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  • Unable to Get values from Web Form to a PHP Class to Display

    - by kentrenholm
    I am having troubles getting the value from my variables submitted via a web form using a PHP class file. Here is my structure of the web page: Order Form Page Process.php Page Book.php Page I can easily get the user data entered (on Order Form Page), process, and display it on the Process.php page. The issue is that I must create a Book class and print the details of the data using the Book class. I have an empty constructor printing out "created" so I know my constructor is being called. I also am able to print the word "title" so I know I can print to the screen by using the Book class. My issue is that I can't get values in my variables in the Book class. Here is my variable declaration: private $title; Here is my printDetails function: public function printDetails () { echo "Title: " . $this->title . "<br />"; } Here is my new instance of the book class: $bookNow = new book; Here are my get and set functions: function __getTitle($title) { return $this->$title; } function __setTitle($title,$value) { $this->$title = $value; } I do have four other variables that I'm looking to display as well. Each of those have their own variable declaration, a line in printDetails, and their own setter and getter. Lastly, I also have a call to the Book class in my process PHP. It looks like this: function __autoload($book) { include $book . '.php'; } $bookNow = new book(); Any help, much appreciated. It must be something so very small (I'm hoping).

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  • SQL Binary Microsoft Access - Combining two tables if specific field values are equal

    - by Jordan
    I am new to Microsoft Access and SQL but have a decent programming background and I believe this problem should be relatively simple. I have two tables that I have imported into Access. I will give you a little context. One table is huge and contains generic, global data. The other table is still big but contains specific, regional data. There is only one common field (or column) between the two tables. Let’s call this common field CF. The other fields in both tables are different. I’ll take you through one iteration of what I need to do. I need to take each CF value in the regional, smaller table and find the common CF value in the larger, global table. After finding the match, I need to take the whole “record” or “row” from the global data and copy it over to the corresponding record in the smaller regional table (This should involve creating the new fields). I need to do this for all CF values in the regional, smaller table. I was recommended to use SQL and a binary search, but I am unfamiliar. Let me know if you have any questions. I appreciate the help!

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  • SELECT SQL Variable - should i avoid using this syntax and always use SET?

    - by Sholom
    Hi All, This may look like a duplicate to here, but it's not. I am trying to get a best practice, not a technical answer (which i already (think) i know). New to SQL Server and trying to form good habits. I found a great explanation of the functional differences between SET @var = and SELECT @var = here: http://vyaskn.tripod.com/differences_between_set_and_select.htm To summarize what each has that the other hasn't (see source for examples): SET: ANSI and portable, recommended by Microsoft. SET @var = (SELECT column_name FROM table_name) fails when the select returns more then one value, eliminating the possibility of unpredictable results. SET @var = (SELECT column_name FROM table_name) will set @var to NULL if that's what SELECT column_name FROM table_name returned, thus never leaving @var at it's prior value. SELECT: Multiple variables can be set in one statement Can return multiple system variables set by the prior DML statement SELECT @var = column_name FROM table_name would set @var to (according to my testing) the last value returned by the select. This could be a feature or a bug. Behavior can be changed with SELECT @j = (SELECT column_name FROM table_name) syntax. Speed. Setting multiple variables with a single SELECT statement as opposed to multiple SET/SELECT statements is much quicker. He has a sample test to prove his point. If you could design a test to prove the otherwise, bring it on! So, what do i do? (Almost) always use SET @var =, using SELECT @var = is messy coding and not standard. OR Use SELECT @var = freely, it could accomplish more for me, unless the code is likely to be ported to another environment. Thanks

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  • How can one make a 'passthru' function in C++ using macros or metaprogramming?

    - by Ryan
    So I have a series of global functions, say: foo_f1(int a, int b, char *c); foo_f2(int a); foo_f3(char *a); I want to make a C++ wrapper around these, something like: MyFoo::f1(int a, int b, char* c); MyFoo::f2(int a); MyFoo::f3(char* a); There's about 40 functions like this, 35 of them I just want to pass through to the global function, the other 5 I want to do something different with. Ideally the implementation of MyFoo.cpp would be something like: PASSTHRU( f1, (int a, int b, char *c) ); PASSTHRU( f2, (int a) ); MyFoo::f3(char *a) { //do my own thing here } But I'm having trouble figuring out an elegant way to make the above PASSTHRU macro. What I really need is something like the mythical X getArgs() below: MyFoo::f1(int a, int b, char *c) { X args = getArgs(); args++; //skip past implicit this.. ::f1(args); //pass args to global function } But short of dropping into assembly I can't find a good implementation of getArgs().

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  • Pass Arguments to Included Module in Ruby?

    - by viatropos
    I'm hoping to implement something like all of the great plugins out there for ruby, so that you can do this: acts_as_commentable has_attached_file :avatar But I have one constraint: That helper method can only include a module; it can't define any variables or methods. The reason for this is because, I want the options hash to define something like type, and that could be converted into one of say 20 different 'workhorse' modules, all of which I could sum up in a line like this: def dynamic_method(options = {}) include ("My::Helpers::#{options[:type].to_s.camelize}").constantize(options) end Then those 'workhorses' would handle the options, doing things like: has_many "#{options[:something]}" Here's what the structure looks like, and I'm wondering if you know the missing piece in the puzzle: # 1 - The workhorse, encapsuling all dynamic variables module My::Module def self.included(base) base.extend ClassMethods base.class_eval do include InstanceMethods end end module InstanceMethods self.instance_eval %Q? def #{options[:my_method]} "world!" end ? end module ClassMethods end end # 2 - all this does is define that helper method module HelperModule def self.included(base) base.extend(ClassMethods) end module ClassMethods def dynamic_method(options = {}) # don't know how to get options through! include My::Module(options) end end end # 3 - send it to active_record ActiveRecord::Base.send(:include, HelperModule) # 4 - what it looks like class TestClass < ActiveRecord::Base dynamic_method :my_method => "hello" end puts TestClass.new.hello #=> "world!" That %Q? I'm not totally sure how to use, but I'm basically just wanting to somehow be able to pass the options hash from that helper method into the workhorse module. Is that possible? That way, the workhorse module could define all sorts of functionality, but I could name the variables whatever I wanted at runtime.

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  • C++: Maybe you know this pitfall?

    - by Martijn Courteaux
    Hi, I'm developing a game. I have a header GameSystem (just methods like the game loop, no class) with two variables: int mouseX and int mouseY. These are updated in my game loop. Now I want to access them from Game.cpp file (a class built by a header-file and the source-file). So, I #include "GameSystem.h" in Game.h. After doing this I get a lot of compile errors. When I remove the include he says of course: Game.cpp:33: error: ‘mouseX’ was not declared in this scope Game.cpp:34: error: ‘mouseY’ was not declared in this scope Where I want to access mouseX and mouseY. All my .h files have Header Guards, generated by Eclipse. I'm using SDL and if I remove the lines that wants to access the variables, everything compiles and run perfectly (*). I hope you can help me... This is the error-log when I #include "GameSystem.h" (All the code he is refering to works, like explained by the (*)): In file included from ../trunk/source/domein/Game.h:14, from ../trunk/source/domein/Game.cpp:8: ../trunk/source/domein/GameSystem.h:30: error: expected constructor, destructor, or type conversion before ‘*’ token ../trunk/source/domein/GameSystem.h:46: error: variable or field ‘InitGame’ declared void ../trunk/source/domein/GameSystem.h:46: error: ‘Game’ was not declared in this scope ../trunk/source/domein/GameSystem.h:46: error: ‘g’ was not declared in this scope ../trunk/source/domein/GameSystem.h:46: error: expected primary-expression before ‘char’ ../trunk/source/domein/GameSystem.h:46: error: expected primary-expression before ‘bool’ ../trunk/source/domein/FPS.h:46: warning: ‘void FPS_SleepMilliseconds(int)’ defined but not used This is the code which try to access the two variables: SDL_Rect pointer; pointer.x = mouseX; pointer.y = mouseY; pointer.w = 3; pointer.h = 3; SDL_FillRect(buffer, &pointer, 0xFF0000);

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  • Can't access form elements

    - by linkcool
    Hi, my problem is that my variables are not working in javascript. all variables need names without some character at the beginning, this is the stupid thing...Anyways, im trying to make a funtion that makes "select all checkboxes". It is not working so i looked at the page source/info and found out that the variables were not changing. this is my input: echo "<input onclick='checkAll(1);' type='checkbox' name='master'/><br/>"; My function: function checkAll(i) { for(var i=1; i < <?php echo $num; ?>; i++) { if(document.demo.master[i].checked == true) { document.demo.message[i].checked = true; } else { document.demo.message[i].checked = false; } } } so yes that's it. I can tell you that i also tried without the <i> in: checkAll("i") Thanks for the help. EDIT: each checkbox for each messsage has this code:echo "<input style='margin-left:-15px;margin-top:20px;' type='checkbox' name='message' value='$rid' /><br/>";

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  • Fatal error: Allowed memory size exhausted...

    - by Nano HE
    HI, I upload my php testing script to online vps server just now. The script used to parse a big size XML file(about 4M, 7000Lines). But my IE explorer show the online error message below. Fatal error: Allowed memory size of 16777216 bytes exhausted (tried to allocate 77 bytes) in /var/www/test/result/index.php on line 26 I am sure I already tested the php script on localhost successfully. Is there any configuration need be enable/modify on my VPS? Such as php.ini or some setting for apache server? I just verified there are about 200M memory usage are avaliable for my VPS. How can I fix this? ...... function startElementHandler ($parser,$name,$attrib){ global $usercount; global $userdata; global $state; // Line #26; //Debug //print "name is: ".$name."\n"; switch ($name) { case $name=="_ID" : { $userdata[$usercount]["first"] = $attrib["FIRST"]; $userdata[$usercount]["last"] = $attrib["LAST"]; $userdata[$usercount]["nick"] = $attrib["NICK"]; $userdata[$usercount]["title"] = $attrib["TITLE"]; break; } ...... default : {$state=$name;break;} } }

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  • Sparc Assembly Call currupts data

    - by Sigge
    I am at the moment working with some assembler code for the Sparc processor family, and i am having some truble with a piece of code.. I think the code and output explains more, but in the short.. When i do a call to the function println my varaibels that i have written to the %fp - 8 memory location is destoryed.. here is my assembler code that i am trying to run !PROCEDURE main .section ".text" .global main .align 4 main: save %sp, -96, %sp L1: set 96, %l0 mov %l0, %o0 call initObject ; nop mov %o0, %l0 mov %l0, %o0 call Test$go ; nop mov %o0, %l0 mov %l0, %o0 call println ; nop L0: ret restore !END main !PROCEDURE Test$go .section ".text" .global Test$go .align 4 Test$go: save %sp, -96, %sp L3: mov %i0, %l0 set 0, %l0 set -8, %l1 add %fp,%l1, %l1 st %l0, [%l1] set 1, %l0 mov %l0, %o0 call println ; nop set -8, %l0 add %fp,%l0, %l0 ld [%l0], %l0 mov %l0, %o0 call println ; nop set 1, %l0 mov %l0, %i0 L2: ret restore !END Test$go Here is the assembler code for the println code .global println .type println,#function println: save %sp,-96,%sp ! block 1 .L193: ! File runtime.c: ! 42 } ! 43 ! 45 /** ! 46 Prints an integer to the standard output stream. ! 47 ! 48 @param i The integer to be printed. ! 49 */ ! 50 void println(int i) { ! 51 printf("%d\n", i); sethi %hi(.L195),%o0 or %o0,%lo(.L195),%o0 call printf mov %i0,%o1 jmp %i7+8 restore This is the out put i get when i run this piece of assembler code 1 67584 1 As u can see, the data that is located at %fp - 8 has been destroyed.. please all feedback is apritiated

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  • Sparc Assembly Call corrupts data

