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How to solve the oversold problem of high price and high price? A problem caused by second kill The biggest problem of second kill is to solve the problem of oversold. One way to solve oversold is as follows: update goods set num = num - 1 WHERE id = 1001 and num > 0 Let's assume that there is only one item left, and num = 1 in the databa ...

01 introduction In the previous blog, we have a certain understanding of the use of Source in Flink's program model. Interested students can refer to the following: Flink tutorial (01) - Flink knowledge mapFlink tutorial (02) - getting started with FlinkFlink tutorial (03) - Flink environment constructionFlink tutorial (04) - getting star ...

background This paper mainly describes the troubleshooting ideas of import problems and the solutions to common problems. Here is a brief description of the processes of different import methods to facilitate everyone to understand the import process and troubleshoot problems. For details, please refer to the documents Import Chapter. Troublesh ...

1.1 ACL permission control: scheme, id and permission are used to identify, mainly covering three aspects: Permission scheme: authorization policy Authorization object (id): the authorized object Permission: the permission granted 1.2. Features of Zookeeper ACL: Zookeeper's permission control is based on znode nodes, and permissions need ...

D * algorithm (Dynamic A Star) Symbol and function description Openlist is a tool that can be used to do Breadth first search Queue of The identification tag s of node state are divided into three categories: those that have not joined the open table (new), those in the open table (open), and those that have been in the open table but have b ...

background In the process of supporting customers, we found that some customers encountered problems with BE service in the process of deploying and using StarRocks. It is generally unclear how to troubleshoot them? What indicators do you focus on? How much more is an unreasonable state, etc. From deployment to use, this article shares common ...

ThreadLocal may be rarely used in the normal development process, but it is indispensable for thread operation. In particular, the communication between threads through Handler is an important part. In this article, I will help you analyze the use and internal principle of ThreadLocal. What is ThreadLocal ThreadLocal is a class about creati ...

character string includes() console.log('abc'.includes('a'));//true console.log('abc'.includes('ab'));//true console.log('abc'.includes('ac'));//false The second parameter - start search location, which is 0 by default console.log('abc'.includes('a', 0));//true console.log('abc'.includes('a', 1));//false Application - URL add parameters ...

AB water question C - 1111gal password Question meaning: give N (\ (2\le N\le 1e6 \)) to find the number of \ (X \) satisfying the following conditions, which needs to be divided by the module (\ (998244353 \)) $X $is \ (N \) digits For each digit of \ (X_1,X_2,...,X_N \) \(1\le X_i \le 9\) \(|X_i - X_{i+1}| \le 1\) Idea: emm, looking dire ...

registerListeners() of Spring source code and publish subscribe modeHello, I'm classmate Tian, a programmer.Today, let's explain the registerListeners() method in the refresh() method, which is often referred to as the publish subscribe mode of Spring. This paper first gives an example of publish subscribe mode, then explains the principles of ...