升级Mac High Sierra 10.13.2后MAMP/AMPPS/XAMPP中MySQL Server无法启动求助

Hey there, let’s work through this frustrating MySQL problem you’re dealing with—since it’s happening across MAMP, AMPPS, and XAMPP, it’s clearly a system-level conflict or leftover issue from the OS upgrade, not just a single stack problem. Here’s a step-by-step breakdown to fix it:

1. Check for Conflicting System-Level MySQL Processes #

Mac High Sierra might have a pre-installed or leftover MySQL daemon running in the background that’s hogging the 3306 port or interfering with your AMP stack’s MySQL.

• First, list all running mysqld processes:

  ps aux | grep mysqld
  

  Look for any processes owned by root or _mysql that aren’t tied to your MAMP/AMPPS/XAMPP installation (the paths should show something like /Applications/MAMP/Library/bin/mysqld for MAMP).

• If you find an unrecognized mysqld process, stop it by unloading its launch daemon:

  # Replace with the actual plist file name if different
  sudo launchctl unload -w /Library/LaunchDaemons/com.mysql.mysqld.plist
  

  Common plist names include com.oracle.oss.mysql.mysqld.plist or com.mysql.mysql.plist—check the /Library/LaunchDaemons/ folder for any MySQL-related files.

2. Inspect MySQL Error Logs for Exact Failures #

The error log will tell you why MySQL won’t start—this is the most critical step. Here’s where to find logs for each stack:

• MAMP: /Applications/MAMP/logs/mysql_error_log.err
• XAMPP: /Applications/XAMPP/xamppfiles/var/mysql/[your-mac-hostname].err
• AMPPS: /Applications/AMPPS/logs/mysql.err

Open the log file and look for recent entries (towards the bottom). Common issues you might see:

• Permission errors on data directories
• Corrupted InnoDB log files
• Port conflicts
• Invalid configuration settings in my.cnf

3. Fix Directory Permission Issues #

OS upgrades often reset file permissions, which can prevent MySQL from accessing its data or log files.

• Locate your MySQL data directory:

  • MAMP: /Applications/MAMP/db/mysql
  • XAMPP: /Applications/XAMPP/xamppfiles/var/mysql
  • AMPPS: /Applications/AMPPS/mysql/data

• Set the correct owner and permissions for the directory:

  # Replace [data-directory-path] with the actual path above
  sudo chown -R _mysql:_mysql [data-directory-path]
  sudo chmod -R 755 [data-directory-path]
  

4. Validate and Adjust MySQL Configuration (my.cnf) #

Outdated or incompatible settings in my.cnf can break startup after an OS upgrade.

• Find your my.cnf file:

  • MAMP: /Applications/MAMP/conf/my.cnf
  • XAMPP: /Applications/XAMPP/xamppfiles/etc/my.cnf
  • AMPPS: /Applications/AMPPS/mysql/etc/my.cnf

• Check these key settings:

  • innodb_log_file_size: If you previously deleted ib_logfile0/ib_logfile1, make sure this value matches what MySQL expects (or comment it out temporarily to let MySQL auto-generate the correct log file size).
  • bind-address: Ensure it’s set to 127.0.0.1 (local only) to avoid network conflicts.
  • port: Confirm it’s set to 3306 (or a different port if you intentionally changed it, but make sure no other process is using that port).

5. Fully Clean Up MySQL Residues Before Reinstalling #

If reinstalling stacks didn’t work, leftover system files are likely causing the issue. Uninstall your current AMP stack, then delete these MySQL-related files/folders:

• /Library/LaunchDaemons/: Any MySQL .plist files
• /Library/StartupItems/MySQLCOM (if it exists)
• /usr/local/mysql (if this folder exists)
• ~/Library/Application Support/: MAMP/AMPPS/XAMPP folders
• /var/db/receipts/: Any MySQL-related .pkg receipt files

After deleting all residues, restart your Mac, then reinstall your preferred AMP stack.

6. Verify Port 3306 Isn’t Occupied by Another App #

Use this command to check if any process is using port 3306:

sudo lsof -i :3306

If you see a process other than your AMP stack’s MySQL, kill it with:

sudo kill -9 [PID]

(Replace [PID] with the process ID from the lsof output.)

内容的提问来源于stack exchange，提问作者fransBernhard