> ## Documentation Index
> Fetch the complete documentation index at: https://wiki.lorenzo0111.me/llms.txt
> Use this file to discover all available pages before exploring further.

# MySQL FAQ

> Frequently asked questions about MySQL synchronization in RocketPlaceholders

# MySQL FAQ

Common questions and answers about using MySQL with RocketPlaceholders.

## General Questions

### What is the difference from MySQL and YML?

**YML (Local Storage):**

* Placeholders stored in local files
* Only available on the server where they're created
* No synchronization between servers

**MySQL:**

* Placeholders stored in a database
* Synchronized across all connected servers
* Centralized management from one main server

<Info>
  Use MySQL if you have multiple servers and want to manage placeholders centrally. Use YML for single-server setups or when you don't need synchronization.
</Info>

### What is a Main Server?

The main server is the server that stores placeholders in the MySQL database. All other servers read placeholders from the database.

<Warning>
  Only one server can be the main server. If multiple servers have `main: true`, it can cause conflicts.
</Warning>

**How it works:**

1. Main server writes placeholders to the database
2. Other servers read placeholders from the database
3. Changes on the main server automatically sync to other servers

### Will the MySQL cause lag?

No, MySQL synchronization is optimized and won't cause noticeable lag. All database operations are performed asynchronously, meaning they don't block the main server thread.

<Info>
  RocketPlaceholders uses efficient database queries and connection pooling to minimize any performance impact.
</Info>

## Configuration Questions

### If I use MySQL, are the config's placeholders read?

Yes! If the server is **not** a main server, you'll have:

* Placeholders from the MySQL database (from the main server)
* Placeholders from the local config file

**Priority:**

1. Database placeholders (from main server)
2. Local config placeholders

Database placeholders take priority over local placeholders.

### How can I delete all my config's placeholders to use only database placeholders?

Simply delete all placeholders from your local `placeholders` folder:

```yaml theme={null}
placeholders:
  # Nothing here ツ
```

This ensures only database placeholders are used.

### Can I have different placeholders on different servers?

Yes, but with limitations:

* Main server: Manages database placeholders (shared across all servers)
* Other servers: Can have local placeholders in addition to database placeholders
* Local placeholders on non-main servers won't sync to other servers

**Example Setup:**

* Main server: Has database placeholders (shared)
* Server 1: Has database placeholders + local server-specific placeholders
* Server 2: Has database placeholders + different local server-specific placeholders

## Troubleshooting

### Placeholders aren't syncing between servers

**Check:**

1. MySQL is enabled on all servers (`enabled: true`)
2. Only one server has `main: true`
3. All servers are connected to the same database
4. Database connection information is correct on all servers
5. Servers have restarted after configuration changes

### Changes on non-main server aren't appearing

**Remember:**

* Only changes on the main server sync to the database
* Changes on other servers are local only
* Make all placeholder changes on the main server

### Can't connect to MySQL

**Check:**

* MySQL server is running
* IP address and port are correct
* Username and password are correct
* Database exists
* Firewall allows connections
* MySQL user has CREATE, SELECT, INSERT, UPDATE, DELETE permissions

### Database connection errors

**Common issues:**

* Incorrect credentials
* Database doesn't exist
* MySQL server not running
* Network/firewall blocking connection
* MySQL user lacks permissions

## Best Practices

### 1. Backup Regularly

Always backup your MySQL database containing placeholders:

```bash theme={null}
mysqldump -u root -p rocketplaceholders > backup.sql
```

### 2. One Main Server

Always have exactly one server set as main. Having zero or multiple main servers can cause issues.

### 3. Test Changes

Test placeholder changes on the main server before expecting them on other servers.

### 4. Monitor Connections

Keep an eye on MySQL connection logs to ensure all servers are connecting properly.

## Related Guides

* [MySQL Setup](/rocketplaceholders/mysql) - Complete MySQL configuration guide
* [Configuration](/rocketplaceholders/configuration) - General configuration guide