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• Why C++ people loves multithreading when it comes to performances?

  - by user1849534

  I have a question, it's about why programmers seems to love concurrency and multi-threaded programs in general. I'm considering 2 main approach here: an async approach basically based on signals, or just an async approach as called by many papers and languages like the new C# 5.0 for example, and a "companion thread" that maanges the policy of your pipeline a concurrent approach or multi-threading approach I will just say that I'm thinking about the hardware here and the worst case scenario, and I have tested this 2 paradigms myself, the async paradigm is a winner at the point that I don't get why people 90% of the time talk about concurrency when they wont to speed up things or make a good use of their resources. I have tested multi-threaded programs and async program on an old machine with an Intel quad-core that doesn't offer a memory controller inside the CPU, the memory is managed entirely by the motherboard, well in this case performances are horrible with a multi-threaded application, even a relatively low number of threads like 3-4-5 can be a problem, the application is unresponsive and is just slow and unpleasant. A good async approach is, on the other hand, probably not faster but it's not worst either, my application just waits for the result and doesn't hangs, it's responsive and there is a much better scaling going on. I have also discovered that a context change in the threading world it's not that cheap in real world scenario, it's infact quite expensive especially when you have more than 2 threads that need to cycle and swap among each other to be computed. On modern CPUs the situation it's not really that different, the memory controller it's integrated but my point is that an x86 CPUs is basically a serial machine and the memory controller works the same way as with the old machine with an external memory controller on the motherboard. The context switch is still a relevant cost in my application and the fact that the memory controller it's integrated or that the newer CPU have more than 2 core it's not bargain for me. For what i have experienced the concurrent approach is good in theory but not that good in practice, with the memory model imposed by the hardware, it's hard to make a good use of this paradigm, also it introduces a lot of issues ranging from the use of my data structures to the join of multiple threads. Also both paradigms do not offer any security abut when the task or the job will be done in a certain point in time, making them really similar from a functional point of view. According to the X86 memory model, why the majority of people suggest to use concurrency with C++ and not just an async aproach ? Also why not considering the worst case scenario of a computer where the context switch is probably more expensive than the computation itself ?

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• Reasons NOT to use JSF [closed]

  - by Vain Fellowman

  I am new to StackExchange, but I figured you would be able to help me. We're crating a new Java Enterprise application, replacing an legacy JSP solution. Due to many many changes, the UI and parts of the business logic will completely be rethought and reimplemented. Our first thought was JSF, as it is the standard in Java EE. At first I had a good impression. But now I am trying to implement a functional prototype, and have some really serious concerns about using it. First of all, it creates the worst, most cluttered invalid pseudo-HTML/CSS/JS mix I've ever seen. It violates every single rule I learned in web-development. Furthermore it throws together, what never should be so tightly coupled: Layout, Design, Logic and Communication with the server. I don't see how I would be able to extend this output comfortably, whether styling with CSS, adding UI candy (like configurable hot-keys, drag-and-drop widgets) or whatever. Secondly, it is way too complicated. Its complexity is outstanding. If you ask me, it's a poor abstraction of basic web technologies, crippled and useless in the end. What benefits do I have? None, if you think about. Hundreds of components? I see ten-thousands of HTML/CSS snippets, ten-thousands of JavaScript snippets and thousands of jQuery plug-ins in addition. It solves really many problems - we wouldn't have if we wouldn't use JSF. Or the front-controller pattern at all. And Lastly, I think we will have to start over in, say 2 years. I don't see how I can implement all of our first GUI mock-up (Besides; we have no JSF Expert in our team). Maybe we could hack it together somehow. And then there will be more. I'm sure we could hack our hack. But at some point, we'll be stuck. Due to everything above the service tier is in control of JSF. And we will have to start over. My suggestion would be to implement a REST api, using JAX-RS. Then create a HTML5/Javascript client with client side MVC. (or some flavor of MVC..) By the way; we will need the REST api anyway, as we are developing a partial Android front-end, too. I doubt, that JSF is the best solution nowadays. As the Internet is evolving, I really don't see why we should use this 'rake'. Now, what are pros/cons? How can I emphasize my point to not use JSF? What are strong points to use JSF over my suggestion?

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• socket operation on nonsocket or bad file descriptor

  - by Magn3s1um

  I'm writing a pthread server which takes requests from clients and sends them back a bunch of .ppm files. Everything seems to go well, but sometimes when I have just 1 client connected, when trying to read from the file descriptor (for the file), it says Bad file Descriptor. This doesn't make sense, since my int fd isn't -1, and the file most certainly exists. Other times, I get this "Socket operation on nonsocket" error. This is weird because other times, it doesn't give me this error and everything works fine. When trying to connect multiple clients, for some reason, it will only send correctly to one, and then the other client gets the bad file descriptor or "nonsocket" error, even though both threads are processing the same messages and do the same routines. Anyone have an idea why? Here's the code that is giving me that error: while(mqueue.head != mqueue.tail && count < dis_m){ printf("Sending to client %s: %s\n", pointer->id, pointer->message); int fd; fd = open(pointer->message, O_RDONLY); char buf[58368]; int bytesRead; printf("This is fd %d\n", fd); bytesRead=read(fd,buf,58368); send(pointer->socket,buf,bytesRead,0); perror("Error:\n"); fflush(stdout); close(fd); mqueue.mcount--; mqueue.head = mqueue.head->next; free(pointer->message); free(pointer); pointer = mqueue.head; count++; } printf("Sending %s\n", pointer->message); int fd; fd = open(pointer->message, O_RDONLY); printf("This is fd %d\n", fd); printf("I am hhere2\n"); char buf[58368]; int bytesRead; bytesRead=read(fd,buf,58368); send(pointer->socket,buf,bytesRead,0); perror("Error:\n"); close(fd); mqueue.mcount--; if(mqueue.head != mqueue.tail){ mqueue.head = mqueue.head->next; } else{ mqueue.head->next = malloc(sizeof(struct message)); mqueue.head = mqueue.head->next; mqueue.head->next = malloc(sizeof(struct message)); mqueue.tail = mqueue.head->next; mqueue.head->message = NULL; } free(pointer->message); free(pointer); pthread_mutex_unlock(&numm); pthread_mutex_unlock(&circ); pthread_mutex_unlock(&slots); The messages for both threads are the same, being of the form ./path/imageXX.ppm where XX is the number that should go to the client. The file size of each image is 58368 bytes. Sometimes, this code hangs on the read, and stops execution. I don't know this would be either, because the file descriptor comes back as valid. Thanks in advanced. Edit: Here's some sample output: Sending to client a: ./support/images/sw90.ppm This is fd 4 Error: : Socket operation on non-socket Sending to client a: ./support/images/sw91.ppm This is fd 4 Error: : Socket operation on non-socket Sending ./support/images/sw92.ppm This is fd 4 I am hhere2 Error: : Socket operation on non-socket My dispatcher has defeated evil Sample with 2 clients (client b was serviced first) Sending to client b: ./support/images/sw87.ppm This is fd 6 Error: : Success Sending to client b: ./support/images/sw88.ppm This is fd 6 Error: : Success Sending to client b: ./support/images/sw89.ppm This is fd 6 Error: : Success This is fd 6 Error: : Bad file descriptor Sending to client a: ./support/images/sw85.ppm This is fd 6 Error: As you can see, who ever is serviced first in this instance can open the files, but not the 2nd person. Edit2: Full code. Sorry, its pretty long and terribly formatted. #include <netinet/in.h> #include <netinet/in.h> #include <netdb.h> #include <arpa/inet.h> #include <sys/types.h> #include <sys/socket.h> #include <errno.h> #include <stdio.h> #include <unistd.h> #include <pthread.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include "ring.h" /* Version 1 Here is what is implemented so far: The threads are created from the arguments specified (number of threads that is) The server will lock and update variables based on how many clients are in the system and such. The socket that is opened when a new client connects, must be passed to the threads. To do this, we need some sort of global array. I did this by specifying an int client and main_pool_busy, and two pointers poolsockets and nonpoolsockets. My thinking on this was that when a new client enters the system, the server thread increments the variable client. When a thread is finished with this client (after it sends it the data), the thread will decrement client and close the socket. HTTP servers act this way sometimes (they terminate the socket as soon as one transmission is sent). *Note down at bottom After the server portion increments the client counter, we must open up a new socket (denoted by new_sd) and get this value to the appropriate thread. To do this, I created global array poolsockets, which will hold all the socket descriptors for our pooled threads. The server portion gets the new socket descriptor, and places the value in the first spot of the array that has a 0. We only place a value in this array IF: 1. The variable main_pool_busy < worknum (If we have more clients in the system than in our pool, it doesn't mean we should always create a new thread. At the end of this, the server signals on the condition variable clientin that a new client has arrived. In our pooled thread, we then must walk this array and check the array until we hit our first non-zero value. This is the socket we will give to that thread. The thread then changes the array to have a zero here. What if our all threads in our pool our busy? If this is the case, then we will know it because our threads in this pool will increment main_pool_busy by one when they are working on a request and decrement it when they are done. If main_pool_busy >= worknum, then we must dynamically create a new thread. Then, we must realloc the size of our nonpoolsockets array by 1 int. We then add the new socket descriptor to our pool. Here's what we need to figure out: NOTE* Each worker should generate 100 messages which specify the worker thread ID, client socket descriptor and a copy of the client message. Additionally, each message should include a message number, starting from 0 and incrementing for each subsequent message sent to the same client. I don't know how to keep track of how many messages were to the same client. Maybe we shouldn't close the socket descriptor, but rather keep an array of structs for each socket that includes how many messages they have been sent. Then, the server adds the struct, the threads remove it, then the threads add it back once they've serviced one request (unless the count is 100). ------------------------------------------------------------- CHANGES Version 1 ---------- NONE: this is the first version. */ #define MAXSLOTS 30 #define dis_m 15 //problems with dis_m ==1 //Function prototypes void inc_clients(); void init_mutex_stuff(pthread_t*, pthread_t*); void *threadpool(void *); void server(int); void add_to_socket_pool(int); void inc_busy(); void dec_busy(); void *dispatcher(); void create_message(long, int, int, char *, char *); void init_ring(); void add_to_ring(char *, char *, int, int, int); int socket_from_string(char *); void add_to_head(char *); void add_to_tail(char *); struct message * reorder(struct message *, struct message *, int); int get_threadid(char *); void delete_socket_messages(int); struct message * merge(struct message *, struct message *, int); int get_request(char *, char *, char*); ///////////////////// //Global mutexes and condition variables pthread_mutex_t startservice; pthread_mutex_t numclients; pthread_mutex_t pool_sockets; pthread_mutex_t nonpool_sockets; pthread_mutex_t m_pool_busy; pthread_mutex_t slots; pthread_mutex_t numm; pthread_mutex_t circ; pthread_cond_t clientin; pthread_cond_t m; /////////////////////////////////////// //Global variables int clients; int main_pool_busy; int * poolsockets, nonpoolsockets; int worknum; struct ring mqueue; /////////////////////////////////////// int main(int argc, char ** argv){ //error handling if not enough arguments to program if(argc != 3){ printf("Not enough arguments to server: ./server portnum NumThreadsinPool\n"); _exit(-1); } //Convert arguments from strings to integer values int port = atoi(argv[1]); worknum = atoi(argv[2]); //Start server portion server(port); } /////////////////////////////////////////////////////////////////////////////////////////////// //The listen server thread///////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////////////// void server(int port){ int sd, new_sd; struct sockaddr_in name, cli_name; int sock_opt_val = 1; int cli_len; pthread_t threads[worknum]; //create our pthread id array pthread_t dis[1]; //create our dispatcher array (necessary to create thread) init_mutex_stuff(threads, dis); //initialize mutexes and stuff //Server setup /////////////////////////////////////////////////////// if ((sd = socket (AF_INET, SOCK_STREAM, 0)) < 0) { perror("(servConn): socket() error"); _exit (-1); } if (setsockopt (sd, SOL_SOCKET, SO_REUSEADDR, (char *) &sock_opt_val, sizeof(sock_opt_val)) < 0) { perror ("(servConn): Failed to set SO_REUSEADDR on INET socket"); _exit (-1); } name.sin_family = AF_INET; name.sin_port = htons (port); name.sin_addr.s_addr = htonl(INADDR_ANY); if (bind (sd, (struct sockaddr *)&name, sizeof(name)) < 0) { perror ("(servConn): bind() error"); _exit (-1); } listen (sd, 5); //End of server Setup ////////////////////////////////////////////////// for (;;) { cli_len = sizeof (cli_name); new_sd = accept (sd, (struct sockaddr *) &cli_name, &cli_len); printf ("Assigning new socket descriptor: %d\n", new_sd); inc_clients(); //New client has come in, increment clients add_to_socket_pool(new_sd); //Add client to the pool of sockets if (new_sd < 0) { perror ("(servConn): accept() error"); _exit (-1); } } pthread_exit(NULL); //Quit } //Adds the new socket to the array designated for pthreads in the pool void add_to_socket_pool(int socket){ pthread_mutex_lock(&m_pool_busy); //Lock so that we can check main_pool_busy int i; //If not all our main pool is busy, then allocate to one of them if(main_pool_busy < worknum){ pthread_mutex_unlock(&m_pool_busy); //unlock busy, we no longer need to hold it pthread_mutex_lock(&pool_sockets); //Lock the socket pool array so that we can edit it without worry for(i = 0; i < worknum; i++){ //Find a poolsocket that is -1; then we should put the real socket there. This value will be changed back to -1 when the thread grabs the sockfd if(poolsockets[i] == -1){ poolsockets[i] = socket; pthread_mutex_unlock(&pool_sockets); //unlock our pool array, we don't need it anymore inc_busy(); //Incrememnt busy (locks the mutex itself) pthread_cond_signal(&clientin); //Signal first thread waiting on a client that a client needs to be serviced break; } } } else{ //Dynamic thread creation goes here pthread_mutex_unlock(&m_pool_busy); } } //Increments the client number. If client number goes over worknum, we must dynamically create new pthreads void inc_clients(){ pthread_mutex_lock(&numclients); clients++; pthread_mutex_unlock(&numclients); } //Increments busy void inc_busy(){ pthread_mutex_lock(&m_pool_busy); main_pool_busy++; pthread_mutex_unlock(&m_pool_busy); } //Initialize all of our mutexes at the beginning and create our pthreads void init_mutex_stuff(pthread_t * threads, pthread_t * dis){ pthread_mutex_init(&startservice, NULL); pthread_mutex_init(&numclients, NULL); pthread_mutex_init(&pool_sockets, NULL); pthread_mutex_init(&nonpool_sockets, NULL); pthread_mutex_init(&m_pool_busy, NULL); pthread_mutex_init(&circ, NULL); pthread_cond_init (&clientin, NULL); main_pool_busy = 0; poolsockets = malloc(sizeof(int)*worknum); int threadreturn; //error checking variables long i = 0; //Loop and create pthreads for(i; i < worknum; i++){ threadreturn = pthread_create(&threads[i], NULL, threadpool, (void *) i); poolsockets[i] = -1; if(threadreturn){ perror("Thread pool created unsuccessfully"); _exit(-1); } } pthread_create(&dis[0], NULL, dispatcher, NULL); } ////////////////////////////////////////////////////////////////////////////////////////// /////////Main pool routines ///////////////////////////////////////////////////////////////////////////////////////// void dec_busy(){ pthread_mutex_lock(&m_pool_busy); main_pool_busy--; pthread_mutex_unlock(&m_pool_busy); } void dec_clients(){ pthread_mutex_lock(&numclients); clients--; pthread_mutex_unlock(&numclients); } //This is what our threadpool pthreads will be running. void *threadpool(void * threadid){ long id = (long) threadid; //Id of this thread int i; int socket; int counter = 0; //Try and gain access to the next client that comes in and wait until server signals that a client as arrived while(1){ pthread_mutex_lock(&startservice); //lock start service (required for cond wait) pthread_cond_wait(&clientin, &startservice); //wait for signal from server that client exists pthread_mutex_unlock(&startservice); //unlock mutex. pthread_mutex_lock(&pool_sockets); //Lock the pool socket so we can get the socket fd unhindered/interrupted for(i = 0; i < worknum; i++){ if(poolsockets[i] != -1){ socket = poolsockets[i]; poolsockets[i] = -1; pthread_mutex_unlock(&pool_sockets); } } printf("Thread #%d is past getting the socket\n", id); int incoming = 1; while(counter < 100 && incoming != 0){ char buffer[512]; bzero(buffer,512); int startcounter = 0; incoming = read(socket, buffer, 512); if(buffer[0] != 0){ //client ID:priority:request:arguments char id[100]; long prior; char request[100]; char arg1[100]; char message[100]; char arg2[100]; char * point; point = strtok(buffer, ":"); strcpy(id, point); point = strtok(NULL, ":"); prior = atoi(point); point = strtok(NULL, ":"); strcpy(request, point); point = strtok(NULL, ":"); strcpy(arg1, point); point = strtok(NULL, ":"); if(point != NULL){ strcpy(arg2, point); } int fd; if(strcmp(request, "start_movie") == 0){ int count = 1; while(count <= 100){ char temp[10]; snprintf(temp, 50, "%d\0", count); strcpy(message, "./support/images/"); strcat(message, arg1); strcat(message, temp); strcat(message, ".ppm"); printf("This is message %s to %s\n", message, id); count++; add_to_ring(message, id, prior, counter, socket); //Adds our created message to the ring counter++; } printf("I'm out of the loop\n"); } else if(strcmp(request, "seek_movie") == 0){ int count = atoi(arg2); while(count <= 100){ char temp[10]; snprintf(temp, 10, "%d\0", count); strcpy(message, "./support/images/"); strcat(message, arg1); strcat(message, temp); strcat(message, ".ppm"); printf("This is message %s\n", message); count++; } } //create_message(id, socket, counter, buffer, message); //Creates our message from the input from the client. Stores it in buffer } else{ delete_socket_messages(socket); break; } } counter = 0; close(socket);//Zero out counter again } dec_clients(); //client serviced, decrement clients dec_busy(); //thread finished, decrement busy } //Creates a message void create_message(long threadid, int socket, int counter, char * buffer, char * message){ snprintf(message, strlen(buffer)+15, "%d:%d:%d:%s", threadid, socket, counter, buffer); } //Gets the socket from the message string (maybe I should just pass in the socket to another method) int socket_from_string(char * message){ char * substr1 = strstr(message, ":"); char * substr2 = substr1; substr2++; int occurance = strcspn(substr2, ":"); char sock[10]; strncpy(sock, substr2, occurance); return atoi(sock); } //Adds message to our ring buffer's head void add_to_head(char * message){ printf("Adding to head of ring\n"); mqueue.head->message = malloc(strlen(message)+1); //Allocate space for message strcpy(mqueue.head->message, message); //copy bytes into allocated space } //Adds our message to our ring buffer's tail void add_to_tail(char * message){ printf("Adding to tail of ring\n"); mqueue.tail->message = malloc(strlen(message)+1); //allocate space for message strcpy(mqueue.tail->message, message); //copy bytes into allocated space mqueue.tail->next = malloc(sizeof(struct message)); //allocate space for the next message struct } //Adds a message to our ring void add_to_ring(char * message, char * id, int prior, int mnum, int socket){ //printf("This is message %s:" , message); pthread_mutex_lock(&circ); //Lock the ring buffer pthread_mutex_lock(&numm); //Lock the message count (will need this to make sure we can't fill the buffer over the max slots) if(mqueue.head->message == NULL){ add_to_head(message); //Adds it to head mqueue.head->socket = socket; //Set message socket mqueue.head->priority = prior; //Set its priority (thread id) mqueue.head->mnum = mnum; //Set its message number (used for sorting) mqueue.head->id = malloc(sizeof(id)); strcpy(mqueue.head->id, id); } else if(mqueue.tail->message == NULL){ //This is the problem for dis_m 1 I'm pretty sure add_to_tail(message); mqueue.tail->socket = socket; mqueue.tail->priority = prior; mqueue.tail->mnum = mnum; mqueue.tail->id = malloc(sizeof(id)); strcpy(mqueue.tail->id, id); } else{ mqueue.tail->next = malloc(sizeof(struct message)); mqueue.tail = mqueue.tail->next; add_to_tail(message); mqueue.tail->socket = socket; mqueue.tail->priority = prior; mqueue.tail->mnum = mnum; mqueue.tail->id = malloc(sizeof(id)); strcpy(mqueue.tail->id, id); } mqueue.mcount++; pthread_mutex_unlock(&circ); if(mqueue.mcount >= dis_m){ pthread_mutex_unlock(&numm); pthread_cond_signal(&m); } else{ pthread_mutex_unlock(&numm); } printf("out of add to ring\n"); fflush(stdout); } ////////////////////////////////// //Dispatcher routines ///////////////////////////////// void *dispatcher(){ init_ring(); while(1){ pthread_mutex_lock(&slots); pthread_cond_wait(&m, &slots); pthread_mutex_lock(&numm); pthread_mutex_lock(&circ); printf("Dispatcher to the rescue!\n"); mqueue.head = reorder(mqueue.head, mqueue.tail, mqueue.mcount); //printf("This is the head %s\n", mqueue.head->message); //printf("This is the tail %s\n", mqueue.head->message); fflush(stdout); struct message * pointer = mqueue.head; int count = 0; while(mqueue.head != mqueue.tail && count < dis_m){ printf("Sending to client %s: %s\n", pointer->id, pointer->message); int fd; fd = open(pointer->message, O_RDONLY); char buf[58368]; int bytesRead; printf("This is fd %d\n", fd); bytesRead=read(fd,buf,58368); send(pointer->socket,buf,bytesRead,0); perror("Error:\n"); fflush(stdout); close(fd); mqueue.mcount--; mqueue.head = mqueue.head->next; free(pointer->message); free(pointer); pointer = mqueue.head; count++; } printf("Sending %s\n", pointer->message); int fd; fd = open(pointer->message, O_RDONLY); printf("This is fd %d\n", fd); printf("I am hhere2\n"); char buf[58368]; int bytesRead; bytesRead=read(fd,buf,58368); send(pointer->socket,buf,bytesRead,0); perror("Error:\n"); close(fd); mqueue.mcount--; if(mqueue.head != mqueue.tail){ mqueue.head = mqueue.head->next; } else{ mqueue.head->next = malloc(sizeof(struct message)); mqueue.head = mqueue.head->next; mqueue.head->next = malloc(sizeof(struct message)); mqueue.tail = mqueue.head->next; mqueue.head->message = NULL; } free(pointer->message); free(pointer); pthread_mutex_unlock(&numm); pthread_mutex_unlock(&circ); pthread_mutex_unlock(&slots); printf("My dispatcher has defeated evil\n"); } } void init_ring(){ mqueue.head = malloc(sizeof(struct message)); mqueue.head->next = malloc(sizeof(struct message)); mqueue.tail = mqueue.head->next; mqueue.mcount = 0; } struct message * reorder(struct message * begin, struct message * end, int num){ //printf("I am reordering for size %d\n", num); fflush(stdout); int i; if(num == 1){ //printf("Begin: %s\n", begin->message); begin->next = NULL; return begin; } else{ struct message * left = begin; struct message * right; int middle = num/2; for(i = 1; i < middle; i++){ left = left->next; } right = left -> next; left -> next = NULL; //printf("Begin: %s\nLeft: %s\nright: %s\nend:%s\n", begin->message, left->message, right->message, end->message); left = reorder(begin, left, middle); if(num%2 != 0){ right = reorder(right, end, middle+1); } else{ right = reorder(right, end, middle); } return merge(left, right, num); } } struct message * merge(struct message * left, struct message * right, int num){ //printf("I am merginging! left: %s %d, right: %s %dnum: %d\n", left->message,left->priority, right->message, right->priority, num); struct message * start, * point; int lenL= 0; int lenR = 0; int flagL = 0; int flagR = 0; int count = 0; int middle1 = num/2; int middle2; if(num%2 != 0){ middle2 = middle1+1; } else{ middle2 = middle1; } while(lenL < middle1 && lenR < middle2){ count++; //printf("In here for count %d\n", count); if(lenL == 0 && lenR == 0){ if(left->priority < right->priority){ start = left; //Set the start point point = left; //set our enum; left = left->next; //move the left pointer point->next = NULL; //Set the next node to NULL lenL++; } else if(left->priority > right->priority){ start = right; point = right; right = right->next; point->next = NULL; lenR++; } else{ if(left->mnum < right->mnum){ ////printf("This is where we are\n"); start = left; //Set the start point point = left; //set our enum; left = left->next; //move the left pointer point->next = NULL; //Set the next node to NULL lenL++; } else{ start = right; point = right; right = right->next; point->next = NULL; lenR++; } } } else{ if(left->priority < right->priority){ point->next = left; left = left->next; //move the left pointer point = point->next; point->next = NULL; //Set the next node to NULL lenL++; } else if(left->priority > right->priority){ point->next = right; right = right->next; point = point->next; point->next = NULL; lenR++; } else{ if(left->mnum < right->mnum){ point->next = left; //set our enum; left = left->next; point = point->next;//move the left pointer point->next = NULL; //Set the next node to NULL lenL++; } else{ point->next = right; right = right->next; point = point->next; point->next = NULL; lenR++; } } } if(lenL == middle1){ flagL = 1; break; } if(lenR == middle2){ flagR = 1; break; } } if(flagL == 1){ point->next = right; point = point->next; for(lenR; lenR< middle2-1; lenR++){ point = point->next; } point->next = NULL; mqueue.tail = point; } else{ point->next = left; point = point->next; for(lenL; lenL< middle1-1; lenL++){ point = point->next; } point->next = NULL; mqueue.tail = point; } //printf("This is the start %s\n", start->message); //printf("This is mqueue.tail %s\n", mqueue.tail->message); return start; } void delete_socket_messages(int a){ }

