Are MySQL Join statements inefficient?

We often hear Join join queries that avoid using MySQL because of poor performance. Is this the case?Let's try it out. 1. Environment MySQL: 5.7.30 Storage Engine: InnoDB Index type: default optimized B+tree   2. Prepare 2.1 Table preparation and data preparation We plan to create five tables and insert 10W pieces of data into them, ...

Posted on Tue, 02 Jun 2020 07:53:10 -0400 by hanpedro

Everyone knows programming - the financial mob asks me for my rate forecast

It's like this. In the middle of the night, I got a question from a big stock broker about programming. Bogor, have you slept? Inner OS: As a financial mob, how come I ask questions about programming so late? Later, I learned that they had organized a competition within their company - interest rate forecasts. That's true. It's not simple. I ...

Posted on Tue, 02 Jun 2020 04:09:52 -0400 by Anco

How to execute a piece of logic immediately after the Spring Boot application starts

1. Preface I don't know if you've received this requirement, so just execute some logic when the project starts.For example, simple cache preheating, or broadcasting after going online, and so on.If you use the Spring Boot framework, you can do so with its interfaces CommandLineRunner and ApplicationRunner. 2. CommandLineRunner org.springframe ...

Posted on Mon, 01 Jun 2020 22:56:55 -0400 by vjbrantner@purd

Spring Boot Implements Configuration File Encryption and Decryption Principle

Spring Boot profile encryption and decryption is as simple as that background Following "Return of Missing Persons, mybatis-plus 3.3.2 Release" [1], provides a very practical function, "Data Security Protection", which not only supports the configuration encryption of data sources, but also enables the encryption of sensitiv ...

Posted on Mon, 01 Jun 2020 21:04:17 -0400 by dspeer

Thread pool of C + + nine Yin scriptures

Role of thread pool: 1. Avoid the cost of creating and destroying threads when processing short-term tasks; 2. In a large number of concurrent tasks, system resources can be used more reasonably to cut peak and level Valley to ensure the stability of system operation; It has the following advantages to build thread pool based on C++11 standa ...

Posted on Mon, 01 Jun 2020 11:39:53 -0400 by scuba

flowable-6.5.0 running official demo

1. Download flowable-6.5.0 from the official website: https://flowable.com/open-source/downloads/ After downloading and unzipping, open the directory wars 2. Find a clean tomcat8 In the war file directory flowable-admin.war  flowable-idm.war  flowable-modeler.war  flowable-rest.war  flowable-task.war A total of 5 war packages are placed in ...

Posted on Mon, 01 Jun 2020 11:10:09 -0400 by krelian

Communication between threads of C + + nine Yin Scripture (message queue)

Message queuing is a common way of communication between threads, which is often used to solve the communication between threads of the classic model producer consumer model. This paper will end the implementation of message queue based on C + + standard library, which can support any parameter type and the number of task parameters. In ord ...

Posted on Mon, 01 Jun 2020 10:21:37 -0400 by gowni

How to use double check lock to implement singleton - ImportNew in Java

This paper is composed of ImportNew-freely flowing style of writing Translation from javacodegeeks . Welcome to join Java team . Please refer to the requirements at the end of the article for reprint. Singleton classes are very common in Java developers, but they pose many challenges to junior developers. One of the key challenges they face i ...

Posted on Mon, 01 Jun 2020 10:01:25 -0400 by will_1990

A troubleshooting of Spring project packaging

A Spring project, which runs after jar package, is normal when there is a network, but once there is no network, an error will be reported. What's the matter? This article will record the troubleshooting process. Background A graphical interface with a local database is required to be able to run in a non network environment. The graphical in ...

Posted on Mon, 01 Jun 2020 00:56:38 -0400 by Ozzapoo

mysql count(*) count count(id) explanation

Environment wins10 8g memory mysql5.7.27 mysql my.ini Configuration note (innodb_flush_log_at_trx_commit=0) configuration [Client] #Set 3306 port port = 3306 [mysqld] #Set 3306 port port = 3306 # Set the installation directory of mysql basedir=E:devmysql-5.7.27-winx64 # Set the storage directory of mysql database data datadir=E:devmysql-5.7.2 ...

Posted on Sun, 31 May 2020 10:10:15 -0400 by cofey12681