The http.max_content_length setting in Elasticsearch controls the maximum size of HTTP request bodies that can be accepted by the cluster. This setting is crucial for managing large bulk requests and preventing potential out-of-memory errors.
Description
- Default Value: 100mb
- Possible Values: Any size value (e.g., 200mb, 1gb)
- Recommendations: Adjust based on your specific use case and available memory. Increase if you need to handle larger bulk requests or document sizes.
This setting is available in all recent versions of Elasticsearch.
Example
To change the http.max_content_length setting using the cluster settings API:
PUT _cluster/settings
{
"persistent": {
"http.max_content_length": "200mb"
}
}
You might want to increase this value if you're working with large documents or performing large bulk operations. However, be cautious as setting it too high could lead to excessive memory usage.
Common Issues and Misuses
- Setting the value too low can result in "Request Content-Length is too large" errors when trying to index large documents or perform bulk operations.
- Setting the value too high without proper memory allocation can lead to out-of-memory errors.
Do's and Don'ts
- Do adjust this setting if you frequently work with large documents or bulk requests.
- Do ensure your cluster has sufficient memory to handle the maximum content length you set.
- Don't set this value arbitrarily high without considering the memory implications.
- Don't ignore this setting when troubleshooting indexing or bulk operation failures.
Frequently Asked Questions
Q: How does http.max_content_length affect bulk operations?
A: This setting limits the size of bulk requests. If a bulk request exceeds this limit, it will be rejected. Increase this setting if you need to perform larger bulk operations.
Q: Can changing http.max_content_length impact cluster performance?
A: Yes, setting it too high can lead to increased memory usage and potential out-of-memory errors. Setting it too low can increase the number of requests needed for large operations, potentially impacting throughput.
Q: Is http.max_content_length the same as index.max_docvalue_fields_search?
A: No, these are different settings. http.max_content_length limits HTTP request size, while index.max_docvalue_fields_search limits the number of doc value fields that can be queried at once.
Q: Can http.max_content_length be set differently for different nodes?
A: While it's possible to set different values on different nodes, it's generally recommended to keep this setting consistent across the cluster to avoid confusion and potential issues.
Q: How does http.max_content_length relate to the maximum document size in Elasticsearch?
A: While http.max_content_length limits the HTTP request size, the maximum document size is also influenced by other factors like the Lucene term byte limit. However, http.max_content_length must be large enough to accommodate your largest documents plus overhead for the request itself.