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• PHP Startup: Unable to load dynamic library '/usr/lib64/php/modules/json.so' undefined symbol: ZVAL_DELREF

  - by crmpicco

  I have an issue where I am unable to use JSON, which would appear to be because of the following error. There is another thread on this forum this touches on a similar issue, but it's not quite the same. I am using CentOS 5.6 and have the following pear packages installed: [crmpicco@eq-www-php53 ~]$ pear list PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib64/php/modules/json.so' - /usr/lib64/php/modules/json.so: undefined symbol: ZVAL_DELREF in Unknown on line 0 Installed packages, channel pear.php.net: ========================================= Package Version State Archive_Tar 1.3.7 stable Auth_SASL 1.0.2 stable Console_Getopt 1.3.1 stable Image_Barcode 1.1.2 stable Mail 1.1.14 stable Net_SMTP 1.2.10 stable Net_Socket 1.0.8 stable PEAR 1.9.4 stable Structures_Graph 1.0.4 stable XML_RPC 1.5.4 stable XML_Util 1.2.1 stable json 1.2.1 stable and have the following PHP packages installed: [crmpicco@eq-www-php53 ~]$ yum list installed | grep php php.x86_64 5.3.10-1.w5 installed php-cli.x86_64 5.3.10-1.w5 installed php-common.x86_64 5.3.10-1.w5 installed php-devel.x86_64 5.3.10-1.w5 installed php-gd.x86_64 5.3.10-1.w5 installed php-ldap.x86_64 5.3.10-1.w5 installed php-mcrypt.x86_64 5.3.10-1.w5 installed php-mysql.x86_64 5.3.10-1.w5 installed php-pdo.x86_64 5.3.10-1.w5 installed php-pear.noarch 1:1.9.4-1.w5 installed php-pear-Net-Socket.noarch 1.0.8-1.el5.centos installed php-soap.x86_64 5.3.10-1.w5 installed php-xml.x86_64 5.3.10-1.w5 installed The error: [crmpicco@eq-www-php53 ~]$ php -v PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib64/php/modules/json.so' - /usr/lib64/php/modules/json.so: undefined symbol: ZVAL_DELREF in Unknown on line 0 PHP 5.3.10 (cli) (built: Feb 2 2012 23:23:12) Copyright (c) 1997-2012 The PHP Group Zend Engine v2.3.0, Copyright (c) 1998-2012 Zend Technologies My repolist reads as: [crmpicco@eq-www-php53 ~]$ yum repolist Loaded plugins: changelog, fastestmirror Excluding Packages in global exclude list Finished repo id repo name status base CentOS-5 - Base 3,548+43 epel Extra Packages for Enterprise Linux 5 - x86_64 6,815+156 extras CentOS-5 - Extras 245+23 rpmforge Red Hat Enterprise 5 - RPMforge.net - dag 11,016+67 updates CentOS-5 - Updates 233 webtatic Webtatic Repository 5 - x86_64 211+183 repolist: 22,068 I am getting HTTP 500 errors everywhere that I use JSON so my application is non functional right now.

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• An Introduction to ASP.NET Web API

