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5.1 There are many types of pages that record data, such as pages for INODE information, pages for undo logs, and so on. This chapter explores the pages where records are stored (INDEX). 5.2 File Header General information for pages Page Header Some information unique to data pages Minimum Records on Page+Maximum Record Two dummy recor ...

1. General A lock is a mechanism by which a computer coordinates multiple processes or threads to access a resource concurrently. In the database, in addition to the contention of computer hardware resources (CPU, RAM, I/O, etc.), data is also a resource shared by many users. How to ensure the consistency and effectiveness of concurrent a ...

This chapter mainly talks about some application rules of index. 7.1 CREATE TABLE single_table ( id INT NOT NULL AUTO_INCREMENT, key1 VARCHAR(100), key2 INT, key3 VARCHAR(100), key_part1 VARCHAR(100), key_part2 VARCHAR(100), key_part3 VARCHAR(100), common_field VARCHAR(100), PRIMARY KEY (id), KEY idx_key1 (key1), UNIQUE KEY uk_key2 ...

catalogue   Backup command: mysqldump Example use 1. Export all database structures of the whole instance 2. Export data of a table under the database 3. Export a table structure in the database (excluding data) 4. Backup a single library without parameters (not recommended for production) 5. Use parameters to back up a single library ( ...

Summary of performance test steps 1. Observe and run for at least one day to see how slow the production is2. Start the slow query log and set the threshold. For example, slow SQL is used for more than 5 seconds, and grab it for processing. You can see the SQL statements that return the most recordsets3.explain + slow SQL analysis4.show p ...

Basic use guide Doris uses MySQL protocol for communication. Users can connect to Doris cluster through MySQL client or MySQL JDBC. When selecting the MySQL client version, it is recommended to use the version after 5.1, because the user name with a length of more than 16 characters cannot be supported before 5.1. Taking MySQL client as an exa ...

1, Multi table join query method If the information source of the query is multiple tables, a multi table connection query can be established by connecting two tables. The syntax of three table connection query is as follows: SELECT feldlist FROM table1 JOIN table2 ON table1.column1=table2.column2_1 JOIN table3 on mable2.colamn2_2=table3.c ...

1, Semi synchronous replication 1. What is semi synchronous replication The so-called semi synchronous replication refers to every transaction committed by the master (in short, an operation to change the data). Ensure that the slave accepts the binlog log file sent by the master server and writes it into its relay log relay log, and th ...

I'm a sophomore. The purpose of writing this article is to make a certain record of my knowledge and technology, and I'm willing to share it with you. Because I'm still young, there are inevitably some mistakes and omissions in the published article. Please forgive me and correct me if you read this article. If you have any questions during rea ...

Spring Boot JPA preface The full name of JPA is Java Persistence API, that is, Java Persistence API. It is a set of ORM based specifications launched by SUN company. It is internally composed of a series of interfaces and abstract classes. JPA describes the mapping relationship between object and relational table through JDK 5.0 annotation, a ...