multithreading

问题 I have an API rate limit table that I'm managing for one of our applications. Here's the definition of it. CREATE TABLE [dbo].[RateLimit] ( [UserId] [int] NOT NULL, [EndPointId] [smallint] NOT NULL, [AllowedRequests] [smallint] NOT NULL, [ResetDateUtc] [datetime2](0) NOT NULL, CONSTRAINT [PK_RateLimit] PRIMARY KEY CLUSTERED ([UserId] ASC, [EndPointId] ASC) ) ON [PRIMARY] The process that performs CRUD operations on this table is multi-threaded, and therefore careful consideration needs to be

问题 The core perl function rand() is not thread-safe, and I need random numbers in a threaded monte carlo simulation. I'm having trouble finding any notes in CPAN on the various random-number generators there as to which (if any) are thread-safe, and every google search I do keeps getting cluttered with C/C++/python/anything but perl. Any suggestions? 回答1: Do not use built-in rand for Monte Carlo on Windows. At least, try: my %r = map { rand() => undef } 1 .. 1_000_000; print scalar keys %r, "\n"

问题 The core perl function rand() is not thread-safe, and I need random numbers in a threaded monte carlo simulation. I'm having trouble finding any notes in CPAN on the various random-number generators there as to which (if any) are thread-safe, and every google search I do keeps getting cluttered with C/C++/python/anything but perl. Any suggestions? 回答1: Do not use built-in rand for Monte Carlo on Windows. At least, try: my %r = map { rand() => undef } 1 .. 1_000_000; print scalar keys %r, "\n"

问题 I am using greendao as ORM library in my Android project and have problems understanding the behaviour of transactions. greendao offers an API runInTx(Runnable r) . My question is, how will two calls of this method from different Threads will be handled? Thread 1 public void thread1() { DaoManager.INSTANCE.getDaoSession().runInTx(new Runnable() { doQueries(); doInsertsAndUpdates(); } } Thread 2 public void thread2() { DaoManager.INSTANCE.getDaoSession().runInTx(new Runnable() { doQueries();

问题 A quote from "Effective Java book" : " The libraries provide the Thread.stop method, but this method was deprecated long ago because it is inherently unsafe—its use can result in data corruption. Do not use Thread.stop " Anyone can tell me why ? 回答1: What if the thread you stop holds a critical lock? What if the thread has placed an object into an inconsistent state and hasn't had a chance to restore it yet? The correct way to stop a thread is with its cooperation, not by forcing it to stop

问题 My code use text file as an input and use multithreading to execute the lines together, I need to output CSV file that every thread fill another column in the file. I can't find a way to do that, is there a way? My code: def generate_values(min, max, amount): arr = [None] * amount for i in range(amount): arr[i] = random.uniform(min, max) if thread.is_alive(): output_csv.write(str(arr[i])) return arr input_file = open("max_min.txt", "r") output_csv= open("uniform_values.csv","w") for lines in

问题 I have just started learning java. I modified the client side code for a server/client communication program, by creating two threads for the client side, main thread for receiving user's input, and inputThread for receiving server's response. I am sure that server has sent the response to client, however, no response message is obtain at client. Here is my code. Can anyone help me to figure it out? Thanks package clientnio; import java.net.*; import java.nio.*; import java.io.*; import java

问题 I have a singleton that manages an array. This singleton can be accessed from multiple threads, so it has its own internal DispatchQueue to manage read/write access across threads. For simplicity we'll say it's a serial queue. There comes a time where the singleton will be reading from the array and updating the UI. How do I handle this? Which thread my internal dispatch queue is not known, right? It's just an implementation detail I'm to not worry about? In most cases this seems fine, but in

问题 I am using a C program, compiled with gcc 4.9.2 on Windows7, using OpenMP 4.0. My computer is dual core, with four threads. I'd like to use thread affinity spread and use 2 threads put on different cores. So when I set the environment variables from DOS with: set OMP_NUM_THREADS=2 set OMP_PROC_BIND=spread set OMP_PLACES="cores" I get, with the variable OMP_DISPLAY_ENV=true, this: libgomp: Invalid value for environment variable OMP_PLACES OPENMP DISPLAY ENVIRONMENT BEGIN _OPENMP = '201307' OMP

问题 Main question: What is the best way to perform safe publication of the contents of an array, collection, or map in Java? Here is what I've tried and some side questions I have: Side question #1 On thread 1, I'm writing to an HashMap: Map<K, V> map = new HashMap<>(); map.put(key, value); My current understanding is that: Collections.unmodifiableMap() does not constitute safe publication of the references stored in the map. By examining these particular implementations of Map.of(), the result