synchronization

问题 In the following console application, if I place a breakpoint on the last line Go(); and execute till breakpoint (in debug mode) by pressing F5, the results are not quite different on each run. Console can be blank (does not output anything): or it can output just part of the results on another run: or, on very rare occasions, the results are "complete" ("actualized"): If I debug by F10 (Step Over) or F11 (Step into), the results of executing are output into console window immediately. Why

问题 I am learning MPI-2 and trying to implement the first simple functionality using MPI-2 one-sided-communication: Have process 0 host one array of fixed size data_size . Each process (including 0) will generate an array and compare with the host array: If the first element of the generated array is smaller than that of the host array, replace the host array with the generated one. In code: vector<int> v1 = {rank,rank+1,rank+2}; v = get_vec(vec); if (v1[0] < v[0]) put_vec(vec,v1); The complete

问题 So I have this little code: public class MyCounterClass { private static int counter = 0; synchronized public static int getCounter(){ return counter++; } } This is the server: public class MyServer implements Runnable{ public static void go() throws IOException { System.out.println("MyServer: Go called..."); ServerSocket serverSocket = new ServerSocket(5000); while(true){ Socket socket = serverSocket.accept(); System.out.println(time() + "MyServer: Connection accepted!"); OutputStream

问题 Amazon php sdk (http://docs.aws.amazon.com/aws-sdk-php/v3/guide/service/s3-transfer.html) sync operations are performed using the above linked methods. I've successfully coded and configured them, but on each call for the method the last modified date on files under the bucket gets updated to the latest time, given that the files were not modified locally to the previous sync call. I wonder whether is it a sync operation at all or just overwriting operation of whatever is sent from the local

问题 I am creating data on several machines, processing the data in parallel, and then aggregating to a separate machine. What is the best way to sort the aggregated data by creation time, accurate to say, +/- 5 seconds? If all of the machines have their system time synchronized via NTP, is tacking on an integer timestamp, from the UNIX epoch, on each source machine, going to be reliable enough? 回答1: After puzzling over this for a very short time, the best technique I can think of so far would be

问题 I need a timer equivalent which will periodically execute some specific actions (e.g. updating some progress in the database or checking for new Jobs to execute in a database). These actions are bound to a WaitHandle which specifies if the job needs to be executed or not. So basically this could be, for example, an AutoResetEvent which is set from outside when there is a new Entity in a database and trigger the search for these new Entities. The timer is necessary because I want to limit the

问题 I hope you will be able to help me in my trouble. My program is doing something I don't really understand. The program purpose is given as below: Create two threads (task_timer and task_read). These threads have to display on the standard output (stdout) the following message : "Tache 1 Tache 2 Tache 1 Tache 2 ..." Code : static void* task_timer(void* arg); static void* task_read(void* p); struct strShared{ pthread_mutex_t mut; pthread_mutex_t mut2; pthread_cond_t synchro; pthread_cond_t

问题 I want to sync my MongoDB data to ElasticSearch , I read a lot of posts talking about elasticsearch river plugin and mongo connector, but all of them are deprecated for mongo 4 and elasticsearch 7! As logstash is a proprietary software I would like to use it to sync both... Anyone knows how it's possible to do it? 回答1: You may sync MongoDB and Elasticsearch with Logstash; syncing is, in fact, one of the major applications of Logstash. After installing Logstash, all that you need to do is

问题 I'm playing around with asyncio module of Python and I don't know what's the problem with my simple code. It doesn't execute the tasks asynchronously. #!/usr/bin/env python3 import asyncio import string async def print_num(): for x in range(0, 10): print('Number: {}'.format(x)) await asyncio.sleep(1) print('print_num is finished!') async def print_alp(): my_list = string.ascii_uppercase for x in my_list: print('Letter: {}'.format(x)) await asyncio.sleep(1) print('print_alp is finished!')

问题 I want to sync 2 database specific records. Let suppose I have two databases; 1.Shop 2.Stock Now lets suppose user change the price of a specific product in stock. I want to change this product price in shop also! What I work out is that - assuming Internet connection is stable, When price change in stock I invoke a web service this service will insert entries in web data table price. Now on shop side I ping that web data table using web service every 20 minutes if I find any new entry I