What are the default values of interactive_timeout and wait_timeout in Amazon RDS?

For Amazon RDS for MySQL, the default value for both interactive_timeout and wait_timeout is 28,800 seconds, which is equivalent to 8 hours.

The interactive_timeout parameter specifically refers to the number of seconds the server waits for activity on an interactive connection before closing it. An interactive client is defined as a client that uses the CLIENT_INTERACTIVE option to perform mysql_real_connect().

As for wait_timeout, it applies to non-interactive connections and serves a similar purpose of timing out idle connections.

Regarding best practices for setting these values:

1. The appropriate settings depend on your specific environment and workload.
2. If you encounter errors related to connections being closed unexpectedly, you might need to gradually increase these values until the errors are resolved.
3. It's generally recommended to keep these timeout values reasonably low to prevent idle connections from consuming resources unnecessarily. However, setting them too low might cause issues for legitimate long-running queries or transactions.
4. Consider your application's behavior and connection patterns when adjusting these values. For example, if your application has long-running transactions or queries, you might need higher timeout values.
5. Monitor your database performance and connection usage to fine-tune these parameters over time.

Remember that changing these parameters may require a restart of your RDS instance, so plan accordingly when making adjustments.

Sources
Best practices for configuring parameters for Amazon RDS for MySQL, part 3: Parameters related to security, operational manageability, and connectivity timeout | AWS Database Blog

Another tip: when the source for the parameter is engine-default that means it will use the same value as the documented engine defaults:

https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_wait_timeout

$ aws rds describe-engine-default-parameters --db-parameter-group-family mysql8.0 --query 'EngineDefaults.Parameters[?ParameterName==`wait_timeout`].{ParameterName:ParameterName, Source:Source}'
[
    {
        "ParameterName": "wait_timeout",
        "Source": "engine-default"
    }
]