string>("Jalpesh", "P", "Vadgama"); Console.WriteLine(tuple); var t = System.Tuple.Create<int, string>(1, "Jalpesh"); Console.WriteLine(t); } } } Following is a output of above as expected. You can also access values insides Tuple with ItemN property. Where N represents particular number of item in tuple. Following is an example of it. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace TupleExample { class Program { static void Main(string[] args) { var tuple = System.Tuple.Create<string, string, string>("Jalpesh", "P", "Vadgama"); Console.WriteLine(tuple.Item1); Console.WriteLine(tuple.Item2); Console.WriteLine(tuple.Item3); } } } Here you can see I have printed items with Item1,Item2 and Item3 . Following is the output of above code.   Even we can create a nested tuple also following is code for nested tuple. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace TupleExample { class Program { static void Main(string[] args) { var tuple = System.Tuple.Create(1,"Jalpesh",new Tuple<string,string>("P","Vadgama")); Console.WriteLine(tuple.Item1); Console.WriteLine(tuple.Item2); Console.WriteLine(tuple.Item3); } } } Following is a output above code as expected. As you can see there are unlimited possibilities we can do lots of things with Tuple. Hope you liked it. Stay tuned for more. Till then Happy Programming!!

  Read the article

• Boost Netbook Speed with an SD Card & ReadyBoost

  - by Matthew Guay

  Looking for a way to increase the performance of your netbook?  Here’s how you can use a standard SD memory card or a USB flash drive to boost performance with ReadyBoost. Most netbooks ship with 1Gb of Ram, and many older netbooks shipped with even less.  Even if you want to add more ram, often they can only be upgraded to a max of 2GB.  With ReadyBoost in Windows 7, it’s easy to boost your system’s performance with flash memory.  If your netbook has an SD card slot, you can insert a memory card into it and just leave it there to always boost your netbook’s memory; otherwise, you can use a standard USB flash drive the same way. Also, you can use ReadyBoost on any desktop or laptop; ones with limited memory will see the most performance increase from using it. Please Note:  ReadyBoost requires at least 256Mb of free space on your flash drive, and also requires minimum read/write speeds.  Most modern memory cards or flash drives meet these requirements, but be aware that an old card may not work with it. Using ReadyBoost Insert an SD card into your card reader, or connect a USB flash drive to a USB port on your computer.  Windows will automatically see if your flash memory is ReadyBoost capable, and if so, you can directly choose to speed up your computer with ReadyBoost. The ReadyBoost settings dialog will open when you select this.  Choose “Use this device” and choose how much space you want ReadyBoost to use. Click Ok, and Windows will setup ReadyBoost and start using it to speed up your computer.  It will automatically use ReadyBoost whenever the card is connected to the computer. When you view your SD card or flash drive in Explorer, you will notice a ReadyBoost file the size you chose before.  This will be deleted when you eject your card or flash drive. If you need to remove your drive to use elsewhere, simply eject as normal. Windows will inform you that the drive is currently being used.  Make sure you have closed any programs or files you had open from the drive, and then press Continue to stop ReadyBoost and eject your drive. If you remove the drive without ejecting it, the ReadyBoost file may still remain on the drive.  You can delete this to save space on the drive, and the cache will be recreated when you use ReadyBoost next time. Conclusion Although ReadyBoost may not make your netbook feel like a Core i7 laptop with 6GB of RAM, it will still help performance and make multitasking even easier.  Also, if you have, say, a memory stick and a flash drive, you can use both of them with ReadyBoost for the maximum benefit.  We have even noticed better battery life when multitasking with ReadyBoost, as it lets you use your hard drive less.  SD cards and thumb drives are relatively cheap today, and many of us have several already, so this is a great way to improve netbook performance cheaply. Similar Articles Productive Geek Tips Speed up Your Windows Vista Computer with ReadyBoostSet the Speed Dial as the Opera Startup PageAsk the Readers: What are Your Computer’s Hardware Specs?Understanding Windows Vista Aero Glass RequirementsReplace Google Chrome’s New Tab Page with Speed Dial TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Recycle ! Find That Elusive Icon with FindIcons Looking for Good Windows Media Player 12 Plug-ins? Find Out the Celebrity You Resemble With FaceDouble Whoa ! Use Printflush to Solve Printing Problems