    - by Sigge
    I am at the moment working with some assembler code for the Sparc processor family, and i am having some truble with a piece of code.. I think the code and output explains more, but in the short.. When i do a call to the function println my varaibels that i have written to the %fp - 8 memory location is destoryed.. here is my assembler code that i am trying to run !PROCEDURE main .section ".text" .global main .align 4 main: save %sp, -96, %sp L1: set 96, %l0 mov %l0, %o0 call initObject ; nop mov %o0, %l0 mov %l0, %o0 call Test$go ; nop mov %o0, %l0 mov %l0, %o0 call println ; nop L0: ret restore !END main !PROCEDURE Test$go .section ".text" .global Test$go .align 4 Test$go: save %sp, -96, %sp L3: mov %i0, %l0 set 0, %l0 set -8, %l1 add %fp,%l1, %l1 st %l0, [%l1] set 1, %l0 mov %l0, %o0 call println ; nop set -8, %l0 add %fp,%l0, %l0 ld [%l0], %l0 mov %l0, %o0 call println ; nop set 1, %l0 mov %l0, %i0 L2: ret restore !END Test$go Here is the assembler code for the println code .global println .type println,#function println: save %sp,-96,%sp ! block 1 .L193: ! File runtime.c: ! 42 } ! 43 ! 45 /** ! 46 Prints an integer to the standard output stream. ! 47 ! 48 @param i The integer to be printed. ! 49 */ ! 50 void println(int i) { ! 51 printf("%d\n", i); sethi %hi(.L195),%o0 or %o0,%lo(.L195),%o0 call printf mov %i0,%o1 jmp %i7+8 restore This is the out put i get when i run this piece of assembler code 1 67584 1 As u can see, the data that is located at %fp - 8 has been destroyed.. please all feedback is apritiated

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  • gems, bundle command, and ruby not found in new terminal window

    - by user3579987
    So I installed ruby with rvm, ran a bundle install and installed a bunch of gems, etc. It all works just fine in the original terminal window I did all of this in but I opened up a new terminal window and now I'm getting errors like bundle: command not found and gem command not found. I tried doing a symbolic link for the gem command but then when I do gem list it displays a much shorter list of my local gems and not at all the ones I need for bundle install. Is there something I need to do to configure bash or rvm so that it recognizes that I did indeed install all the gems I have installed? name@crunchbang:~/ug_research_portal$ which gem /home/name/.rvm/rubies/ruby-2.1.1/bin/gem name@crunchbang:~/ug_research_portal$ which ruby /home/name/.rvm/rubies/ruby-2.1.1/bin/ruby And in ~/.bashrc: GEM_HOME="/home/name/.rvm/gems/ruby-2.1.1" GEMGLOBAL_HOME="/home/ name/.rvm/gems/ruby-2.1.1@global" export PATH=$PATH:$GEM_HOME/bin:$GEMGLOBAL_HOME/bin:$HOME/.rvm/bin Edit: Looks like my $PATH is somehow wrong? bash: /home/name/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games:/home/name/.rvm/gems/ruby-2.1.1/bin:/home/name/.rvm/gems/ruby-2.1.1@global/bin:/home/name/.rvm/bin/: No such file or directory which is odd since ls for /home/name/.rvm/bin and /home/name/.rvm/gems/ruby-2.1.1@global/bin and /home/name/.rvm/gems/ruby-2.1.1/bin work just fine Psych, I was just doing $PATH instead of echo "$PATH" which was giving me the No such file or directory error. The original problem still stands though.

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  • cuda 5.0 namespaces for contant memory variable usage

    - by Psypher
    In my program I want to use a structure containing constant variables and keep it on device all long as the program executes to completion. I have several header files containing the declaration of 'global' functions and their respective '.cu' files for their definitions. I kept this scheme because it helps me contain similar code in one place. e.g. all the 'device' functions required to complete 'KERNEL_1' are separated from those 'device' functions required to complete 'KERNEL_2' along with kernels definitions. I had no problems with this scheme during compilation and linking. Until I encountered constant variables. I want to use the same constant variable through all kernels and device functions but it doesn't seem to work. ########################################################################## CODE EXAMPLE ########################################################################### filename: 'common.h' -------------------------------------------------------------------------- typedef struct { double height; double weight; int age; } __CONSTANTS; __constant__ __CONSTANTS d_const; --------------------------------------------------------------------------- filename: main.cu --------------------------------------------------------------------------- #include "common.h" #include "gpukernels.h" int main(int argc, char **argv) { __CONSTANTS T; T.height = 1.79; T.weight = 73.2; T.age = 26; cudaMemcpyToSymbol(d_consts, &T, sizeof(__CONSTANTS)); test_kernel <<< 1, 16 >>>(); cudaDeviceSynchronize(); } --------------------------------------------------------------------------- filename: gpukernels.h --------------------------------------------------------------------------- __global__ void test_kernel(); --------------------------------------------------------------------------- filename: gpukernels.cu --------------------------------------------------------------------------- #include <stdio.h> #include "gpukernels.h" #include "common.h" __global__ void test_kernel() { printf("Id: %d, height: %f, weight: %f\n", threadIdx.x, d_const.height, d_const.weight); } When I execute this code, the kernel executes, displays the thread ids, but the constant values are displayed as zeros. How can I fix this?

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  • Should I use a class in this: Reading a XML file using lxml.

    - by PulpFiction
    Hi everyone. This question is in continuation to my previous question, in which I asked about passing around an ElementTree. I need to read the XML files only and to solve this, I decided to create a global ElementTree and then parse it wherever required. My question is: Is this an acceptable practice? I heard global variables are bad. If I don't make it global, I was suggested to make a class. But do I really need to create a class? What benefits would I have from that approach. Note that I would be handling only one ElementTree instance per run, the operations are read-only. If I don't use a class, how and where do I declare that ElementTree so that it available globally? (Note that I would be importing this module) Please answer this question in the respect that I am a beginner to development, and at this stage I can't figure out whether to use a class or just go with the functional style programming approach.

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  • Clustered Graphs Visualization Techniques

    - by jameszhao00
    I need to visualize a relatively large graph (6K nodes, 8K edges) that has the following properties: Distinct Clusters. Approximately 50-100 Nodes per cluster and moderate interconnectivity at the cluster level Minimal (5-10 inter-cluster edges per cluster) interconnectivity between clusters Let global edge overlap = The edge overlaps caused by directly visualizing a graph of Clusters = {A, B, C, D, E}, Edges = {Pentagram of those clusters, which is non-planar by the way and will definitely generate edge overlap if you draw it out directly} Let Local Edge Overlap = the above but { A, B, C, D, E } are just nodes. I need to visualize graphs with the above in a way that satisfies the following requirements No global edge overlap (i.e. edge overlaps caused by inter-cluster properties is not okay) Local edge overlap within a cluster is fine Anyone have thoughts on how to best visualize a graph with the requirements above? One solution I've come up with to deal with the global edge overlap is to make sure a cluster A can only have a max of 1 direct edge to another cluster (B) during visualization. Any additional inter-cluster edges between cluster A - C, A - D, ... are disconnected and additional node/edges A - A_C, C - C_A, A - A_D, D - D_A... are created. Anyone have any thoughts?

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  • NoSQL with RavenDB and ASP.NET MVC - Part 1

    - by shiju
     A while back, I have blogged NoSQL with MongoDB, NoRM and ASP.NET MVC Part 1 and Part 2 on how to use MongoDB with an ASP.NET MVC application. The NoSQL movement is getting big attention and RavenDB is the latest addition to the NoSQL and document database world. RavenDB is an Open Source (with a commercial option) document database for the .NET/Windows platform developed  by Ayende Rahien.  Raven stores schema-less JSON documents, allow you to define indexes using Linq queries and focus on low latency and high performance. RavenDB is .NET focused document database which comes with a fully functional .NET client API  and supports LINQ. RavenDB comes with two components, a server and a client API. RavenDB is a REST based system, so you can write your own HTTP cleint API. As a .NET developer, RavenDB is becoming my favorite document database. Unlike other document databases, RavenDB is supports transactions using System.Transactions. Also it's supports both embedded and server mode of database. You can access RavenDB site at http://ravendb.netA demo App with ASP.NET MVCLet's create a simple demo app with RavenDB and ASP.NET MVC. To work with RavenDB, do the following steps. Go to http://ravendb.net/download and download the latest build.Unzip the downloaded file.Go to the /Server directory and run the RavenDB.exe. This will start the RavenDB server listening on localhost:8080You can change the port of RavenDB  by modifying the "Raven/Port" appSetting value in the RavenDB.exe.config file.When running the RavenDB, it will automatically create a database in the /Data directory. You can change the directory name data by modifying "Raven/DataDirt" appSetting value in the RavenDB.exe.config file.RavenDB provides a browser based admin tool. When the Raven server is running, You can be access the browser based admin tool and view and edit documents and index using your browser admin tool. The web admin tool available at http://localhost:8080The below is the some screen shots of web admin tool     Working with ASP.NET MVC  To working with RavenDB in our demo ASP.NET MVC application, do the following steps Step 1 - Add reference to Raven Cleint API In our ASP.NET MVC application, Add a reference to the Raven.Client.Lightweight.dll from the Client directory. Step 2 - Create DocumentStoreThe document store would be created once per application. Let's create a DocumentStore on application start-up in the Global.asax.cs. documentStore = new DocumentStore { Url = "http://localhost:8080/" }; documentStore.Initialise(); The above code will create a Raven DB document store and will be listening the server locahost at port 8080    Step 3 - Create DocumentSession on BeginRequest   Let's create a DocumentSession on BeginRequest event in the Global.asax.cs. We are using the document session for every unit of work. In our demo app, every HTTP request would be a single Unit of Work (UoW). BeginRequest += (sender, args) =>   HttpContext.Current.Items[RavenSessionKey] = documentStore.OpenSession(); Step 4 - Destroy the DocumentSession on EndRequest  EndRequest += (o, eventArgs) => {     var disposable = HttpContext.Current.Items[RavenSessionKey] as IDisposable;     if (disposable != null)         disposable.Dispose(); };  At the end of HTTP request, we are destroying the DocumentSession  object.The below  code block shown all the code in the Global.asax.cs  private const string RavenSessionKey = "RavenMVC.Session"; private static DocumentStore documentStore;   protected void Application_Start() { //Create a DocumentStore in Application_Start //DocumentStore should be created once per application and stored as a singleton. documentStore = new DocumentStore { Url = "http://localhost:8080/" }; documentStore.Initialise(); AreaRegistration.RegisterAllAreas(); RegisterRoutes(RouteTable.Routes); //DI using Unity 2.0 ConfigureUnity(); }   public MvcApplication() { //Create a DocumentSession on BeginRequest   //create a document session for every unit of work BeginRequest += (sender, args) =>     HttpContext.Current.Items[RavenSessionKey] = documentStore.OpenSession(); //Destroy the DocumentSession on EndRequest EndRequest += (o, eventArgs) => { var disposable = HttpContext.Current.Items[RavenSessionKey] as IDisposable; if (disposable != null) disposable.Dispose(); }; }   //Getting the current DocumentSession public static IDocumentSession CurrentSession {   get { return (IDocumentSession)HttpContext.Current.Items[RavenSessionKey]; } }  We have setup all necessary code in the Global.asax.cs for working with RavenDB. For our demo app, Let’s write a domain class  public class Category {       public string Id { get; set; }       [Required(ErrorMessage = "Name Required")]     [StringLength(25, ErrorMessage = "Must be less than 25 characters")]     public string Name { get; set;}     public string Description { get; set; }   } We have created simple domain entity Category. Let's create repository class for performing CRUD operations against our domain entity Category.  public interface ICategoryRepository {     Category Load(string id);     IEnumerable<Category> GetCategories();     void Save(Category category);     void Delete(string id);       }    public class CategoryRepository : ICategoryRepository {     private IDocumentSession session;     public CategoryRepository()     {             session = MvcApplication.CurrentSession;     }     //Load category based on Id     public Category Load(string id)     {         return session.Load<Category>(id);     }     //Get all categories     public IEnumerable<Category> GetCategories()     {         var categories= session.LuceneQuery<Category>()                 .WaitForNonStaleResults()             .ToArray();         return categories;       }     //Insert/Update category     public void Save(Category category)     {         if (string.IsNullOrEmpty(category.Id))         {             //insert new record             session.Store(category);         }         else         {             //edit record             var categoryToEdit = Load(category.Id);             categoryToEdit.Name = category.Name;             categoryToEdit.Description = category.Description;         }         //save the document session         session.SaveChanges();     }     //delete a category     public void Delete(string id)     {         var category = Load(id);         session.Delete<Category>(category);         session.SaveChanges();     }        } For every CRUD operations, we are taking the current document session object from HttpContext object. session = MvcApplication.CurrentSession; We are calling the static method CurrentSession from the Global.asax.cs public static IDocumentSession CurrentSession {     get { return (IDocumentSession)HttpContext.Current.Items[RavenSessionKey]; } }  Retrieve Entities  The Load method get the single Category object based on the Id. RavenDB is working based on the REST principles and the Id would be like categories/1. The Id would be created by automatically when a new object is inserted to the document store. The REST uri categories/1 represents a single category object with Id representation of 1.   public Category Load(string id) {    return session.Load<Category>(id); } The GetCategories method returns all the categories calling the session.LuceneQuery method. RavenDB is using a lucen query syntax for querying. I will explain more details about querying and indexing in my future posts.   public IEnumerable<Category> GetCategories() {     var categories= session.LuceneQuery<Category>()             .WaitForNonStaleResults()         .ToArray();     return categories;   } Insert/Update entityFor insert/Update a Category entity, we have created Save method in repository class. If  the Id property of Category is null, we call Store method of Documentsession for insert a new record. For editing a existing record, we load the Category object and assign the values to the loaded Category object. The session.SaveChanges() will save the changes to document store.  //Insert/Update category public void Save(Category category) {     if (string.IsNullOrEmpty(category.Id))     {         //insert new record         session.Store(category);     }     else     {         //edit record         var categoryToEdit = Load(category.Id);         categoryToEdit.Name = category.Name;         categoryToEdit.Description = category.Description;     }     //save the document session     session.SaveChanges(); }  Delete Entity  In the Delete method, we call the document session's delete method and call the SaveChanges method to reflect changes in the document store.  public void Delete(string id) {     var category = Load(id);     session.Delete<Category>(category);     session.SaveChanges(); }  Let’s create ASP.NET MVC controller and controller actions for handling CRUD operations for the domain class Category  public class CategoryController : Controller { private ICategoryRepository categoyRepository; //DI enabled constructor public CategoryController(ICategoryRepository categoyRepository) {     this.categoyRepository = categoyRepository; } public ActionResult Index() {         var categories = categoyRepository.GetCategories();     if (categories == null)         return RedirectToAction("Create");     return View(categories); }   [HttpGet] public ActionResult Edit(string id) {     var category = categoyRepository.Load(id);         return View("Save",category); } // GET: /Category/Create [HttpGet] public ActionResult Create() {     var category = new Category();     return View("Save", category); } [HttpPost] public ActionResult Save(Category category) {     if (!ModelState.IsValid)     {         return View("Save", category);     }           categoyRepository.Save(category);         return RedirectToAction("Index");     }        [HttpPost] public ActionResult Delete(string id) {     categoyRepository.Delete(id);     var categories = categoyRepository.GetCategories();     return PartialView("CategoryList", categories);      }        }  RavenDB is an awesome document database and I hope that it will be the winner in .NET space of document database world.  The source code of demo application available at http://ravenmvc.codeplex.com/

