The http.max_warning_header_count setting in Elasticsearch controls the maximum number of warning headers that can be included in an HTTP response.
Description
- Default value: 8
- Possible values: Any positive integer
- Recommendation: Keep the default value unless you have specific requirements
This setting limits the number of warning headers that Elasticsearch will include in its HTTP responses. Warning headers are used to communicate non-critical issues or deprecation notices to clients.
Version Information
This setting was introduced in Elasticsearch 7.0.0.
Example
To change the http.max_warning_header_count setting using the cluster settings API:
PUT /_cluster/settings
{
"persistent": {
"http.max_warning_header_count": 10
}
}
Increasing this value allows more warning headers to be included in responses, which can be useful for debugging or when you need more detailed information about potential issues. However, setting it too high might increase the response size unnecessarily.
Common Issues
- Setting the value too low may result in important warnings being omitted from responses.
- Setting the value too high may lead to unnecessarily large HTTP responses.
Do's and Don'ts
- Do monitor your application logs and adjust this setting if you notice truncated warnings.
- Don't set this value excessively high without a good reason, as it may impact performance.
- Do consider the needs of your monitoring and logging systems when configuring this setting.
Frequently Asked Questions
Q: What happens if the number of warnings exceeds the http.max_warning_header_count?
A: If the number of warnings exceeds the limit, Elasticsearch will truncate the list and include only the most important warnings up to the specified limit.
Q: Can setting http.max_warning_header_count to a very high value impact performance?
A: While the impact is generally minimal, setting it to an extremely high value could potentially increase the size of HTTP responses and the processing time required to generate them.
Q: Is it possible to disable warning headers completely?
A: While it's not recommended, you can effectively disable warning headers by setting http.max_warning_header_count to 0. However, this may make it harder to identify and address potential issues.
Q: How can I view the current value of http.max_warning_header_count?
A: You can view the current value by using the cluster settings API: GET /_cluster/settings?include_defaults=true
Q: Are warning headers related to deprecation notices?
A: Yes, deprecation warnings are one type of warning that can be included in these headers. They inform users about features or APIs that may be removed or changed in future versions of Elasticsearch.