  Read the article

• SQL SERVER – Weekend Project – Experimenting with ACID Transactions, SQL Compliant, Elastically Scalable Database

  - by pinaldave

  Database technology is huge and big world. I like to explore always beyond what I know and share the learning. Weekend is the best time when I sit around download random software on my machine which I like to call as a lab machine (it is a pretty old laptop, hardly a quality as lab machine) and experiment it. There are so many free betas available for download that it’s hard to keep track and even harder to find the time to play with very many of them.  This blog is about one you shouldn’t miss if you are interested in the learning various relational databases. NuoDB just released their Beta 7.  I had already downloaded their Beta 6 and yesterday did the same for 7.   My impression is that they are onto something very very interesting.  In fact, it might be something really promising in terms of database elasticity, scale and operational cost reduction. The folks at NuoDB say they are working on the world’s first “emergent” database which they tout as a brand new transitional database that is intended to dramatically change what’s possible with OLTP.  It is SQL compliant, guarantees ACID transactions, yet scales elastically on heterogeneous and decentralized cloud-based resources. Interesting note for sure, making me explore more. Based on what I’ve seen so far, they are solving the architectural challenge that exists between elastic, cloud-based compute infrastructures designed to scale out in response to workload requirements versus the traditional relational database management system’s architecture of central control. Here’s my experience with the NuoDB Beta 6 so far: First they pretty much threw away all the features you’d associate with existing RDBMS architectures except the SQL and ACID transactions which they were smart to keep.  It looks like they have incorporated a number of the big ideas from various algorithms, systems and techniques to achieve maximum DB scalability. From a user’s perspective, the NuoDB Beta software behaves like any other traditional SQL database and seems to offer all the benefits users have come to expect from standards-based SQL solutions. One of the interesting feature is that one can run a transactional node and a storage node on my Windows laptop as well on other platforms – indeed interesting for sure. It’s quite amazing to see a database elastically scale across machine boundaries. So, one of the basic NuoDB concepts is that as you need to scale out, you can easily use more inexpensive hardware when/where you need it.  This is unlike what we have traditionally done to scale a database for an application – we replace the hardware with something more powerful (faster CPU and Disks). This is where I started to feel like NuoDB is on to something that has the potential to elastically scale on commodity hardware while reducing operational expense for a big OLTP database to a degree we’ve never seen before. NuoDB is able to fully leverage the cloud in an asynchronous and highly decentralized manner – while providing both SQL compliance and ACID transactions. Basically what NuoDB is doing is so new that it is all hard to believe until you’ve experienced it in action.  I will keep you up to date as I test the NuoDB Beta 7 but if you are developing a web-scale application or have an on-premise app you are thinking of moving to the cloud, testing this beta is worth your time. If you do try it, let me know what you think.  Before I say anything more, I am going to do more experiments and more test on this product and compare it with other existing similar products. For me it was a weekend worth spent on learning something new. I encourage you to download Beta 7 version and share your opinions here. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Documentation, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• Speaker Idol Montréal