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  • A Taxonomy of Numerical Methods v1

    - by JoshReuben
    Numerical Analysis – When, What, (but not how) Once you understand the Math & know C++, Numerical Methods are basically blocks of iterative & conditional math code. I found the real trick was seeing the forest for the trees – knowing which method to use for which situation. Its pretty easy to get lost in the details – so I’ve tried to organize these methods in a way that I can quickly look this up. I’ve included links to detailed explanations and to C++ code examples. I’ve tried to classify Numerical methods in the following broad categories: Solving Systems of Linear Equations Solving Non-Linear Equations Iteratively Interpolation Curve Fitting Optimization Numerical Differentiation & Integration Solving ODEs Boundary Problems Solving EigenValue problems Enjoy – I did ! Solving Systems of Linear Equations Overview Solve sets of algebraic equations with x unknowns The set is commonly in matrix form Gauss-Jordan Elimination http://en.wikipedia.org/wiki/Gauss%E2%80%93Jordan_elimination C++: http://www.codekeep.net/snippets/623f1923-e03c-4636-8c92-c9dc7aa0d3c0.aspx Produces solution of the equations & the coefficient matrix Efficient, stable 2 steps: · Forward Elimination – matrix decomposition: reduce set to triangular form (0s below the diagonal) or row echelon form. If degenerate, then there is no solution · Backward Elimination –write the original matrix as the product of ints inverse matrix & its reduced row-echelon matrix à reduce set to row canonical form & use back-substitution to find the solution to the set Elementary ops for matrix decomposition: · Row multiplication · Row switching · Add multiples of rows to other rows Use pivoting to ensure rows are ordered for achieving triangular form LU Decomposition http://en.wikipedia.org/wiki/LU_decomposition C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-lu-decomposition-for-solving.html Represent the matrix as a product of lower & upper triangular matrices A modified version of GJ Elimination Advantage – can easily apply forward & backward elimination to solve triangular matrices Techniques: · Doolittle Method – sets the L matrix diagonal to unity · Crout Method - sets the U matrix diagonal to unity Note: both the L & U matrices share the same unity diagonal & can be stored compactly in the same matrix Gauss-Seidel Iteration http://en.wikipedia.org/wiki/Gauss%E2%80%93Seidel_method C++: http://www.nr.com/forum/showthread.php?t=722 Transform the linear set of equations into a single equation & then use numerical integration (as integration formulas have Sums, it is implemented iteratively). an optimization of Gauss-Jacobi: 1.5 times faster, requires 0.25 iterations to achieve the same tolerance Solving Non-Linear Equations Iteratively find roots of polynomials – there may be 0, 1 or n solutions for an n order polynomial use iterative techniques Iterative methods · used when there are no known analytical techniques · Requires set functions to be continuous & differentiable · Requires an initial seed value – choice is critical to convergence à conduct multiple runs with different starting points & then select best result · Systematic - iterate until diminishing returns, tolerance or max iteration conditions are met · bracketing techniques will always yield convergent solutions, non-bracketing methods may fail to converge Incremental method if a nonlinear function has opposite signs at 2 ends of a small interval x1 & x2, then there is likely to be a solution in their interval – solutions are detected by evaluating a function over interval steps, for a change in sign, adjusting the step size dynamically. Limitations – can miss closely spaced solutions in large intervals, cannot detect degenerate (coinciding) solutions, limited to functions that cross the x-axis, gives false positives for singularities Fixed point method http://en.wikipedia.org/wiki/Fixed-point_iteration C++: http://books.google.co.il/books?id=weYj75E_t6MC&pg=PA79&lpg=PA79&dq=fixed+point+method++c%2B%2B&source=bl&ots=LQ-5P_taoC&sig=lENUUIYBK53tZtTwNfHLy5PEWDk&hl=en&sa=X&ei=wezDUPW1J5DptQaMsIHQCw&redir_esc=y#v=onepage&q=fixed%20point%20method%20%20c%2B%2B&f=false Algebraically rearrange a solution to isolate a variable then apply incremental method Bisection method http://en.wikipedia.org/wiki/Bisection_method C++: http://numericalcomputing.wordpress.com/category/algorithms/ Bracketed - Select an initial interval, keep bisecting it ad midpoint into sub-intervals and then apply incremental method on smaller & smaller intervals – zoom in Adv: unaffected by function gradient à reliable Disadv: slow convergence False Position Method http://en.wikipedia.org/wiki/False_position_method C++: http://www.dreamincode.net/forums/topic/126100-bisection-and-false-position-methods/ Bracketed - Select an initial interval , & use the relative value of function at interval end points to select next sub-intervals (estimate how far between the end points the solution might be & subdivide based on this) Newton-Raphson method http://en.wikipedia.org/wiki/Newton's_method C++: http://www-users.cselabs.umn.edu/classes/Summer-2012/csci1113/index.php?page=./newt3 Also known as Newton's method Convenient, efficient Not bracketed – only a single initial guess is required to start iteration – requires an analytical expression for the first derivative of the function as input. Evaluates the function & its derivative at each step. Can be extended to the Newton MutiRoot method for solving multiple roots Can be easily applied to an of n-coupled set of non-linear equations – conduct a Taylor Series expansion of a function, dropping terms of order n, rewrite as a Jacobian matrix of PDs & convert to simultaneous linear equations !!! Secant Method http://en.wikipedia.org/wiki/Secant_method C++: http://forum.vcoderz.com/showthread.php?p=205230 Unlike N-R, can estimate first derivative from an initial interval (does not require root to be bracketed) instead of inputting it Since derivative is approximated, may converge slower. Is fast in practice as it does not have to evaluate the derivative at each step. Similar implementation to False Positive method Birge-Vieta Method http://mat.iitm.ac.in/home/sryedida/public_html/caimna/transcendental/polynomial%20methods/bv%20method.html C++: http://books.google.co.il/books?id=cL1boM2uyQwC&pg=SA3-PA51&lpg=SA3-PA51&dq=Birge-Vieta+Method+c%2B%2B&source=bl&ots=QZmnDTK3rC&sig=BPNcHHbpR_DKVoZXrLi4nVXD-gg&hl=en&sa=X&ei=R-_DUK2iNIjzsgbE5ID4Dg&redir_esc=y#v=onepage&q=Birge-Vieta%20Method%20c%2B%2B&f=false combines Horner's method of polynomial evaluation (transforming into lesser degree polynomials that are more computationally efficient to process) with Newton-Raphson to provide a computational speed-up Interpolation Overview Construct new data points for as close as possible fit within range of a discrete set of known points (that were obtained via sampling, experimentation) Use Taylor Series Expansion of a function f(x) around a specific value for x Linear Interpolation http://en.wikipedia.org/wiki/Linear_interpolation C++: http://www.hamaluik.com/?p=289 Straight line between 2 points à concatenate interpolants between each pair of data points Bilinear Interpolation http://en.wikipedia.org/wiki/Bilinear_interpolation C++: http://supercomputingblog.com/graphics/coding-bilinear-interpolation/2/ Extension of the linear function for interpolating functions of 2 variables – perform linear interpolation first in 1 direction, then in another. Used in image processing – e.g. texture mapping filter. Uses 4 vertices to interpolate a value within a unit cell. Lagrange Interpolation http://en.wikipedia.org/wiki/Lagrange_polynomial C++: http://www.codecogs.com/code/maths/approximation/interpolation/lagrange.php For polynomials Requires recomputation for all terms for each distinct x value – can only be applied for small number of nodes Numerically unstable Barycentric Interpolation http://epubs.siam.org/doi/pdf/10.1137/S0036144502417715 C++: http://www.gamedev.net/topic/621445-barycentric-coordinates-c-code-check/ Rearrange the terms in the equation of the Legrange interpolation by defining weight functions that are independent of the interpolated value of x Newton Divided Difference Interpolation http://en.wikipedia.org/wiki/Newton_polynomial C++: http://jee-appy.blogspot.co.il/2011/12/newton-divided-difference-interpolation.html Hermite Divided Differences: Interpolation polynomial approximation for a given set of data points in the NR form - divided differences are used to approximately calculate the various differences. For a given set of 3 data points , fit a quadratic interpolant through the data Bracketed functions allow Newton divided differences to be calculated recursively Difference table Cubic Spline Interpolation http://en.wikipedia.org/wiki/Spline_interpolation C++: https://www.marcusbannerman.co.uk/index.php/home/latestarticles/42-articles/96-cubic-spline-class.html Spline is a piecewise polynomial Provides smoothness – for interpolations with significantly varying data Use weighted coefficients to bend the function to be smooth & its 1st & 2nd derivatives are continuous through the edge points in the interval Curve Fitting A generalization of interpolating whereby given data points may contain noise à the curve does not necessarily pass through all the points Least Squares Fit http://en.wikipedia.org/wiki/Least_squares C++: http://www.ccas.ru/mmes/educat/lab04k/02/least-squares.c Residual – difference between observed value & expected value Model function is often chosen as a linear combination of the specified functions Determines: A) The model instance in which the sum of squared residuals has the least value B) param values for which model best fits data Straight Line Fit Linear correlation between independent variable and dependent variable Linear Regression http://en.wikipedia.org/wiki/Linear_regression C++: http://www.oocities.org/david_swaim/cpp/linregc.htm Special case of statistically exact extrapolation Leverage least squares Given a basis function, the sum of the residuals is determined and the corresponding gradient equation is expressed as a set of normal linear equations in matrix form that can be solved (e.g. using LU Decomposition) Can be weighted - Drop the assumption that all errors have the same significance –-> confidence of accuracy is different for each data point. Fit the function closer to points with higher weights Polynomial Fit - use a polynomial basis function Moving Average http://en.wikipedia.org/wiki/Moving_average C++: http://www.codeproject.com/Articles/17860/A-Simple-Moving-Average-Algorithm Used for smoothing (cancel fluctuations to highlight longer-term trends & cycles), time series data analysis, signal processing filters Replace each data point with average of neighbors. Can be simple (SMA), weighted (WMA), exponential (EMA). Lags behind latest data points – extra weight can be given to more recent data points. Weights can decrease arithmetically or exponentially according to distance from point. Parameters: smoothing factor, period, weight basis Optimization Overview Given function with multiple variables, find Min (or max by minimizing –f(x)) Iterative approach Efficient, but not necessarily reliable Conditions: noisy data, constraints, non-linear models Detection via sign of first derivative - Derivative