• Read optimistic lock and pessimistic lock and mvcc in database


    preface In the actual use of the database, we often encounter situations in which we do not want the data to be written or read at the same time. For example, in the second kill scenario, two requests read to the system at the same time, and there is one inventory in the system, and […]

  • Spring dependency injection best practices


    [note] this paper is translated from:https://springframework.guru/…    in this article, I’ll show you how to use project Lombok in spring framework dependency injection to get best practices.   the spring framework itself has many ways to perform dependency injection. The flexibility of options is an advantage of the spring framework. However, not all dependency injection options […]

  • Alink tips: how to read batch CSV data?


    Alink is a machine learning algorithm platform based on Flink. Please visit alink’s GitHub for more information. This article mainly shares one of the use skills of alink, how to use batch CSV to read data. basic operation Let’s download a CSV file to use as the test data. Download the data file locally, and […]

  • A complete understanding of MySQL index optimization explain Encyclopedia


    1. MySQL logical architecture In the process of curd, you can’t avoid dealing with databases. Most businesses can’t do without the design of database tables and the writing of SQL. How can you make your SQL statements perform better? Let’s take a look at the logic architecture of MySQL as a whole The overall logic […]

  • Write a good SQL, where should you start?


    Sometimes we will encounter: when querying SQL, if there are 100W pieces of data, there will be slow SQL alarm. At this time, you should go around the SQL log to find out the reason. There are many possible reasons for this. They are index miss and paging failure. Then we have to optimize SQL. […]

  • [redis5 source code learning] April 15, 2019 simple dynamic string SDS


    baiyan All videos: https://segmentfault.com/a/11… Today we officially enter the study of redis5 source code. Redis is a key value database written in C language, which is memory based, single process and persistent. It solves the problem of slow disk access and greatly improves the data access speed, so it is often used as a cache. […]

  • Comparison test of time series data between dry goods dolphin dB and mongodb


    Both dolphin dB and mongodb are databases for big data. But there is a big difference between the two. The former is a column storage multi model database, which is mainly used for high-speed storage, query and analysis of structured time series data. The latter is a document NoSQL database, which can be used to […]

  • Hands on Wheel: implement a simple dependency injection (3) — support attribute injection


    Hands on Wheel: implement a simple dependency injection (3) — support attribute injection Intro We have written several articles about dependency injection in front of us. If you are interested, please refer to the end of the articleReferenceSome of the links in this section have always been supported by small partners who want to add […]

  • Openresty based web API framework


    Using openresty to build a simple web API framework, convenient for later use when quickly generating project structure Project address click here directory structure The structure includes four directories: config, controller, LIBS and model config The configuration file directory is used for the configuration of app, redis and database App application related return { default_ […]

  • Learn the validator Library of gin framework’s parameter validation. This article is enough


    preface Hello, everyone. I’m asong. This is my tenth original article. This week in the company to do the project, in doing the API part of the development, you need to check the request parameters to prevent users from malicious requests. For example, date format, user age, gender, etc. must be normal values, which cannot […]

  • djang data migration


    djang data migration In the process of using Django framework development, we inevitably encounter changes in the models layer, which involves changes in database tables. Django provides me with a migration tool to make changes in these database tables. djang migration If you don’t add appName, it means all the apps that contain the migrations […]

  • Index in mongodb


    Index is the most effective way to improve query efficiency. Index is a special data structure. Index stores part of the data (such as a specific field or a group of field values) in a form that is easy to traverse. Index will sort the stored values according to certain rules, and the storage location […]