Avoid the trap of duplicate indexes in MySQL-Mysql Tutorial-php.cn

Home

Database

Mysql Tutorial

Avoid the trap of duplicate indexes in MySQL

DDD

Apr 08, 2025 pm 04:33 PM

mysqlWhy

Avoid the trap of duplicate indexes in MySQL

MySQL indexing is the cornerstone of database performance optimization and can significantly improve data retrieval speed and efficiency. However, duplicate indexing may backfire, resulting in waste of resources and degrading query performance. This article is intended to provide practical guides to help you understand and avoid the pitfalls of duplicate indexing.

The dangers of repeated indexes

Repeated indexes can bring a series of problems:

Waste of storage space: Every redundant index takes up valuable disk space, which is particularly worrying for large databases.
Query efficiency decreases: MySQL query optimizer may experience difficulties when selecting the best index, which affects query performance.
Increased replication latency: The transmission of duplicate data between nodes will prolong replication time.
Reduced backup efficiency: Larger backup files can lead to extended backup and recovery times and increase maintenance downtime.

How to identify and delete duplicate indexes:

To identify duplicate indexes, you can use the following SQL statements:

 <code class="language-sql">SHOW INDEX FROM [table_name];</code>

Once the redundant index is found, it can be deleted using the following command:

 <code class="language-sql">DROP INDEX [idx_name] ON [table_name];</code>

Follow the above steps to maintain the efficiency and manageability of the database.

FAQ

What is duplicate indexing?

Repeated indexes are the same index created on the same column, usually due to human error.

Why is repeated indexing harmful?

They can lead to waste of resources, slow query speeds, and bloat backup files.

How to find duplicate indexes?

You can use DESCRIBE [table_name] or SHOW INDEX FROM [table_name] command to view index information on the table.

How to delete duplicate indexes?

Use the DROP INDEX command to delete unwanted indexes.

Summarize

Repeated indexing is a common problem in database optimization and can seriously affect database performance. By identifying and deleting duplicate indexes in a timely manner, you can optimize database storage, improve query performance, and simplify database maintenance processes. For more information, please refer to the related article: Duplicate Indexing in MySQL – Pros and Cons Analysis.

The above is the detailed content of Avoid the trap of duplicate indexes in MySQL. For more information, please follow other related articles on the PHP Chinese website!

Statement

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

How do you handle database upgrades in MySQL?Apr 30, 2025 am 12:28 AM

The steps for upgrading MySQL database include: 1. Backup the database, 2. Stop the current MySQL service, 3. Install the new version of MySQL, 4. Start the new version of MySQL service, 5. Recover the database. Compatibility issues are required during the upgrade process, and advanced tools such as PerconaToolkit can be used for testing and optimization.

What are the different backup strategies you can use for MySQL?Apr 30, 2025 am 12:28 AM

MySQL backup policies include logical backup, physical backup, incremental backup, replication-based backup, and cloud backup. 1. Logical backup uses mysqldump to export database structure and data, which is suitable for small databases and version migrations. 2. Physical backups are fast and comprehensive by copying data files, but require database consistency. 3. Incremental backup uses binary logging to record changes, which is suitable for large databases. 4. Replication-based backup reduces the impact on the production system by backing up from the server. 5. Cloud backups such as AmazonRDS provide automation solutions, but costs and control need to be considered. When selecting a policy, database size, downtime tolerance, recovery time, and recovery point goals should be considered.

What is MySQL clustering?Apr 30, 2025 am 12:28 AM

MySQLclusteringenhancesdatabaserobustnessandscalabilitybydistributingdataacrossmultiplenodes.ItusestheNDBenginefordatareplicationandfaulttolerance,ensuringhighavailability.Setupinvolvesconfiguringmanagement,data,andSQLnodes,withcarefulmonitoringandpe

How do you optimize database schema design for performance in MySQL?Apr 30, 2025 am 12:27 AM

Optimizing database schema design in MySQL can improve performance through the following steps: 1. Index optimization: Create indexes on common query columns, balancing the overhead of query and inserting updates. 2. Table structure optimization: Reduce data redundancy through normalization or anti-normalization and improve access efficiency. 3. Data type selection: Use appropriate data types, such as INT instead of VARCHAR, to reduce storage space. 4. Partitioning and sub-table: For large data volumes, use partitioning and sub-table to disperse data to improve query and maintenance efficiency.

How can you optimize MySQL performance?Apr 30, 2025 am 12:26 AM

TooptimizeMySQLperformance,followthesesteps:1)Implementproperindexingtospeedupqueries,2)UseEXPLAINtoanalyzeandoptimizequeryperformance,3)Adjustserverconfigurationsettingslikeinnodb_buffer_pool_sizeandmax_connections,4)Usepartitioningforlargetablestoi

How to use MySQL functions for data processing and calculationApr 29, 2025 pm 04:21 PM

MySQL functions can be used for data processing and calculation. 1. Basic usage includes string processing, date calculation and mathematical operations. 2. Advanced usage involves combining multiple functions to implement complex operations. 3. Performance optimization requires avoiding the use of functions in the WHERE clause and using GROUPBY and temporary tables.

An efficient way to batch insert data in MySQLApr 29, 2025 pm 04:18 PM

Efficient methods for batch inserting data in MySQL include: 1. Using INSERTINTO...VALUES syntax, 2. Using LOADDATAINFILE command, 3. Using transaction processing, 4. Adjust batch size, 5. Disable indexing, 6. Using INSERTIGNORE or INSERT...ONDUPLICATEKEYUPDATE, these methods can significantly improve database operation efficiency.

Steps to add and delete fields to MySQL tablesApr 29, 2025 pm 04:15 PM

In MySQL, add fields using ALTERTABLEtable_nameADDCOLUMNnew_columnVARCHAR(255)AFTERexisting_column, delete fields using ALTERTABLEtable_nameDROPCOLUMNcolumn_to_drop. When adding fields, you need to specify a location to optimize query performance and data structure; before deleting fields, you need to confirm that the operation is irreversible; modifying table structure using online DDL, backup data, test environment, and low-load time periods is performance optimization and best practice.

See all articles