  - by pluginbaby

  C’est le grand retour du concours Speaker Idol de la Communauté .NET Montréal!!! Pour le dernier meeting de l'année nous vous invitons à venir présenter votre techno préférée, votre librairie fétiche, votre projet open source innovateur ou tout autre sujet touchant le développement logiciel.  En fait, le choix de la techno n'est pas si important, ce qui l'est c'est de gagner de l'expérience pour présenter un sujet technique.  C'est un "soft skill" qui est primordial dans le développement de votre carrière.  En effet, vous aurez à faire des présentations à des clients ou à vos patrons. Une présentation bâclée ou mal présentée peut être un frein à un projet, une vente ou même une promotion. > Rappelez-vous que ce qui sera jugé est votre présentation et non la techno que vous présentez.   L’aventure vous tente ? Nous vous suggérons de visionner la formation Plurasight gratuite "Get Involved" de Scott Hanselman et Jeff Attwood: http://getinvolved.hanselman.com Ainsi que: Professional Technical Speaker Tips 11 Top Tips for a Successful Technical Presentation Tips for Preparing for a Technical Presentation Prix* à gagner pour les présentateurs: 1 Xbox One*!! 1 certificat* pour formation gratuite au choix chez Intertech.com 1 licence* Telerik DevCraft Complete 1 licence* Jetbrains au choix (dont resharper) 1 licence* Mindscape au choix (sauf MegaPack) 2 licences* de Cerebrata Azure Management Studio *Les prix (sauf la XBox One) sont des gracieusetés des fabricants.  Sans aucun engagement de la part de la Communauté .NET. Informations sur le concours Présentation de 10 minutes: en français ou en anglais, avec support visuel comme un PowerPoint et du code. Attention, 10 minutes c'est très court pour les démos en direct.  Assurez-vous d'introduire votre sujet, d'expliquer la problématique qu'il essaie de régler, de le démontrer et de conclure/résumer à la fin.  Et le tout en seulement 10 minutes!  Oui c'est un gros défi alors assurez-vous de vous concentrer sur l'essentiel et le message que vous voulez passer. Une première présentation en publique: Le concours est ouvert uniquement aux personnes qui n'ont jamais fait de présentation technique dans un user group ou une conférence. Date limite: Vous avez jusqu'au lundi 26 mai 23h59 pour soumettre votre candidature. Veuillez envoyer une brève description (200 mots max.) de votre présentation ainsi que votre bio à [email protected] Nombre maximum de participants: Parmi les candidatures reçus, les 8 meilleures seront choisies pour présenter. L'annonce des candidatures retenues sera faite le vendredi 30 mai. L'ordre des présentations: En ordre alphabétique des noms de famille. Panel d'expert: Après chaque présentation un panel d'expert va donner un retour aux participants basé sur Maitrise du sujet Qualité de la présentation Aptitude à faire passer votre message Qualité du PowerPoint Important: les experts sont là pour vous aider à vous améliorer en vous donnant des conseils. Ce qui va être fourni: Un laptop avec les plus récents outils Visual Studio et SQL Server Express.  Si vous avez besoin d'outils particuliers veuillez apporter votre propre laptop. Ce que vous devez amener: Dans tous les cas assurez vous d'avoir une clé USB avec votre présentation PowerPoint et votre code. Vote du publique: À la fin de la soirée le publique dans la salle vont voter et des prix seront remis aux meilleures présentations (1 par participant, voir la liste ci-haut). Le gagnant aura la possibilité de faire une présentation complète d'une heure la prochaine saison.