  - by Rick Strahl

  Microsoft recently released ASP.NET MVC 4.0 and .NET 4.5 and along with it, the brand spanking new ASP.NET Web API. Web API is an exciting new addition to the ASP.NET stack that provides a new, well-designed HTTP framework for creating REST and AJAX APIs (API is Microsoft’s new jargon for a service, in case you’re wondering). Although Web API ships and installs with ASP.NET MVC 4, you can use Web API functionality in any ASP.NET project, including WebForms, WebPages and MVC or just a Web API by itself. And you can also self-host Web API in your own applications from Console, Desktop or Service applications. If you're interested in a high level overview on what ASP.NET Web API is and how it fits into the ASP.NET stack you can check out my previous post: Where does ASP.NET Web API fit? In the following article, I'll focus on a practical, by example introduction to ASP.NET Web API. All the code discussed in this article is available in GitHub: https://github.com/RickStrahl/AspNetWebApiArticle [republished from my Code Magazine Article and updated for RTM release of ASP.NET Web API] Getting Started To start I’ll create a new empty ASP.NET application to demonstrate that Web API can work with any kind of ASP.NET project. Although you can create a new project based on the ASP.NET MVC/Web API template to quickly get up and running, I’ll take you through the manual setup process, because one common use case is to add Web API functionality to an existing ASP.NET application. This process describes the steps needed to hook up Web API to any ASP.NET 4.0 application. Start by creating an ASP.NET Empty Project. Then create a new folder in the project called Controllers. Add a Web API Controller Class Once you have any kind of ASP.NET project open, you can add a Web API Controller class to it. Web API Controllers are very similar to MVC Controller classes, but they work in any kind of project. Add a new item to this folder by using the Add New Item option in Visual Studio and choose Web API Controller Class, as shown in Figure 1. Figure 1: This is how you create a new Controller Class in Visual Studio   Make sure that the name of the controller class includes Controller at the end of it, which is required in order for Web API routing to find it. Here, the name for the class is AlbumApiController. For this example, I’ll use a Music Album model to demonstrate basic behavior of Web API. The model consists of albums and related songs where an album has properties like Name, Artist and YearReleased and a list of songs with a SongName and SongLength as well as an AlbumId that links it to the album. You can find the code for the model (and the rest of these samples) on Github. To add the file manually, create a new folder called Model, and add a new class Album.cs and copy the code into it. There’s a static AlbumData class with a static CreateSampleAlbumData() method that creates a short list of albums on a static .Current that I’ll use for the examples. Before we look at what goes into the controller class though, let’s hook up routing so we can access this new controller. Hooking up Routing in Global.asax To start, I need to perform the one required configuration task in order for Web API to work: I need to configure routing to the controller. Like MVC, Web API uses routing to provide clean, extension-less URLs to controller methods. Using an extension method to ASP.NET’s static RouteTable class, you can use the MapHttpRoute() (in the System.Web.Http namespace) method to hook-up the routing during Application_Start in global.asax.cs shown in Listing 1.using System; using System.Web.Routing; using System.Web.Http; namespace AspNetWebApi { public class Global : System.Web.HttpApplication { protected void Application_Start(object sender, EventArgs e) { RouteTable.Routes.MapHttpRoute( name: "AlbumVerbs", routeTemplate: "albums/{title}", defaults: new { symbol = RouteParameter.Optional, controller="AlbumApi" } ); } } } This route configures Web API to direct URLs that start with an albums folder to the AlbumApiController class. Routing in ASP.NET is used to create extensionless URLs and allows you to map segments of the URL to specific Route Value parameters. A route parameter, with a name inside curly brackets like {name}, is mapped to parameters on the controller methods. Route parameters can be optional, and there are two special route parameters – controller and action – that determine the controller to call and the method to activate respectively. HTTP Verb Routing Routing in Web API can route requests by HTTP Verb in addition to standard {controller},{action} routing. For the first examples, I use HTTP Verb routing, as shown Listing 1. Notice that the route I’ve defined does not include an {action} route value or action value in the defaults. Rather, Web API can use the HTTP Verb in this route to determine the method to call the controller, and a GET request maps to any method that starts with Get. So methods called Get() or GetAlbums() are matched by a GET request and a POST request maps to a Post() or PostAlbum(). Web API matches a method by name and parameter signature to match a route, query string or POST values. In lieu of the method name, the [HttpGet,HttpPost,HttpPut,HttpDelete, etc] attributes can also be used to designate the accepted verbs explicitly if you don’t want to follow the verb naming conventions. Although HTTP Verb routing is a good practice for REST style resource APIs, it’s not required and you can still use more traditional routes with an explicit {action} route parameter. When {action} is supplied, the HTTP verb routing is ignored. I’ll talk more about alternate routes later. When you’re finished with initial creation of files, your project should look like Figure 2.   Figure 2: The initial project has the new API Controller Album model   Creating a small Album Model Now it’s time to create some controller methods to serve data. For these examples, I’ll use a very simple Album and Songs model to play with, as shown in Listing 2. public class Song { public string AlbumId { get; set; } [Required, StringLength(80)] public string SongName { get; set; } [StringLength(5)] public string SongLength { get; set; } } public class Album { public string Id { get; set; } [Required, StringLength(80)] public string AlbumName { get; set; } [StringLength(80)] public string Artist { get; set; } public int YearReleased { get; set; } public DateTime Entered { get; set; } [StringLength(150)] public string AlbumImageUrl { get; set; } [StringLength(200)] public string AmazonUrl { get; set; } public virtual List<Song> Songs { get; set; } public Album() { Songs = new List<Song>(); Entered = DateTime.Now; // Poor man's unique Id off GUID hash Id = Guid.NewGuid().GetHashCode().ToString("x"); } public void AddSong(string songName, string songLength = null) { this.Songs.Add(new Song() { AlbumId = this.Id, SongName = songName, SongLength = songLength }); } } Once the model has been created, I also added an AlbumData class that generates some static data in memory that is loaded onto a static .Current member. The signature of this class looks like this and that's what I'll access to retrieve the base data:public static class AlbumData { // sample data - static list public static List<Album> Current = CreateSampleAlbumData(); /// <summary> /// Create some sample data /// </summary> /// <returns></returns> public static List<Album> CreateSampleAlbumData() { … }} You can check out the full code for the data generation online. Creating an AlbumApiController Web API shares many concepts of ASP.NET MVC, and the implementation of your API logic is done by implementing a subclass of the System.Web.Http.ApiController class. Each public method in the implemented controller is a potential endpoint for the HTTP API, as long as a matching route can be found to invoke it. The class name you create should end in Controller, which is how Web API matches the controller route value to figure out which class to invoke. Inside the controller you can implement methods that take standard .NET input parameters and return .NET values as results. Web API’s binding tries to match POST data, route values, form values or query string values to your parameters. Because the controller is configured for HTTP Verb based routing (no {action} parameter in the route), any methods that start with Getxxxx() are called by an HTTP GET operation. You can have multiple methods that match each HTTP Verb as long as the parameter signatures are different and can be matched by Web API. In Listing 3, I create an AlbumApiController with two methods to retrieve a list of albums and a single album by its title .public class AlbumApiController : ApiController { public IEnumerable<Album> GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); return albums; } public Album GetAlbum(string title) { var album = AlbumData.Current .SingleOrDefault(alb => alb.AlbumName.Contains(title)); return album; }} To access the first two requests, you can use the following URLs in your browser: http://localhost/aspnetWebApi/albumshttp://localhost/aspnetWebApi/albums/Dirty%20Deeds Note that you’re not specifying the actions of GetAlbum or GetAlbums in these URLs. Instead Web API’s routing uses HTTP GET verb to route to these methods that start with Getxxx() with the first mapping to the parameterless GetAlbums() method and the latter to the GetAlbum(title) method that receives the title parameter mapped as optional in the route. Content Negotiation When you access any of the URLs above from a browser, you get either an XML or JSON result returned back. The album list result for Chrome 17 and Internet Explorer 9 is shown Figure 3. Figure 3: Web API responses can vary depending on the browser used, demonstrating Content Negotiation in action as these two browsers send different HTTP Accept headers.   Notice that the results are not the same: Chrome returns an XML response and IE9 returns a JSON response. Whoa, what’s going on here? Shouldn’t we see the same result in both browsers? Actually, no. Web API determines what type of content to return based on Accept headers. HTTP clients, like browsers, use Accept headers to specify what kind of content they’d like to see returned. Browsers generally ask for HTML first, followed by a few additional content types. Chrome (and most other major browsers) ask for: Accept: text/html, application/xhtml+xml,application/xml; q=0.9,*/*;q=0.8 IE9 asks for: Accept: text/html, application/xhtml+xml, */* Note that Chrome’s Accept header includes application/xml, which Web API finds in its list of supported media types and returns an XML response. IE9 does not include an Accept header type that works on Web API by default, and so it returns the default format, which is JSON. This is an important and very useful feature that was missing from any previous Microsoft REST tools: Web API automatically switches output formats based on HTTP Accept headers. Nowhere in the server code above do you have to explicitly specify the output format. Rather, Web API determines what format the client is requesting based on the Accept headers and automatically returns the result based on the available formatters. This means that a single method can handle both XML and JSON results.. Using this simple approach makes it very easy to create a single controller method that can return JSON, XML, ATOM or even OData feeds by providing the appropriate Accept header from the client. By default you don’t have to worry about the output format in your code. Note that you can still specify an explicit output format if you choose, either globally by overriding the installed formatters, or individually by returning a lower level HttpResponseMessage instance and setting the formatter explicitly. More on that in a minute. Along the same lines, any content sent to the server via POST/PUT is parsed by Web API based on the HTTP Content-type of the data sent. The same formats allowed for output are also allowed on input. Again, you don’t have to do anything in your code – Web API automatically performs the deserialization from the content. Accessing Web API JSON Data with jQuery A very common scenario for Web API endpoints is to retrieve data for AJAX calls from the Web browser. Because JSON is the default format for Web API, it’s easy to access data from the server using jQuery and its getJSON() method. This example receives the albums array from GetAlbums() and databinds it into the page using knockout.js.$.getJSON("albums/", function (albums) { // make knockout template visible $(".album").show(); // create view object and attach array var view = { albums: albums }; ko.applyBindings(view); }); Figure 4 shows this and the next example’s HTML output. You can check out the complete HTML and script code at http://goo.gl/Ix33C (.html) and http://goo.gl/tETlg (.js). Figu Figure 4: The Album Display sample uses JSON data loaded from Web API.   The result from the getJSON() call is a JavaScript object of the server result, which comes back as a JavaScript array. In the code, I use knockout.js to bind this array into the UI, which as you can see, requires very little code, instead using knockout’s data-bind attributes to bind server data to the UI. Of course, this is just one way to use the data – it’s entirely up to you to decide what to do with the data in your client code. Along the same lines, I can retrieve a single album to display when the user clicks on an album. The response returns the album information and a child array with all the songs. The code to do this is very similar to the last example where we pulled the albums array:$(".albumlink").live("click", function () { var id = $(this).data("id"); // title $.getJSON("albums/" + id, function (album) { ko.applyBindings(album, $("#divAlbumDialog")[0]); $("#divAlbumDialog").show(); }); }); Here the URL looks like this: /albums/Dirty%20Deeds, where the title is the ID captured from the clicked element’s data ID attribute. Explicitly Overriding Output Format When Web API automatically converts output using content negotiation, it does so by matching Accept header media types to the GlobalConfiguration.Configuration.Formatters and the SupportedMediaTypes of each individual formatter. You can add and remove formatters to globally affect what formats are available and it’s easy to create and plug in custom formatters.The example project includes a JSONP formatter that can be plugged in to provide JSONP support for requests that have a callback= querystring parameter. Adding, removing or replacing formatters is a global option you can use to manipulate content. It’s beyond the scope of this introduction to show how it works, but you can review the sample code or check out my blog entry on the subject (http://goo.gl/UAzaR). If automatic processing is not desirable in a particular Controller method, you can override the response output explicitly by returning an HttpResponseMessage instance. HttpResponseMessage is similar to ActionResult in ASP.NET MVC in that it’s a common way to return an abstract result message that contains content. HttpResponseMessage s parsed by the Web API framework using standard interfaces to retrieve the response data, status code, headers and so on[MS2] . Web API turns every response – including those Controller methods that return static results – into HttpResponseMessage instances. Explicitly returning an HttpResponseMessage instance gives you full control over the output and lets you mostly bypass WebAPI’s post-processing of the HTTP response on your behalf. HttpResponseMessage allows you to customize the response in great detail. Web API’s attention to detail in the HTTP spec really shows; many HTTP options are exposed as properties and enumerations with detailed IntelliSense comments. Even if you’re new to building REST-based interfaces, the API guides you in the right direction for returning valid responses and response codes. For example, assume that I always want to return JSON from the GetAlbums() controller method and ignore the default media type content negotiation. To do this, I can adjust the output format and headers as shown in Listing 4.public HttpResponseMessage GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); // Create a new HttpResponse with Json Formatter explicitly var resp = new HttpResponseMessage(HttpStatusCode.OK); resp.Content = new ObjectContent<IEnumerable<Album>>( albums, new JsonMediaTypeFormatter()); // Get Default Formatter based on Content Negotiation //var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); resp.Headers.ConnectionClose = true; resp.Headers.CacheControl = new CacheControlHeaderValue(); resp.Headers.CacheControl.Public = true; return resp; } This example returns the same IEnumerable<Album> value, but it wraps the response into an HttpResponseMessage so you can control the entire HTTP message result including the headers, formatter and status code. In Listing 4, I explicitly specify the formatter using the JsonMediaTypeFormatter to always force the content to JSON.  If you prefer to use the default content negotiation with HttpResponseMessage results, you can create the Response instance using the Request.CreateResponse method:var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); This provides you an HttpResponse object that's pre-configured with the default formatter based on Content Negotiation. Once you have an HttpResponse object you can easily control most HTTP aspects on this object. What's sweet here is that there are many more detailed properties on HttpResponse than the core ASP.NET Response object, with most options being explicitly configurable with enumerations that make it easy to pick the right headers and response codes from a list of valid codes. It makes HTTP features available much more discoverable even for non-hardcore REST/HTTP geeks. Non-Serialized Results The output returned doesn’t have to be a serialized value but can also be raw data, like strings, binary data or streams. You can use the HttpResponseMessage.Content object to set a number of common Content classes. Listing 5 shows how to return a binary image using the ByteArrayContent class from a Controller method. [HttpGet] public HttpResponseMessage AlbumArt(string title) { var album = AlbumData.Current.FirstOrDefault(abl => abl.AlbumName.StartsWith(title)); if (album == null) { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found")); return resp; } // kinda silly - we would normally serve this directly // but hey - it's a demo. var http = new WebClient(); var imageData = http.DownloadData(album.AlbumImageUrl); // create response and return var result = new HttpResponseMessage(HttpStatusCode.OK); result.Content = new ByteArrayContent(imageData); result.Content.Headers.ContentType = new MediaTypeHeaderValue("image/jpeg"); return result; } The image retrieval from Amazon is contrived, but it shows how to return binary data using ByteArrayContent. It also demonstrates that you can easily return multiple types of content from a single controller method, which is actually quite common. If an error occurs - such as a resource can’t be found or a validation error – you can return an error response to the client that’s very specific to the error. In GetAlbumArt(), if the album can’t be found, we want to return a 404 Not Found status (and realistically no error, as it’s an image). Note that if you are not using HTTP Verb-based routing or not accessing a method that starts with Get/Post etc., you have to specify one or more HTTP Verb attributes on the method explicitly. Here, I used the [HttpGet] attribute to serve the image. Another option to handle the error could be to return a fixed placeholder image if no album could be matched or the album doesn’t have an image. When returning an error code, you can also return a strongly typed response to the client. For example, you can set the 404 status code and also return a custom error object (ApiMessageError is a class I defined) like this:return Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found") );   If the album can be found, the image will be returned. The image is downloaded into a byte[] array, and then assigned to the result’s Content property. I created a new ByteArrayContent instance and assigned the image’s bytes and the content type so that it displays properly in the browser. There are other content classes available: StringContent, StreamContent, ByteArrayContent, MultipartContent, and ObjectContent are at your disposal to return just about any kind of content. You can create your own Content classes if you frequently return custom types and handle the default formatter assignments that should be used to send the data out . Although HttpResponseMessage results require more code than returning a plain .NET value from a method, it allows much more control over the actual HTTP processing than automatic processing. It also makes it much easier to test your controller methods as you get a response object that you can check for specific status codes and output messages rather than just a result value. Routing Again Ok, let’s get back to the image example. Using the original routing we have setup using HTTP Verb routing there's no good way to serve the image. In order to return my album art image I’d like to use a URL like this: http://localhost/aspnetWebApi/albums/Dirty%20Deeds/image In order to create a URL like this, I have to create a new Controller because my earlier routes pointed to the AlbumApiController using HTTP Verb routing. HTTP Verb based routing is great for representing a single set of resources such as albums. You can map operations like add, delete, update and read easily using HTTP Verbs. But you cannot mix action based routing into a an HTTP Verb routing controller - you can only map HTTP Verbs and each method has to be unique based on parameter signature. You can't have multiple GET operations to methods with the same signature. So GetImage(string id) and GetAlbum(string title) are in conflict in an HTTP GET routing scenario. In fact, I was unable to make the above Image URL work with any combination of HTTP Verb plus Custom routing using the single Albums controller. There are number of ways around this, but all involve additional controllers.  Personally, I think it’s easier to use explicit Action routing and then add custom routes if you need to simplify your URLs further. So in order to accommodate some of the other examples, I created another controller – AlbumRpcApiController – to handle all requests that are explicitly routed via actions (/albums/rpc/AlbumArt) or are custom routed with explicit routes defined in the HttpConfiguration. I added the AlbumArt() method to this new AlbumRpcApiController class. For the image URL to work with the new AlbumRpcApiController, you need a custom route placed before the default route from Listing 1.RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); Now I can use either of the following URLs to access the image: Custom route: (/albums/rpc/{title}/image)http://localhost/aspnetWebApi/albums/PowerAge/image Action route: (/albums/rpc/action/{title})http://localhost/aspnetWebAPI/albums/rpc/albumart/PowerAge Sending Data to the Server To send data to the server and add a new album, you can use an HTTP POST operation. Since I’m using HTTP Verb-based routing in the original AlbumApiController, I can implement a method called PostAlbum()to accept a new album from the client. Listing 6 shows the Web API code to add a new album.public HttpResponseMessage PostAlbum(Album album) { if (!this.ModelState.IsValid) { // my custom error class var error = new ApiMessageError() { message = "Model is invalid" }; // add errors into our client error model for client foreach (var prop in ModelState.Values) { var modelError = prop.Errors.FirstOrDefault(); if (!string.IsNullOrEmpty(modelError.ErrorMessage)) error.errors.Add(modelError.ErrorMessage); else error.errors.Add(modelError.Exception.Message); } return Request.CreateResponse<ApiMessageError>(HttpStatusCode.Conflict, error); } // update song id which isn't provided foreach (var song in album.Songs) song.AlbumId = album.Id; // see if album exists already var matchedAlbum = AlbumData.Current .SingleOrDefault(alb => alb.Id == album.Id || alb.AlbumName == album.AlbumName); if (matchedAlbum == null) AlbumData.Current.Add(album); else matchedAlbum = album; // return a string to show that the value got here var resp = Request.CreateResponse(HttpStatusCode.OK, string.Empty); resp.Content = new StringContent(album.AlbumName + " " + album.Entered.ToString(), Encoding.UTF8, "text/plain"); return resp; } The PostAlbum() method receives an album parameter, which is automatically deserialized from the POST buffer the client sent. The data passed from the client can be either XML or JSON. Web API automatically figures out what format it needs to deserialize based on the content type and binds the content to the album object. Web API uses model binding to bind the request content to the parameter(s) of controller methods. Like MVC you can check the model by looking at ModelState.IsValid. If it’s not valid, you can run through the ModelState.Values collection and check each binding for errors. Here I collect the error messages into a string array that gets passed back to the client via the result ApiErrorMessage object. When a binding error occurs, you’ll want to return an HTTP error response and it’s best to do that with an HttpResponseMessage result. In Listing 6, I used a custom error class that holds a message and an array of detailed error messages for each binding error. I used this object as the content to return to the client along with my Conflict HTTP Status Code response. If binding succeeds, the example returns a string with the name and date entered to demonstrate that you captured the data. Normally, a method like this should return a Boolean or no response at all (HttpStatusCode.NoConent). The sample uses a simple static list to hold albums, so once you’ve added the album using the Post operation, you can hit the /albums/ URL to see that the new album was added. The client jQuery code to call the POST operation from the client with jQuery is shown in Listing 7. var id = new Date().getTime().toString(); var album = { "Id": id, "AlbumName": "Power Age", "Artist": "AC/DC", "YearReleased": 1977, "Entered": "2002-03-11T18:24:43.5580794-10:00", "AlbumImageUrl": http://ecx.images-amazon.com/images/…, "AmazonUrl": http://www.amazon.com/…, "Songs": [ { "SongName": "Rock 'n Roll Damnation", "SongLength": 3.12}, { "SongName": "Downpayment Blues", "SongLength": 4.22 }, { "SongName": "Riff Raff", "SongLength": 2.42 } ] } $.ajax( { url: "albums/", type: "POST", contentType: "application/json", data: JSON.stringify(album), processData: false, beforeSend: function (xhr) { // not required since JSON is default output xhr.setRequestHeader("Accept", "application/json"); }, success: function (result) { // reload list of albums page.loadAlbums(); }, error: function (xhr, status, p3, p4) { var err = "Error"; if (xhr.responseText && xhr.responseText[0] == "{") err = JSON.parse(xhr.responseText).message; alert(err); } }); The code in Listing 7 creates an album object in JavaScript to match the structure of the .NET Album class. This object is passed to the $.ajax() function to send to the server as POST. The data is turned into JSON and the content type set to application/json so that the server knows what to convert when deserializing in the Album instance. The jQuery code hooks up success and failure events. Success returns the result data, which is a string that’s echoed back with an alert box. If an error occurs, jQuery returns the XHR instance and status code. You can check the XHR to see if a JSON object is embedded and if it is, you can extract it by de-serializing it and accessing the .message property. REST standards suggest that updates to existing resources should use PUT operations. REST standards aside, I’m not a big fan of separating out inserts and updates so I tend to have a single method that handles both. But if you want to follow REST suggestions, you can create a PUT method that handles updates by forwarding the PUT operation to the POST method:public HttpResponseMessage PutAlbum(Album album) { return PostAlbum(album); } To make the corresponding $.ajax() call, all you have to change from Listing 7 is the type: from POST to PUT. Model Binding with UrlEncoded POST Variables In the example in Listing 7 I used JSON objects to post a serialized object to a server method that accepted an strongly typed object with the same structure, which is a common way to send data to the server. However, Web API supports a number of different ways that data can be received by server methods. For example, another common way is to use plain UrlEncoded POST  values to send to the server. Web API supports Model Binding that works similar (but not the same) as MVC's model binding where POST variables are mapped to properties of object parameters of the target method. This is actually quite common for AJAX calls that want to avoid serialization and the potential requirement of a JSON parser on older browsers. For example, using jQUery you might use the $.post() method to send a new album to the server (albeit one without songs) using code like the following:$.post("albums/",{AlbumName: "Dirty Deeds", YearReleased: 1976 … },albumPostCallback); Although the code looks very similar to the client code we used before passing JSON, here the data passed is URL encoded values (AlbumName=Dirty+Deeds&YearReleased=1976 etc.). Web API then takes this POST data and maps each of the POST values to the properties of the Album object in the method's parameter. Although the client code is different the server can both handle the JSON object, or the UrlEncoded POST values. Dynamic Access to POST Data There are also a few options available to dynamically access POST data, if you know what type of data you're dealing with. If you have POST UrlEncoded values, you can dynamically using a FormsDataCollection:[HttpPost] public string PostAlbum(FormDataCollection form) { return string.Format("{0} - released {1}", form.Get("AlbumName"),form.Get("RearReleased")); } The FormDataCollection is a very simple object, that essentially provides the same functionality as Request.Form[] in ASP.NET. Request.Form[] still works if you're running hosted in an ASP.NET application. However as a general rule, while ASP.NET's functionality is always available when running Web API hosted inside of an  ASP.NET application, using the built in classes specific to Web API makes it possible to run Web API applications in a self hosted environment outside of ASP.NET. If your client is sending JSON to your server, and you don't want to map the JSON to a strongly typed object because you only want to retrieve a few simple values, you can also accept a JObject parameter in your API methods:[HttpPost] public string PostAlbum(JObject jsonData) { dynamic json = jsonData; JObject jalbum = json.Album; JObject juser = json.User; string token = json.UserToken; var album = jalbum.ToObject<Album>(); var user = juser.ToObject<User>(); return String.Format("{0} {1} {2}", album.AlbumName, user.Name, token); } There quite a few options available to you to receive data with Web API, which gives you more choices for the right tool for the job. Unfortunately one shortcoming of Web API is that POST data is always mapped to a single parameter. This means you can't pass multiple POST parameters to methods that receive POST data. It's possible to accept multiple parameters, but only one can map to the POST content - the others have to come from the query string or route values. I have a couple of Blog POSTs that explain what works and what doesn't here: Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API   Handling Delete Operations Finally, to round out the server API code of the album example we've been discussin, here’s the DELETE verb controller method that allows removal of an album by its title:public HttpResponseMessage DeleteAlbum(string title) { var matchedAlbum = AlbumData.Current.Where(alb => alb.AlbumName == title) .SingleOrDefault(); if (matchedAlbum == null) return new HttpResponseMessage(HttpStatusCode.NotFound); AlbumData.Current.Remove(matchedAlbum); return new HttpResponseMessage(HttpStatusCode.NoContent); } To call this action method using jQuery, you can use:$(".removeimage").live("click", function () { var $el = $(this).parent(".album"); var txt = $el.find("a").text(); $.ajax({ url: "albums/" + encodeURIComponent(txt), type: "Delete", success: function (result) { $el.fadeOut().remove(); }, error: jqError }); }   Note the use of the DELETE verb in the $.ajax() call, which routes to DeleteAlbum on the server. DELETE is a non-content operation, so you supply a resource ID (the title) via route value or the querystring. Routing Conflicts In all requests with the exception of the AlbumArt image example shown so far, I used HTTP Verb routing that I set up in Listing 1. HTTP Verb Routing is a recommendation that is in line with typical REST access to HTTP resources. However, it takes quite a bit of effort to create REST-compliant API implementations based only on HTTP Verb routing only. You saw one example that didn’t really fit – the return of an image where I created a custom route albums/{title}/image that required creation of a second controller and a custom route to work. HTTP Verb routing to a controller does not mix with custom or action routing to the same controller because of the limited mapping of HTTP verbs imposed by HTTP Verb routing. To understand some of the problems with verb routing, let’s look at another example. Let’s say you create a GetSortableAlbums() method like this and add it to the original AlbumApiController accessed via HTTP Verb routing:[HttpGet] public IQueryable<Album> SortableAlbums() { var albums = AlbumData.Current; // generally should be done only on actual queryable results (EF etc.) // Done here because we're running with a static list but otherwise might be slow return albums.AsQueryable(); } If you compile this code and try to now access the /albums/ link, you get an error: Multiple Actions were found that match the request. HTTP Verb routing only allows access to one GET operation per parameter/route value match. If more than one method exists with the same parameter signature, it doesn’t work. As I mentioned earlier for the image display, the only solution to get this method to work is to throw it into another controller. Because I already set up the AlbumRpcApiController I can add the method there. First, I should rename the method to SortableAlbums() so I’m not using a Get prefix for the method. This also makes the action parameter look cleaner in the URL - it looks less like a method and more like a noun. I can then create a new route that handles direct-action mapping:RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); As I am explicitly adding a route segment – rpc – into the route template, I can now reference explicit methods in the Web API controller using URLs like this: http://localhost/AspNetWebApi/rpc/SortableAlbums Error Handling I’ve already done some minimal error handling in the examples. For example in Listing 6, I detected some known-error scenarios like model validation failing or a resource not being found and returning an appropriate HttpResponseMessage result. But what happens if your code just blows up or causes an exception? If you have a controller method, like this:[HttpGet] public void ThrowException() { throw new UnauthorizedAccessException("Unauthorized Access Sucka"); } You can call it with this: http://localhost/AspNetWebApi/albums/rpc/ThrowException The default exception handling displays a 500-status response with the serialized exception on the local computer only. When you connect from a remote computer, Web API throws back a 500  HTTP Error with no data returned (IIS then adds its HTML error page). The behavior is configurable in the GlobalConfiguration:GlobalConfiguration .Configuration .IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Never; If you want more control over your error responses sent from code, you can throw explicit error responses yourself using HttpResponseException. When you throw an HttpResponseException the response parameter is used to generate the output for the Controller action. [HttpGet] public void ThrowError() { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.BadRequest, new ApiMessageError("Your code stinks!")); throw new HttpResponseException(resp); } Throwing an HttpResponseException stops the processing of the controller method and immediately returns the response you passed to the exception. Unlike other Exceptions fired inside of WebAPI, HttpResponseException bypasses the Exception Filters installed and instead just outputs the response you provide. In this case, the serialized ApiMessageError result string is returned in the default serialization format – XML or JSON. You can pass any content to HttpResponseMessage, which includes creating your own exception objects and consistently returning error messages to the client. Here’s a small helper method on the controller that you might use to send exception info back to the client consistently:private void ThrowSafeException(string message, HttpStatusCode statusCode = HttpStatusCode.BadRequest) { var errResponse = Request.CreateResponse<ApiMessageError>(statusCode, new ApiMessageError() { message = message }); throw new HttpResponseException(errResponse); } You can then use it to output any captured errors from code:[HttpGet] public void ThrowErrorSafe() { try { List<string> list = null; list.Add("Rick"); } catch (Exception ex) { ThrowSafeException(ex.Message); } }   Exception Filters Another more global solution is to create an Exception Filter. Filters in Web API provide the ability to pre- and post-process controller method operations. An exception filter looks at all exceptions fired and then optionally creates an HttpResponseMessage result. Listing 8 shows an example of a basic Exception filter implementation.public class UnhandledExceptionFilter : ExceptionFilterAttribute { public override void OnException(HttpActionExecutedContext context) { HttpStatusCode status = HttpStatusCode.InternalServerError; var exType = context.Exception.GetType(); if (exType == typeof(UnauthorizedAccessException)) status = HttpStatusCode.Unauthorized; else if (exType == typeof(ArgumentException)) status = HttpStatusCode.NotFound; var apiError = new ApiMessageError() { message = context.Exception.Message }; // create a new response and attach our ApiError object // which now gets returned on ANY exception result var errorResponse = context.Request.CreateResponse<ApiMessageError>(status, apiError); context.Response = errorResponse; base.OnException(context); } } Exception Filter Attributes can be assigned to an ApiController class like this:[UnhandledExceptionFilter] public class AlbumRpcApiController : ApiController or you can globally assign it to all controllers by adding it to the HTTP Configuration's Filters collection:GlobalConfiguration.Configuration.Filters.Add(new UnhandledExceptionFilter()); The latter is a great way to get global error trapping so that all errors (short of hard IIS errors and explicit HttpResponseException errors) return a valid error response that includes error information in the form of a known-error object. Using a filter like this allows you to throw an exception as you normally would and have your filter create a response in the appropriate output format that the client expects. For example, an AJAX application can on failure expect to see a JSON error result that corresponds to the real error that occurred rather than a 500 error along with HTML error page that IIS throws up. You can even create some custom exceptions so you can differentiate your own exceptions from unhandled system exceptions - you often don't want to display error information from 'unknown' exceptions as they may contain sensitive system information or info that's not generally useful to users of your application/site. This is just one example of how ASP.NET Web API is configurable and extensible. Exception filters are just one example of how you can plug-in into the Web API request flow to modify output. Many more hooks exist and I’ll take a closer look at extensibility in Part 2 of this article in the future. Summary Web API is a big improvement over previous Microsoft REST and AJAX toolkits. The key features to its usefulness are its ease of use with simple controller based logic, familiar MVC-style routing, low configuration impact, extensibility at all levels and tight attention to exposing and making HTTP semantics easily discoverable and easy to use. Although none of the concepts used in Web API are new or radical, Web API combines the best of previous platforms into a single framework that’s highly functional, easy to work with, and extensible to boot. I think that Microsoft has hit a home run with Web API. Related Resources Where does ASP.NET Web API fit? Sample Source Code on GitHub Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API Creating a JSONP Formatter for ASP.NET Web API Removing the XML Formatter from ASP.NET Web API Applications© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• Oracle Support Master Note for Troubleshooting Advanced Queuing and Oracle Streams Propagation Issues (Doc ID 233099.1)

