synchronization

Django Model Sync Table

由 淺唱寂寞╮ 提交于 2019-12-04 08:43:37
问题 If I change a field in a Django model, how can I synchronize it with the database tables? Do I need to do it manually on the database or is there a tool that does helps with the process? 回答1: Alas, Django does not support any easy solution to this. The only thing django will do for you, is restart your database with new tables that match your new models: $ #DON'T DO THIS UNLESS YOU CAN AFFORD TO LOSE ALL YOUR DATA! $ python PROJECT_DIR/manage.py syncdb the next option is to use the various

Do good multiplayer/mmo client<>server games use latency within movement calculations?

由 半世苍凉 提交于 2019-12-04 08:22:28
问题 There's a couple of questions here. Imagine I have client A who's going to send the following message to Server: "START MOVEMENT FORWARD". The server will not receive this message instantly, as there is a delay because of latency. Question 1: ping (or better: round trip time) is the amount of time it takes for the client to send a message to the server and receive a response back. Does this mean the following if you can ignore the time it takes for the server to notice that it has received a

What important difference exists between Monitor.TryEnter(object) And Monitor.TryEnter(object, ref bool)?

由 怎甘沉沦 提交于 2019-12-04 08:19:17
问题 It seems that these code snippets ought to behave identically: 1: Monitor.TryEnter(object) if (Monitor.TryEnter(lockObject)) { try { DoSomething(); } finally { Monitor.Exit(lockObject); } } 2: Monitor.TryEnter(object, ref bool) - introduced in .NET 4.0 bool lockAcquired; try { Monitor.TryEnter(lockObject, ref lockAcquired); if (lockAcquired) { DoSomething(); } } finally { if (lockAcquired) { Monitor.Exit(lockObject); } } I see from the MSDN documentation on the overload taking a ref bool

Swift Core Data Sync With Web Server

由 早过忘川 提交于 2019-12-04 08:06:51
问题 I am making an app (in Swift) which needs to run in offline and online mode. When its in offline mode, data will be stored locally on CoreData. Once it detects network (online) it should sync with server and update the backend database. How should one go about it. Are there libraries or pods? I have seen this post but nothing is actionable. It is too high level and I am not sure where to start. I have seen this link from Ray Wenderlich but don't know how to translate to Swift. Any tutorial

Best way of using sync.WaitGroup with external function

由 冷暖自知 提交于 2019-12-04 07:51:50
问题 I have some issues with the following code: package main import ( "fmt" "sync" ) // This program should go to 11, but sometimes it only prints 1 to 10. func main() { ch := make(chan int) var wg sync.WaitGroup wg.Add(2) go Print(ch, wg) // go func(){ for i := 1; i <= 11; i++ { ch <- i } close(ch) defer wg.Done() }() wg.Wait() //deadlock here } // Print prints all numbers sent on the channel. // The function returns when the channel is closed. func Print(ch <-chan int, wg sync.WaitGroup) { for

Pthread conditional signal - not working as expected

由 北城余情 提交于 2019-12-04 07:48:04
I am working on a project and trying to use pthread_cond_wait() and pthread_cond_signal() to synchronize two threads. My code looks something like this: pthread_mutex_t lock_it = PTHREAD_MUTEX_INITIALIZER; pthread_cond_t write_it = PTHREAD_COND_INITIALIZER; int main(int argc, char**argv) { pthread_t t_send_segments, t_recv_acks; pthread_create(&t_send_segments, NULL, send_segments, (void*)NULL); pthread_create(&t_recv_acks, NULL, recv_acks, (void*)NULL); pthread_join(t_recv_acks, (void**)NULL); pthread_mutex_destroy(&lock_it); pthread_cond_destroy(&write_it); } void* send_segments(void *v) {

Windows Mobile Synchronization Error

由 送分小仙女□ 提交于 2019-12-04 07:41:12
I am new to Windows Mobile development and have been investigating methods to synchronize data between PDA's running WM6 and a SQL Server 2005 Database. After some research I decided to go with Windows Synchronization Services. I started by looking at the sample: SyncServicesForDevicesSample I downloaded and installed all the prerequisite software outlined in the readme including: Visual Studio 2008 Professional SP1 SQL Server Compact 3.5 Service Pack 1 (SP1) Synchronization Services for ADO.NET 1.0 (devices) When I load the sample I noted that the System.Data.SqlServerCe.dll reference in the

sync.Once implementation

由 僤鯓⒐⒋嵵緔 提交于 2019-12-04 07:15:28
问题 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

send synchrouns request angular 6 [closed]

由 ↘锁芯ラ 提交于 2019-12-04 07:08:21
问题 Closed . This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 7 months ago . i want to send synchrouns request this nested for loop in angular 6. it all for loop must wait each other response. Please give some example in https://stackblitz.com protected plateInfo(debug = true) { for (let i = 0; i < 8; i++) { for (let k = 0; k < 8; k++) { if (k % 2 !== 0) { for (let

How to sync serial queue for URLSession tasks?

由 泄露秘密 提交于 2019-12-04 07:04:50
Using XCode-8.2.1, Swift-3.0.2 and iOS-10.2.1, I am trying to call two different URLSession.shared.dataTasks (the first is a simple URL-request and the second is a POST-request). Since my first dataTask delivers a result that is needed in the httpBody of the second dataTask, the two URLSession.shared.dataTasks shall run in series, one after the other! (and also the preparative code shall run consecutively). I tried, so far, using two consecutive serialQueue.sync{} queues. But I had to realize that the code does not perform in the order I would like to. The print-statement in the log turn out
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