bitsCN.com
修改MySQL 5.5的max_allowed_packet属性的方法
今天在部署一个实验系统的时候，报出下面这个错：
Your 'max_allowed_packet' variable is set to less than 16777216 Byte (16MB).
也很容易理解，就是需要修改一下MySQL的配置文件，但是这里面有个小技巧（在Windows 7中）：如果直接使用记事本或notepad++打开MySQL 5.5文件夹底下的my.ini，会提示该文件被其他程序占用，或者拒绝访问之类的（如：“please check if this file is opended in another program”）。如果已经停止了MySQL服务，那么其实就不是程序占用的问题。解决方法也很简单，首先，在MySQL 5.5安装目录下，将my.ini剪切到别处，这时会要求用管理员身份继续。
然后呢，在MySQL 5.5安装目录下，有很多和my.ini类似的文件，如my-small.ini，使用管理员身份启动某个文本编辑软件（如notepad++），将my.ini和my-small.ini都打开，将my-small.ini里面的这几行：
[plain]
[mysqldump]
quick
max_allowed_packet = 16M
拷贝到my.ini文件中，然后就可以保存成功了。再使用管理员身份拷贝到MySQL 5.5安装目录下，就可以实现我们的目的了。
就这么简单，记录一下。
bitsCN.com
What are some tools you can use to monitor MySQL performance?Apr 23, 2025 am 12:21 AMHow to effectively monitor MySQL performance? Use tools such as mysqladmin, SHOWGLOBALSTATUS, PerconaMonitoring and Management (PMM), and MySQL EnterpriseMonitor. 1. Use mysqladmin to view the number of connections. 2. Use SHOWGLOBALSTATUS to view the query number. 3.PMM provides detailed performance data and graphical interface. 4.MySQLEnterpriseMonitor provides rich monitoring functions and alarm mechanisms.
How does MySQL differ from SQL Server?Apr 23, 2025 am 12:20 AMThe difference between MySQL and SQLServer is: 1) MySQL is open source and suitable for web and embedded systems, 2) SQLServer is a commercial product of Microsoft and is suitable for enterprise-level applications. There are significant differences between the two in storage engine, performance optimization and application scenarios. When choosing, you need to consider project size and future scalability.
In what scenarios might you choose SQL Server over MySQL?Apr 23, 2025 am 12:20 AMIn enterprise-level application scenarios that require high availability, advanced security and good integration, SQLServer should be chosen instead of MySQL. 1) SQLServer provides enterprise-level features such as high availability and advanced security. 2) It is closely integrated with Microsoft ecosystems such as VisualStudio and PowerBI. 3) SQLServer performs excellent in performance optimization and supports memory-optimized tables and column storage indexes.
How does MySQL handle character sets and collations?Apr 23, 2025 am 12:19 AMMySQLmanagescharactersetsandcollationsbyusingUTF-8asthedefault,allowingconfigurationatdatabase,table,andcolumnlevels,andrequiringcarefulalignmenttoavoidmismatches.1)Setdefaultcharactersetandcollationforadatabase.2)Configurecharactersetandcollationfor
What are triggers in MySQL?Apr 23, 2025 am 12:11 AMA MySQL trigger is an automatically executed stored procedure associated with a table that is used to perform a series of operations when a specific data operation is performed. 1) Trigger definition and function: used for data verification, logging, etc. 2) Working principle: It is divided into BEFORE and AFTER, and supports row-level triggering. 3) Example of use: Can be used to record salary changes or update inventory. 4) Debugging skills: Use SHOWTRIGGERS and SHOWCREATETRIGGER commands. 5) Performance optimization: Avoid complex operations, use indexes, and manage transactions.
How do you create and manage user accounts in MySQL?Apr 22, 2025 pm 06:05 PMThe steps to create and manage user accounts in MySQL are as follows: 1. Create a user: Use CREATEUSER'newuser'@'localhost'IDENTIFIEDBY'password'; 2. Assign permissions: Use GRANTSELECT, INSERT, UPDATEONmydatabase.TO'newuser'@'localhost'; 3. Fix permission error: Use REVOKEALLPRIVILEGESONmydatabase.FROM'newuser'@'localhost'; then reassign permissions; 4. Optimization permissions: Use SHOWGRA
How does MySQL differ from Oracle?Apr 22, 2025 pm 05:57 PMMySQL is suitable for rapid development and small and medium-sized applications, while Oracle is suitable for large enterprises and high availability needs. 1) MySQL is open source and easy to use, suitable for web applications and small and medium-sized enterprises. 2) Oracle is powerful and suitable for large enterprises and government agencies. 3) MySQL supports a variety of storage engines, and Oracle provides rich enterprise-level functions.
What are the disadvantages of using MySQL compared to other relational databases?Apr 22, 2025 pm 05:49 PMThe disadvantages of MySQL compared to other relational databases include: 1. Performance issues: You may encounter bottlenecks when processing large-scale data, and PostgreSQL performs better in complex queries and big data processing. 2. Scalability: The horizontal scaling ability is not as good as Google Spanner and Amazon Aurora. 3. Functional limitations: Not as good as PostgreSQL and Oracle in advanced functions, some functions require more custom code and maintenance.
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),
SublimeText3 English version
Recommended: Win version, supports code prompts!
WebStorm Mac version
Useful JavaScript development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
SublimeText3 Linux new version
SublimeText3 Linux latest version
