synchronization

问题 Is it possible to upload only the file change (delta) with AWS S3 (using the Node.JS SDK or Pre-signed URL) ? 回答1: No. That is not possible For adding a Delta, you will have to fetch the object locally, add the delta and then upload back to s3 来源： https://stackoverflow.com/questions/43141078/aws-s3-upload-only-the-file-change-delta

问题 I have asked something similar before, but never go to the solution I need. So am starting a new stack to not confuse my issues, and to make a little clearer. What I need to do I have multiple flash objects on a html page, they are all identical, and all of them need to be sync'd with the correct time. In its current state, each one queries the timeserver, and gets the time, which works great. BUT what I want to achieve is the first one to load to be the only one that sync's with the time

问题 I've read the following Behavior differences between performBlock: and performBlockAndWait:? But wasn't able to find an answer to my question. The following code is picked up from an RayWenderlich video. Specifically at 10:05 the code is something like this: class CoreDataStack { var coordinator : NSPersistentStoreCoordinator init(coordinator: NSPersistentStoreCoordinator){ self.coordinator = coordinator } // private, parent, in background used for saving private lazy var savingContext :

问题 I understand the basic rules for memory ordering in C++11, especially release-acquire ordering. I have a big chunk of memory shared between two threads, where I do not need atomicity, but want to ensure that eventually all the changes done by a thread is visible in another, especially on platforms with relaxed memory model. Is it ok to simply use an atomic guard var only to trigger memory synchronization? E.g., std::atomic<bool> guardVar; char *shared_mem=get_shared_mem(); (thread 1) while

问题 As noted here, I added code to my handheld app to (attempt to) prevent certain types of files (by extension) from being synced to the PC. But this doesn't work if the user, on the PC, uses ActiveStync to enable file sharing. On doing so, regardless of handheld registry settings, it copies files from the handheld to the PC (from the handheld's \My Documents folder to the PC's C:\Users\clay\Documents\Documents on Clay's Device folder). Is there a way to programmatically prevent (on the handheld

问题 StringBuffer is synchronized but StringBuilder is not ! This has been discussed deeply at Difference between StringBuilder and StringBuffer. There is an example code there (Answered by @NicolasZozol), which address two issues: compares the performance of these StringBuffer and StringBuilder shows the StringBuilder could fail in a multithread environment. My question is about second part , exactly what makes it to go wrong?! When you run the code some times, the stack trace is displayed as

问题 java.util.concurrent provides many thread safe collections like ConcurrentHashMap , ConcurrentSkipListMap , ConcurrentSkipListSet and ConcurrentLinkedQueue . These collections are supposed to minimize contention by allowing concurrent access to different parts of the data structure. Java also has synchronized wrappers to allow concurrent access to non thread safe collections like HashMap and Arraylist . Map<KeyType, ValType> m = Collections.synchronizedMap(new HashMap<KeyType, ValType>()); Do

问题 I am using a cloud backup/sync service (SpiderOak) which automatically Syncs folders across several computers / devices. I am trying to figure out a way to automatically sync all my databases across my work computer and personal laptop, without actually needing to backup/restore from one instance to the other. So what I am thinking of is to create a new sql instance on my laptop which is identical to my work desktop instance, then to pick both SQL Server directories in Program Files to sync

问题 I am using a cloud backup/sync service (SpiderOak) which automatically Syncs folders across several computers / devices. I am trying to figure out a way to automatically sync all my databases across my work computer and personal laptop, without actually needing to backup/restore from one instance to the other. So what I am thinking of is to create a new sql instance on my laptop which is identical to my work desktop instance, then to pick both SQL Server directories in Program Files to sync

问题 if I have a getter method that has only one statement like this public class NumberClass{ int number; public int getNumber() { return number; } ... } and multiple threads access this method, do I have to synchronize this method or it is not necessary since it has only one statement?? 回答1: I have to synchronize this [get] method or it is not necessary since it has only one statement?? It has nothing to do with 1 or more statements. It depends on whether or not the value has been updated in