  Read the article

• Xorg does not see my monitor EDID

  - by sean farley

  Below is the output from my Xorg.0. X.Org X Server 1.11.3 Release Date: 2011-12-16 [ 22.311] X Protocol Version 11, Revision 0 [ 22.311] Build Operating System: Linux 2.6.42-23-generic x86_64 Ubuntu [ 22.311] Current Operating System: Linux sean-P55-USB3 3.2.0-34-generic #53-Ubuntu SMP Thu Nov 15 10:48:16 UTC 2012 x86_64 [ 22.311] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-3.2.0-34-generic root=UUID=0a34603e-aee9-44d1-8982-a5a5a38c3e4d ro quiet splash [ 22.311] Build Date: 29 August 2012 12:12:33AM [ 22.311] xorg-server 2:1.11.4-0ubuntu10.8 (For technical support please see http://www.ubuntu.com/support) [ 22.311] Current version of pixman: 0.24.4 [ 22.311] Before reporting problems, check http://wiki.x.org to make sure that you have the latest version. [ 22.311] Markers: (--) probed, (**) from config file, (==) default setting, (++) from command line, (!!) notice, (II) informational, (WW) warning, (EE) error, (NI) not implemented, (??) unknown. [ 22.311] (==) Log file: "/var/log/Xorg.0.log", Time: Sat Nov 17 13:20:45 2012 [ 22.311] (==) Using config file: "/etc/X11/xorg.conf" [ 22.311] (==) Using system config directory "/usr/share/X11/xorg.conf.d" [ 22.311] (==) No Layout section. Using the first Screen section. [ 22.311] (==) No screen section available. Using defaults. [ 22.311] (**) |-->Screen "Default Screen Section" (0) [ 22.311] (**) | |-->Monitor "<default monitor>" [ 22.311] (==) No device specified for screen "Default Screen Section". Using the first device section listed. [ 22.311] (**) | |-->Device "Default Device" [ 22.311] (==) No monitor specified for screen "Default Screen Section". Using a default monitor configuration. [ 22.311] (==) Automatically adding devices I have searched all over, and followed lots of dead ends and unanswered questions on this issue. I need to get this monitor recognised so I can use the native resolution of 1600x1200. The Nvidia driver in Windows has no problem with this. The monitor is an old Iiyama HM204DT A. Is there a way of configuring Xorg manually to get these working? I have tried xrandr but this will not work. Output:- sean@sean-P55-USB3:~$ xrandr Screen 0: minimum 8 x 8, current 1152 x 864, maximum 16384 x 16384 DVI-I-0 connected 1152x864+0+0 (normal left inverted right x axis y axis) 0mm x 0mm 1024x768 60.0 + 1360x768 60.0 59.8 1152x864 60.0* 800x600 72.2 60.3 56.2 680x384 119.9 119.6 640x480 59.9 512x384 120.0 400x300 144.4 320x240 120.1 DVI-I-1 disconnected (normal left inverted right x axis y axis) DVI-I-2 disconnected (normal left inverted right x axis y axis) HDMI-0 disconnected (normal left inverted right x axis y axis) DVI-I-3 disconnected (normal left inverted right x axis y axis) Tried Nvidia Xorg.config: sean@sean-P55-USB3:~$ sudo nvidia-xconfig [sudo] password for sean: Using X configuration file: "/etc/X11/xorg.conf". VALIDATION ERROR: Data incomplete in file /etc/X11/xorg.conf. Device section "Default Device" must have a Driver line. Backed up file '/etc/X11/xorg.conf' as '/etc/X11/xorg.conf.nvidia-xconfig-original' Backed up file '/etc/X11/xorg.conf' as '/etc/X11/xorg.conf.backup' New X configuration file written to '/etc/X11/xorg.conf' How do I insert a driver line? This is a bit of a pain as I want to use my Vectorworks cad program in a WinXP Vbox at 1600x1200 but all virtual drives are restricted to the host screen resolution. Do i need to manually create EIDI info in Xorg? I am slightly confused about how Xorg and Nvidia relate Please help

  Read the article

• New January 2013 Release of the Ajax Control Toolkit

  - by Stephen.Walther

  I am super excited to announce the January 2013 release of the Ajax Control Toolkit! I have one word to describe this release and that word is “Charts” – we’ve added lots of great new chart controls to the Ajax Control Toolkit. You can download the new release directly from http://AjaxControlToolkit.CodePlex.com – or, just fire the following command from the Visual Studio Library Package Manager Console Window (NuGet): Install-Package AjaxControlToolkit You also can view the new chart controls by visiting the “live” Ajax Control Toolkit Sample Site. 5 New Ajax Control Toolkit Chart Controls The Ajax Control Toolkit contains five new chart controls: the AreaChart, BarChart, BubbleChart, LineChart, and PieChart controls. Here is a sample of each of the controls: AreaChart: BarChart: BubbleChart: LineChart: PieChart: We realize that people love to customize the appearance of their charts so all of the chart controls include properties such as color properties. The chart controls render the chart on the browser using SVG. The chart controls are compatible with any browser which supports SVG including Internet Explorer 9 and new and recent versions of Google Chrome, Mozilla Firefox, and Apple Safari. (If you attempt to display a chart on a browser which does not support SVG then you won’t get an error – you just won’t get anything). Updates to the HTML Sanitizer If you are using the HtmlEditorExtender on a public-facing website then it is really important that you enable the HTML Sanitizer to prevent Cross-Site Scripting (XSS) attacks. The HtmlEditorExtender uses the HTML Sanitizer by default. The HTML Sanitizer strips out any suspicious content (like JavaScript code and CSS expressions) from the HTML submitted with the HtmlEditorExtender. We followed the recommendations of OWASP and ha.ckers.org to identify suspicious content. We updated the HTML Sanitizer with this release to protect against new types of XSS attacks. The HTML Sanitizer now has over 220 unit tests. The Ajax Control Toolkit team would like to thank Gil Cohen who helped us identify and block additional XSS attacks. Change in Ajax Control Toolkit Version Format We ran out of numbers. The Ajax Control Toolkit was first released way back in 2006. In previous releases, the version of the Ajax Control Toolkit followed the format: Release Year + Date. So, the previous release was 60919 where 6 represented the 6th release year and 0919 represent September 19. Unfortunately, the AssembyVersion attribute uses a UInt16 data type which has a maximum size of 65,534. The number 70123 is bigger than 65,534 so we had to change our version format with this release. Fortunately, the AssemblyVersion attribute actually accepts four UInt16 numbers so we used another one. This release of the Ajax Control Toolkit is officially version 7.0123. This new version format should work for another 65,000 years. And yes, I realize that 7.0123 is less than 60,919, but we ran out of numbers. Summary I hope that you find the chart controls included with this latest release of the Ajax Control Toolkit useful. Let me know if you use them in applications that you build. And, let me know if you run into any issues using the new chart controls. Next month, back to improving the File Upload control – more exciting stuff.