of saddle points will be 0 Local minima Bisection method Similar method for finding a root for a non-linear equation Start with an interval that contains a minimum Golden Search method http://en.wikipedia.org/wiki/Golden_section_search C++: http://www.codecogs.com/code/maths/optimization/golden.php Bisect intervals according to golden ratio 0.618.. Achieves reduction by evaluating a single function instead of 2 Newton-Raphson Method Brent method http://en.wikipedia.org/wiki/Brent's_method C++: http://people.sc.fsu.edu/~jburkardt/cpp_src/brent/brent.cpp Based on quadratic or parabolic interpolation – if the function is smooth & parabolic near to the minimum, then a parabola fitted through any 3 points should approximate the minima – fails when the 3 points are collinear , in which case the denominator is 0 Simplex Method http://en.wikipedia.org/wiki/Simplex_algorithm C++: http://www.codeguru.com/cpp/article.php/c17505/Simplex-Optimization-Algorithm-and-Implemetation-in-C-Programming.htm Find the global minima of any multi-variable function Direct search – no derivatives required At each step it maintains a non-degenerative simplex – a convex hull of n+1 vertices. Obtains the minimum for a function with n variables by evaluating the function at n-1 points, iteratively replacing the point of worst result with the point of best result, shrinking the multidimensional simplex around the best point. Point replacement involves expanding & contracting the simplex near the worst value point to determine a better replacement point Oscillation can be avoided by choosing the 2nd worst result Restart if it gets stuck Parameters: contraction & expansion factors Simulated Annealing http://en.wikipedia.org/wiki/Simulated_annealing C++: http://code.google.com/p/cppsimulatedannealing/ Analogy to heating & cooling metal to strengthen its structure Stochastic method – apply random permutation search for global minima - Avoid entrapment in local minima via hill climbing Heating schedule - Annealing schedule params: temperature, iterations at each temp, temperature delta Cooling schedule – can be linear, step-wise or exponential Differential Evolution http://en.wikipedia.org/wiki/Differential_evolution C++: http://www.amichel.com/de/doc/html/ More advanced stochastic methods analogous to biological processes: Genetic algorithms, evolution strategies Parallel direct search method against multiple discrete or continuous variables Initial population of variable vectors chosen randomly – if weighted difference vector of 2 vectors yields a lower objective function value then it replaces the comparison vector Many params: #parents, #variables, step size, crossover constant etc Convergence is slow – many more function evaluations than simulated annealing Numerical Differentiation Overview 2 approaches to finite difference methods: · A) approximate function via polynomial interpolation then differentiate · B) Taylor series approximation – additionally provides error estimate Finite Difference methods http://en.wikipedia.org/wiki/Finite_difference_method C++: http://www.wpi.edu/Pubs/ETD/Available/etd-051807-164436/unrestricted/EAMPADU.pdf Find differences between high order derivative values - Approximate differential equations by finite differences at evenly spaced data points Based on forward & backward Taylor series expansion of f(x) about x plus or minus multiples of delta h. Forward / backward difference - the sums of the series contains even derivatives and the difference of the series contains odd derivatives – coupled equations that can be solved. Provide an approximation of the derivative within a O(h^2) accuracy There is also central difference & extended central difference which has a O(h^4) accuracy Richardson Extrapolation http://en.wikipedia.org/wiki/Richardson_extrapolation C++: http://mathscoding.blogspot.co.il/2012/02/introduction-richardson-extrapolation.html A sequence acceleration method applied to finite differences Fast convergence, high accuracy O(h^4) Derivatives via Interpolation Cannot apply Finite Difference method to discrete data points at uneven intervals – so need to approximate the derivative of f(x) using the derivative of the interpolant via 3 point Lagrange Interpolation Note: the higher the order of the derivative, the lower the approximation precision Numerical Integration Estimate finite & infinite integrals of functions More accurate procedure than numerical differentiation Use when it is not possible to obtain an integral of a function analytically or when the function is not given, only the data points are Newton Cotes Methods http://en.wikipedia.org/wiki/Newton%E2%80%93Cotes_formulas C++: http://www.siafoo.net/snippet/324 For equally spaced data points Computationally easy – based on local interpolation of n rectangular strip areas that is piecewise fitted to a polynomial to get the sum total area Evaluate the integrand at n+1 evenly spaced points – approximate definite integral by Sum Weights are derived from Lagrange Basis polynomials Leverage Trapezoidal Rule for default 2nd formulas, Simpson 1/3 Rule for substituting 3 point formulas, Simpson 3/8 Rule for 4 point formulas. For 4 point formulas use Bodes Rule. Higher orders obtain more accurate results Trapezoidal Rule uses simple area, Simpsons Rule replaces the integrand f(x) with a quadratic polynomial p(x) that uses the same values as f(x) for its end points, but adds a midpoint Romberg Integration http://en.wikipedia.org/wiki/Romberg's_method C++: http://code.google.com/p/romberg-integration/downloads/detail?name=romberg.cpp&can=2&q= Combines trapezoidal rule with Richardson Extrapolation Evaluates the integrand at equally spaced points The integrand must have continuous derivatives Each R(n,m) extrapolation uses a higher order integrand polynomial replacement rule (zeroth starts with trapezoidal) à a lower triangular matrix set of equation coefficients where the bottom right term has the most accurate approximation. The process continues until the difference between 2 successive diagonal terms becomes sufficiently small. Gaussian Quadrature http://en.wikipedia.org/wiki/Gaussian_quadrature C++: http://www.alglib.net/integration/gaussianquadratures.php Data points are chosen to yield best possible accuracy – requires fewer evaluations Ability to handle singularities, functions that are difficult to evaluate The integrand can include a weighting function determined by a set of orthogonal polynomials. Points & weights are selected so that the integrand yields the exact integral if f(x) is a polynomial of degree <= 2n+1 Techniques (basically different weighting functions): · Gauss-Legendre Integration w(x)=1 · Gauss-Laguerre Integration w(x)=e^-x · Gauss-Hermite Integration w(x)=e^-x^2 · Gauss-Chebyshev Integration w(x)= 1 / Sqrt(1-x^2) Solving ODEs Use when high order differential equations cannot be solved analytically Evaluated under boundary conditions RK for systems – a high order differential equation can always be transformed into a coupled first order system of equations Euler method http://en.wikipedia.org/wiki/Euler_method C++: http://rosettacode.org/wiki/Euler_method First order Runge–Kutta method. Simple recursive method – given an initial value, calculate derivative deltas. Unstable & not very accurate (O(h) error) – not used in practice A first-order method - the local error (truncation error per step) is proportional to the square of the step size, and the global error (error at a given time) is proportional to the step size In evolving solution between data points xn & xn+1, only evaluates derivatives at beginning of interval xn à asymmetric at boundaries Higher order Runge Kutta http://en.wikipedia.org/wiki/Runge%E2%80%93Kutta_methods C++: http://www.dreamincode.net/code/snippet1441.htm 2nd & 4th order RK - Introduces parameterized midpoints for more symmetric solutions à accuracy at higher computational cost Adaptive RK – RK-Fehlberg – estimate the truncation at each integration step & automatically adjust the step size to keep error within prescribed limits. At each step 2 approximations are compared – if in disagreement to a specific accuracy, the step size is reduced Boundary Value Problems Where solution of differential equations are located at 2 different values of the independent variable x à more difficult, because cannot just start at point of initial value – there may not be enough starting conditions available at the end points to produce a unique solution An n-order equation will require n boundary conditions – need to determine the missing n-1 conditions which cause the given conditions at the other boundary to be satisfied Shooting Method http://en.wikipedia.org/wiki/Shooting_method C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-shooting-method-for-solving.html Iteratively guess the missing values for one end & integrate, then inspect the discrepancy with the boundary values of the other end to adjust the estimate Given the starting boundary values u1 & u2 which contain the root u, solve u given the false position method (solving the differential equation as an initial value problem via 4th order RK), then use u to solve the differential equations. Finite Difference Method For linear & non-linear systems Higher order derivatives require more computational steps – some combinations for boundary conditions may not work though Improve the accuracy by increasing the number of mesh points Solving EigenValue Problems An eigenvalue can substitute a matrix when doing matrix multiplication à convert matrix multiplication into a polynomial EigenValue For a given set of equations in matrix form, determine what are the solution eigenvalue & eigenvectors Similar Matrices - have same eigenvalues. Use orthogonal similarity transforms to reduce a matrix to diagonal form from which eigenvalue(s) & eigenvectors can be computed iteratively Jacobi method http://en.wikipedia.org/wiki/Jacobi_method C++: http://people.sc.fsu.edu/~jburkardt/classes/acs2_2008/openmp/jacobi/jacobi.html Robust but Computationally intense – use for small matrices < 10x10 Power Iteration http://en.wikipedia.org/wiki/Power_iteration For any given real symmetric matrix, generate the largest single eigenvalue & its eigenvectors Simplest method – does not compute matrix decomposition à suitable for large, sparse matrices Inverse Iteration Variation of power iteration method – generates the smallest eigenvalue from the inverse matrix Rayleigh Method http://en.wikipedia.org/wiki/Rayleigh's_method_of_dimensional_analysis Variation of power iteration method Rayleigh Quotient Method Variation of inverse iteration method Matrix Tri-diagonalization Method Use householder algorithm to reduce an NxN symmetric matrix to a tridiagonal real symmetric matrix vua N-2 orthogonal transforms     Whats Next Outside of Numerical Methods there are lots of different types of algorithms that I’ve learned over the decades: Data Mining – (I covered this briefly in a previous post: http://geekswithblogs.net/JoshReuben/archive/2007/12/31/ssas-dm-algorithms.aspx ) Search & Sort Routing Problem Solving Logical Theorem Proving Planning Probabilistic Reasoning Machine Learning Solvers (eg MIP) Bioinformatics (Sequence Alignment, Protein Folding) Quant Finance (I read Wilmott’s books – interesting) Sooner or later, I’ll cover the above topics as well.

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  • Automatic Standby Recreation for Data Guard