  - by faye.todd(at)oracle.com

  Master Note for Troubleshooting Advanced Queuing and Oracle Streams Propagation Issues (Doc ID 233099.1) Copyright (c) 2010, Oracle Corporation. All Rights Reserved. In this Document  Purpose  Last Review Date  Instructions for the Reader  Troubleshooting Details     1. Scope and Application      2. Definitions and Classifications     3. How to Use This Guide     4. Basic AQ Propagation Troubleshooting     5. Additional Troubleshooting Steps for AQ Propagation of User-Enqueued and Dequeued Messages     6. Additional Troubleshooting Steps for Propagation in an Oracle Streams Environment     7. Performance Issues  References Applies to: Oracle Server - Enterprise Edition - Version: 8.1.7.0 to 11.2.0.2 - Release: 8.1.7 to 11.2Information in this document applies to any platform. Purpose This document presents a step-by-step methodology for troubleshooting and resolving problems with Advanced Queuing Propagation in both Streams and basic Advanced Queuing environments. It also serves as a master reference for other more specific notes on Oracle Streams Propagation and Advanced Queuing Propagation issues. Last Review Date December 20, 2010 Instructions for the Reader A Troubleshooting Guide is provided to assist in debugging a specific issue. When possible, diagnostic tools are included in the document to assist in troubleshooting. Troubleshooting Details 1. Scope and Application This note is intended for Database Administrators of Oracle databases where issues are being encountered with propagating messages between advanced queues, whether the queues are used for user-created messaging systems or for Oracle Streams. It contains troubleshooting steps and links to notes for further problem resolution.It can also be used a template to document a problem when it is necessary to engage Oracle Support Services. Knowing what is NOT happening can frequently speed up the resolution process by focusing solely on the pertinent problem area. This guide is divided into five parts: Section 2: Definitions and Classifications (discusses the different types and features of propagations possible - helpful for understanding the rest of the guide) Section 3: How to Use this Guide (to be used as a start part for determining the scope of the problem and what sections to consult) Section 4. Basic AQ propagation troubleshooting (applies to both AQ propagation of user enqueued and dequeued messages as well as Oracle Streams propagations) Section 5. Additional troubleshooting steps for AQ propagation of user enqueued and dequeued messages Section 6. Additional troubleshooting steps for Oracle Streams propagation Section 7. Performance issues 2. Definitions and Classifications Given the potential scope of issues that can be encountered with AQ propagation, the first recommended step is to do some basic diagnosis to determine the type of problem that is being encountered. 2.1. What Type of Propagation is Being Used? 2.1.1. Buffered Messaging For an advanced queue, messages can be maintained on disk (persistent messaging) or in memory (buffered messaging). To determine if a queue is buffered or not, reference the GV_$BUFFERED_QUEUES view. If the queue does not appear in this view, it is persistent. 2.1.2. Propagation mode - queue-to-dblink vs queue-to-queue As of 10.2, an AQ propagation can also be defined as queue-to-dblink, or queue-to-queue: queue-to-dblink: The propagation delivers messages or events from the source queue to all subscribing queues at the destination database identified by the dblink. A single propagation schedule is used to propagate messages to all subscribing queues. Hence any changes made to this schedule will affect message delivery to all the subscribing queues. This mode does not support multiple propagations from the same source queue to the same target database. queue-to-queue: Added in 10.2, this propagation mode delivers messages or events from the source queue to a specific destination queue identified on the database link. This allows the user to have fine-grained control on the propagation schedule for message delivery. This new propagation mode also supports transparent failover when propagating to a destination Oracle RAC system. With queue-to-queue propagation, you are no longer required to re-point a database link if the owner instance of the queue fails on Oracle RAC. This mode supports multiple propagations to the same target database if the target queues are different. The default is queue-to-dblink. To verify if queue-to-queue propagation is being used, in non-Streams environments query DBA_QUEUE_SCHEDULES.DESTINATION - if a remote queue is listed along with the remote database link, then queue-to-queue propagation is being used. For Streams environments, the DBA_PROPAGATION.QUEUE_TO_QUEUE column can be checked.See the following note for a method to switch between the two modes:Document 827473.1 How to alter propagation from queue-to-queue to queue-to-dblink 2.1.3. Combined Capture and Apply (CCA) for Streams In 11g Oracle Streams environments, an optimization called Combined Capture and Apply (CCA) is implemented by default when possible. Although a propagation is configured in this case, Streams does not use it; instead it passes information directly from capture to an apply receiver. To see if CCA is in use: COLUMN CAPTURE_NAME HEADING 'Capture Name' FORMAT A30COLUMN OPTIMIZATION HEADING 'CCA Mode?' FORMAT A10SELECT CAPTURE_NAME, DECODE(OPTIMIZATION,0, 'No','Yes') OPTIMIZATIONFROM V$STREAMS_CAPTURE; Also, see the following note:Document 463820.1 Streams Combined Capture and Apply in 11g 2.2. Queue Table Compatibility There are three types of queue table compatibility. In more recent databases, queue tables may be present in all three modes of compatibility: 8.0 - earliest version, deprecated in 10.2 onwards 8.1 - support added for RAC, asynchronous notification, secure queues, queue level access control, rule-based subscribers, separate storage of history information 10.0 - if the database is in 10.1-compatible mode, then the default value for queue table compatibility is 10.0 2.3. Single vs Multiple Consumer Queue Tables If more than one recipient can dequeue a message from a queue, then its queue table is multiple consumer. You can propagate messages from a multiple-consumer queue to a single-consumer queue. Propagation from a single-consumer queue to a multiple-consumer queue is not possible. 3. How to Use This Guide 3.1. Are Messages Being Propagated at All, or is the Propagation Just Slow? Run the following query on the source database for the propagation (assuming that it is running): select TOTAL_NUMBER from DBA_QUEUE_SCHEDULES where QNAME='<source_queue_name>'; If TOTAL_NUMBER is increasing, then propagation is most likely functioning, although it may be slow. For performance issues, see Section 7. 3.2. Propagation Between Persistent User-Created Queues See Sections 4 and 5 (and optionally Section 6 if performance is an issue). 3.3. Propagation Between Buffered User-Created Queues See Sections 4, 5, and 6 (and optionally Section 7 if performance is an issue). 3.4. Propagation between Oracle Streams Queues (without Combined Capture and Apply (CCA) Optimization) See Sections 4 and 6 (and optionally Section 7 if performance is an issue). 3.5. Propagation between Oracle Streams Queues (with Combined Capture and Apply (CCA) Optimization) Although an AQ propagation is not used directly in this case, some characteristics of the message transfer are inferred from the propagation parameters used. Some parts of Sections 4 and 6 still apply. 3.6. Messaging Gateway Propagations This note does not apply to Messaging Gateway propagations. 4. Basic AQ Propagation Troubleshooting 4.1. Double-check Your Code Make sure that you are consistent in your usage of the database link(s) names, queue names, etc. It may be useful to plot a diagram of which queues are connected via which database links to make sure that the logical structure is correct. 4.2. Verify that Job Queue Processes are Running 4.2.1. Versions 10.2 and Lower - DBA_JOBS Package For versions 10.2 and lower, a scheduled propagation is managed by DBMS_JOB package. The propagation is performed by job queue process background processes. Therefore we need to verify that there are sufficient processes available for the propagation process. We should have at least 4 job queue processes running and preferably more depending on the number of other jobs running in the database. It should be noted that for AQ specific work, AQ will only ever use half of the job queue processes available.An issue caused by an inadequate job queue processes parameter setting is described in the following note:Document 298015.1 Kwqjswproc:Excep After Loop: Assigning To Self 4.2.1.1. Job Queue Processes in Initalization Parameter File The parameter JOB_QUEUE_PROCESSES in the init.ora/spfile should be > 0. The value can be changed dynamically via connect / as sysdbaalter system set JOB_QUEUE_PROCESSES=10; 4.2.1.2. Job Queue Processes in Memory The following command will show how many job queue processes are currentlyin use by this instance (this may be different than what is in the init.ora/spfile): connect / as sysdbashow parameter job; 4.2.1.3. OS PIDs Corresponding to Job Queue Processes Identify the operating system process ids (spids) of job queue processes involved in propagation via select p.SPID, p.PROGRAM from V$PROCESS p, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j where s.SID=jr.SID and s.PADDR=p.ADDR and jr.JOB=j.JOBand j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%'; and these SPIDs can be used to check at the operating system level that they exist.In 8i a job queue process will have a name similar to: ora_snp1_<instance_name>.In 9i onwards you will see a coordinator process: ora_cjq0_ and multiple slave processes: ora_jnnn_<instance_name>, where nnn is an integer between 1 and 999. 4.2.2. Version 11.1 and Above - Oracle Scheduler In version 11.1 and above, Oracle Scheduler is used to perform AQ and Streams propagations. Oracle Scheduler automatically tunes the number of slave processes for these jobs based on the load on the computer system, and the JOB_QUEUE_PROCESSES initialization parameter is only used to specify the maximum number of slave processes. Therefore, the JOB_QUEUE_PROCESSES initialization parameter does not need to be set (it defaults to a very high number), unless you want to limit the number of slaves that can be created. If JOB_QUEUE_PROCESSES = 0, no propagation jobs will run.See the following note for a discussion of Oracle Streams 11g and Oracle Scheduler:Document 1083608.1 11g Streams and Oracle Scheduler 4.2.2.1. Job Queue Processes in Initalization Parameter File The parameter JOB_QUEUE_PROCESSES in the init.ora/spfile should be > 0, and preferably be left at its default value. The value can be changed dynamically via connect / as sysdbaalter system set JOB_QUEUE_PROCESSES=10; To set the JOB_QUEUE_PROCESSES parameter to its default value, run: connect / as sysdbaalter system reset JOB_QUEUE_PROCESSES; and then bounce the instance. 4.2.2.2. Job Queue Processes in Memory The following command will show how many job queue processes are currently in use by this instance (this may be different than what is in the init.ora/spfile): connect / as sysdbashow parameter job; 4.2.2.3. OS PIDs Corresponding to Job Queue Processes Identify the operating system process ids (SPIDs) of job queue processes involved in propagation via col PROGRAM for a30select p.SPID, p.PROGRAM, j.JOB_namefrom v$PROCESS p, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j where s.SID=jr.SESSION_ID and s.PADDR=p.ADDRand jr.JOB_name=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%'; and these SPIDs can be used to check at the operating system level that they exist.You will see a coordinator process: ora_cjq0_ and multiple slave processes: ora_jnnn_<instance_name>, where nnn is an integer between 1 and 999. 4.3. Check the Alert Log and Any Associated Trace Files The first place to check for propagation failures is the alert logs at all sites (local and if relevant all remote sites). When a job queue process attempts to execute a schedule and fails it will always write an error stack to the alert log. This error stack will also be written in a job queue process trace file, which will be written to the BACKGROUND_DUMP_DEST location for 10.2 and below, and in the DIAGNOSTIC_DEST location for 11g. The fact that errors are written to the alert log demonstrates that the schedule is executing. This means that the problem could be with the set up of the schedule. In this example the ORA-02068 demonstrates that the failure was at the remote site. Further investigation revealed that the remote database was not open, hence the ORA-03114 error. Starting the database resolved the problem. Thu Feb 14 10:40:05 2002 Propagation Schedule for (AQADM.MULTIPLEQ, SHANE816.WORLD) encountered following error:ORA-04052: error occurred when looking up Remote object [email protected]: error occurred at recursive SQL level 4ORA-02068: following severe error from SHANE816ORA-03114: not connected to ORACLEORA-06512: at "SYS.DBMS_AQADM_SYS", line 4770ORA-06512: at "SYS.DBMS_AQADM", line 548ORA-06512: at line 1 Other potential errors that may be written to the alert log can be found in the following notes:Document 827184.1 AQ Propagation with CLOB data types Fails with ORA-22990 (11.1)Document 846297.1 AQ Propagation Fails : ORA-00600[kope2upic2954] or Ora-00600[Kghsstream_copyn] (10.2, 11.1)Document 731292.1 ORA-25215 Reported on Local Propagation When Using Transformation with ANYDATA queue tables (10.2, 11.1, 11.2)Document 365093.1 ORA-07445 [kwqppay2aqe()+7360] Reported on Propagation of a Transformed Message (10.1, 10.2)Document 219416.1 Advanced Queuing Propagation Fails with ORA-22922 (9.0)Document 1203544.1 AQ Propagation Aborted with ORA-600 [ociksin: invalid status] on SYS.DBMS_AQADM_SYS.AQ$_PROPAGATION_PROCEDURE After Upgrade (11.1, 11.2)Document 1087324.1 ORA-01405 ORA-01422 reported by Advanced Queuing Propagation schedules after RAC reconfiguration (10.2)Document 1079577.1 Advanced Queuing Propagation Fails With "ORA-22370 incorrect usage of method" (9.2, 10.2, 11.1, 11.2)Document 332792.1 ORA-04061 error relating to SYS.DBMS_PRVTAQIP reported when setting up Statspack (8.1, 9.0, 9.2, 10.1)Document 353325.1 ORA-24056: Internal inconsistency for QUEUE <queue_name> and destination <dblink> (8.1, 9.0, 9.2, 10.1, 10.2, 11.1, 11.2)Document 787367.1 ORA-22275 reported on Propagating Messages with LOB component when propagating between 10.1 and 10.2 (10.1, 10.2)Document 566622.1 ORA-22275 when propagating >4K AQ$_JMS_TEXT_MESSAGEs from 9.2.0.8 to 10.2.0.1 (9.2, 10.1)Document 731539.1 ORA-29268: HTTP client error 401 Unauthorized Error when the AQ Servlet attempts to Propagate a message via HTTP (9.0, 9.2, 10.1, 10.2, 11.1)Document 253131.1 Concurrent Writes May Corrupt LOB Segment When Using Auto Segment Space Management (ORA-1555) (9.2)Document 118884.1 How to unschedule a propagation schedule stuck in pending stateDocument 222992.1 DBMS_AQADM.DISABLE_PROPAGATION_SCHEDULE Returns ORA-24082Document 282987.1 Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueDocument 1204080.1 AQ Propagation Failing With ORA-25329 After Upgraded From 8i or 9i to 10g or 11g.Document 1233675.1 AQ Propagation stops after upgrade to 11.2.0.1 ORA-30757 4.3.1. Errors Related to Incorrect Network Configuration The most common propagation errors result from an incorrect network configuration. The list below contains common errors caused by tnsnames.ora file or database links being configured incorrectly: - ORA-12154: TNS:could not resolve service name- ORA-12505: TNS:listener does not currently know of SID given in connect descriptor- ORA-12514: TNS:listener could not resolve SERVICE_NAME - ORA-12541: TNS-12541 TNS:no listener 4.4. Check the Database Links Exist and are Functioning Correctly For schedules to remote databases confirm the database link exists via. SQL> col DBLINK for a45SQL> select QNAME, NVL(REGEXP_SUBSTR(DESTINATION, '[^@]+', 1, 2), DESTINATION) dblink2 from DBA_QUEUE_SCHEDULES3 where MESSAGE_DELIVERY_MODE = 'PERSISTENT';QNAME DBLINK------------------------------ ---------------------------------------------MY_QUEUE ORCL102B.WORLD Connect as the owner of the link and select across it to verify it works and connects to the database we expect. i.e. select * from ALL_QUEUES@ ORCL102B.WORLD; You need to ensure that the userid that scheduled the propagation (using DBMS_AQADM.SCHEDULE_PROPAGATION or DBMS_PROPAGATION_ADM.CREATE_PROPAGATION if using Streams) has access to the database link for the destination. 