  Read the article

• Oracle TimesTen In-Memory Database Performance on SPARC T4-2

  - by Brian

  The Oracle TimesTen In-Memory Database is optimized to run on Oracle's SPARC T4 processor platforms running Oracle Solaris 11 providing unsurpassed scalability, performance, upgradability, protection of investment and return on investment. The following demonstrate the value of combining Oracle TimesTen In-Memory Database with SPARC T4 servers and Oracle Solaris 11: On a Mobile Call Processing test, the 2-socket SPARC T4-2 server outperforms: Oracle's SPARC Enterprise M4000 server (4 x 2.66 GHz SPARC64 VII+) by 34%. Oracle's SPARC T3-4 (4 x 1.65 GHz SPARC T3) by 2.7x, or 5.4x per processor. Utilizing the TimesTen Performance Throughput Benchmark (TPTBM), the SPARC T4-2 server protects investments with: 2.1x the overall performance of a 4-socket SPARC Enterprise M4000 server in read-only mode and 1.5x the performance in update-only testing. This is 4.2x more performance per processor than the SPARC64 VII+ 2.66 GHz based system. 10x more performance per processor than the SPARC T2+ 1.4 GHz server. 1.6x better performance per processor than the SPARC T3 1.65 GHz based server. In replication testing, the two socket SPARC T4-2 server is over 3x faster than the performance of a four socket SPARC Enterprise T5440 server in both asynchronous replication environment and the highly available 2-Safe replication. This testing emphasizes parallel replication between systems. Performance Landscape Mobile Call Processing Test Performance System Processor Sockets/Cores/Threads Tps SPARC T4-2 SPARC T4, 2.85 GHz 2 16 128 218,400 M4000 SPARC64 VII+, 2.66 GHz 4 16 32 162,900 SPARC T3-4 SPARC T3, 1.65 GHz 4 64 512 80,400 TimesTen Performance Throughput Benchmark (TPTBM) Read-Only System Processor Sockets/Cores/Threads Tps SPARC T3-4 SPARC T3, 1.65 GHz 4 64 512 7.9M SPARC T4-2 SPARC T4, 2.85 GHz 2 16 128 6.5M M4000 SPARC64 VII+, 2.66 GHz 4 16 32 3.1M T5440 SPARC T2+, 1.4 GHz 4 32 256 3.1M TimesTen Performance Throughput Benchmark (TPTBM) Update-Only System Processor Sockets/Cores/Threads Tps SPARC T4-2 SPARC T4, 2.85 GHz 2 16 128 547,800 M4000 SPARC64 VII+, 2.66 GHz 4 16 32 363,800 SPARC T3-4 SPARC T3, 1.65 GHz 4 64 512 240,500 TimesTen Replication Tests System Processor Sockets/Cores/Threads Asynchronous 2-Safe SPARC T4-2 SPARC T4, 2.85 GHz 2 16 128 38,024 13,701 SPARC T5440 SPARC T2+, 1.4 GHz 4 32 256 11,621 4,615 Configuration Summary Hardware Configurations: SPARC T4-2 server 2 x SPARC T4 processors, 2.85 GHz 256 GB memory 1 x 8 Gbs FC Qlogic HBA 1 x 6 Gbs SAS HBA 4 x 300 GB internal disks Sun Storage F5100 Flash Array (40 x 24 GB flash modules) 1 x Sun Fire X4275 server configured as COMSTAR head SPARC T3-4 server 4 x SPARC T3 processors, 1.6 GHz 512 GB memory 1 x 8 Gbs FC Qlogic HBA 8 x 146 GB internal disks 1 x Sun Fire X4275 server configured as COMSTAR head SPARC Enterprise M4000 server 4 x SPARC64 VII+ processors, 2.66 GHz 128 GB memory 1 x 8 Gbs FC Qlogic HBA 1 x 6 Gbs SAS HBA 2 x 146 GB internal disks Sun Storage F5100 Flash Array (40 x 24 GB flash modules) 1 x Sun Fire X4275 server configured as COMSTAR head Software Configuration: Oracle Solaris 11 11/11 Oracle TimesTen 11.2.2.4 Benchmark Descriptions TimesTen Performance Throughput BenchMark (TPTBM) is shipped with TimesTen and measures the total throughput of the system. The workload can test read-only, update-only, delete and insert operations as required. Mobile Call Processing is a customer-based workload for processing calls made by mobile phone subscribers. The workload has a mixture of read-only, update, and insert-only transactions. The peak throughput performance is measured from multiple concurrent processes executing the transactions until a peak performance is reached via saturation of the available resources. Parallel Replication tests using both asynchronous and 2-Safe replication methods. For asynchronous replication, transactions are processed in batches to maximize the throughput capabilities of the replication server and network. In 2-Safe replication, also known as no data-loss or high availability, transactions are replicated between servers immediately emphasizing low latency. For both environments, performance is measured in the number of parallel replication servers and the maximum transactions-per-second for all concurrent processes. See Also SPARC T4-2 Server oracle.com OTN Oracle TimesTen In-Memory Database oracle.com OTN Oracle Solaris oracle.com OTN Oracle Database 11g Release 2 Enterprise Edition oracle.com OTN Disclosure Statement Copyright 2012, Oracle and/or its affiliates. All rights reserved. Oracle and Java are registered trademarks of Oracle and/or its affiliates. Other names may be trademarks of their respective owners. Results as of 1 October 2012.

