synchronization

Using a central database server for many sites: plausible?

由 六月ゝ 毕业季﹏ 提交于 2019-12-06 04:01:32
问题 Basically, I need some parts of database data synchronized on up to several dozens of sites. The perfect solution would be creating a central server to host that data. Each pageload will have to fetch data from both database servers - the local and remote one and writes to the remote server will be quite common too. While the db server can be as fast as desired hardware-wise, I'm cautious of the bottlenecks: Multiple database connections must be established on each pageload. Latency of the

Android : Sync Adapter not running in some devices

由 二次信任 提交于 2019-12-06 03:46:48
In my android project i have a sync adapter that will sync data from android device to the server and its working fine, but recently i noticed that the onPerfomSync is not calling in my moto g3 android phone, I don't know whether there is the same problem in any other phones,I have tested it in some other Samsung phones with different android api level,but didn't find any problem there.I have configured the sync when a successful user login found.What will be the reason for this behaviour.Correct me if i am doing anything wrong. Below is my codes. private void finishLogin(Intent intent) {

How to sync serial queue for URLSession tasks?

由 ⅰ亾dé卋堺 提交于 2019-12-06 03:42:54
问题 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

python subprocess hide stdout and wait it to complete

由 旧时模样 提交于 2019-12-06 03:39:59
问题 I have this code: def method_a(self): command_line = 'somtoolbox GrowingSOM ' + som_prop_path subprocess.Popen(shlex.split(command_line)) ...... def method_b(self): ..... .... and like you all see, method_a has a subprocess that is calling the somtoolbox program. But this program have a long stdout, and I want to hide it. I tried: subprocess.Popen(shlex.split(command_line), stdout=subprocess.PIPE) But it returned this sentence: cat: record error: Broked Pipe (this is a translation of the

Pthread conditional signal - not working as expected

由 女生的网名这么多〃 提交于 2019-12-06 03:17:49
问题 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

Multi-threading Delphi synchronization using Critical Sections between a Timer and other threads

由 只谈情不闲聊 提交于 2019-12-06 03:13:21
问题 It is a problem of synchronization. I made a simplification for my problem so I have a VCL Timer and a few threads. The threads are trying to write things in two bitmaps, and the timer is trying to draw the bitmaps into Images(TImage). Here is a modification of my code to be easier to understand(this paste code is very vague). //------------------------------------------------------------------------------ Procedure TMyForm.Add(iX,iY,iNr:integer); begin EnterCriticalSection(csCriticalSection)

Possible race condition in std::condition_variable?

由 时光毁灭记忆、已成空白 提交于 2019-12-06 02:49:40
问题 I've looked into the VC++ implementation of std::condition_variable(lock,pred) , basically, it looks like this: template<class _Predicate> void wait(unique_lock<mutex>& _Lck, _Predicate _Pred) { // wait for signal and test predicate while (!_Pred()) wait(_Lck); } Basically , the naked wait calls _Cnd_waitX which calls _Cnd_wait which calls do_wait which calls cond->_get_cv()->wait(cs); (all of these are in the file cond.c). cond->_get_cv() returns Concurrency::details::stl_condition_variable

mySQL authoritative database - combined with Firebase

由 时光总嘲笑我的痴心妄想 提交于 2019-12-06 02:47:41
问题 We have built a LAMP-stack API application via PHP Laravel. This currently uses a local mySQL instance. We have mostly implemented views in AngularJS. In order to use Firebase, we need to sync data between the authoritative store in mySQL with anything relevant that exists on Firebase, as close to real-time as possible. This means that other parts of the app which are not real-time and don't use Firebase can also serve up fresh content that's very recently been entered into the system. I know

CUDA __syncthreads() usage within a warp

由 我们两清 提交于 2019-12-06 02:42:55
问题 If it was absolutely required for all the threads in a block to be at the same point in the code, do we require the __syncthreads function if the number of threads being launched is equal to the number of threads in a warp? Note: No extra threads or blocks, just a single warp for the kernel. Example code: shared _voltatile_ sdata[16]; int index = some_number_between_0_and_15; sdata[tid] = some_number; output[tid] = x ^ y ^ z ^ sdata[index]; 回答1: Updated with more information about using

Synchronizing access to a doubly-linked list

由 末鹿安然 提交于 2019-12-06 02:24:02
问题 I'm trying to implement a (special kind of) doubly-linked list in C, in a pthreads environment but using only C-wrapped synchronization instructions like atomic CAS, etc. rather than pthread primitives. (The elements of the list are fixed-size chunks of memory and almost surely cannot fit pthread_mutex_t etc. inside them.) I don't actually need full arbitrary doubly-linked list methods, only: insertion at the end of the list deletion from the beginning of the list deletion at arbitrary points
订阅 synchronization