4.5. Has Propagation Been Correctly Scheduled? Check that the propagation schedule has been created and that a job queue process has been assigned. Look for the entry in DBA_QUEUE_SCHEDULES and SYS.AQ$_SCHEDULES for your schedule. For 10g and below, check that it has a JOBNO entry in SYS.AQ$_SCHEDULES, and that there is an entry in DBA_JOBS with that JOBNO. For 11g and above, check that the schedule has a JOB_NAME entry in SYS.AQ$_SCHEDULES, and that there is an entry in DBA_SCHEDULER_JOBS with that JOB_NAME. Check the destination is as intended and spelled correctly. SQL> select SCHEMA, QNAME, DESTINATION, SCHEDULE_DISABLED, PROCESS_NAME from DBA_QUEUE_SCHEDULES;SCHEMA QNAME DESTINATION S PROCESS------- ---------- ------------------ - -----------AQADM MULTIPLEQ AQ$_LOCAL N J000 AQ$_LOCAL in the destination column shows that the queue to which we are propagating to is in the same database as the source queue. If the propagation was to a remote (different) database, a database link will be in the DESTINATION column. The entry in the SCHEDULE_DISABLED column, N, means that the schedule is NOT disabled. If Y (yes) appears in this column, propagation is disabled and the schedule will not be executed. If not using Oracle Streams, propagation should resume once you have enabled the schedule by invoking DBMS_AQADM.ENABLE_PROPAGATION_SCHEDULE (for 10.2 Oracle Streams and above, the DBMS_PROPAGATION_ADM.START_PROPAGATION procedure should be used). The PROCESS_NAME is the name of the job queue process currently allocated to execute the schedule. This process is allocated dynamically at execution time. If the PROCESS_NAME column is null (empty) the schedule is not currently executing. You may need to execute this statement a number of times to verify if a process is being allocated. If a process is at some time allocated to the schedule, it is attempting to execute. SQL> select SCHEMA, QNAME, LAST_RUN_DATE, NEXT_RUN_DATE from DBA_QUEUE_SCHEDULES;SCHEMA QNAME LAST_RUN_DATE NEXT_RUN_DATE------ ----- ----------------------- ----------------------- AQADM MULTIPLEQ 13-FEB-2002 13:18:57 13-FEB-2002 13:20:30 In 11g, these dates are expressed in TIMESTAMP WITH TIME ZONE datatypes. If the NEXT_RUN_DATE and NEXT_RUN_TIME columns are null when this statement is executed, the scheduled propagation is currently in progress. If they never change it would suggest that the schedule itself is never executing. If the next scheduled execution is too far away, change the NEXT_TIME parameter of the schedule so that schedules are executed more frequently (assuming that the window is not set to be infinite). Parameters of a schedule can be changed using the DBMS_AQADM.ALTER_PROPAGATION_SCHEDULE call. In 10g and below, scheduling propagation posts a job in the DBA_JOBS view. The columns are more or less the same as DBA_QUEUE_SCHEDULES so you just need to recognize the job and verify that it exists. SQL> select JOB, WHAT from DBA_JOBS where WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%';JOB WHAT---- ----------------- 720 next_date := sys.dbms_aqadm.aq$_propaq(job); For 11g, scheduling propagation posts a job in DBA_SCHEDULER_JOBS instead: SQL> select JOB_NAME from DBA_SCHEDULER_JOBS where JOB_NAME like 'AQ_JOB$_%';JOB_NAME------------------------------AQ_JOB$_41 If no job exists, check DBA_QUEUE_SCHEDULES to make sure that the schedule has not been disabled. For 10g and below, the job number is dynamic for AQ propagation schedules. The procedure that is executed to expedite a propagation schedule runs, removes itself from DBA_JOBS, and then reposts a new job for the next scheduled propagation. The job number should therefore always increment unless the schedule has been set up to run indefinitely. 4.6. Is the Schedule Executing but Failing to Complete? Run the following query: SQL> select FAILURES, LAST_ERROR_MSG from DBA_QUEUE_SCHEDULES;FAILURES LAST_ERROR_MSG------------ -----------------------1 ORA-25207: enqueue failed, queue AQADM.INQ is disabled from enqueueingORA-02063: preceding line from SHANE816 The failures column shows how many times we have attempted to execute the schedule and failed. Oracle will attempt to execute the schedule 16 times after which it will be removed from the DBA_JOBS or DBA_SCHEDULER_JOBS view and the schedule will become disabled. The column DBA_QUEUE_SCHEDULES.SCHEDULE_DISABLED will show 'Y'. For 11g and above, the DBA_SCHEDULER_JOBS.STATE column will show 'BROKEN' for the job corresponding to DBA_QUEUE_SCHEDULES.JOB_NAME. Prior to 10g the back off algorithm for failures was exponential, whereas from 10g onwards it is linear. The propagation will become disabled on the 17th attempt. Only the last execution failure will be reflected in the LAST_ERROR_MSG column. That is, if the schedule fails 5 times for 5 different reasons, only the last set of errors will be recorded in DBA_QUEUE_SCHEDULES. Any errors need to be resolved to allow propagation to continue. If propagation has also become disabled due to 17 failures, first resolve the reason for the error and then re-enable the schedule using the DBMS_AQADM.ENABLE_PROPAGATION_SCHEDULE procedure, or DBMS_PROPAGATION_ADM.START_PROPAGATION if using 10.2 or above Oracle Streams. As soon as the schedule executes successfully the error message entries will be deleted. Oracle does not keep a history of past failures. However, when using Oracle Streams, the errors will be retained in the DBA_PROPAGATION view even after the schedule resumes successfully. See the following note for instructions on how to clear out the errors from the DBA_PROPAGATION view:Document 808136.1 How to clear the old errors from DBA_PROPAGATION view?If a schedule is active and no errors are being reported then the source queue may not have any messages to be propagated. 4.7. Do the Propagation Notification Queue Table and Queue Exist? Check to see that the propagation notification queue table and queue exist and are enabled for enqueue and dequeue. Propagation makes use of the propagation notification queue for handling propagation run-time events, and the messages in this queue are stored in a SYS-owned queue table. This queue should never be stopped or dropped and the corresponding queue table never be dropped. 10g and belowThe propagation notification queue table is of the format SYS.AQ$_PROP_TABLE_n, where 'n' is the RAC instance number, i.e. '1' for a non-RAC environment. This queue and queue table are created implicitly when propagation is first scheduled. If propagation has been scheduled and these objects do not exist, try unscheduling and rescheduling propagation. If they still do not exist contact Oracle Support. SQL> select QUEUE_TABLE from DBA_QUEUE_TABLES2 where QUEUE_TABLE like '%PROP_TABLE%' and OWNER = 'SYS';QUEUE_TABLE------------------------------AQ$_PROP_TABLE_1SQL> select NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED2 from DBA_QUEUES where owner='SYS'3 and QUEUE_TABLE like '%PROP_TABLE%';NAME ENQUEUE DEQUEUE------------------------------ ------- -------AQ$_PROP_NOTIFY_1 YES YESAQ$_AQ$_PROP_TABLE_1_E NO NO If the AQ$_PROP_NOTIFY_1 queue is not enabled for enqueue or dequeue, it should be so enabled using DBMS_AQADM.START_QUEUE. However, the exception queue AQ$_AQ$_PROP_TABLE_1_E should not be enabled for enqueue or dequeue.11g and aboveThe propagation notification queue table is of the format SYS.AQ_PROP_TABLE, and is created when the database is created. If they do not exist, contact Oracle Support. SQL> select QUEUE_TABLE from DBA_QUEUE_TABLES2 where QUEUE_TABLE like '%PROP_TABLE%' and OWNER = 'SYS';QUEUE_TABLE------------------------------AQ_PROP_TABLESQL> select NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED2 from DBA_QUEUES where owner='SYS'3 and QUEUE_TABLE like '%PROP_TABLE%';NAME ENQUEUE DEQUEUE------------------------------ ------- -------AQ_PROP_NOTIFY YES YESAQ$_AQ_PROP_TABLE_E NO NO If the AQ_PROP_NOTIFY queue is not enabled for enqueue or dequeue, it should be so enabled using DBMS_AQADM.START_QUEUE. However, the exception queue AQ$_AQ$_PROP_TABLE_E should not be enabled for enqueue or dequeue. 4.8. Does the Remote Queue Exist and is it Enabled for Enqueueing? Check that the remote queue the propagation is transferring messages to exists and is enabled for enqueue: SQL> select DESTINATION from USER_QUEUE_SCHEDULES where QNAME = 'OUTQ';DESTINATION-----------------------------------------------------------------------------"AQADM"."INQ"@M2V102.ESSQL> select OWNER, NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED from [email protected];OWNER NAME ENQUEUE DEQUEUE-------- ------ ----------- -----------AQADM INQ YES YES 4.9. Do the Target and Source Database Charactersets Differ? If a message fails to propagate, check the database charactersets of the source and target databases. Investigate whether the same message can propagate between the databases with the same characterset or it is only a particular combination of charactersets which causes a problem. 4.10. Check the Queue Table Type Agreement Propagation is not possible between queue tables which have types that differ in some respect. One way to determine if this is the case is to run the DBMS_AQADM.VERIFY_QUEUE_TYPES procedure for the two queues that the propagation operates on. If the types do not agree, DBMS_AQADM.VERIFY_QUEUE_TYPES will return '0'.For AQ propagation between databases which have different NLS_LENGTH_SEMANTICS settings, propagation will not work, unless the queues are Oracle Streams ANYDATA queues.See the following notes for issues caused by lack of type agreement:Document 1079577.1 Advanced Queuing Propagation Fails With "ORA-22370: incorrect usage of method"Document 282987.1 Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueDocument 353754.1 Streams Messaging Propagation Fails between Single and Multi-byte Charactersets when using Chararacter Length Semantics in the ADT 4.11. Enable Propagation Tracing 4.11.1. System Level This is set it in the init.ora/spfile as follows: event="24040 trace name context forever, level 10" and restart the instanceThis event cannot be set dynamically with an alter system command until version 10.2: SQL> alter system set events '24040 trace name context forever, level 10'; To unset the event: SQL> alter system set events '24040 trace name context off'; Debugging information will be logged to job queue trace file(s) (jnnn) as propagation takes place. You can check the trace file for errors, and for statements indicating that messages have been sent. For the most part the trace information is understandable. This trace should also be uploaded to Oracle Support if a service request is created. 4.11.2. Attaching to a Specific Process We can also attach to an existing job queue processes that is running a propagation schedule and trace it individually using the oradebug utility, as follows:10.2 and below connect / as sysdbaselect p.SPID, p.PROGRAM from v$PROCESS p, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j where s.SID=jr.SID and s.PADDR=p.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%';-- For the process id (SPID) attach to it via oradebug and generate the following traceoradebug setospid <SPID>oradebug unlimitoradebug Event 10046 trace name context forever, level 12oradebug Event 24040 trace name context forever, level 10-- Trace the process for 5 minutesoradebug Event 10046 trace name context offoradebug Event 24040 trace name context off-- The following command returns the pathname/filename to the file being written tooradebug tracefile_name 11g connect / as sysdbacol PROGRAM for a30select p.SPID, p.PROGRAM, j.JOB_NAMEfrom v$PROCESS p, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j where s.SID=jr.SESSION_ID and s.PADDR=p.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%';-- For the process id (SPID) attach to it via oradebug and generate the following traceoradebug setospid <SPID>oradebug unlimitoradebug Event 10046 trace name context forever, level 12oradebug Event 24040 trace name context forever, level 10-- Trace the process for 5 minutesoradebug Event 10046 trace name context offoradebug Event 24040 trace name context off-- The following command returns the pathname/filename to the file being written tooradebug tracefile_name 4.11.3. Further Tracing The previous tracing steps only trace the job queue process executing the propagation on the source. At times it is useful to trace the propagation receiver process (the session which is enqueueing the messages into the target queue) on the target database which is associated with the job queue process on the source database.These following queries provide ways of identifying the processes involved in propagation so that you can attach to them via oradebug to generate trace information.In order to identify the propagation receiver process you need to execute the query as a user with privileges to access the v$ views in both the local and remote databases so the database link must connect as a user with those privileges in the remote database. The <DBLINK> in the queries should be replaced by the appropriate database link.The queries have two forms due to the differences between operating systems. The value returned by 'Rem Process' is the operating system identifier of the propagation receiver on the remote database. Once identified, this process can be attached to and traced on the remote database using the commands given in Section 4.11.2.10.2 and below - Windows select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from v$PROCESS pl, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SID and s.PADDR=pl.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%' and pl.SPID=substr(sr.PROCESS, instr(sr.PROCESS,':')+1); 10.2 and below - Unix select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SID and s.PADDR=pl.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%' and pl.SPID=sr.PROCESS; 11g - Windows select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SESSION_ID and s.PADDR=pl.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%%' and pl.SPID=substr(sr.PROCESS, instr(sr.PROCESS,':')+1); 11g - Unix select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SESSION_ID and s.PADDR=pl.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%%' and pl.SPID=sr.PROCESS;   5. Additional Troubleshooting Steps for AQ Propagation of User-Enqueued and Dequeued Messages 5.1. Check the Privileges of All Users Involved Ensure that the owner of the database link has the necessary privileges on the aq packages. SQL> select TABLE_NAME, PRIVILEGE from USER_TAB_PRIVS;TABLE_NAME PRIVILEGE------------------------------ ----------------------------------------DBMS_LOCK EXECUTEDBMS_AQ EXECUTEDBMS_AQADM EXECUTEDBMS_AQ_BQVIEW EXECUTEQT52814_BUFFER SELECT Note that when queue table is created, a view called QT<nnn>_BUFFER is created in the SYS schema, and the queue table owner is given SELECT privileges on it. The <nnn> corresponds to the object_id of the associated queue table. SQL> select * from USER_ROLE_PRIVS;USERNAME GRANTED_ROLE ADM DEF OS_------------------------------ ------------------------------ ---- ---- ---AQ_USER1 AQ_ADMINISTRATOR_ROLE NO YES NOAQ_USER1 CONNECT NO YES NOAQ_USER1 RESOURCE NO YES NO It is good practice to configure central AQ administrative user. All admin and processing jobs are created, executed and administered as this user. This configuration is not mandatory however, and the database link can be owned by any existing queue user. If this latter configuration is used, ensure that the connecting user has the necessary privileges on the AQ packages and objects involved. Privileges for an AQ Administrative user Execute on DBMS_AQADM Execute on DBMS_AQ Granted the AQ_ADMINISTRATOR_ROLE Privileges for an AQ user Execute on DBMS_AQ Execute on the message payload Enqueue privileges on the remote queue Dequeue privileges on the originating queue Privileges need to be confirmed on both sites when propagation is scheduled to remote destinations. Verify that the user ID used to login to the destination through the database link has been granted privileges to use AQ. 5.2. Verify Queue Payload Types AQ will not propagate messages from one queue to another if the payload types of the two queues are not verified to be equivalent. An AQ administrator can verify if the source and destination's payload types match by executing the DBMS_AQADM.VERIFY_QUEUE_TYPES procedure. The results of the type checking will be stored in the SYS.AQ$_MESSAGE_TYPES table. This table can be accessed using the object identifier OID of the source queue and the address database link of the destination queue, i.e. [schema.]queue_name[@destination]. Prior to Oracle 9i the payload (message type) had to be the same for all the queue tables involved in propagation. From Oracle9i onwards a transformation can be used so that payloads can be converted from one type to another. The following procedural call made on the source database can verify whether we can propagate between the source and the destination queue tables. connect aq_user1/[email protected] serverout onDECLARErc_value number;BEGINDBMS_AQADM.VERIFY_QUEUE_TYPES(src_queue_name => 'AQ_USER1.Q_1', dest_queue_name => 'AQ_USER2.Q_2',destination => 'dbl_aq_user2.es',rc => rc_value);dbms_output.put_line('rc_value code is '||rc_value);END;/ If propagation is possible then the return code value will be 1. If it is 0 then propagation is not possible and further investigation of the types and transformations used by and in conjunction with the queue tables is required. With regard to comparison of the types the following sql can be used to extract the DDL for a specific type with' %' changed appropriately on the source and target. This can then be compared for the source and target. SET LONG 20000 set pagesize 50 EXECUTE DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM, 'STORAGE',false); SELECT DBMS_METADATA.GET_DDL('TYPE',t.type_name) from user_types t WHERE t.type_name like '%'; EXECUTE DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM, 'DEFAULT'); 5.3. Check Message State and Destination The first step in this process is to identify the queue table associated with the problem source queue. Although you schedule propagation for a specific queue, most of the meta-data associated with that queue is stored in the underlying queue table. The following statement finds the queue table for a given queue (note that this is a multiple-consumer queue table). SQL> select QUEUE_TABLE from DBA_QUEUES where NAME = 'MULTIPLEQ';QUEUE_TABLE --------------------MULTIPLEQTABLE For a small amount of messages in a multiple-consumer queue table, the following query can be run: SQL> select MSG_STATE, CONSUMER_NAME, ADDRESS from AQ$MULTIPLEQTABLE where QUEUE = 'MULTIPLEQ';MSG_STATE CONSUMER_NAME ADDRESS-------------- ----------------------- -------------READY AQUSER2 [email protected] AQUSER1READY AQUSER3 AQADM.INQ In this example we see 2 messages ready to be propagated to remote queues and 1 that is not. If the address column is blank, the message is not scheduled for propagation and can only be dequeued from the queue upon which it was enqueued. The MSG_STATE column values are discussed in Document 102330.1 Advanced Queueing MSG_STATE Values and their Interpretation. If the address column has a value, the message has been enqueued for propagation to another queue. The first row in the example includes a database link (@M2V102.ES). This demonstrates that the message should be propagated to a queue at a remote database. The third row does not include a database link so will be propagated to a queue that resides on the same database as the source queue. The consumer name is the intended recipient at the target queue. Note that we are not querying the base queue table directly; rather, we are querying a view that is available on top of every queue table, AQ$<queue_table_name>.A more realistic query in an environment where the queue table contains thousands of messages is8.0.3-compatible multiple-consumer queue table and all compatibility single-consumer queue tables select count(*), MSG_STATE, QUEUE from AQ$<queue_table_name>  group by MSG_STATE, QUEUE; 8.1.3 and 10.0-compatible queue tables select count(*), MSG_STATE, QUEUE, CONSUMER_NAME from AQ$<queue_table_name>group by MSG_STATE, QUEUE, CONSUMER_NAME; For multiple-consumer queue tables, if you did not see the expected CONSUMER_NAME , check the syntax of the enqueue code and verify the recipients are declared correctly. If a recipients list is not used on enqueue, check the subscriber list in the AQ$_<queue_table_name>_S view (note that a single-consumer queue table does not have a subscriber view. This view records all members of the default subscription list which were added using the DBMS_AQADM.ADD_SUBSCRIBER procedure and also those enqueued using a recipient list. SQL> select QUEUE, NAME, ADDRESS from AQ$MULTIPLEQTABLE_S;QUEUE NAME ADDRESS---------- ----------- -------------MULTIPLEQ AQUSER2 [email protected] AQUSER1 In this example we have 2 subscribers registered with the queue. We have a local subscriber AQUSER1, and a remote subscriber AQUSER2, on the queue INQ, owned by AQADM, at M2V102.ES. Unless overridden with a recipient list during enqueue every message enqueued to this queue will be propagated to INQ at M2V102.ES.For 8.1 style and above multiple consumer queue tables, you can also check the following information at the target: select CONSUMER_NAME, DEQ_TXN_ID, DEQ_TIME, DEQ_USER_ID, PROPAGATED_MSGID from AQ$<queue_table_name> where QUEUE = '<QUEUE_NAME>'; For 8.0 style queues, if the queue table supports multiple consumers you can obtain the same information from the history column of the queue table: select h.CONSUMER, h.TRANSACTION_ID, h.DEQ_TIME, h.DEQ_USER, h.PROPAGATED_MSGIDfrom AQ$<queue_table_name> t, table(t.history) h where t.Q_NAME = '<QUEUE_NAME>'; A non-NULL TRANSACTION_ID indicates that the message was successfully propagated. Further, the DEQ_TIME indicates the time of propagation, the DEQ_USER indicates the userid used for propagation, and the PROPAGATED_MSGID indicates the message ID of the message that was enqueued at the destination. 