CodeIgniter生产环境数据库连接异常排查及配置调整咨询

Let me break down how to fix this "unable to connect to your database server" error you're seeing—this is a super common issue, so we can work through it step by step.

First, Verify the Basics #

Before tweaking your config, let's rule out the most obvious culprits:

• Test connectivity directly from your web server: Log into your production server via SSH and run this command to check if you can connect using your exact credentials:

  mysql -u infomagi_user -p'Sdf!23!@#$5' -h localhost infomagi_infodb
  

  If localhost doesn't work, try your database server's actual IP/domain here. If this command fails, the problem isn't CodeIgniter—it's your credentials, permissions, or server reachability.

Key Config Adjustments & Fixes #

Based on your provided settings, here are the critical changes and checks to make:

1. Update the Database Hostname #

In production, localhost often doesn't point to the correct database server—especially if your web server and database are on separate machines (common in shared hosting or cloud setups):

• Replace 'localhost' with your actual database server address (ask your host for this if unsure; it might be a domain like db.yourdomain.com or an internal IP):

  $db['default']['hostname'] = '10.0.0.5'; // Example database server IP
  

2. Fix Database User Permissions #

Most production databases restrict which IPs can connect to a user account. Your infomagi_user might only be allowed to connect from localhost, but your web server is on a different IP:

• Log into your database (via phpMyAdmin or SSH) and run these commands to grant access from your web server's IP:

  GRANT ALL PRIVILEGES ON infomagi_infodb.* TO 'infomagi_user'@'YOUR_WEB_SERVER_IP' IDENTIFIED BY 'Sdf!23!@#$5';
  FLUSH PRIVILEGES;
  

  Replace YOUR_WEB_SERVER_IP with the public IP of your web host.

3. Tweak Production-Friendly Settings #

Your current config has a couple of settings that aren't ideal for production, and might even contribute to connection issues:

• Disable debug mode: db_debug = TRUE exposes sensitive database details to users when errors occur. Fix this:

  $db['default']['db_debug'] = FALSE;
  

• Try persistent connections: Some hosting providers require persistent connections to handle load. If direct tests work but CodeIgniter still fails, toggle this:

  $db['default']['pconnect'] = TRUE;
  

Final Checks #

• Confirm your MySQL/MariaDB service is running on the database server.
• Verify port 3306 (default MySQL port) is open between your web server and database server.
• Double-check that the infomagi_infodb database exists and hasn't been renamed or deleted.

内容的提问来源于stack exchange，提问作者sachu