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The original content of GreatSQL community cannot be used without authorization. Please contact Xiaobian and indicate the source for reprint. 1. Problems encountered Tester Xiao Ling plans to deploy the MGR cluster in the docker environment for some tests. She has three containers with IP addresses: 172.33.0.2 172.33.0.3 172.33.0.4 Install a ...

mysql pxc high availability 1, pxc introduction PXC (Percona XtraDB Cluster) is an open source MySQL high availability solution. He integrates Percona Server and XtraBackup with the Galera library for synchronous multi master replication. The high availability solutions based on Galera mainly include MariaDB Galera Cluster and Percona Xtra ...

Indexing principle and slow query optimization 1. What is an index? Index is a data structure in the storage engine, or the organization of data, also known as key. It is a data structure used by the storage engine to quickly find records. Building an index for data is like building a directory for a book, or creating a phonetic order ...

I often encounter the development and testing of children's shoes and ask if a DDL has been executed in the offline development and testing environment. I find that it has not been executed for a long time. Is it blocked? How to solve it? Including in the group, we often encounter similar problems: DDL is blocked. How to find the SQL blocking i ...

1, Optimize index 1. Not indexed 2. The index is not effective //explain check index usage explain select * from `tb_order` where code='002'; Reason for index failure 3. Wrong index For the same sql, only the input parameters are different. Sometimes it's index a, but sometimes it's index b? This is because mysql will select the wrong ...

I believe that friends with development experience have encountered such a demand. Suppose you are developing a comment function for a news website. Readers can comment on the original text and even reply to each other. This demand is not simple. Replying to each other will lead to infinite branches and infinite ancestor offspring relationship ...

There are many special symbols in MySQL that are quite disgusting. For example, there are single quotation marks ('), double quotation marks ("), backslashes (\) and so on in the string. Students can make up for the possible problems first? In our usual SQL operations, if you don't pay attention to these symbols, you will be given a pot o ...

In many scenarios, we need to view the table comments in MySQL or the comments of all fields under a table, so this article will count and compare several ways to query comments.Create test databaseBefore we start, let's create a database for the following demonstration.-- If it exists, delete the database first drop database if exists test2022 ...

Welcome to the MySQL technical articles shared by the great SQL community. If you have any questions or want to learn, you can leave a message in the comment area below. After seeing it, you will answer itProblem descriptionThe problem comes from a group friend. In short, he uses mysqlbinlog tool to read binlog for recovery, but finds that the ...

Do you want to accurately find the MySQL articles you want to read? Here → MySQL column directory | click here    MySQL row column conversion must be familiar or even impressive to students who often process data, because it probably bothers you and makes you stunned ~ but when you see this article, this problem is no longer ...