6. Additional Troubleshooting Steps for Propagation in an Oracle Streams Environment 6.1. Is the Propagation Enabled? For a propagation job to propagate messages, the propagation must be enabled. For Streams, a special view called DBA_PROPAGATION exists to convey information about Streams propagations. If messages are not being propagated by a propagation as expected, then the propagation might not be enabled. To query for this: SELECT p.PROPAGATION_NAME, DECODE(s.SCHEDULE_DISABLED, 'Y', 'Disabled','N', 'Enabled') SCHEDULE_DISABLED, s.PROCESS_NAME, s.FAILURES, s.LAST_ERROR_MSGFROM DBA_QUEUE_SCHEDULES s, DBA_PROPAGATION pWHERE p.DESTINATION_DBLINK = NVL(REGEXP_SUBSTR(s.DESTINATION, '[^@]+', 1, 2), s.DESTINATION) AND s.SCHEMA = p.SOURCE_QUEUE_OWNER AND s.QNAME = p.SOURCE_QUEUE_NAME AND MESSAGE_DELIVERY_MODE = 'PERSISTENT' order by PROPAGATION_NAME; At times, the propagation job may become "broken" or fail to start after an error has been encountered or after a database restart. If an error is indicated by the above query, an attempt to disable the propagation and then re-enable it can be made. In the examples below, for the propagation named STRMADMIN_PROPAGATE where the queue name is STREAMS_QUEUE owned by STRMADMIN and the destination database link is ORCL2.WORLD, the commands would be:10.2 and above exec dbms_propagation_adm.stop_propagation('STRMADMIN_PROPAGATE'); exec dbms_propagation_adm.start_propagation('STRMADMIN_PROPAGATE'); If the above does not fix the problem, stop the propagation specifying the force parameter (2nd parameter on stop_propagation) as TRUE: exec dbms_propagation_adm.stop_propagation('STRMADMIN_PROPAGATE',true); exec dbms_propagation_adm.start_propagation('STRMADMIN_PROPAGATE'); The statistics for the propagation as well as any old error messages are cleared when the force parameter is set to TRUE. Therefore if the propagation schedule is stopped with FORCE set to TRUE, and upon restart there is still an error message in DBA_PROPAGATION, then the error message is current.9.2 or 10.1 exec dbms_aqadm.disable_propagation_schedule('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); exec dbms.aqadm.enable_propagation_schedule('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); If the above does not fix the problem, perform an unschedule of propagation and then schedule_propagation: exec dbms_aqadm.unschedule_propagation('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); exec dbms_aqadm.schedule_propagation('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); Typically if the error from the first query in Section 6.1 recurs after restarting the propagation as shown above, further troubleshooting of the error is needed. 6.2. Check Propagation Rule Sets and Transformations Inspect the configuration of the rules in the rule set that is associated with the propagation process to make sure that they evaluate to TRUE as expected. If not, then the object or schema will not be propagated. Remember that when a negative rule evaluates to TRUE, the specified object or schema will not be propagated. Finally inspect any rule-based transformations that are implemented with propagation to make sure they are changing the data in the intended way.The following query shows what rule sets are assigned to a propagation: select PROPAGATION_NAME, RULE_SET_OWNER||'.'||RULE_SET_NAME "Positive Rule Set",NEGATIVE_RULE_SET_OWNER||'.'||NEGATIVE_RULE_SET_NAME "Negative Rule Set"from DBA_PROPAGATION; The next two queries list the propagation rules and their conditions. The first is for the positive rule set, the second is for the negative rule set: set long 4000select rsr.RULE_SET_OWNER||'.'||rsr.RULE_SET_NAME RULE_SET ,rsr.RULE_OWNER||'.'||rsr.RULE_NAME RULE_NAME,r.RULE_CONDITION CONDITION fromDBA_RULE_SET_RULES rsr, DBA_RULES rwhere rsr.RULE_NAME = r.RULE_NAME and rsr.RULE_OWNER = r.RULE_OWNER and RULE_SET_NAME in(select RULE_SET_NAME from DBA_PROPAGATION) order by rsr.RULE_SET_OWNER, rsr.RULE_SET_NAME;   set long 4000select c.PROPAGATION_NAME, rsr.RULE_SET_OWNER||'.'||rsr.RULE_SET_NAME RULE_SET ,rsr.RULE_OWNER||'.'||rsr.RULE_NAME RULE_NAME,r.RULE_CONDITION CONDITION fromDBA_RULE_SET_RULES rsr, DBA_RULES r ,DBA_PROPAGATION cwhere rsr.RULE_NAME = r.RULE_NAME and rsr.RULE_OWNER = r.RULE_OWNER andrsr.RULE_SET_OWNER=c.NEGATIVE_RULE_SET_OWNER and rsr.RULE_SET_NAME=c.NEGATIVE_RULE_SET_NAMEand rsr.RULE_SET_NAME in(select NEGATIVE_RULE_SET_NAME from DBA_PROPAGATION) order by rsr.RULE_SET_OWNER, rsr.RULE_SET_NAME; 6.3. Determining the Total Number of Messages and Bytes Propagated As in Section 3.1, determining if messages are flowing can be instructive to see whether the propagation is entirely hung or just slow. If the propagation is not in flow control (see Section 6.5.2), but the statistics are incrementing slowly, there may be a performance issue. For Streams implementations two views are available that can assist with this that can show the number of messages sent by a propagation, as well as the number of acknowledgements being returned from the target site: the V$PROPAGATION_SENDER view at the Source site and the V$PROPAGATION_RECEIVER view at the destination site. It is helpful to query both to determine if messages are being delivered to the target. Look for the statistics to increase.Source: select QUEUE_SCHEMA, QUEUE_NAME, DBLINK,HIGH_WATER_MARK, ACKNOWLEDGEMENT, TOTAL_MSGS, TOTAL_BYTESfrom V$PROPAGATION_SENDER; Target: select SRC_QUEUE_SCHEMA, SRC_QUEUE_NAME, SRC_DBNAME, DST_QUEUE_SCHEMA, DST_QUEUE_NAME, HIGH_WATER_MARK, ACKNOWLEDGEMENT, TOTAL_MSGS from V$PROPAGATION_RECEIVER; 6.4. Check Buffered Subscribers The V$BUFFERED_SUBSCRIBERS view displays information about subscribers for all buffered queues in the instance. This view can be queried to make sure that the site that the propagation is propagating to is listed as a subscriber address for the site being propagated from: select QUEUE_SCHEMA, QUEUE_NAME, SUBSCRIBER_ADDRESS from V$BUFFERED_SUBSCRIBERS; The SUBSCRIBER_ADDRESS column will not be populated when the propagation is local (between queues on the same database). 6.5. Common Streams Propagation Errors 6.5.1. ORA-02082: A loopback database link must have a connection qualifier. This error can occur if you use the Streams Setup Wizard in Oracle Enterprise Manager without first configuring the GLOBAL_NAME for your database. 6.5.2. ORA-25307: Enqueue rate too high. Enable flow control DBA_QUEUE_SCHEDULES will display this informational message for propagation when the automatic flow control (10g feature of Streams) has been invoked.Similar to Streams capture processes, a Streams propagation process can also go into a state of 'flow control. This is an informative message that indicates flow control has been automatically enabled to reduce the rate at which messages are being enqueued into at target queue.This typically occurs when the target site is unable to keep up with the rate of messages flowing from the source site. Other than checking that the apply process is running normally on the target site, usually no action is required by the DBA. Propagation and the capture process will be resumed automatically when the target site is able to accept more messages.The following document contains more information:Document 302109.1 Streams Propagation Error: ORA-25307 Enqueue rate too high. Enable flow controlSee the following document for one potential cause of this situation:Document 1097115.1 Oracle Streams Apply Reader is in 'Paused' State 6.5.3. ORA-25315 unsupported configuration for propagation of buffered messages This error typically occurs when the target database is RAC and usually indicates that an attempt was made to propagate buffered messages with the database link pointing to an instance in the destination database which is not the owner instance of the destination queue. To resolve the problem, use queue-to-queue propagation for buffered messages. 6.5.4. ORA-600 [KWQBMCRCPTS101] after dropping / recreating propagation For cause/fixes refer to:Document 421237.1 ORA-600 [KWQBMCRCPTS101] reported by a Qmon slave process after dropping a Streams Propagation 6.5.5. Stopping or Dropping a Streams Propagation Hangs See the following note:Document 1159787.1 Troubleshooting Streams Propagation When It is Not Functioning and Attempts to Stop It Hang 6.6. Streams Propagation-Related Notes for Common Issues Document 437838.1 Streams Specific PatchesDocument 749181.1 How to Recover Streams After Dropping PropagationDocument 368912.1 Queue to Queue Propagation Schedule encountered ORA-12514 in a RAC environmentDocument 564649.1 ORA-02068/ORA-03114/ORA-03113 Errors From Streams Propagation Process - Remote Database is Available and Unschedule/Reschedule Does Not ResolveDocument 553017.1 Stream Propagation Process Errors Ora-4052 Ora-6554 From 11g To 10201Document 944846.1 Streams Propagation Fails Ora-7445 [kohrsmc]Document 745601.1 ORA-23603 'STREAMS enqueue aborted due to low SGA' Error from Streams Propagation, and V$STREAMS_CAPTURE.STATE Hanging on 'Enqueuing Message'Document 333068.1 ORA-23603: Streams Enqueue Aborted Eue To Low SGADocument 363496.1 Ora-25315 Propagating on RAC StreamsDocument 368237.1 Unable to Unschedule Propagation. Streams Queue is InvalidDocument 436332.1 dbms_propagation_adm.stop_propagation hangsDocument 727389.1 Propagation Fails With ORA-12528Document 730911.1 ORA-4063 Is Reported After Dropping Negative Prop.RulesetDocument 460471.1 Propagation Blocked by Qmon Process - Streams_queue_table / 'library cache lock' waitsDocument 1165583.1 ORA-600 [kwqpuspse0-ack] In Streams EnvironmentDocument 1059029.1 Combined Capture and Apply (CCA) : Capture aborts : ORA-1422 after schedule_propagationDocument 556309.1 Changing Propagation/ queue_to_queue : false -> true does does not work; no LCRs propagatedDocument 839568.1 Propagation failing with error: ORA-01536: space quota exceeded for tablespace ''Document 311021.1 Streams Propagation Process : Ora 12154 After Reboot with Transparent Application Failover TAF configuredDocument 359971.1 STREAMS propagation to Primary of physical Standby configuation errors with Ora-01033, Ora-02068Document 1101616.1 DBMS_PROPAGATION_ADM.DROP_PROPAGATION FAILS WITH ORA-1747 7. Performance Issues A propagation may seem to be slow if the queries from Sections 3.1 and 6.3 show that the message statistics are not changing quickly. In Oracle Streams, this more usually is due to a slow apply process at the target rather than a slow propagation. Propagation could be inferred to be slow if the message statistics are changing, and the state of a capture process according to V$STREAMS_CAPTURE.STATE is PAUSED FOR FLOW CONTROL, but an ORA-25307 'Enqueue rate too high. Enable flow control' warning is NOT observed in DBA_QUEUE_SCHEDULES per Section 6.5.2. If this is the case, see the following notes / white papers for suggestions to increase performance:Document 335516.1 Master Note for Streams Performance RecommendationsDocument 730036.1 Overview for Troubleshooting Streams Performance IssuesDocument 780733.1 Streams Propagation Tuning with Network ParametersWhite Paper: http://www.oracle.com/technetwork/database/features/availability/maa-wp-10gr2-streams-performance-130059.pdfWhite Paper: Oracle Streams Configuration Best Practices: Oracle Database 10g Release 10.2, http://www.oracle.com/technetwork/database/features/availability/maa-10gr2-streams-configuration-132039.pdf, See APPENDIX A: USING STREAMS CONFIGURATIONS OVER A NETWORKFor basic AQ propagation, the network tuning in the aforementioned Appendix A of the white paper 'Oracle Streams Configuration Best Practices: Oracle Database 10g Release 10.2' is applicable. References NOTE:102330.1 - Advanced Queueing MSG_STATE Values and their InterpretationNOTE:102771.1 - Advanced Queueing Propagation using PL/SQLNOTE:1059029.1 - Combined Capture and Apply (CCA) : Capture aborts : ORA-1422 after schedule_propagationNOTE:1079577.1 - Advanced Queuing Propagation Fails With "ORA-22370: incorrect usage of method"NOTE:1083608.1 - 11g Streams and Oracle SchedulerNOTE:1087324.1 - ORA-01405 ORA-01422 reported by Adavanced Queueing Propagation schedules after RAC reconfigurationNOTE:1097115.1 - Oracle Streams Apply Reader is in 'Paused' StateNOTE:1101616.1 - DBMS_PROPAGATION_ADM.DROP_PROPAGATION FAILS WITH ORA-1747NOTE:1159787.1 - Troubleshooting Streams Propagation When It is Not Functioning and Attempts to Stop It HangNOTE:1165583.1 - ORA-600 [kwqpuspse0-ack] In Streams EnvironmentNOTE:118884.1 - How to unschedule a propagation schedule stuck in pending stateNOTE:1203544.1 - AQ PROPAGATION ABORTED WITH ORA-600[OCIKSIN: INVALID STATUS] ON SYS.DBMS_AQADM_SYS.AQ$_PROPAGATION_PROCEDURE AFTER UPGRADENOTE:1204080.1 - AQ Propagation Failing With ORA-25329 After Upgraded From 8i or 9i to 10g or 11g.NOTE:219416.1 - Advanced Queuing Propagation fails with ORA-22922NOTE:222992.1 - DBMS_AQADM.DISABLE_PROPAGATION_SCHEDULE Returns ORA-24082NOTE:253131.1 - Concurrent Writes May Corrupt LOB Segment When Using Auto Segment Space Management (ORA-1555)NOTE:282987.1 - Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueNOTE:298015.1 - Kwqjswproc:Excep After Loop: Assigning To SelfNOTE:302109.1 - Streams Propagation Error: ORA-25307 Enqueue rate too high. Enable flow controlNOTE:311021.1 - Streams Propagation Process : Ora 12154 After Reboot with Transparent Application Failover TAF configuredNOTE:332792.1 - ORA-04061 error relating to SYS.DBMS_PRVTAQIP reported when setting up StatspackNOTE:333068.1 - ORA-23603: Streams Enqueue Aborted Eue To Low SGANOTE:335516.1 - Master Note for Streams Performance RecommendationsNOTE:353325.1 - ORA-24056: Internal inconsistency for QUEUE and destination NOTE:353754.1 - Streams Messaging Propagation Fails between Single and Multi-byte Charactersets when using Chararacter Length Semantics in the ADT.NOTE:359971.1 - STREAMS propagation to Primary of physical Standby configuation errors with Ora-01033, Ora-02068NOTE:363496.1 - Ora-25315 Propagating on RAC StreamsNOTE:365093.1 - ORA-07445 [kwqppay2aqe()+7360] reported on Propagation of a Transformed MessageNOTE:368237.1 - Unable to Unschedule Propagation. Streams Queue is InvalidNOTE:368912.1 - Queue to Queue Propagation Schedule encountered ORA-12514 in a RAC environmentNOTE:421237.1 - ORA-600 [KWQBMCRCPTS101] reported by a Qmon slave process after dropping a Streams PropagationNOTE:436332.1 - dbms_propagation_adm.stop_propagation hangsNOTE:437838.1 - Streams Specific PatchesNOTE:460471.1 - Propagation Blocked by Qmon Process - Streams_queue_table / 'library cache lock' waitsNOTE:463820.1 - Streams Combined Capture and Apply in 11gNOTE:553017.1 - Stream Propagation Process Errors Ora-4052 Ora-6554 From 11g To 10201NOTE:556309.1 - Changing Propagation/ queue_to_queue : false -> true does does not work; no LCRs propagatedNOTE:564649.1 - ORA-02068/ORA-03114/ORA-03113 Errors From Streams Propagation Process - Remote Database is Available and Unschedule/Reschedule Does Not ResolveNOTE:566622.1 - ORA-22275 when propagating >4K AQ$_JMS_TEXT_MESSAGEs from 9.2.0.8 to 10.2.0.1NOTE:727389.1 - Propagation Fails With ORA-12528NOTE:730036.1 - Overview for Troubleshooting Streams Performance IssuesNOTE:730911.1 - ORA-4063 Is Reported After Dropping Negative Prop.RulesetNOTE:731292.1 - ORA-25215 Reported On Local Propagation When Using Transformation with ANYDATA queue tablesNOTE:731539.1 - ORA-29268: HTTP client error 401 Unauthorized Error when the AQ Servlet attempts to Propagate a message via HTTPNOTE:745601.1 - ORA-23603 'STREAMS enqueue aborted due to low SGA' Error from Streams Propagation, and V$STREAMS_CAPTURE.STATE Hanging on 'Enqueuing Message'NOTE:749181.1 - How to Recover Streams After Dropping PropagationNOTE:780733.1 - Streams Propagation Tuning with Network ParametersNOTE:787367.1 - ORA-22275 reported on Propagating Messages with LOB component when propagating between 10.1 and 10.2NOTE:808136.1 - How to clear the old errors from DBA_PROPAGATION view ?NOTE:827184.1 - AQ Propagation with CLOB data types Fails with ORA-22990NOTE:827473.1 - How to alter propagation from queue_to_queue to queue_to_dblinkNOTE:839568.1 - Propagation failing with error: ORA-01536: space quota exceeded for tablespace ''NOTE:846297.1 - AQ Propagation Fails : ORA-00600[kope2upic2954] or Ora-00600[Kghsstream_copyn]NOTE:944846.1 - Streams Propagation Fails Ora-7445 [kohrsmc]

