synchronization

问题 SQL Server is not my strong point and I start to get lost when going past the basic Create Table, Select from Table etc. I am attempting to set up a database synchronisation scenario with an Microsoft SQLCompact 3.5 database being Synced through a Proxy to and SQL 2008 R2 database. It is being synced through the Microsoft Sync Framework 2.1. I got everything set up and working fine through the proxy when the user account is the db_owner of the database. Of course this now needs to be locked

问题 Consider the following method: public void add(final List<ReportingSTG> message) { if(stopRequested.get()) { synchronized (this) { if(stopRequested.get()) { retryQueue.put(message); } } } messages.add(message); if(messages.size() >= batchSize && waitingThreads.get() == 0) { synchronized (this) { if(messages.size() >= batchSize && waitingThreads.get() == 0) { final List<List<ReportingSTG>> clone = new ArrayList<List<ReportingSTG>>(messages); messages.clear(); if(processors.size()>

问题 A countdown latch (a.k.a. CountDownLatch) is a synchronization primitive that ensures that all of the used resources are released before the primitive is destroyed. It is like a QSemaphore , but working in reverse: we want to block not to acquire a resource, but to ensure that all of them have been released. What would be an easy way to implement it in Qt? 回答1: Here's an implementation that leverages QSemaphore : // https://github.com/KubaO/stackoverflown/tree/master/questions/countdown-latch

问题 I saw a snippet of code in this question which I could not understand (most probably due to the fact am a beginner in this area). The question talks about "an obvious race condition where sometimes the producer will finish, signal it, and the ConsumerWorkers will stop BEFORE consuming everything in the queue." In my understanding, "isRunning" will be set on the consumers only after the producer decides not to add anymore items in the queue. So, if a consumer thread sees isRunning as FALSE AND

问题 I need to solve Producer-Consumer problem in c++ using primitive synchronization objects - events, I already wrote this code static int g_x = 0; HANDLE hEvent1; HANDLE aThread[2]; DWORD ThreadID; //tread 1 void Producer() { for (int i = 0; i < 100; ++i) { WaitForSingleObject(hEvent1, INFINITE); g_x = i; SetEvent(hEvent1); } } //thread 2 void Consumer() { for (;;) { WaitForSingleObject(hEvent1, INFINITE); SetEvent(hEvent1); } } int createthreads() { hEvent1 = CreateEvent(NULL, FALSE, TRUE,

问题 I am using Eclipse for Android. I had a fresh/clean new workspace created. I had a folder where a pre-existing Android project was exported to from Eclipse. I open Eclipse from using this new workspace and do Import > Existing Projects into Workspace > I select the project folder which is a previous export > Finish . All is great with this importing, as the files are all there and the directory structure is as it should be. Then after some edits I do Export > General - File System > I select

问题 I am using Core data and iCloud for syncing purpose in my app.I am facing a problem when sync with two devices. Example : I am using customerID as primary key in my database.when i entered a data in my one device that ID is no.1 and the same time If i entered a different data in my another device,that one also will be no.1,So when it sync and refresh the database my app is getting crashed due to same customerID which should be unique one. Note : customer ID automatically get the next

问题 for synchronizing access to my NHibernate session at web environment I try use Mutex: public class FactoryRepository { private FactoryRepository() { } private static Mutex _sessionMutex = new Mutex(); private static ISessionFactory factory; public static ISessionFactory SessionFactory { get { factory = factory ?? new Configuration().Configure().BuildSessionFactory(); return factory; } } public static ISession Session { get { ISession currentSession; _sessionMutex.WaitOne(); if (HttpContext

问题 We have a launcher app that does some setup (starting a server), launches a child process, waits (via a worker thread) for the child process to exit, and then does some cleanup (stopping the server). This is already in place and works fine. However, some of our apps can launch other apps. So for example, the launcher might start app A, and then I might click a button in app A that starts app B. Then I close app A, the launcher's Process.WaitForExit call returns, and the launcher stops the

问题 I'm building a .NET application which will have a local CouchDB instance where all data is written to, and a central CouchDB where the local CouchDB is synchronised to. The difficulty is that there will be multiple clients which will synchronise with the database at different points (and could edit existing data, creating conflicts). The internet connection will not be consistent, so consequently the majority of data will be created/ edited while offline. I believe that CouchDB handles this