    - by pablo.boixeda(at)oracle.com
    Hi,Unfortunately sometimes a Standby Instance needs to be recreated. This can happen for many reasons such as lost archive logs, standby data files, failover, among others.This is why we wanted to have one script to recreate standby instances in an easy way.This script recreates the standby considering some prereqs:-Database Version should be at least 11gR1-Dummy instance started on the standby node (Seeking to improve this so it won't be needed)-Broker configuration hasn't been removed-In our case we have two TNSNAMES files, one for the Standby creation (using SID) and the other one for production using service names (including broker service name)-Some environment variables set up by the environment db script (like ORACLE_HOME, PATH...)-The directory tree should not have been modified in the stanby hostWe are currently using it on our 11gR2 Data Guard tests.Any improvements will be welcome! Normal 0 21 false false false ES X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} #!/bin/ksh ###    NOMBRE / VERSION ###       recrea_dg.sh   v.1.00 ### ###    DESCRIPCION ###       reacreacion de la Standby ### ###    DEVUELVE ###       0 Creacion de STANDBY correcta ###       1 Fallo ### ###    NOTAS ###       Este shell script NO DEBE MODIFICARSE. ###       Todas las variables y constantes necesarias se toman del entorno. ### ###    MODIFICADO POR:    FECHA:        COMENTARIOS: ###    ---------------    ----------    ------------------------------------- ###      Oracle           15/02/2011    Creacion. ### ### ### Cargar entorno ### V_ADMIN_DIR=`dirname $0` . ${V_ADMIN_DIR}/entorno_bd.sh 1>>/dev/null if [ $? -ne 0 ] then   echo "Error Loading the environment."   exit 1 fi V_RET=0 V_DATE=`/bin/date` V_DATE_F=`/bin/date +%Y%m%d_%H%M%S` V_LOGFILE=${V_TRAZAS}/recrea_dg_${V_DATE_F}.log exec 4>&1 tee ${V_FICH_LOG} >&4 |& exec 1>&p 2>&1 ### ### Variables para Recrear el Data Guard ### V_DB_BR=`echo ${V_DB_NAME}|tr '[:lower:]' '[:upper:]'` if [ "${ORACLE_SID}" = "${V_DB_NAME}01" ] then         V_LOCAL_BR=${V_DB_BR}'01'         V_REMOTE_BR=${V_DB_BR}'02' else         V_LOCAL_BR=${V_DB_BR}'02'         V_REMOTE_BR=${V_DB_BR}'01' fi echo " Getting local instance ROLE ${ORACLE_SID} ..." sqlplus -s /nolog 1>>/dev/null 2>&1 <<-! whenever sqlerror exit 1 connect / as sysdba variable salida number declare   v_database_role v\$database.database_role%type; begin   select database_role into v_database_role from v\$database;   :salida := case v_database_role        when 'PRIMARY' then 2        when 'PHYSICAL STANDBY' then 3        else 4      end; end; / exit :salida ! case $? in 1) echo " ERROR: Cannot get instance ROLE ." | tee -a ${V_LOGFILE}   2>&1    V_RET=1 ;; 2) echo " Local Instance with PRIMARY role." | tee -a ${V_LOGFILE}   2>&1    V_DB_ROLE_LCL=PRIMARY ;; 3) echo " Local Instance with PHYSICAL STANDBY role." | tee -a ${V_LOGFILE}   2>&1    V_DB_ROLE_LCL=STANDBY ;; *) echo " ERROR: UNKNOWN ROLE." | tee -a ${V_LOGFILE}   2>&1    V_RET=1 ;; esac if [ "${V_DB_ROLE_LCL}" = "PRIMARY" ] then         echo "####################################################################" | tee -a ${V_LOGFILE}   2>&1         echo "${V_DATE} - Reacreating  STANDBY Instance." | tee -a ${V_LOGFILE}   2>&1         echo "" | tee -a ${V_LOGFILE}   2>&1         echo "DATAFILES, CONTROL FILES, REDO LOGS and ARCHIVE LOGS in standby instance ${V_REMOTE_BR} will be removed" | tee -a ${V_LOGFILE}   2>&1         echo "" | tee -a ${V_LOGFILE}   2>&1         V_PRIMARY=${V_LOCAL_BR}         V_STANDBY=${V_REMOTE_BR} fi if [ "${V_DB_ROLE_LCL}" = "STANDBY" ] then         echo "####################################################################" | tee -a ${V_LOGFILE}   2>&1         echo "${V_DATE} - Reacreating  STANDBY Instance." | tee -a ${V_LOGFILE}   2>&1         echo "" | tee -a ${V_LOGFILE}   2>&1         echo "DATAFILES, CONTROL FILES, REDO LOGS and ARCHIVE LOGS in standby instance ${V_LOCAL_BR} will be removed" | tee -a ${V_LOGFILE}   2>&1         echo "" | tee -a ${V_LOGFILE}   2>&1         V_PRIMARY=${V_REMOTE_BR}         V_STANDBY=${V_LOCAL_BR} fi # Cargamos las variables de los hosts # Cargamos las variables de los hosts PRY_HOST=`sqlplus  /nolog << EOF | grep KEEP | sed 's/KEEP//;s/[   ]//g' connect sys/${V_DB_PWD}@${V_PRIMARY} as sysdba select 'KEEP',host_name from v\\$instance; EOF` SBY_HOST=`sqlplus  /nolog << EOF | grep KEEP | sed 's/KEEP//;s/[   ]//g' connect sys/${V_DB_PWD}@${V_STANDBY} as sysdba select 'KEEP',host_name from v\\$instance; EOF` echo "el HOST primary es: ${PRY_HOST}" | tee -a ${V_LOGFILE}   2>&1 echo "el HOST standby es: ${SBY_HOST}" | tee -a ${V_LOGFILE}   2>&1 echo "" | tee -a ${V_LOGFILE}   2>&1 ## ## Paramos la instancia STANDBY ## V_DATE=`/bin/date` echo "${V_DATE} - Shutting down Standby instance" | tee -a ${V_LOGFILE}   2>&1 echo "" | tee -a ${V_LOGFILE}   2>&1 echo "********************************************************************************" | tee -a ${V_LOGFILE}   2>&1 ## ## Paramos la instancia STANDBY ## SBY_STATUS=`sqlplus  /nolog << EOF | grep KEEP | sed 's/KEEP//;s/[   ]//g' connect sys/${V_DB_PWD}@${V_STANDBY} as sysdba select 'KEEP',status from v\\$instance; EOF` if [ ${SBY_STATUS} = 'STARTED' ] || [ ${SBY_STATUS} = 'MOUNTED' ] || [ ${SBY_STATUS} = 'OPEN' ] then         echo "${V_DATE} - Standby instance shutdown in progress..." | tee -a ${V_LOGFILE}   2>&1         echo "" | tee -a ${V_LOGFILE}   2>&1         echo "********************************************************************************" | tee -a ${V_LOGFILE}   2>&1         sqlplus -s /nolog 1>>/dev/null 2>&1 <<-!         whenever sqlerror exit 1         connect sys/${V_DB_PWD}@${V_STANDBY} as sysdba         shutdown abort         ! fi V_DATE=`/bin/date` echo "" echo "${V_DATE} - Standby instance stopped" | tee -a ${V_LOGFILE}   2>&1 echo "" | tee -a ${V_LOGFILE}   2>&1 echo "********************************************************************************" | tee -a ${V_LOGFILE}   2>&1 ## ## Eliminamos los ficheros de la base de datos ## V_SBY_SID=`echo ${V_STANDBY}|tr '[:upper:]' '[:lower:]'` V_PRY_SID=`echo ${V_PRIMARY}|tr '[:upper:]' '[:lower:]'` ssh ${SBY_HOST} rm /opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/data/*.dbf ssh ${SBY_HOST} rm /opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/arch/*.arc ssh ${SBY_HOST} rm /opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/ctl/*.ctl ssh ${SBY_HOST} rm /opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/redo/*.ctl ssh ${SBY_HOST} rm /opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/redo/*.rdo ## ## Startup nomount stby instance ## V_DATE=`/bin/date` echo "" | tee -a ${V_LOGFILE}   2>&1 echo "${V_DATE} - Starting  DUMMY Standby Instance " | tee -a ${V_LOGFILE}   2>&1 echo "" | tee -a ${V_LOGFILE}   2>&1 echo "********************************************************************************" | tee -a ${V_LOGFILE}   2>&1 ssh ${SBY_HOST} touch /home/oracle/init_dg.ora ssh ${SBY_HOST} 'echo "DB_NAME='${V_DB_NAME}'">>/home/oracle/init_dg.ora' ssh ${SBY_HOST} touch /home/oracle/start_dummy.sh ssh ${SBY_HOST} 'echo "ORACLE_HOME=/opt/oracle/db/db'${V_DB_NAME}'/soft/db11.2.0.2 ">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "export ORACLE_HOME">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "PATH=\$ORACLE_HOME/bin:\$PATH">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "export PATH">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "ORACLE_SID='${V_SBY_SID}'">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "export ORACLE_SID">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "sqlplus -s /nolog <<-!" >>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "      whenever sqlerror exit 1 ">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "      connect / as sysdba ">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "      startup nomount pfile='\''/home/oracle/init_dg.ora'\''">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "! ">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'chmod 744 /home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'sh /home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'rm /home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'rm /home/oracle/init_dg.ora' ## ## TNSNAMES change, specific for RMAN duplicate ## V_DATE=`/bin/date` echo "" | tee -a ${V_LOGFILE}   2>&1 echo "${V_DATE} - Setting up TNSNAMES in PRIMARY host " | tee -a ${V_LOGFILE}   2>&1 echo "" | tee -a ${V_LOGFILE}   2>&1 echo "********************************************************************************" | tee -a ${V_LOGFILE}   2>&1 ssh ${PRY_HOST} 'cp /opt/oracle/db/db'${V_DB_NAME}'/soft/db11.2.0.2/network/admin/tnsnames.ora.inst  /opt/oracle/db/db'${V_DB_NAME}'/soft/db11.2.0.2/network/admin/tnsnames.ora' V_DATE=`/bin/date` echo "" | tee -a ${V_LOGFILE}   2>&1 echo "${V_DATE} - Starting STANDBY creation with RMAN.. " | tee -a ${V_LOGFILE}   2>&1 echo "" | tee -a ${V_LOGFILE}   2>&1 echo "********************************************************************************" | tee -a ${V_LOGFILE}   2>&1 rman<<-! >>${V_LOGFILE} connect target sys/${V_DB_PWD}@${V_PRIMARY} connect auxiliary sys/${V_DB_PWD}@${V_STANDBY} run { allocate channel prmy1 type disk; allocate channel prmy2 type disk; allocate channel prmy3 type disk; allocate channel prmy4 type disk; allocate auxiliary channel stby type disk; duplicate target database for standby from active database dorecover spfile parameter_value_convert '${V_PRY_SID}','${V_SBY_SID}' set control_files='/opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/ctl/control01.ctl','/opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/redo/control02.ctl' set db_file_name_convert='/opt/oracle/db/db${V_DB_NAME}/${V_PRY_SID}/','/opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/' set log_file_name_convert='/opt/oracle/db/db${V_DB_NAME}/${V_PRY_SID}/','/opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/' set 'db_unique_name'='${V_SBY_SID}' set log_archive_config='DG_CONFIG=(${V_PRIMARY},${V_STANDBY})' set fal_client='${V_STANDBY}' set fal_server='${V_PRIMARY}' set log_archive_dest_1='LOCATION=/opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/arch DB_UNIQUE_NAME=${V_SBY_SID} MANDATORY VALID_FOR=(ALL_LOGFILES,ALL_ROLES)' set log_archive_dest_2='SERVICE="${V_PRIMARY}"','SYNC AFFIRM DB_UNIQUE_NAME=${V_PRY_SID} DELAY=0 MAX_FAILURE=0 REOPEN=300 REGISTER VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE)' nofilenamecheck ; } ! V_DATE=`/bin/date` if [ $? -ne 0 ] then         echo ""         echo "${V_DATE} - Error creating STANDBY instance"         echo ""         echo "********************************************************************************" else         echo ""         echo "${V_DATE} - STANDBY instance created SUCCESSFULLY "         echo ""         echo "********************************************************************************" fi sqlplus -s /nolog 1>>/dev/null 2>&1 <<-!         whenever sqlerror exit 1         connect sys/${V_DB_PWD}@${V_STANDBY} as sysdba         alter system set local_listener='(ADDRESS=(PROTOCOL=TCP)(HOST=${SBY_HOST})(PORT=1544))' scope=both;         alter system set service_names='${V_DB_NAME}.eu.roca.net,${V_SBY_SID}.eu.roca.net,${V_SBY_SID}_DGMGRL.eu.roca.net' scope=both;         alter database recover managed standby database using current logfile disconnect from session;         alter system set dg_broker_start=true scope=both; ! ## ## TNSNAMES change, back to Production Mode ## V_DATE=`/bin/date` echo " " | tee -a ${V_LOGFILE}   2>&1 echo "${V_DATE} - Restoring TNSNAMES in PRIMARY "  | tee -a ${V_LOGFILE}   2>&1 echo ""  | tee -a ${V_LOGFILE}   2>&1 echo "********************************************************************************"  | tee -a ${V_LOGFILE}   2>&1 ssh ${PRY_HOST} 'cp /opt/oracle/db/db'${V_DB_NAME}'/soft/db11.2.0.2/network/admin/tnsnames.ora.prod  /opt/oracle/db/db'${V_DB_NAME}'/soft/db11.2.0.2/network/admin/tnsnames.ora' echo ""  | tee -a ${V_LOGFILE}   2>&1 echo "${V_DATE} -  Waiting for media recovery before check the DATA GUARD Broker"  | tee -a ${V_LOGFILE}   2>&1 echo ""  | tee -a ${V_LOGFILE}   2>&1 echo "********************************************************************************"  | tee -a ${V_LOGFILE}   2>&1 sleep 200 dgmgrl <<-! | grep SUCCESS 1>/dev/null 2>&1     connect ${V_DB_USR}/${V_DB_PWD}@${V_STANDBY}     show configuration verbose; ! if [ $? -ne 0 ] ; then         echo "       ERROR: El status del Broker no es SUCCESS" | tee -a ${V_LOGFILE}   2>&1 ;         V_RET=1 else          echo "      DATA GUARD OK " | tee -a ${V_LOGFILE}   2>&1 ; Normal 0 21 false false false ES X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}         V_RET=0 fi Hope it helps.

