one database of user balance, one database of order table, one database of fund details users use balance to place orders, how to ensure that no more orders will be placed and the data are consistent in the case of large concurrency ...
problem description in Chapter 7 of "Java concurrent programming practice ", the author implements thread cancellation through newTaskFor method encapsulation. The demo given is as follows: public abstract class SocketUsingTask <T> implement...
Let me ask you a question : if you have just taken over a strange Spring application, the hang stops during startup, and the Spring container does not start or fail, so the hang is there all the time. There is no obvious error log in the business log (...
1. The scenario in which the problem occurs 1. Network delay, or use the FD tool to simulate requests sql select time form order where uid= 15 order by time desc limit 0 br > if (current time-time < 15) { exit (do not request frequently); } INS...
problem description it takes 3, 000 threads to request under the same ip, but the real scenario is 3, 000 different ip,. In the former case, socket, can be reused. It seems that the real scenario is slower. Is there any way to simulate it? related c...
read a section of the concurrent programming network http: ifeve.com volatile Volatile is a lightweight synchronized, that ensures the " visibility "of shared variables in multiprocessor development . Visibility means that when one thread modifies a...
Conceptual problems, I found some articles that I didn t understand. most articles say that NodeJs is suitable to be an IO server because of the high throughput of the asynchronous model. But the asynchronous model is supposed to mean that initiating...
in Java, why does the code b = = (b = a) not always return true? in a multithreaded environment a can be modified by multiple threads. b initializes to b = a when printing b = = (b = a), the result is not necessarily true. however, isn t the pri...
< H1 > Hello, everyone. When I was reading an article, the content mentioned < H1 >. < H2 > "the atomicity of a single method does not guarantee the atomicity of compound operation " < H2 >. < H2 > what is the meaning of the compound operation in ...
Today, there are 30,000 pieces of data found by export. The result of processing will be timed out. think of multithread traversing list to find this code on the Internet: public String list2Str(List<String> list, final int nThreads) throws Exce...
Server configuration: 4core 8G there are several nginx+rails+mongodb+redis+sidekiq services. where rails starts 2 worker, and one worker10 thread sidekiq concurrency is set to 15 how should I optimize or upgrade the server? ...
there is some doubt about the reading semantics of volatile: Why can t normal read and volatile read after volatile read be reordered? volatile read I know it is to fetch variable values directly from main memory, but since they are both reads, will i...
the first four requests I think nginx will be assigned to those four worker will the fifth fail? ...
all the spin locks I see are implemented using CAS technology, without mutexes, and are often used for lock-free programming, so spin locks should not be locks, am I right? In addition, is there any other way to implement spin lock besides using CAS? ...
A multithreading experiment of Java Socket is done on the local machine, server and client are in, the idea is that both server and client want to use multithreading, and socket is reused, and an exception is encountered. describe and its environment: ...
Why do thread pools use blocking queues? Can you complete a task with a general queue? ...
the approximate code is as follows: func(id, ip){ int countId = jedis.hget("count", id); int countIP = jedis.get("count", ip); if(countId >= 5 || countIP>=5){ return; } ...
in working memory, there are method stack frames and registers. Pc, is understandable, but why should some referenced main memory variables be copied to working memory? I don t think it s necessary at all, which leads to cache consistency problems. Or...
currently in the project, you want to use php s pcntl_fork to create multiple processes (such as 8) to consume redis queue messages in parallel. But running the log found that there were not eight processes generated, but two or three. As shown below: ...
1. You can find out how much money you can get for each order first. Note: you can t inquire about it when you place an order. (the current consideration is to slow down the memory when querying, but if this order is checked, the order will not necessa...
problem description for example, if you get a rtmp stream and play it on a web page, you can use video.js to find it on the Internet, but you can t play streaming media through your own research. related codes Please paste the code text below...
premise: to generate a landing page according to a template, DB stores only the pictures or text information to be replaced. < hr > to make an online landing page creation tool, how to realize the preview function after the H5 page is finished, simil...
is ajax.call in ecshop a js encapsulated by ecshop itself or something? Where do you keep his papers? ...
axios has been installed and has been introduced in the entry file. I wrote the following in the component but reported this error. at first I wrote not this.axios but axios, but this indicates that axios is not defined, but I have introduced it in th...
to implement a list, add an active class when you click on each item. can t e.currentTarget get the current element? Adding styles has no effect. The format of the output is also different from the previous one it is not clear whether there is a...