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On October 4, 2021, when the National Day holiday is full of people, Python officially Officially released Python 3 ten . As a stationary coder during the holiday, I naturally experienced a wave for the first time. Compared with the previous version, this version has the following major changes. ps: want to see a better typesetting? visit: ...

summary As we all know, we often encounter many exceptions and error messages in the production environment. We need to check the log information to check the errors. Most of the current systems are complex. Even behind a service, there is a cluster of machines running. It is obviously laborious and unrealistic to check the logs one by one. I ...

introduce The concept of idempotency is that the impact of any multiple executions is the same as that of one execution. According to this meaning, the final explanation is that the impact on the database can only be one-time and cannot be processed repeatedly. The means are as follows Create a unique index of the database token mechanism ...

Advance preparation For the smooth development of the story, we first create a table and insert some records into the table. The following is the SQL statement: CREATE TABLE hero ( number INT, name VARCHAR(100), country varchar(100), PRIMARY KEY (number), KEY idx_name (name) ) Engine=InnoDB CHARSET=utf8; INSERT INTO hero ...

Special invited author of enjoying learning class: Dream chasing youth Reprint, please state the source! ###Foreword When we do development, we always emphasize the concept of data type. In Java, it is divided into basic type and reference data type. There are eight basic data types. In addition to classes, we can also use the way of interfa ...

Introduction to Docker What is Docker? To tell you the truth about what Docker is, let me show you what Docker is through four points. Docker is the world's leading software container platform, developed and implemented in the Go Language.Docker frees developers by automating repetitive tasks such as setting up and configuring development en ...

Basic concepts of pointer What is the address Address in life: Memory address: Address and data in memory unit are two completely different concepts The address is like the room number. According to this number, we can find the corresponding roomMemory units are like rooms, which are dedicated to storing data Variable address: The ...

##Foreword I wrote a paragraph of logic in Java 8, but my colleagues said they couldn't understand it. The following is the business background. You can have a look together! Business background First of all, the business needs are as follows: pull all orders from the third-party e-commerce platform and save them to the company's own database ...

In this article, we mainly share a practical case: unknown bytecode instruction. Next, we will take a look at the application of bytecode by introducing some common features in the Java language. Because there are many Java features, here we will only introduce some features we often encounter. javap is a sharp weapon in your hand. Complex con ...

In one work, there was a small accident. The result of a redis write and read method was always different from what was expected. After careful consideration, it was found that because all nodes in the cluster use shared caches and queues, resource competition may occur among nodes in some scenarios, There may be a "thread insecurity probl ...