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  • PTLQueue : a scalable bounded-capacity MPMC queue

    - by Dave
    Title: Fast concurrent MPMC queue -- I've used the following concurrent queue algorithm enough that it warrants a blog entry. I'll sketch out the design of a fast and scalable multiple-producer multiple-consumer (MPSC) concurrent queue called PTLQueue. The queue has bounded capacity and is implemented via a circular array. Bounded capacity can be a useful property if there's a mismatch between producer rates and consumer rates where an unbounded queue might otherwise result in excessive memory consumption by virtue of the container nodes that -- in some queue implementations -- are used to hold values. A bounded-capacity queue can provide flow control between components. Beware, however, that bounded collections can also result in resource deadlock if abused. The put() and take() operators are partial and wait for the collection to become non-full or non-empty, respectively. Put() and take() do not allocate memory, and are not vulnerable to the ABA pathologies. The PTLQueue algorithm can be implemented equally well in C/C++ and Java. Partial operators are often more convenient than total methods. In many use cases if the preconditions aren't met, there's nothing else useful the thread can do, so it may as well wait via a partial method. An exception is in the case of work-stealing queues where a thief might scan a set of queues from which it could potentially steal. Total methods return ASAP with a success-failure indication. (It's tempting to describe a queue or API as blocking or non-blocking instead of partial or total, but non-blocking is already an overloaded concurrency term. Perhaps waiting/non-waiting or patient/impatient might be better terms). It's also trivial to construct partial operators by busy-waiting via total operators, but such constructs may be less efficient than an operator explicitly and intentionally designed to wait. A PTLQueue instance contains an array of slots, where each slot has volatile Turn and MailBox fields. The array has power-of-two length allowing mod/div operations to be replaced by masking. We assume sensible padding and alignment to reduce the impact of false sharing. (On x86 I recommend 128-byte alignment and padding because of the adjacent-sector prefetch facility). Each queue also has PutCursor and TakeCursor cursor variables, each of which should be sequestered as the sole occupant of a cache line or sector. You can opt to use 64-bit integers if concerned about wrap-around aliasing in the cursor variables. Put(null) is considered illegal, but the caller or implementation can easily check for and convert null to a distinguished non-null proxy value if null happens to be a value you'd like to pass. Take() will accordingly convert the proxy value back to null. An advantage of PTLQueue is that you can use atomic fetch-and-increment for the partial methods. We initialize each slot at index I with (Turn=I, MailBox=null). Both cursors are initially 0. All shared variables are considered "volatile" and atomics such as CAS and AtomicFetchAndIncrement are presumed to have bidirectional fence semantics. Finally T is the templated type. I've sketched out a total tryTake() method below that allows the caller to poll the queue. tryPut() has an analogous construction. Zebra stripping : alternating row colors for nice-looking code listings. See also google code "prettify" : https://code.google.com/p/google-code-prettify/ Prettify is a javascript module that yields the HTML/CSS/JS equivalent of pretty-print. -- pre:nth-child(odd) { background-color:#ff0000; } pre:nth-child(even) { background-color:#0000ff; } border-left: 11px solid #ccc; margin: 1.7em 0 1.7em 0.3em; background-color:#BFB; font-size:12px; line-height:65%; " // PTLQueue : Put(v) : // producer : partial method - waits as necessary assert v != null assert Mask = 1 && (Mask & (Mask+1)) == 0 // Document invariants // doorway step // Obtain a sequence number -- ticket // As a practical concern the ticket value is temporally unique // The ticket also identifies and selects a slot auto tkt = AtomicFetchIncrement (&PutCursor, 1) slot * s = &Slots[tkt & Mask] // waiting phase : // wait for slot's generation to match the tkt value assigned to this put() invocation. // The "generation" is implicitly encoded as the upper bits in the cursor // above those used to specify the index : tkt div (Mask+1) // The generation serves as an epoch number to identify a cohort of threads // accessing disjoint slots while s-Turn != tkt : Pause assert s-MailBox == null s-MailBox = v // deposit and pass message Take() : // consumer : partial method - waits as necessary auto tkt = AtomicFetchIncrement (&TakeCursor,1) slot * s = &Slots[tkt & Mask] // 2-stage waiting : // First wait for turn for our generation // Acquire exclusive "take" access to slot's MailBox field // Then wait for the slot to become occupied while s-Turn != tkt : Pause // Concurrency in this section of code is now reduced to just 1 producer thread // vs 1 consumer thread. // For a given queue and slot, there will be most one Take() operation running // in this section. // Consumer waits for producer to arrive and make slot non-empty // Extract message; clear mailbox; advance Turn indicator // We have an obvious happens-before relation : // Put(m) happens-before corresponding Take() that returns that same "m" for T v = s-MailBox if v != null : s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 // unlock slot to admit next producer and consumer return v Pause tryTake() : // total method - returns ASAP with failure indication for auto tkt = TakeCursor slot * s = &Slots[tkt & Mask] if s-Turn != tkt : return null T v = s-MailBox // presumptive return value if v == null : return null // ratify tkt and v values and commit by advancing cursor if CAS (&TakeCursor, tkt, tkt+1) != tkt : continue s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 return v The basic idea derives from the Partitioned Ticket Lock "PTL" (US20120240126-A1) and the MultiLane Concurrent Bag (US8689237). The latter is essentially a circular ring-buffer where the elements themselves are queues or concurrent collections. You can think of the PTLQueue as a partitioned ticket lock "PTL" augmented to pass values from lock to unlock via the slots. Alternatively, you could conceptualize of PTLQueue as a degenerate MultiLane bag where each slot or "lane" consists of a simple single-word MailBox instead of a general queue. Each lane in PTLQueue also has a private Turn field which acts like the Turn (Grant) variables found in PTL. Turn enforces strict FIFO ordering and restricts concurrency on the slot mailbox field to at most one simultaneous put() and take() operation. PTL uses a single "ticket" variable and per-slot Turn (grant) fields while MultiLane has distinct PutCursor and TakeCursor cursors and abstract per-slot sub-queues. Both PTL and MultiLane advance their cursor and ticket variables with atomic fetch-and-increment. PTLQueue borrows from both PTL and MultiLane and has distinct put and take cursors and per-slot Turn fields. Instead of a per-slot queues, PTLQueue uses a simple single-word MailBox field. PutCursor and TakeCursor act like a pair of ticket locks, conferring "put" and "take" access to a given slot. PutCursor, for instance, assigns an incoming put() request to a slot and serves as a PTL "Ticket" to acquire "put" permission to that slot's MailBox field. To better explain the operation of PTLQueue we deconstruct the operation of put() and take() as follows. Put() first increments PutCursor obtaining a new unique ticket. That ticket value also identifies a slot. Put() next waits for that slot's Turn field to match that ticket value. This is tantamount to using a PTL to acquire "put" permission on the slot's MailBox field. Finally, having obtained exclusive "put" permission on the slot, put() stores the message value into the slot's MailBox. Take() similarly advances TakeCursor, identifying a slot, and then acquires and secures "take" permission on a slot by waiting for Turn. Take() then waits for the slot's MailBox to become non-empty, extracts the message, and clears MailBox. Finally, take() advances the slot's Turn field, which releases both "put" and "take" access to the slot's MailBox. Note the asymmetry : put() acquires "put" access to the slot, but take() releases that lock. At any given time, for a given slot in a PTLQueue, at most one thread has "put" access and at most one thread has "take" access. This restricts concurrency from general MPMC to 1-vs-1. We have 2 ticket locks -- one for put() and one for take() -- each with its own "ticket" variable in the form of the corresponding cursor, but they share a single "Grant" egress variable in the form of the slot's Turn variable. Advancing the PutCursor, for instance, serves two purposes. First, we obtain a unique ticket which identifies a slot. Second, incrementing the cursor is the doorway protocol step to acquire the per-slot mutual exclusion "put" lock. The cursors and operations to increment those cursors serve double-duty : slot-selection and ticket assignment for locking the slot's MailBox field. At any given time a slot MailBox field can be in one of the following states: empty with no pending operations -- neutral state; empty with one or more waiting take() operations pending -- deficit; occupied with no pending operations; occupied with one or more waiting put() operations -- surplus; empty with a pending put() or pending put() and take() operations -- transitional; or occupied with a pending take() or pending put() and take() operations -- transitional. The partial put() and take() operators can be implemented with an atomic fetch-and-increment operation, which may confer a performance advantage over a CAS-based loop. In addition we have independent PutCursor and TakeCursor cursors. Critically, a put() operation modifies PutCursor but does not access the TakeCursor and a take() operation modifies the TakeCursor cursor but does not access the PutCursor. This acts to reduce coherence traffic relative to some other queue designs. It's worth noting that slow threads or obstruction in one slot (or "lane") does not impede or obstruct operations in other slots -- this gives us some degree of obstruction isolation. PTLQueue is not lock-free, however. The implementation above is expressed with polite busy-waiting (Pause) but it's trivial to implement per-slot parking and unparking to deschedule waiting threads. It's also easy to convert the queue to a more general deque by replacing the PutCursor and TakeCursor cursors with Left/Front and Right/Back cursors that can move either direction. Specifically, to push and pop from the "left" side of the deque we would decrement and increment the Left cursor, respectively, and to push and pop from the "right" side of the deque we would increment and decrement the Right cursor, respectively. We used a variation of PTLQueue for message passing in our recent OPODIS 2013 paper. ul { list-style:none; padding-left:0; padding:0; margin:0; margin-left:0; } ul#myTagID { padding: 0px; margin: 0px; list-style:none; margin-left:0;} -- -- There's quite a bit of related literature in this area. I'll call out a few relevant references: Wilson's NYU Courant Institute UltraComputer dissertation from 1988 is classic and the canonical starting point : Operating System Data Structures for Shared-Memory MIMD Machines with Fetch-and-Add. Regarding provenance and priority, I think PTLQueue or queues effectively equivalent to PTLQueue have been independently rediscovered a number of times. See CB-Queue and BNPBV, below, for instance. But Wilson's dissertation anticipates the basic idea and seems to predate all the others. Gottlieb et al : Basic Techniques for the Efficient Coordination of Very Large Numbers of Cooperating Sequential Processors Orozco et al : CB-Queue in Toward high-throughput algorithms on many-core architectures which appeared in TACO 2012. Meneghin et al : BNPVB family in Performance evaluation of inter-thread communication mechanisms on multicore/multithreaded architecture Dmitry Vyukov : bounded MPMC queue (highly recommended) Alex Otenko : US8607249 (highly related). John Mellor-Crummey : Concurrent queues: Practical fetch-and-phi algorithms. Technical Report 229, Department of Computer Science, University of Rochester Thomasson : FIFO Distributed Bakery Algorithm (very similar to PTLQueue). Scott and Scherer : Dual Data Structures I'll propose an optimization left as an exercise for the reader. Say we wanted to reduce memory usage by eliminating inter-slot padding. Such padding is usually "dark" memory and otherwise unused and wasted. But eliminating the padding leaves us at risk of increased false sharing. Furthermore lets say it was usually the case that the PutCursor and TakeCursor were numerically close to each other. (That's true in some use cases). We might still reduce false sharing by incrementing the cursors by some value other than 1 that is not trivially small and is coprime with the number of slots. Alternatively, we might increment the cursor by one and mask as usual, resulting in a logical index. We then use that logical index value to index into a permutation table, yielding an effective index for use in the slot array. The permutation table would be constructed so that nearby logical indices would map to more distant effective indices. (Open question: what should that permutation look like? Possibly some perversion of a Gray code or De Bruijn sequence might be suitable). As an aside, say we need to busy-wait for some condition as follows : "while C == 0 : Pause". Lets say that C is usually non-zero, so we typically don't wait. But when C happens to be 0 we'll have to spin for some period, possibly brief. We can arrange for the code to be more machine-friendly with respect to the branch predictors by transforming the loop into : "if C == 0 : for { Pause; if C != 0 : break; }". Critically, we want to restructure the loop so there's one branch that controls entry and another that controls loop exit. A concern is that your compiler or JIT might be clever enough to transform this back to "while C == 0 : Pause". You can sometimes avoid this by inserting a call to a some type of very cheap "opaque" method that the compiler can't elide or reorder. On Solaris, for instance, you could use :"if C == 0 : { gethrtime(); for { Pause; if C != 0 : break; }}". It's worth noting the obvious duality between locks and queues. If you have strict FIFO lock implementation with local spinning and succession by direct handoff such as MCS or CLH,then you can usually transform that lock into a queue. Hidden commentary and annotations - invisible : * And of course there's a well-known duality between queues and locks, but I'll leave that topic for another blog post. * Compare and contrast : PTLQ vs PTL and MultiLane * Equivalent : Turn; seq; sequence; pos; position; ticket * Put = Lock; Deposit Take = identify and reserve slot; wait; extract & clear; unlock * conceptualize : Distinct PutLock and TakeLock implemented as ticket lock or PTL Distinct arrival cursors but share per-slot "Turn" variable provides exclusive role-based access to slot's mailbox field put() acquires exclusive access to a slot for purposes of "deposit" assigns slot round-robin and then acquires deposit access rights/perms to that slot take() acquires exclusive access to slot for purposes of "withdrawal" assigns slot round-robin and then acquires withdrawal access rights/perms to that slot At any given time, only one thread can have withdrawal access to a slot at any given time, only one thread can have deposit access to a slot Permissible for T1 to have deposit access and T2 to simultaneously have withdrawal access * round-robin for the purposes of; role-based; access mode; access role mailslot; mailbox; allocate/assign/identify slot rights; permission; license; access permission; * PTL/Ticket hybrid Asymmetric usage ; owner oblivious lock-unlock pairing K-exclusion add Grant cursor pass message m from lock to unlock via Slots[] array Cursor performs 2 functions : + PTL ticket + Assigns request to slot in round-robin fashion Deconstruct protocol : explication put() : allocate slot in round-robin fashion acquire PTL for "put" access store message into slot associated with PTL index take() : Acquire PTL for "take" access // doorway step seq = fetchAdd (&Grant, 1) s = &Slots[seq & Mask] // waiting phase while s-Turn != seq : pause Extract : wait for s-mailbox to be full v = s-mailbox s-mailbox = null Release PTL for both "put" and "take" access s-Turn = seq + Mask + 1 * Slot round-robin assignment and lock "doorway" protocol leverage the same cursor and FetchAdd operation on that cursor FetchAdd (&Cursor,1) + round-robin slot assignment and dispersal + PTL/ticket lock "doorway" step waiting phase is via "Turn" field in slot * PTLQueue uses 2 cursors -- put and take. Acquire "put" access to slot via PTL-like lock Acquire "take" access to slot via PTL-like lock 2 locks : put and take -- at most one thread can access slot's mailbox Both locks use same "turn" field Like multilane : 2 cursors : put and take slot is simple 1-capacity mailbox instead of queue Borrow per-slot turn/grant from PTL Provides strict FIFO Lock slot : put-vs-put take-vs-take at most one put accesses slot at any one time at most one put accesses take at any one time reduction to 1-vs-1 instead of N-vs-M concurrency Per slot locks for put/take Release put/take by advancing turn * is instrumental in ... * P-V Semaphore vs lock vs K-exclusion * See also : FastQueues-excerpt.java dice-etc/queue-mpmc-bounded-blocking-circular-xadd/ * PTLQueue is the same as PTLQB - identical * Expedient return; ASAP; prompt; immediately * Lamport's Bakery algorithm : doorway step then waiting phase Threads arriving at doorway obtain a unique ticket number Threads enter in ticket order * In the terminology of Reed and Kanodia a ticket lock corresponds to the busy-wait implementation of a semaphore using an eventcount and a sequencer It can also be thought of as an optimization of Lamport's bakery lock was designed for fault-tolerance rather than performance Instead of spinning on the release counter, processors using a bakery lock repeatedly examine the tickets of their peers --

