Understanding and Case Study of InnoDB Line Lock in MySQL

Last-Modified: September 27, 2019, 12:12:20 This article is mainly about personal notes and related understanding of the course 20,21,30 in MySQL Actual Fighting 45.The order of the first part of this article will be a little confused, and it will be sorted out later. lock Below is InnoDB for MySQL only. In order to avoid polluting the original ...

Posted on Fri, 27 Sep 2019 01:12:56 -0700 by frost

Do you remember these common Mysql commands?

Preface Recording Common Command Operations of mysql Basic operation Command line login mysql Mysql-u username-p user password Increase creation time and update time for tables ALTER TABLE order_info_tbl ADD COLUMN create_time TIMESTAMP DEFAULT CURRENT_TIMESTAMP COMMENT 'Creation time'; ALTER TABLE order_info_tbl ADD COLUMN update_time TIMESTA ...

Posted on Wed, 25 Sep 2019 08:09:44 -0700 by WilliamNz

Mybatis Level 1 and Level 2 Cache Implementation Principles and Guidelines

Mybatis, like Hibernate, supports Level 1 and Level 2 caching. First-level cache refers to the Session-level cache, that is, if the same SQL statement is executed multiple times in a session and the parameters are the same, the subsequent queries will not be sent to the database and will be retrieved directly from the Session cache. Secondary c ...

Posted on Mon, 23 Sep 2019 21:02:25 -0700 by larissahn

Spark Series-Structured API of Spark SQL

1. Creating DataFrame and Dataset 1.1 Create DataFrame The entry point for all functions in Spark is SparkSession, which can be created using SparkSession.builder(). Once created, the application can create a DataFrame from an existing RDD, Hive table, or Spark data source. Examples are as follows: val spark = SparkSession.builder().appName("S ...

Posted on Mon, 23 Sep 2019 08:14:31 -0700 by Vibralux

mysql Json Column uses

mysql json column ## Use scenarios When we create tables, we are always used to reserve more columns in order to prevent future demand increases or changes. If we add columns of tables, we lock tables in a very large amount of data. But if we add associated tables, queries will slow down. Most of the ...

Posted on Mon, 23 Sep 2019 02:52:28 -0700 by azaidi7

18 - Oracle Scheduler Scheduling

The eighteenth lesson 18. Oracle Scheduler Scheduling Homework job program Scheduling schedule Chain chain window Operational Class CJQ0 process: job queue Coordinator Jnnn process: running jobs Parameter: job_queue_processes Create jobs: 18.1 Scheduling schedule Time-based scheduling BEGIN sys. ...

Posted on Mon, 23 Sep 2019 01:20:09 -0700 by kattar

mybatis-plus 2.x Upgrade 3.x Notes

The main upgrades from 2.0 to 3.0 are: Upgrading JDK 8 + Optimizing Performance Wrapper Support lambda Syntax Modular MP allocates each package structure reasonably Reconstructing injection method to support any method to simplify injection mode Global Configuration Underline Conversion Eliminates Injection of AS Statements Modify Wrapper to Q ...

Posted on Sat, 21 Sep 2019 03:06:18 -0700 by alconebay

Operational Weapon: Introduction to WEB Log Analysis Scenarios

Why do you want to analyze Web logs? With the continuous development of Web technology, Web has been applied more and more widely. Nowadays, many enterprises provide services to a website, so the business behavior and security of the website is very important. As the security industry put it, "There are only two kinds of people in the wor ...

Posted on Thu, 19 Sep 2019 20:14:49 -0700 by tomtimms

MySQL database related operations in python

Installation Basic Environment 1 Introduction MySQL is developed on the basis of TCP protocol, but after network connection, the data transmitted must follow the protocol of MySQL, encapsulating the package of MySQL protocol, which is the driver. MySQL Driver MySQLDB's most famous library, which encapsulates and implements MySQL's C Clien ...

Posted on Thu, 19 Sep 2019 07:12:15 -0700 by BITRU

Don't come and see? I'll teach you how to speculate in stocks.

Recently, stock speculation is to buy what falls, has been losing money, cry, as a person who has learned python how to tolerate, before also speculated in the stock that use the k-line like Yang Baoyin to select the stock is good. So just do it. I can use python to write a stock selection program. Good! idea is the first step, how to achieve i ...

Posted on Thu, 19 Sep 2019 07:02:46 -0700 by Fjerpje