synchronization

This question already has an answer here: Client-server synchronization pattern / algorithm? 6 answers I am starting to setup the core data model for a large scale app, and was hoping for some feedback on proper synchronization methods/techniques when it comes to server database and offline capabilities. I use PHP and mySQL for my web server / database. I already know how to connect, receive data, store to core data, etc etc. I am looking more for help with the methodologies and particular instances of tracking data changes to: A) Ensure the app and server are in sync during online and offline

I am trying to use mutexes to avoid multiple writes to the same thread inC/Cpp. Below is the flow of my program. I am confused as to where to include my lock and unlock code. main() { spawn a worker thread } worker_thread() { read the input file name read some content write the content to the given file name } Most of the implementation that I see, seem to have something like this: main() { pthread_mutex_init(&myMutex;,0); *spawn a worker thread* pthread_join(thread1, 0); pthread_mutex_destroy(&myMutex;); } worker_thread() { read the input file name read some content write the content to the

I've a server/client architecture implemented, where all state changes are sent to the function, validated and broadcasted to all clients connected. This works rather well, but the system does not maintain synchronization between the client instances of the game as of now. If there happened to be a 5 second lag between the server and a particular client then he would receive the state change 5 seconds after the rest of the clients thus leaving him with game state out of sync. I've been searching for various ways to implement a synchronization system between the clients but haven't found much

I'm in the middle of brainstorming a cloud sync solution for a Core Data app that I am currently developing. I'm planning to open source the code for this once its done, for anyone to use with their Core Data apps, so input from the community on how this system should work is much appreciated :-) Here's what I'm thinking: Server Side Storage Provider As with all cloud sync systems, storage is a major piece of the puzzle. There are many ways to handle this. I could set up my own server for storage, or use a service like Amazon S3, but because I'm starting out with $0 capital, at this moment, a

I am developing an Android App that stores different types of data in the built-in SQLite provided by the Android Platform. Inside the App I have placed a "Sync" button which is supposed to Sync the data between the local SQLite Database, with an Online SQL Server database on my server. What is the workaround to handle this? This feature can be found in Google Calendar, where you can view the calendar's events on your mobile, and when you add a new event and Sync the data, you can view the updated data by going to your online account too. Note: I don't want to centralize my database online,

I have a question about sync.Once() in Go 1.12. The source code is below: // Because no call to Do returns until the one call to f returns, if f causes // Do to be called, it will deadlock. func (o *Once) Do(f func()) { if atomic.LoadUint32(&o.done) == 1 { return } // Slow-path. o.m.Lock() defer o.m.Unlock() if o.done == 0 { defer atomic.StoreUint32(&o.done, 1) f() } } Why not just use an uint32 variable, then do CAS on this variable. It seems to be more effective, and will not lead to deadlock. The code like: type Once uint32 func (o *Once) Do(f func()) { if atomic.CompareAndSwapUint32((

I have a problem in my project. To describe this issue I have wrote simplified code snippet: function waitFor(fnReady, fnCallback) { var check = function() { if (fnReady()) { fnCallback(); } else { setTimeout(check, 100); // wait another 100ms, and try again } }; check(); } var result = 0; var flag = true; function ajaxRequest() { setTimeout( function() { flag = false; console.log('ping'); },3000 ); } function ajaxRequestHandler() { setTimeout( function() { flag = true; console.log('pong'); }, 200 ); } for(var i =0;i<10; i++){ waitFor(function() { return flag; }, ajaxRequest); waitFor(function

I'm using a third party library "Reachability.swift" https://github.com/ashleymills/Reachability.swift Followed this blog post to identify network event using Notification Center, So the change in network event can be identified dynamically in the foreground https://blog.pusher.com/handling-internet-connection-reachability-swift/ My Requirement:- I need to run a background service that uses Alamofire (Information not needed for alamofire) to push the locally saved SQLite data to the server whenever internet connection status is Active Important note:- iOS Application should not run in the

From Operating System Concepts In the solution to the first readers–writers problem, the reader processes share the following data structures: semaphore rw mutex = 1; semaphore mutex = 1; int read_count = 0; do { wait(rw_mutex); . . . /* writing is performed */ . . . signal(rw_mutex); } while (true); Figure 5.11 The structure of a writer process. do { wait(mutex); read count++; if (read_count == 1) wait(rw mutex); signal(mutex); . . . /* reading is performed */ . . . wait(mutex); read count--; if (read_count == 0) signal(rw_mutex); signal(mutex); } while (true); Figure 5.12 The structure of a