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  • How to Remove Header in LaTex

    - by Tim
    Hi, I would like to not show the name of each chapter on the header of its each page. I also like to have nothing in the headers for abstract, acknowledgement, table of content, list of figures and list of tables. But currently I have header on each page, for example: Here is my code when specifying these parts in my tex file \begin{abstract} ... \end{abstract} \begin{acknowledgement} ... \end{acknowledgement} % generate table of contents \tableofcontents % generate list of tables \listoftables % generate list of figures \listoffigures \chapter{Introduction} \label{chp1} %% REFERENCES \appendix \input{appendiximages.tex} \bibliographystyle{plain} %%\bibliographystyle{abbrvnat} \bibliography{thesis} Here is what I believe to be the definition of the commands. More details can be found in these two files jhu12.clo and thesis.cls. % \chapter: \def\chaptername{Chapter} % ABSTRACT % MODIFIED to include section name in headers \def\abstract{ \newpage \dsp \chapter*{\abstractname\@mkboth{\uppercase{\abstractname}}{\uppercase{\abstractname}}} \fmfont \vspace{8pt} \addcontentsline{toc}{chapter}{\abstractname} } \def\endabstract{\par\vfil\null} % DEDICATION % Modified to make dedication its own section %\newenvironment{dedication} %{\begin{alwayssingle}} %{\end{alwayssingle}} \def\dedication{ \newpage \dsp \chapter*{Dedication\@mkboth{DEDICATION}{DEDICATION}} \fmfont} \def\endacknowledgement{\par\vfil\null} % ACKNOWLEDGEMENTS % MODIFIED to include section name in headers \def\acknowledgement{ \newpage \dsp \chapter*{\acknowledgename\@mkboth{\uppercase{\acknowledgename}}{\uppercase{\acknowledgename}}} \fmfont \addcontentsline{toc}{chapter}{\acknowledgename} } \def\endacknowledgement{\par\vfil\null} \def\thechapter {\arabic{chapter}} % \@chapapp is initially defined to be '\chaptername'. The \appendix % command redefines it to be '\appendixname'. % \def\@chapapp{\chaptername} \def\chapter{ \clearpage \thispagestyle{plain} \if@twocolumn % IF two-column style \onecolumn % THEN \onecolumn \@tempswatrue % @tempswa := true \else \@tempswafalse % ELSE @tempswa := false \fi \dsp % double spacing \secdef\@chapter\@schapter} % TABLEOFCONTENTS % In ucthesis style, \tableofcontents, \listoffigures, etc. are always % set in single-column style. @restonecol \def\tableofcontents{\@restonecolfalse \if@twocolumn\@restonecoltrue\onecolumn\fi %%%%% take care of getting page number in right spot %%%%% \clearpage % starts new page \thispagestyle{botcenter} % Page style of frontmatter is botcenter \global\@topnum\z@ % Prevents figures from going at top of page %%%%% \@schapter{\contentsname \@mkboth{\uppercase{\contentsname}}{\uppercase{\contentsname}}}% {\ssp\@starttoc{toc}}\if@restonecol\twocolumn\fi} \def\l@part#1#2{\addpenalty{-\@highpenalty}% \addvspace{2.25em plus\p@}% space above part line \begingroup \@tempdima 3em % width of box holding part number, used by \parindent \z@ \rightskip \@pnumwidth %% \numberline \parfillskip -\@pnumwidth {\large \bfseries % set line in \large boldface \leavevmode % TeX command to enter horizontal mode. #1\hfil \hbox to\@pnumwidth{\hss #2}}\par \nobreak % Never break after part entry \global\@nobreaktrue %% Added 24 May 89 as \everypar{\global\@nobreakfalse\everypar{}}%% suggested by %% Jerry Leichter \endgroup} % LIST OF FIGURES % % Single-space list of figures, add it to the table of contents. \def\listoffigures{\@restonecolfalse \if@twocolumn\@restonecoltrue\onecolumn\fi %%%%% take care of getting page number in right spot %%%%% \clearpage \thispagestyle{botcenter} % Page style of frontmatter is botcenter \global\@topnum\z@ % Prevents figures from going at top of page. \@schapter{\listfigurename\@mkboth{\uppercase{\listfigurename}}% {\uppercase{\listfigurename}}} \addcontentsline{toc}{chapter}{\listfigurename} {\ssp\@starttoc{lof}}\if@restonecol\twocolumn\fi} \def\l@figure{\@dottedtocline{1}{1.5em}{2.3em}} % bibliography \def\thebibliography#1{\chapter*{\bibname\@mkboth {\uppercase{\bibname}}{\uppercase{\bibname}}} \addcontentsline{toc}{chapter}{\bibname} \list{\@biblabel{\arabic{enumiv}}}{\settowidth\labelwidth{\@biblabel{#1}}% \leftmargin\labelwidth \advance\leftmargin\labelsep \usecounter{enumiv}% \let\p@enumiv\@empty \def\theenumiv{\arabic{enumiv}}}% \def\newblock{\hskip .11em plus.33em minus.07em}% \sloppy\clubpenalty4000\widowpenalty4000 \sfcode`\.=\@m} Thanks and regards! EDIT: I just replaced \thispagestyle{botcenter} with \thispagestyle{plain}. The latter is said to clear the header (http://en.wikibooks.org/wiki/LaTeX/Page_Layout), but it does not. How shall I do? Thanks!

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  • Execute a SQlite command with Entity Framework

    - by Filimindji
    Hi everybody, I use a SQLite database and Entity Framework (with .net framework 3.5). I'm trying to execute a simple SQL non query command to create a new table in this datase. My Entity Framework already contains the object model for this table : I just want to generate the corresponding table using a command. (By the way, there is maybe a better way to do this. Any ideas someone :) My problem is that I'm not able to execute any command, even the simple commands. Here is my code : EntityConnection entityConnection = new EntityConnection(entitiesConnectionString); Entities db = new Entities(entityConnection); DbCommand command = db.Connection.CreateCommand(); command.CommandText ="CREATE TABLE MyTable (Id int NOT NULL, OtherTable_Id nchar(40) REFERENCES OtherTable (Id) On Delete CASCADE On Update NO ACTION, SomeData nvarchar(1024) NOT NULL, Primary Key(Id) );"; command.ExecuteNonQuery(); I got this error : System.Data.EntitySqlException: The query syntax is not valid., near identifier 'TABLE', line 1, column 8. at System.Data.Common.EntitySql.CqlParser.yyerror(String s) at System.Data.Common.EntitySql.CqlParser.yyparse() at System.Data.Common.EntitySql.CqlParser.Parse(String query) at System.Data.Common.EntitySql.CqlQuery.Parse(String query, ParserOptions parserOptions) at System.Data.Common.EntitySql.CqlQuery.Compile(String query, Perspective perspective, ParserOptions parserOptions, Dictionary`2 parameters, Dictionary`2 variables, Boolean validateTree) at System.Data.EntityClient.EntityCommand.MakeCommandTree() at System.Data.EntityClient.EntityCommand.CreateCommandDefinition() at System.Data.EntityClient.EntityCommand.TryGetEntityCommandDefinitionFromQueryCache(EntityCommandDefinition& entityCommandDefinition) at System.Data.EntityClient.EntityCommand.GetCommandDefinition() at System.Data.EntityClient.EntityCommand.InnerPrepare() at System.Data.EntityClient.EntityCommand.ExecuteReader(CommandBehavior behavior) at System.Data.EntityClient.EntityCommand.ExecuteScalar[T_Result](Func`2 resultSelector) It's seem to be a syntax error, but I can't figure where is the problem and how to resolve it. The entityConnection is ok because I can use any entities generated with EF. I tried with another simple command, but it throw another exception : DbCommand command = db.Connection.CreateCommand(); command.CommandText = "SELECT COUNT(Id) From OtherTable;"; int result = (int)command.ExecuteScalar(); And I got this error, witch is not the same, but may help : System.Data.EntitySqlException: 'Groupe' could not be resolved in the current scope or context. Make sure that all referenced variables are in scope, that required schemas are loaded, and that namespaces are referenced correctly., near simple identifier, line 1, column 23. at System.Data.Common.EntitySql.CqlErrorHelper.ReportIdentifierError(Expr expr, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.ConvertIdentifier(Expr expr, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.Convert(Expr astExpr, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.ProcessAliasedFromClauseItem(AliasExpr aliasedExpr, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.ProcessFromClauseItem(FromClauseItem fromClauseItem, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.ProcessFromClause(FromClause fromClause, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.ConvertQuery(Expr expr, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.Convert(Expr astExpr, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.ConvertRootExpression(Expr astExpr, SemanticResolver sr) at System.Data.Common.EntitySql.SemanticAnalyzer.ConvertGeneralExpression(Expr astExpr, SemanticResolver sr) at System.Data.Common.EntitySql.CqlQuery.AnalyzeSemantics(Expr astExpr, Perspective perspective, ParserOptions parserOptions, Dictionary`2 parameters, Dictionary`2 variables) at System.Data.Common.EntitySql.CqlQuery.Compile(String query, Perspective perspective, ParserOptions parserOptions, Dictionary`2 parameters, Dictionary`2 variables, Boolean validateTree) at System.Data.EntityClient.EntityCommand.MakeCommandTree() at System.Data.EntityClient.EntityCommand.CreateCommandDefinition() at System.Data.EntityClient.EntityCommand.TryGetEntityCommandDefinitionFromQueryCache(EntityCommandDefinition& entityCommandDefinition) at System.Data.EntityClient.EntityCommand.GetCommandDefinition() at System.Data.EntityClient.EntityCommand.InnerPrepare() at System.Data.EntityClient.EntityCommand.ExecuteReader(CommandBehavior behavior) at System.Data.EntityClient.EntityCommand.ExecuteScalar[T_Result](Func`2 resultSelector)

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  • What is the difference between Anycast and GeoDNS / GeoIP wrt HA?