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• Internal disk not correctly recognised by Windows 7

  - by david

  i'm having problems configuring a disk in a brand new, clean windows-7 install. here are some system specifics- . disk- western digital velociraptor wd6000hlhx . mobo- gigabyte z77x-ud3h . bios sata-mode set to ahci [not raid], w/disk connected to sata0 [6gb/s hi-speed sata]. . windows 7 enterprise sp1 x64 the disk is recognized by bios and correctly identified [name & size ok]. the disk is also recognized by windows on a h/w level, but it won't show up in the explorer. windows reports the device is working correctly. windows disk manager shows the drive, but says it's uninitialized and has no partitions [which is incorrect]. if i try to initialize the drive, windows throws an error saying that it "cannot find the file specified". [which file???] before connecting the drive to the new machine, i partitioned and formatted the disk under windows xp sp2, giving it 2 partitions [mbr, not gpt] and copying over a boatload of data. obviously none of this appears under windows 7. removing the disk from the new machine and replacing it back in the windows xp machine shows the disk and all data are intact and functional. i'd like to have windows 7 recognize the disk w/o having to lose the data and start over. is this possible? if so, how would i do that? I checked this post, but even though the problem seems identical, the information didn't help. any help appreciated. thanks!

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• Windows 2003 DNS or IIS6 Problem?

  - by Mario

  Weird DNS problem... We have an intranet located internally on a windows 2003 / iis6 server - DNS handled internally on another windows 2003 server. The intranet, amongst other functions, hosts a ecommerce store I wrote that sells nike apparel embroidered with our company logo. Up until recently, it would send an email to payroll and the cost would be deducted from the employees paycheck. lets say this store is located at http://mydomain.com (only available internally) Now, we've been told by the accountants that we can no longer auto deduct from payroll and the employee needs to pay with a credit card or cash. So i went to thawte.com and ordered an SSL cert to be on the safe side (even though the CC gateway is secure) and they told me i need to drop the .com from the domain name Not wanting to mess with a system thats perfectly functional, i created another DNS entry that just points to mydomain (no .com) and left the old one in there. so they would go to http://mydomain On my Mac (OS X 10.6) i can hit either one just fine On Windows XP / Windows XP Embedded or Windows 7 (the vast majority of the pc's on our network) http://mydomain - returns nothing http://mydomain.com still works https://mydomain.com works but says the cert is invalid (as it should, it was issued to mydomain - not mydomain.com) my question is: why does it work on my Mac and not on a Windows PC (i get dhcp and dns just like any other pc on the network) and will removing the .com one from the DNS server resolve this? I've done all the usual attempts - ipconfig /flushdns, ipconfig /renew and release even going so far as to stop and restart DNS client on my Windows 7 box; rebooting and shutting down - adding a regedit entry something along the lines of SecureResponses and rebooting nothing works... I think its the .com and the not conflicting in DNS but i'm not sure - and why not on OS X We're closed on sunday and i'm going to remote in and see what happens if i remove the .com from DNS but any other ideas? -Mario

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• How many users can be in a AD LDS group?

  - by ixe013

  Microsoft published the recommended maximum limits for users in an Active Directory group. It basically says : Starting with Windows Server 2003, the ability to replicate discrete changes to linked multivalued properties was introduced as a technology called Linked Value Replication (LVR). and This allows the number of group memberships to exceed the former recommended limit of 5,000 for Windows 2000 or Windows Server 2003 at a forest functional level of Windows 2000. Given the replication meta data below, can anybody tell me what is the maximum number of users a AD-LDS group can hold ? Getting 'CN=Member,CN=Schema,CN=Configuration,CN={67B333FE-ADB4-430D-AAEE-D4CCE4B98A2E}' metadata... 23 entries. AttID Ver Loc.USN Originating DSA Org.USN Org.Time/Date ===== === ======= =============== ======= ============= 0 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 3 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 20001 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 20002 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 2001e 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 20020 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 20021 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 20032 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 200a9 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 200c2 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 200da 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 200e2 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 200e7 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 20119 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 2014e 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 201cc 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 90001 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 90094 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 90095 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 900aa 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 90177 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 9027f 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49 9030e 1 95 8ba30efb-9aa4-4e55-8f7c-268e3dcc536b 95 2012-07-17 14:25:49

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• Nginx with PAM authentication through pam_script

  - by Envek

  Have anyone set up such a configuration? It's not work for me. So, I've installed nginx-extras on Ubuntu 12.04 (it's built with PAM module), and write to site config: location ^~ /restricted_place/ { auth_pam "Please specify login and password from main_site"; auth_pam_service_name "nginx"; } Afterwards, in /etc/pam.d/nginx: auth required pam_script.so dir=/path/to/my/auth_scripts And wrote simplest /path/to/my/auth_scripts/pam_script_auth (also I've tried to write complicated scripts) #!/bin/sh exit 0 # should allow anyone Doesn't work. The script is launched (I've wrote full functional script, that successfully executes, check credentials, writes to its own log and returns correct exit code, and executes noticeably long). But no access granted. Only rejected. In /var/log/nginx/error.log appears next record: 2012/09/13 10:44:42 [alert] 1666#0: waitpid() failed (10: No child processes) If I'm specify in /etc/pam.d/nginx: auth required pam_unix.so and grant for www-data user right to read /etc/shadow, unix authorization works fine. But script auth doesn't work. Can't understand, where is trouble. In nginx module, or in pam_script module.

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• What do I need in order to extract and combine text files from multiple ZIP files, via command line?

  - by Iszi

  I've got an interesting scripting challenge in front of me. I'm fairly certain there's a way to do it, but I feel like I'm probably lacking some particular tools and/or functional knowledge. There's some fifty-plus ZIP files that each contain, among other things, text files that need to be merged with one another. The structure is something like this: C:\Reports\FirstJob-1.zip |-MyName |-FirstJob |-1 |-[Some other folders] |-TXTReports |-English |-[Some other files] |-Report.txt C:\Reports\FirstJob-2.zip |-MyName |-FirstJob |-1 |-[Some other folders] |-TXTReports |-English |-[Some other files] |-Report.txt C:\Reports\SecondJob-1.zip |-MyName |-SecondJob |-1 |-[Some other folders] |-TXTReports |-English |-[Some other files] |-Report.txt If I had all the Report.txt files in one regular folder, and uniquely named, I could probably just write a FOR statement that targets *.txt and runs something like type filename.txt >> Consolidated.txt on each. However, these all have the same file name and are embedded deep within separate ZIP files. The potentially useful tools I currently have at my disposal are Windows XP Professional SP3, PowerShell, and WinZip. I'd rather not download or install anything else, but I do understand that third-party tools (or additional tools from Microsoft or WinZip) may be necessary. Whatever tools I use should run natively in Windows. I really don't want to have to mess with Cygwin or other emulators on this system. At the very least, I need a tool that will allow me to analyze and manipulate ZIP files from the command line. Also, are there any other particular complications to this that I've not yet thought of?

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• Domino to Exchange 2007 (or 2010) Design Concerns?