  Read the article

• Validating Petabytes of Data with Regularity and Thoroughness

  - by rickramsey

  by Brian Zents When former Intel CEO Andy Grove said “only the paranoid survive,” he wasn’t necessarily talking about tape storage administrators, but it’s a lesson they’ve learned well. After all, tape storage is the last line of defense to prevent data loss, so tape administrators are extra cautious in making sure their data is secure. Not surprisingly, we are often asked for ways to validate tape media and the files on them. In the past, an administrator could validate the media, but doing so was often tedious or disruptive or both. The debut of the Data Integrity Validation (DIV) and Library Media Validation (LMV) features in the Oracle T10000C drive helped eliminate many of these pains. Also available with the Oracle T10000D drive, these features use hardware-assisted CRC checks that not only ensure the data is written correctly the first time, but also do so much more efficiently. Traditionally, a CRC check takes at least 25 seconds per 4GB file with a 2:1 compression ratio, but the T10000C/D drives can reduce the check to a maximum of nine seconds because the entire check is contained within the drive. No data needs to be sent to a host application. A time savings of at least 64 percent is extremely beneficial over the course of checking an entire 8.5TB T10000D tape. While the DIV and LMV features are better than anything else out there, what storage administrators really need is a way to check petabytes of data with regularity and thoroughness. With the launch of Oracle StorageTek Tape Analytics (STA) 2.0 in April, there is finally a solution that addresses this longstanding need. STA bundles these features into one interface to automate all media validation activities across all Oracle SL3000 and SL8500 tape libraries in an environment. And best of all, the validation process can be associated with the health checks an administrator would be doing already through STA. In fact, STA validates the media based on any of the following policies: Random Selection – Randomly selects media for validation whenever a validation drive in the standalone library or library complex is available. Media Health = Action – Selects media that have had a specified number of successive exchanges resulting in an Exchange Media Health of “Action.” You can specify from one to five exchanges. Media Health = Evaluate – Selects media that have had a specified number of successive exchanges resulting in an Exchange Media Health of “Evaluate.” You can specify from one to five exchanges. Media Health = Monitor – Selects media that have had a specified number of successive exchanges resulting in an Exchange Media Health of “Monitor.” You can specify from one to five exchanges. Extended Period of Non-Use – Selects media that have not had an exchange for a specified number of days. You can specify from 365 to 1,095 days (one to three years). Newly Entered – Selects media that have recently been entered into the library. Bad MIR Detected – Selects media with an exchange resulting in a “Bad MIR Detected” error. A bad media information record (MIR) indicates degraded high-speed access on the media. To avoid disrupting host operations, an administrator designates certain drives for media validation operations. If a host requests a file from media currently being validated, the host’s request takes priority. To ensure that the administrator really knows it is the media that is bad, as opposed to the drive, STA includes drive calibration and qualification features. In addition, validation requests can be re-prioritized or cancelled as needed. To ensure that a specific tape isn’t validated too often, STA prevents a tape from being validated twice within 24 hours via one of the policies described above. A tape can be validated more often if the administrator manually initiates the validation. When the validations are complete, STA reports the results. STA does not report simply a “good” or “bad” status. It also reports if media is even degraded so the administrator can migrate the data before there is a true failure. From that point, the administrators’ paranoia is relieved, as they have the necessary information to make a sound decision about the health of the tapes in their environment. About the Photograph Photograph taken by Rick Ramsey in Death Valley, California, May 2014 - Brian Follow OTN Garage on: Web | Facebook | Twitter | YouTube