    - by Riyad
    Based on the Wikipedia description of Anycast, it includes both the distribution of a domain-name-to-many-IP-mapping across many DNS servers as well as replying to clients with the most geographically close (or fastest) server. In the context of a globally distributed, highly available site like google.com (or any CDN service with many global edge locations) this sounds like the two key features one would need. DNS services like Amazon's Route53, EasyDNS and DNSMadeEasy all advertise themselves as Anycast-enabled networks. Therefore my assumption is that each of these DNS services transparently offer me those two killer features: multi-IP-to-domain mapping AND routing clients to the closest node. However, each of these services seem to separate out these two functionalities, referring to the 2nd one (routing clients to closest node) as "GeoDNS", "GeoIP" or "Global Traffic Director" and charge extra for the service. If a core tenant of an Anycast-capable system is to already do this, why is this functionality being earmarked as this extra feature? What is this "GeoDNS" feature doing that a standard Anycast DNS service won't do (according to the definition of Anycast from Wikipedia -- I understand what is being advertised, just not why it isn't implied already). I get extra-confused when a DNS service like Route53 that doesn't support this nebulous "GeoDNS" feature lists functionality like: Fast – Using a global anycast network of DNS servers around the world, Route 53 is designed to automatically route your users to the optimal location depending on network conditions. As a result, the service offers low query latency for your end users, as well as low update latency for your DNS record management needs. ... which sounds exactly like what GeoDNS is intended to do, but geographically directing clients is something they explicitly don't support it yet. Ultimately I am looking for the two following features from a DNS provider: Map multiple IP addresses to a single domain name (like google.com, amazon.com, etc. does) Utilize a DNS service that will respond to client requests for that domain with the IP address of the nearest server to the requestee. As mentioned, it seems like this is all part of an "Anycast" DNS service (all of which these services are), but the features and marketing I see from them suggest otherwise, making me think I need to learn a bit more about how DNS works before making a deployment choice. Thanks in advance for any clarifications.

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  • Trouble connecting a Ubuntu system to IPv6 tunnel over NAT

    - by John Millikin
    I'm trying to set up an IPv6 tunnel, via Hurricane Electric's tunnel-broker service. I've configured my system using their example commands: # $ipv4a = tunnel server's IPv4 IP # $ipv4b = user's IPv4 IP # $ipv6a = tunnel server's side of point-to-point /64 allocation # $ipv6b = user's side of point-to-point /64 allocation ip tunnel add he-ipv6 mode sit remote $ipv4a local $ipv4b ttl 255 ip link set he-ipv6 up ip addr add $ipv6b dev he-ipv6 ip route add ::/0 dev he-ipv6 And have configured my desktop to be in my NAT router's DMZ. The router is running Tomato firmware. But I can't ping any IPv6 services: $ ping6 -I he-ipv6 '2001:470:1f04:454::1' PING 2001:470:1f04:454::1(2001:470:1f04:454::1) from 2001:470:1f04:454::2 he-ipv6: 56 data bytes From 2001:470:1f04:454::2 icmp_seq=1 Destination unreachable: Address unreachable From 2001:470:1f04:454::2 icmp_seq=2 Destination unreachable: Address unreachable I can ping my local address: $ ping6 -I he-ipv6 '2001:470:1f04:454::2' PING 2001:470:1f04:454::2(2001:470:1f04:454::2) from 2001:470:1f04:454::2 he-ipv6: 56 data bytes 64 bytes from 2001:470:1f04:454::2: icmp_seq=1 ttl=64 time=0.037 ms 64 bytes from 2001:470:1f04:454::2: icmp_seq=2 ttl=64 time=0.039 ms I don't know much about routing, but results I found online suggested the output of ip -6 route and ip addr could be useful: $ ip -6 route 2001:470:1f04:454::/64 via :: dev he-ipv6 proto kernel metric 256 mtu 1480 advmss 1420 hoplimit 4294967295 fe80::/64 dev virbr0 proto kernel metric 256 mtu 1500 advmss 1440 hoplimit 4294967295 fe80::/64 dev eth1 proto kernel metric 256 mtu 1500 advmss 1440 hoplimit 4294967295 fe80::/64 via :: dev he-ipv6 proto kernel metric 256 mtu 1480 advmss 1420 hoplimit 4294967295 default dev he-ipv6 metric 1024 mtu 1480 advmss 1420 hoplimit 4294967295 $ ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 100 link/ether 00:1c:c0:a1:98:b2 brd ff:ff:ff:ff:ff:ff inet 192.168.1.10/24 brd 192.168.1.255 scope global eth1 inet6 fe80::21c:c0ff:fea1:98b2/64 scope link valid_lft forever preferred_lft forever 3: virbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN link/ether 36:4c:33:ab:0d:c6 brd ff:ff:ff:ff:ff:ff inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0 inet6 fe80::344c:33ff:feab:dc6/64 scope link valid_lft forever preferred_lft forever 4: vboxnet0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000 link/ether 00:76:62:6e:65:74 brd ff:ff:ff:ff:ff:ff 5: pan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN link/ether 7e:29:5e:7c:ba:93 brd ff:ff:ff:ff:ff:ff 6: sit0: <NOARP> mtu 1480 qdisc noop state DOWN link/sit 0.0.0.0 brd 0.0.0.0 7: he-ipv6@NONE: <POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1480 qdisc noqueue state UNKNOWN link/sit 24.130.225.239 peer 72.52.104.74 inet6 2001:470:1f04:454::2/64 scope global valid_lft forever preferred_lft forever inet6 fe80::1882:e1ef/128 scope link valid_lft forever preferred_lft forever

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  • Random haproxy 408 errors

    - by Errol Fitzgerald
    I keep getting random 408 timeout messages from haproxy, but can't figure out if its a bug in 1.5-dev25 or something in my config file global log 127.0.0.1 local0 log 127.0.0.1 local1 info #log loghost local0 info maxconn 80000 #debug #quiet user haproxy group haproxy stats socket /tmp/haproxy.sock defaults log global mode http errorfile 503 /etc/haproxy/errors/503.http option httplog option dontlognull retries 3 option redispatch maxconn 80000 timeout client 12s timeout server 120s timeout queue 120s timeout connect 10s timeout http-request 30s option http-server-close timeout http-keep-alive 3000 option abortonclose option httpchk ... Does anyone see anything wrong with these config settings?

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  • Output php mail calls to log file

    - by Tom McQuarrie
    This question relates to the question found here: Find the php script thats sending mails Trying to do the exact same thing but can't get the log to output what I need. Not too experienced with serverfault and ideally I'd post my followup on the original question, or PM adam to see if he ever found a solution, but looks as though server fault doesn't work that way. I can post an "answer" but that's definitely not what this is. I have a script located at /usr/local/bin/sendmail-php-logged, with the following: #!/bin/sh logger -p mail.info sendmail-php: site=${HTTP_HOST}, client=${REMOTE_ADDR}, script=${SCRIPT_NAME}, filename=${SCRIPT_FILENAME}, docroot=${DOCUMENT_ROOT}, pwd=${PWD}, uid=${UID}, user=$(whoami) /usr/sbin/sendmail -t -i $* This is logging to /var/log/maillog, but as Adam mentions in his question, none of the server variables work. Output I'm getting is: Oct 4 12:16:21 fluke logger: sendmail-php: site=, client=, script=, filename=, docroot=, pwd=/var/www/html/aro_chroot/sites/arocms, uid=48, user=apache Oct 4 12:16:21 fluke logger: sendmail-php: site=, client=, script=, filename=, docroot=, pwd=/var/www/html/aro_chroot/sites/arocms, uid=48, user=apache Oct 4 12:17:03 fluke logger: sendmail-php: site=, client=, script=, filename=, docroot=, pwd=/var/www/html/aro_chroot/sites/arocms, uid=48, user=apache Oct 4 12:17:05 fluke logger: sendmail-php: site=, client=, script=, filename=, docroot=, pwd=/root, uid=0, user=root Oct 4 12:17:11 fluke logger: sendmail-php: site=, client=, script=, filename=, docroot=, pwd=/var/www/html/aro_chroot/sites/arocms, uid=48, user=apache Oct 4 12:17:14 fluke logger: sendmail-php: site=, client=, script=, filename=, docroot=, pwd=/root, uid=0, user=root Oct 4 12:17:29 fluke logger: sendmail-php: site=, client=, script=, filename=, docroot=, pwd=/root, uid=0, user=root Oct 4 12:17:41 fluke logger: sendmail-php: site=, client=, script=, filename=, docroot=, pwd=/root, uid=0, user=root User ID, current user, and pwd are all working, probably because they're globally accessible script resources, and not specific to PHP, like all the others are. I've tried using other server variables as per labradort's instructions, but no joy. Here's some sample tests: logger -p mail.info sendmail-php SCRIPT_NAME: ${SCRIPT_NAME} logger -p mail.info sendmail-php SCRIPT_FILENAME: ${SCRIPT_FILENAME} logger -p mail.info sendmail-php PATH_INFO: ${PATH_INFO} logger -p mail.info sendmail-php PHP_SELF: ${PHP_SELF} logger -p mail.info sendmail-php DOCUMENT_ROOT: ${DOCUMENT_ROOT} logger -p mail.info sendmail-php REMOTE_ADDR: ${REMOTE_ADDR} logger -p mail.info sendmail-php SCRIPT_NAME: $SCRIPT_NAME logger -p mail.info sendmail-php SCRIPT_FILENAME: $SCRIPT_FILENAME logger -p mail.info sendmail-php PATH_INFO: $PATH_INFO logger -p mail.info sendmail-php PHP_SELF: $PHP_SELF logger -p mail.info sendmail-php DOCUMENT_ROOT: $DOCUMENT_ROOT logger -p mail.info sendmail-php REMOTE_ADDR: $REMOTE_ADDR And the output: Oct 4 12:58:02 fluke logger: sendmail-php SCRIPT_NAME: Oct 4 12:58:02 fluke logger: sendmail-php SCRIPT_FILENAME: Oct 4 12:58:02 fluke logger: sendmail-php PATH_INFO: Oct 4 12:58:02 fluke logger: sendmail-php PHP_SELF: Oct 4 12:58:02 fluke logger: sendmail-php DOCUMENT_ROOT: Oct 4 12:58:02 fluke logger: sendmail-php REMOTE_ADDR: Oct 4 12:58:02 fluke logger: sendmail-php SCRIPT_NAME: Oct 4 12:58:02 fluke logger: sendmail-php SCRIPT_FILENAME: Oct 4 12:58:02 fluke logger: sendmail-php PATH_INFO: Oct 4 12:58:02 fluke logger: sendmail-php PHP_SELF: Oct 4 12:58:02 fluke logger: sendmail-php DOCUMENT_ROOT: Oct 4 12:58:02 fluke logger: sendmail-php REMOTE_ADDR: I'm running php 5.3.10. Unfortunately register_globals is on, for compatibility with legacy systems, but you wouldn't think that would cause the environment variables to stop working. If someone can give me some hints as to why this might not be working I'll be a very happy man :)

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  • Temporarily Utilizing 304 Header on Apache for Crawlers

    - by Volomike
    I have a client who has a hosting arrangement with 400 customer sites all hosted through SuPHP in CGI mode on Apache. The sysop is now gone and the client is calling on me for rolling out a new PHP thing. Trouble is -- server load is very high right now and we have found that it's due to the crawlers. We had one customer in particular who complained of slow websites, and we engaged a 304 header plugin in his site against most crawlers, and his site perked right up. We'd like to lower that load by issuing a global 304 header to all the crawlers, letting human visitors through. I have a long list of user agent keywords to trap for. What's the best way to temporarily engage that global 304 header, while allowing human visitors to get right on through? I mean, I could roll out 400 .htaccess file changes, but it would be ideal to make this change in like one central Apache config and then it automatically affect all the sites at once.

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