Description
- Default value: 4kb
- Possible values: Any positive byte size value (e.g., 8kb, 16kb)
- Recommendations: The default value is suitable for most use cases. Increase only if you encounter issues with long request lines.
This setting limits the length of the initial line in an HTTP request, which typically includes the HTTP method, URL, and protocol version. If a request exceeds this limit, Elasticsearch will reject it with a 414 (Request-URI Too Long) error.
Example
To change the http.max_initial_line_length setting using the cluster settings API:
PUT /_cluster/settings
{
"persistent": {
"http.max_initial_line_length": "8kb"
}
}
You might want to increase this value if you're working with very long URLs or query strings in your Elasticsearch requests. However, be cautious as extremely large values can potentially expose your cluster to denial-of-service attacks.
Common Issues or Misuses
- Setting the value too low can result in legitimate requests being rejected, especially if your application uses long URLs or query strings.
- Setting the value too high might expose your cluster to potential security risks or resource exhaustion attacks.
Do's and Don'ts
- Do monitor your Elasticsearch logs for 414 errors to identify if you need to increase this setting.
- Do consider alternative approaches (like POST requests with request bodies) for very large queries instead of relying on long URLs.
- Don't set this value unnecessarily high without considering the security implications.
- Don't change this setting without testing the impact on your specific use case and environment.
Frequently Asked Questions
Q: How does the http.max_initial_line_length setting affect Elasticsearch performance?
A: This setting primarily affects the handling of incoming HTTP requests. A higher value allows for longer request lines but may slightly increase memory usage for request parsing. In most cases, the performance impact is negligible unless set to extremely high values.
Q: Can changing http.max_initial_line_length solve "Request-URI Too Long" errors?
A: Yes, increasing this setting can resolve 414 (Request-URI Too Long) errors. However, it's important to investigate why such long URIs are being used and consider alternative approaches if possible.
Q: Is it safe to increase http.max_initial_line_length in a production environment?
A: While it's generally safe to increase this value moderately, it's recommended to test any changes in a non-production environment first. Significant increases should be carefully considered due to potential security implications.
Q: How does this setting relate to the maximum URL length in web browsers?
A: Web browsers have their own limits on URL length, which are typically much lower than Elasticsearch's default 4kb. Increasing this setting in Elasticsearch won't affect browser limitations, so client-side considerations are still necessary.
Q: Can http.max_initial_line_length be set differently for individual nodes in a cluster?
A: While it's possible to set different values on individual nodes, it's generally recommended to keep this setting consistent across all nodes in a cluster to ensure uniform request handling and avoid unexpected behavior.
