How to Set max_result_window in Elasticsearch for Large Result Sets

To set max_result_window in Elasticsearch, update the index settings using the PUT API with the index.max_result_window parameter. This controls the maximum number of search hits you can page through, and you must apply it per index.

Syntax

The max_result_window setting is configured per index using the PUT /{index}/_settings API call. You specify the new limit inside index.max_result_window in the JSON body.

Example parts:

• {index}: The name of your Elasticsearch index.
• index.max_result_window: The maximum number of results you want to allow for pagination.

json

PUT /my_index/_settings
{
  "index" : {
    "max_result_window" : 50000
  }
}

Example

This example increases the max_result_window to 50,000 for an index named products. This allows you to page through up to 50,000 search results instead of the default 10,000.

json

PUT /products/_settings
{
  "index" : {
    "max_result_window" : 50000
  }
}

Output

{
  "acknowledged" : true
}

Common Pitfalls

Common mistakes when setting max_result_window include:

• Trying to set it globally instead of per index. It must be set on each index individually.
• Setting a very high value can cause high memory use and slow queries.
• Not refreshing the index settings after update, so the change doesn't take effect immediately.

Always test performance impact when increasing this value.

json

### Wrong: Trying to set globally (this will fail)
PUT /_settings
{
  "index" : {
    "max_result_window" : 50000
  }
}

### Right: Set per index
PUT /my_index/_settings
{
  "index" : {
    "max_result_window" : 50000
  }
}

Quick Reference

Setting	Description	Default Value	Notes
index.max_result_window	Maximum number of search results that can be paged through	10000	Set per index; increasing may impact performance
API Endpoint	Where to set the value	PUT /{index}/_settings	Replace {index} with your index name
Effect	Controls max offset for from+size pagination	10000	Use scroll or search_after for deep pagination instead

Key Takeaways

Set max_result_window per index using PUT /{index}/_settings with index.max_result_window.

Default max_result_window is 10,000; increase only if you need to page deeper.

High max_result_window values can cause performance and memory issues.

Use scroll or search_after APIs for efficient deep pagination instead of very large max_result_window.

Always verify changes with acknowledged response and test query performance.