message-queue

问题 The normal implementations of a work queue I have seen involve mutexes and condition variables. Consumer: A) Acquires Lock B) While Queue empty Wait on Condition Variable (thus suspending thread and releasing lock) C) Work object retrieved from queue D) Lock is released E) Do Work F) GOTO A Producer: A) Acquires Lock B) Work is added to queue C) condition variable is signaled (potentially releasing worker) D) Lock is released I have been browsing some code and I saw an implementation using

问题 When you store a message in a queue, isn't it more of meta data information so whoever pulls from the queue knows how to process the data? the actual information in the queue doesn't always hold all the information. Say you have an app like Twitter, whenever someone posts a message, you would still need to store the actual message text in the database correct? The queue would be more used to broadcast to other subscribers that a new message has arrived, and then those services could take

问题 I need to implement a queue using table. The business requirement is to have a single queue which will be accessed by 5-10 boxes to get the next job/jobs. There will not be more than 5000 jobs per day. Also, a batch of jobs should be "dequeued" at one time. Just wondering what are the problem areas and issues I might run into as I havent done it before. If anyone has faced this/done this before, can you please point me to a design/sample implementation or issues that need to be taken care of.

问题 Using PHP, I have a query that goes through my DB looking for pending tasks with reminder triggers at certain times of the day. I have a cronjob that runs every 10 mins and checks the DB for any rows that has "remind_me" field set to go off within the next 10 mins. If it does find something, what's the best way to queue an email with the task information? I guess I'll need some sort of message queue system, but how does the email part work? Will I need another cronjob that runs every minute

问题 I need a simple table that acts as a Queue. My MySQL server restriction is I can't use InnoDB tables, only MyISAM. Clients/workers will work at the same time and they will need to receive differents jobs each time. My idea is to do the following (pseudo-code): $job <- SELECT * FROM queue ORDER BY last_pop ASC LIMIT 1; UPDATE queue SET last_pop WHERE id = $job->id return $job I had tried table lock and "GET_LOCK" but nothing happends, workers sometimes receives same jobs. 回答1: You need to turn

问题 I understand that Apache Thrift and ZeroMQ are softwares belonging to different categories, and it is not easy to do a comparison since it is an apple to orange comparison. But I don't know why they belong to different categories. Aren't they both used to pass data between different services, which may or may not be written in different languages? When should I use Thrift and when should I use a message queue? 回答1: They belong to different categories primarily because they are targetted at

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 5 years ago . I have requests coming in for different samples (s1, s2, ..) that need to be processed in a linear fashion (i.e. only one say s1-request at the time can be processed). I have N-number of worker services that can process given requests. How can I implement rpc-queue pattern so that

问题 I have the following code: import threading def send_to_server(lst): #Some logic to send the list to the server. while 1: lst = [] for i in range(1000): lst.append(i) task = threading.Thread(target=send_to_server,args(copy(lst),)) task.start() I have a few Questions: 1) The idea for using threads is because sending to server takes time and I want to continue generating the data without any stop. The problem with this code is that if I created thread #3 and its taking long time to process, By

问题 I've more than one Handlers in an Activity. I create all the handlers in the onCreate() of the main activity. My understanding is the handleMessage() method of each handler will never be called at the same time because all messages are put in the same queue (the Activity thread MessageQueue). Therefore, they will be executed in the order in which are put into the Queue. They will also be executed in the main activity thread. Is this correct ? public void onCreate() { this.handler1 = new

问题 For a Windows Service, I need a timer to perform a certain task regularly. Of course, there are many options that seem superior to a timer (multithreading, calling method directly from the service's main thread), but they all have their disadvantages in this particular situation. However, for obvious reasons, SetTimer() does not work without the message queue of a GUI. What I have done (in Free Pascal) is the following: Create the timer: MyTimerID := SetTimer(0, 0, 3333, @MyTimerProc); In the