  Read the article

• Autoscaling in a modern world&hellip;. Part 4

  - by Steve Loethen

  Now that I have the rules and services XML files in the cloud, it is time to sever the bounds of earth and live totally in the cloud.  I have to host the Autoscaling object in Azure as well, point it to the rules, tell it the management certs and get out of the way. A couple of questions.  Where to host?  The most obvious place to me was a worker role.  A simple, single purpose worker role, doing nothing but watching my app.  Here are the steps I used. 1) Created a project.  Separate project from my web site.  I wanted to be able to run the web in the cloud and the autoscaler local for debugging purposes.  Seemed like the easiest way.  2) Add the Wasabi block to the project. 3) Configure the settings.  I used the same settings used for the console app.  It points to the same web role, uses the same rules file.  4) Make sure the certification needed to manage the role is added to the cert store in the sky (“LocalMachine” and “My” are default locations). I ran the worker role in the local fabric.  It worked.  I then published to the cloud, and verified it worked again.  Here is what my code looked like. public override bool OnStart() { Trace.WriteLine("Set Default Connection Limit", "Information"); // Set the maximum number of concurrent connections ServicePointManager.DefaultConnectionLimit = 12; Trace.WriteLine("Set up configuration change code", "Information"); // set up config CloudStorageAccount.SetConfigurationSettingPublisher((configName, configSetter) => configSetter(RoleEnvironment.GetConfigurationSettingValue(configName))); Trace.WriteLine("Get current diagnostic configuration", "Information"); // Get current diagnostic configuration DiagnosticMonitorConfiguration dmc = DiagnosticMonitor.GetDefaultInitialConfiguration(); Trace.WriteLine("Set Diagnostic Buffer Size", "Information"); // Set Diagnostic Buffer size dmc.Logs.BufferQuotaInMB = 4; Trace.WriteLine("Set log transfer period", "Information"); // Set log transfer period dmc.Logs.ScheduledTransferPeriod = TimeSpan.FromMinutes(1); Trace.WriteLine("Set log verbosity", "Information"); // Set log filter to verbose dmc.Logs.ScheduledTransferLogLevelFilter = LogLevel.Verbose; Trace.WriteLine("Start the diagnostic monitor", "Information"); // Start the diagnostic monitor DiagnosticMonitor.Start("Microsoft.WindowsAzure.Plugins.Diagnostics.ConnectionString", dmc); Trace.WriteLine("Get the current Autoscaler from the EntLib Container", "Information"); // Get the current Autoscaler from the EntLib Container scaler = EnterpriseLibraryContainer.Current.GetInstance<Autoscaler>(); Trace.WriteLine("Start the autoscaler", "Information"); // Start the autoscaler scaler.Start(); Trace.WriteLine("call the base class OnStart", "Information"); // call the base class OnStart return base.OnStart(); } public override void OnStop() { Trace.WriteLine("Stop the Autoscaler", "Information"); // Stop the Autoscaler scaler.Stop(); } I did have to turn on some basic logging for wasabi, which will cover in the next post.  This let me figure out that I hadn’t done the certificate step.

  Read the article

< Previous Page | 91 92 93 94 95 96 97 98 99 100 101 102  | Next Page >