wxbty opened a new pull request, #12223: URL: https://github.com/apache/dubbo/pull/12223
## What is the purpose of the change Issue Number: close https://github.com/apache/dubbo/issues/12153 ## Brief changelog The MergingDigest data structure of the t-Digest package uses a cache with a default size (1050) to improve efficiency, and the cache increments by +1 each time it is added. If the cache is full, the space will be merged and tempUsed=0 will be reset. In this process, there are common concurrency problems in the judgment and merge methods, which need to be fixed. 1. Add synchronized to the mergeNewValues method. This method will be executed about 1050 times (the reason for the 0.1% error rate), so there is no need to worry about performance issues. 2. The cache offset tempUsed is changed from int type to AtomicInteger, and volatile modification is added 3. Because the source code of t-Digest cannot be modified directly, copy the corresponding code to the dubbo source code separately private void add(double x, int w, List<Double> history) { if (Double.isNaN(x)) { throw new IllegalArgumentException("Cannot add NaN to t-digest"); } if (tempUsed >= tempWeight.length - lastUsedCell - 1) { //判断是否达到缓存上限，tempWeight.length =1050 mergeNewValues(); } int where = tempUsed++; // 每次add自增 // ... }  ## Verifying this change 1、git pull 3.2 2、modify the ConsumerApplication code of dubbo-demo-spring-boot-consumer as follows. About 0.1% error rate before the change, no error rate after the change public static void main(String[] args) { ConfigurableApplicationContext context = SpringApplication.run(ConsumerApplication.class, args); ConsumerApplication application = context.getBean(ConsumerApplication.class); String result = application.doSayHello(); System.out.println("result: " + result); } public String doSayHello() { int index = 0; while (index < 200) { System.out.println("-------------:" + index); for (int i = 0; i < 100; i++) { new Thread(() -> { try { String result = demoService.sayHello("world"); } catch (Exception e) { e.printStackTrace(); } }).start(); } index++; try { Thread.sleep(500); } catch (InterruptedException e) { e.printStackTrace(); } } return ""; } -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