  - by NickToyota

  Today we got the executive green light to proceed with changing from a Domino platform to Exchange. The business prefers Exchange for a messaging platform. (even though IMO IBM Domino is fine - if it aint broke, don't fix it but it was not my call). I have been put in charge of Domino to Exchange process goes smoothly as possible. I have also been told to put together costs for this project. I have some questions and concerns re: network design, licensing, costs: The current setup is as follows. 1 HQ office (100 users), 1 secondary office (50 users), 5 branch offices (under 10 users). 5 different email domains Windows Server 2003 functional level with a few 2008 R2 Servers Lotus Domino Notes Servers (one in each office) Ironmail Appliance Public Domino Web Mail server Majority G5+ Proliant Servers Domino Blackberry Enterprise license and server No VoIP phones What are the basic hardware requirements for Exchange 2007 or 2010? Can I simply purchase a single physical server? Will each office require an Exchange server or possibly additional servers (roles)? How is email routed to the smaller branch offices? Standard or Enterprise licenses? The business has been running Domino (messaging and application services) for over 10 years and also want Exchange to support email services, Blackberry, Outlook Web Access, possibly support for iPhone devices. Thank you Serverfault universe.

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• Getting a TTY in a Connectback Shell

  - by Asad R.

  I'm often asked by friends to help with small Linux problems, and more often than not I'm required to login to the remote system. Usually there are a lot of issues with making an account and logging in (sometimes the box is behind a NAT device, sometimes SSHD isn't installed, etc.) so I usually just ask them to make a connect-back shell using netcat (nc -e /bin/bash ). If they don't have netcat I can just ask them to grab a copy of a statically compiled binary which isn't that hard or time consuming to download and run. Though this works well enough for me to enter simple commands, I can't run any apps that require a tty (vi, for example) and can't use any job control functions. I managed to bypass this issue by running in.telnetd with a few arguments within the connect-back shell that would assign me a terminal and drop me to a shell. Unfortunately in.telnetd isn't usually installed by default on most systems. What's the easiest way to get a fully functional connect-back terminal shell without requiring any non-standard packages? (A small C program that does the job would be fine as well, I just can't seem to find much documentation on how a TTY is assigned/allocated. A solution that doesn't require me to plough through the source code for SSHD and TELNETD would be nice :))

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• DFS replication and the SYSTEM user (NTFS permissions)

  - by HopelessN00b

  Question for which I'm having trouble finding an answer on Google or Technet... Does granting the SYSTEM user permissions to DFS-shared files and folders have any effect on DFS replication? (And while we're at it, is there any good reason not to let SYSTEM have permissions to DFS-shared files?) It comes up because I have a collection of DFS namespaces and folders that I'm not able to make someone else's problem, and while troubleshooting a problem where one DFS replica just wasn't replicating with another for no discernible reason, I observed that the SYSTEM didn't have any permissions granted to any of the files or folders in the folder in question. So I set SYSTEM to have full control and propagated it down, and our DFS health diagnostic reports went from showing a backlog of ~80 files to a backlog of ~100,000... and things started replicating, including a number of files that had been missing on one server or the other (so more than just the permissions changes started replicating). Naturally, this made me curious as to whether or not DFS needs the SYSTEM account to have permissions to do its work, or if perhaps it was just any change to folder tree in question that prompted DFS to jump into action. If it matters, our DFS namespaces were set up under 2000/2003, and I have just recently finished upgrading all the servers to 2008 R2 or 2012 (with UAC enabled, blech), but have not yet gotten around to raising the DFS namespace functional levels to Server 2008. (And bonus points if anyone has an official Microsoft article on NTFS file permissions and the SYSTEM account as it pertains to DFS or network files.)

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• How do I switch java versions to an earlier version in Fedora 17?

  - by JHutson456

  I just installed Fedora 17. I'm setting up the Android Build Environment and need Java. I downloaded and installed jdk-6u32-linux-amd64.rpm I ran java -version and it spit out the correct version. Well a day or two later i tried my first compile in Fedora 17 and it complained about java and failed. I ran java -version again and low and behold it spits out $ java -version java version "1.7.0_03-icedtea" OpenJDK Runtime Environment (fedora-2.1.fc17.7-x86_64) OpenJDK 64-Bit Server VM (build 22.0-b10, mixed mode) I'm stumped. I mean, i've run the update/upgrade commands since i installed but i didn't think that updated full version revisions... So, I ran alternatives --config java and that only gave me the java 1.7 version. While digging around more I discovered that the recommended version of Java for the build environment is jdk-6u27-linux-x64-rpm.bin so I downloaded that from here: Oracle Download When I ran: sudo sh jdk-6u27-linux-x64-rpm.bin it returned: Unpacking... Checksumming... Extracting... UnZipSFX 5.50 of 17 February 2002, by Info-ZIP ([email protected]). inflating: jdk-6u27-linux-amd64.rpm inflating: sun-javadb-common-10.6.2-1.1.i386.rpm inflating: sun-javadb-core-10.6.2-1.1.i386.rpm inflating: sun-javadb-client-10.6.2-1.1.i386.rpm inflating: sun-javadb-demo-10.6.2-1.1.i386.rpm inflating: sun-javadb-docs-10.6.2-1.1.i386.rpm inflating: sun-javadb-javadoc-10.6.2-1.1.i386.rpm Preparing... ########################################### [100%] package jdk-2000:1.6.0_32-fcs.x86_64 (which is newer than jdk-2000:1.6.0_27-fcs.x86_64) is already installed Done. so now I'm confused. I ran: alternatives --config java again but it's still only returning 1.7 so I don't know what to do.I want to end up with 6u27 as the installed and functional version of the JDK. Thank you.

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• Ubuntu rm not deleting files

  - by ILMV

  My colleague and I have been struggling with deleting a directory and its contents. We are working on a new version of our websites source code on Ubuntu 8.04 (dir: /var/www/websites), what we want to do is delete the websites directory and recreate it from a .tar backup we created a couple weeks ago. The purpose of this is so we can run our deployment procedure in a local environment before we do so on our live / public environment. We use this command: rm -r websites This deletes the directory and the files within it. The problem occurs when we un-tar our backup file and view the website we are getting files that don't exist in the .tar backup, in fact these files were only created a few days ago and should have been deleted. We delete the directory once more in the manner stated above, we then create a new websites directory using the mkdir command. Strangely at this stage the 'deleted files' do not come back, but if we unpack our .tar file the 'deleted files' appear again. Is there a way to ensure these files are deleted, or at least the pointers that associate them with said directory. Our .tar backup does not include these files We do not want to use the shred command We do not want to use 3rd party applications Solution should be functional via terminal (SSH) Many thanks! EDIT Er... we fixed it. Turns out the files that are reappearing are because of a link we have to another directory (outside the /var/www/websites), we were restoring the link but not deleting the files on the other end. D'oh! Many thanks for your help guys... friday afternoon syndrome :-)

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• How can I get my routers to forward ports correctly?

  - by Giffyguy

  My network currently looks like this (simplified): Note that Router #2 is connected to the LAN interface of Router #1. This should be familiar to anyone who has seen a standard static-IP setup with an additional firewall for a residence or other small building. Router #1 is actually my cable gateway, but since it is a fully functional router/firewall, I am going to refer to it as a router. Now, I need to open various ports in both firewalls for incoming communication to my server - port 80 is a good example. So I've opened up port 80 in Router #2, and so far all incoming traffic at the public IP X.X.X.129 is being routed correctly. The problem is that I also need my server to respond to incoming traffic at the public IP X.X.X.130 on the WAN interface of Router #1. Naturally, I can't just tell Router #1 to forward port 80 to another public IP. Port forwarding is only supported when the traffic is being directed to the LAN subnet. I am willing to restructure my network topology if required, with the following conditions: Router #1 cannot have its WAN IP reassigned - X.X.X.130 is mandatory. Router #1 cannot be moved or disconnected from the cloud. The server cannot be given a second IP address. I would prefer the server to have a private IP address - e.g. 10.0.0.10 I'd like to keep Router #2, but it can have a private IP - e.g. 10.0.1.10 Following these rules, I need to get my server to receive incoming traffic on port 80 from both public IP addresses. Does anyone on SU know if this is possible? So far my only theories have been to set up a static route on either router, or to somehow combine my two subnets into a single subnet.

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• Fast Ethernet module for Cisco 2620

  - by Kenny Rasschaert

  I have a Cisco 2620 Router. It comes with one fast ethernet port built in (circled in red), and one old AUI ethernet module is installed (circled in blue). I figure I can put a transceiver on the AUI interface to get a second RJ45 connector. What I'd really like to have is a second fast ethernet connector. The ideal candidate to achieve this would be the NM-1FE-TX module. Cisco claims on their website that this module is not suitable for the Cisco 2620 and Cisco 2620XM. It says so in "Table 2 Physical Limitation of Serial Modules per Chassis". Indeed, this module was designed for the 3600 series of routers. I've seen claims on the internet, however, of people having this module on a 2620XM, and it being fully functional. This claim gains some credibility because of the fact that in Cisco's own Packet Tracer software, you can install this module on the 2620XM router. I'm looking for a definitive answer. Will this module work on a Cisco 2620? Is there perhaps another way to get a second fast ethernet port on this device?

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• How to restore broken Ethernet functionality on Mac G5 running Mac OS 10.4.11 (Tiger)

  - by willc2

  I had a disk error that rendered my Mac unbootable. I repaired it with Tech Tool 4, but now networking does not work. Network Preferences reports that my Ethernet cable is unplugged. I know this is bogus because when I boot from an emergency partition, networking works correctly. Furthermore, wireless networking is also broken, which I tested with a known-good Wi-Fi dongle. Whenever I try to change Network Port Configurations by creating a New or Renaming an existing one, example: I get this message in the console: Error - PortScanner - setDevice, device == nil! Error - PortScanner - setDevice, device == nil! In sets of two as shown. When I try to invoke the Network Diagnostics app, it immediately crashes. My first thought is to reinstall Tiger with the Archive and Install method so I don't have to reinstall all my applications but I have lost my Tiger installer disk. My next thought is to buy Leopard for $107 on Amazon. If there is any way I can just repair my Tiger install I would be happy to save that money, though. This is not my main machine and I am loathe to put more money into it. How can I recover my network functionality? UPDATE: I found my Tiger install disk and tried an Archive and Install. It failed with an unhelpful error message along the lines of "Can't install, try again". I tried again but had the same error. My guess is, some corrupt or missing file in my User folder is preventing migration. I have a backup created with Super Duper that is a bit out of date but will startup the machine (with functional networking). I would love to just copy over the file(s) that got messed up but I don't even know where to look. What is the likely location of the System files that would cause the aforementioned symptoms?

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• Password Policy seems to be ignored for new Domain on Windows Server 2008 R2

  - by Earl Sven

  I have set up a new Windows Server 2008 R2 domain controller, and have attempted to configure the Default Domain Policy to permit all types of passwords. When I want to create a new user (just a normal user) in the Domain Users and Computers application, I am prevented from doing so because of password complexity/length reasons. The password policy options configured in the Default Domain Policy are not defined in the Default Domain Controllers Policy, but having run the Group Policy Modelling Wizard these settings do not appear to be set for the Domain Controllers OU, should they not be inherited from the Default Domain policy? Additionally, if I link the Default Domain policy to the Domain Controllers OU, the Group Policy Modelling Wizard indicates the expected values for complexity etc, but I still cannot create a new user with my desired password. The domain is running at the Windows Server 2008 R2 functional level. Any thoughts? Thanks! Update: Here is the "Account policy/Password policy" Section from the GPM Wizard: Policy Value Winning GPO Enforce password history 0 Passwords Remembered Default Domain Policy Maximum password age 0 days Default Domain Policy Minimum password age 0 days Default Domain Policy Minimum password length 0 characters Default Domain Policy Passwords must meet complexity Disabled Default Domain Policy These results were taken from running the GPM Wizard at the Domain Controllers OU. I have typed them out by hand as the system I am working on is standalone, this is why the table is not exactly the wording from the Wizard. Are there any other policies that could override the above? Thanks!

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• Kernel hacking methodology - how to find out where to hack the linux kernel

  - by Flavius

  I have a throw-away cheap laptop I'd like to twiddle around, a Thinkpad SL 500. What bothers me are two leds, the one for wireless connectivity, and the one for hibernation, which don't light up at all, although they're functional, I've tried it on windows. So I would like to write a kernel driver for them, nothing big, it just looks like a good idea to play around with the kernel. My question is what methodology should I follow systematically to find out what devices are responsible for those leds (in general, not necessarily specific to my hardware), and what drivers are responsible for the other two leds that work, bluetooth and the battery indicator? And when I say methodology, I really mean the methodology, step by step, with reasons for each step, like in the answer I've gave to someone else over here: What does && mean in void *p = &&abc; I am profficient at fgrepping through big code repositories, using static code analysers & co, but I think my lack of hardware knowledge hinders me on this problem. PS: I'm using ArchLinux, so almost the latest kernel version.

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• Diagnosing SAN connectivity issues (RHEL5)

  - by Matthew

  We are currently utilizing GFS2 to share a SAN LUN between 3 servers. However due to a feature problem with vendor software we are using, we currently have the volume unmounted on two of the boxes, and are instead exporting the GFS2 filesystem via NFS from the first one (the software requires some weird locking mechanics that GFS2 doesn't support). As of this morning, NFS was no longer able to read/write to the volume from any of the servers, including the NFS server. I then tried checking the normal mount (the directory that is exported on the NFS server) and I received a weird input/output error just trying to CD into it. When I tried running multipath, I got a DM error, however multipath -l worked just fine. I tried unmounting the GFS2 volume, and the CLI hung. I ran init 0 which killed most services, but then the shutdown appeared to have been hung. I logged in via out of band access (hp ILO) and saw that the shutdown was hung trying to unmount GFS2 volumes. My main priority was getting the box back online so after about 5 minutes of waiting I did a hard reset. I am now trying to figure out what went wrong. What are the correct logs to investigate? I've never run into SAN issues like this before. The SAN is connected via 2 fibre connections. Any help would really be appreciated. Everything appears to be up and functional now.

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• Virtual machines interconnection inside Proxmox 2.1 Cluster

  - by Anton

  We have 3 physical servers (each with 1 NIC) in different datacentres, all of them are interconnected by openvpn bridged private network (10.x.x.x). Inside this network we have fully functional 3 nodes Proxmox 2.1 cluster. So, actually question is: Is there any "proper" way to make "global" local network (172.16.x.x) for all VMs inside cluster, so even if we move VM from one node to other we could reach it by static IP regardless of it's physical location? BTW, we can't add dedicated NIC to each server. Thanks in advance. EDIT: I have tried to make a separate openvpn bridge for 172.16.x.x, now I have at each server two interfaces: SRV1: openvpnbr1 - 172.16.13.1 vmbr0 - 172.16.1.1 SRV2: openvpnbr1 - 172.16.13.2 vmbr0 - 172.16.2.1 But now there is no connection between those ifaces: SRV1: ping 172.16.13.2 From 172.16.1.1 icmp_seq=2 Destination Host Unreachable SRV2: ping 172.16.13.1 From 172.16.2.1 icmp_seq=2 Destination Host Unreachable If I shut down vmbr0 interfaces, so there is connection between servers over openvpn, but vmbr0 is used by Proxmox... Where I am wrong?

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• Cisco Pix 515 ip addressing

  - by Rickard

  I have just gotten my hands on a Cisco Pix 515 (not 515E) with 3 interfaces, and are just about to start some labs. In my lab, I am using a real life scenario from an actual setup at work. As I have no access to the device at work, I am simply trying to replicate the scenario by trial and error. At work, we are given two IP addresses from the provider, which is 1-to-1 nated addresses. The addresses we are allowed to use are: 10.131.35.4-5/29 Now, we have 3 servers on a DMZ, 192.168.2.2-4/24 and 17 client computers on 192.168.1.100-117/24 aswell as some static addressed devices on 192.168.1.8-18/27 My question is, how would I best set up so that the machines on the DMZ get's translated to 10.131.35.4 and the machines on 192.168.1.* will be translated to 10.131.35.5 I don't expect or want anyone to give me a fully functional config, I may learn from it, but I'd prefer to just have some advices or maybe a guide on how to set it up. I hope someone can shed some light over my situation, have been looking through google but I guess I don't the searchwords I'm using isn't too good as I can't find any good clues. THank you very much! PS. Maybe I should add, I am not unfamiliar with the Cisco CLI, as I prefer using that before any gui's. So not really looking for any solutions for the ASDM. DS.

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• In spite of correct DNS, Exchange sending to wrong destination server for single outbound domain

  - by beporter

  My company uses an SBS 2003 server and makes use of Exchange to host our own email. We also have a linux server hosting domains for some of our clients. In order for us to send to those clients, we had internal DNS set up to shadow the client domains to provide "correct" MX records inside our network. For example, public DNS for a domain abc.com might point to 1.2.3.4, but internally we have MX records set up to route mail for abc.com to 172.16.0.4, which is the linux email server. This setup was entirely functional; this is just back story. We've recently moved one of our client domains from our internal linux server to an external email provider. When we did that, we naturally deleted our internal shadow DNS records so our Exchange server would fetch correct (public) DNS records and route mail out to the new external host. This has NOT had any effect on Exchange though. Even after rebooting the Exchange server and completely flushing the DNS cache (nslookups on the Exchange machine itself correctly resolve to the new external address) Exchange still attempts to deliver messages for the domain to our internal server! Exchange correctly routes to all other internal and external domains when sending email. Somehow Exchange is trying to deliver to a machine that by all accounts it has no business trying to use for just this one domain. Is there a DNS cache that Exchange uses internally? Is there a way to flush that internal cache? What else could I be missing?

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