This article summarizes the solutions to MYSQL is marked as crashed and should be repaired. Friends in need can refer to it. problem analysis As for the cause of the error, some netizens said that it was an index error caused by frequent querying and updating of the [data table] table. Because my page was not statically generated, but a dynamic page, I quite agree with this statement. It is also said that the MYSQL database has been damaged for some reason. For example, a sudden power outage of the database server, some operation on the original file of the table when providing services to the database table may cause the MYSQL database to be damaged. The table is corrupted and the data cannot be read. In short, the watch is damaged due to some unfathomable problems. Solution The fix is as follows. Find myisamchk under your mysql/bin. Enter at the command line: code show as below Copy code
1. 10 recommended articles about the mysql_stat() function
Introduction: This article summarizes the solutions to MYSQL is marked as crashed and should be repaired. Friends in need can refer to it. Problem analysis: The cause of the error was analyzed. Some netizens said that it was an index error caused by frequent querying and updating of the [data table] table. Because my page was not statically generated, but a dynamic page, I quite agree with this statement. It is also said that the MYSQL database has been damaged for some reason, such as: sudden power outage of the database server,...
2. MYSQL is marked as crashed and should be repaired solution
Introduction: This article summarizes the solution for MYSQL is marked as crashed and should be repaired. Friends in need can refer to it. one time.
3. Solution to "mysqld is dead, but subsys is locked" when installing MYSQL on Red Hat Linux 9
Introduction : I installed MYSQL on Red Hat Linux 9 today, but after service mysql start, the following prompt appears when checking service mysql status: mysqld
4. mysql_stat() queries the MySQL server Current system status
Introduction: mysql tutorial: mysql_stat() queries the current system status definition and usage of the MySQL server. The mysql_stat() function returns the current system status of the MySQL server. If successful, the function returns status. On failure, returns false. Syntax mysql_stat(connection) Parameter description connection can
5. Basic introduction to MySQL database commands
Introduction: The following The article is mainly a detailed analysis of the basics of MySQL database commands. We first start by displaying the basic information of the MySQL database to conduct a detailed analysis of the basics of the MySQL database commands. The following is a description of the specific content of the article. Display basic MySQL information: MySQL status; View variables: showvariableslike'%ver
6. View the default encoding of the MySQL database
Introduction: Check the default encoding of the MySQL database. Use the status command to display the related information of the database. The example is as follows: mysql status; ———— mysql Ver 14.12 Distrib 5.0.77, for Win32 (ia32) Connectionid: 1072 Current database : Currentuser: test@119.119.247.6 SSL: Not in use Usin
Introduction :001 Check the version mysql --version mysql select version(); mysql status; 002 Create a new MySQL user and authorize insert into mysql.user(Host,User,Password) values(localhost,username,password(yourpassword)); GRANT ALL PRIVILEGES ON *.* TO 'username'@'localhost'
Introduction: [shengting @login ~]$ mysql -V mysql Ver 14.7 Distrib 4.1.10a, for redhat-linux-gnu (i686) 2: In mysql: mysql status; The following is the code snippet: mysql status; -------- ------ mysql Ver 14.7 Distrib 4.1.10a, for redhat-linux-gnu (i686) Connection id:
9. The optimal choice of MySQL data types
Introduction: Welcome to the Linux Community Forum and interact with 2 million technical personnel> >Enter 5 rows in set (0.06 sec) mysql status; -------------- mysql Ver 14.14 Distrib 5.5.16, for Linux (i686) using EditLine wrapper Connection id: 1 Current database : information_schema Curre
10. Cannot open mysql on the ubuntu server, please answer online!
Introduction: When querying the status, it prints as follows xxx@r10f17332:~$ service mysql status mysql stop/waiting. When starting, it prints as follows xxx@r10f17332:~$ service mysql start start: Rejected send message, 1 matched rules; type="method_call", sender=":1.114" (uid=121493 pid=29149 comm=&quo
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InnoDB uses redologs and undologs to ensure data consistency and reliability. 1.redologs record data page modification to ensure crash recovery and transaction persistence. 2.undologs records the original data value and supports transaction rollback and MVCC.

Key metrics for EXPLAIN commands include type, key, rows, and Extra. 1) The type reflects the access type of the query. The higher the value, the higher the efficiency, such as const is better than ALL. 2) The key displays the index used, and NULL indicates no index. 3) rows estimates the number of scanned rows, affecting query performance. 4) Extra provides additional information, such as Usingfilesort prompts that it needs to be optimized.

Usingtemporary indicates that the need to create temporary tables in MySQL queries, which are commonly found in ORDERBY using DISTINCT, GROUPBY, or non-indexed columns. You can avoid the occurrence of indexes and rewrite queries and improve query performance. Specifically, when Usingtemporary appears in EXPLAIN output, it means that MySQL needs to create temporary tables to handle queries. This usually occurs when: 1) deduplication or grouping when using DISTINCT or GROUPBY; 2) sort when ORDERBY contains non-index columns; 3) use complex subquery or join operations. Optimization methods include: 1) ORDERBY and GROUPB

MySQL/InnoDB supports four transaction isolation levels: ReadUncommitted, ReadCommitted, RepeatableRead and Serializable. 1.ReadUncommitted allows reading of uncommitted data, which may cause dirty reading. 2. ReadCommitted avoids dirty reading, but non-repeatable reading may occur. 3.RepeatableRead is the default level, avoiding dirty reading and non-repeatable reading, but phantom reading may occur. 4. Serializable avoids all concurrency problems but reduces concurrency. Choosing the appropriate isolation level requires balancing data consistency and performance requirements.

MySQL is suitable for web applications and content management systems and is popular for its open source, high performance and ease of use. 1) Compared with PostgreSQL, MySQL performs better in simple queries and high concurrent read operations. 2) Compared with Oracle, MySQL is more popular among small and medium-sized enterprises because of its open source and low cost. 3) Compared with Microsoft SQL Server, MySQL is more suitable for cross-platform applications. 4) Unlike MongoDB, MySQL is more suitable for structured data and transaction processing.

MySQL index cardinality has a significant impact on query performance: 1. High cardinality index can more effectively narrow the data range and improve query efficiency; 2. Low cardinality index may lead to full table scanning and reduce query performance; 3. In joint index, high cardinality sequences should be placed in front to optimize query.

The MySQL learning path includes basic knowledge, core concepts, usage examples, and optimization techniques. 1) Understand basic concepts such as tables, rows, columns, and SQL queries. 2) Learn the definition, working principles and advantages of MySQL. 3) Master basic CRUD operations and advanced usage, such as indexes and stored procedures. 4) Familiar with common error debugging and performance optimization suggestions, such as rational use of indexes and optimization queries. Through these steps, you will have a full grasp of the use and optimization of MySQL.

MySQL's real-world applications include basic database design and complex query optimization. 1) Basic usage: used to store and manage user data, such as inserting, querying, updating and deleting user information. 2) Advanced usage: Handle complex business logic, such as order and inventory management of e-commerce platforms. 3) Performance optimization: Improve performance by rationally using indexes, partition tables and query caches.


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