index.mapping.ignore_above

The ignore_above setting, typically used at the field level, can also be applied at the index level using index.mapping.ignore_above. This setting lets you define a maximum string length for all applicable fields across the index, including keyword, wildcard, and keyword values in flattened fields. Any values that exceed this limit will be ignored during indexing and won’t be stored.

This index-wide setting ensures a consistent approach to managing excessively long values. It works the same as the field-level setting—if a string’s length goes over the specified limit, that string won’t be indexed or stored. When dealing with arrays, each element is evaluated separately, and only the elements that exceed the limit are ignored.

const response = await client.indices.create({
  index: "my-index-000001",
  settings: {
    "index.mapping.ignore_above": 256,
  },
});
console.log(response);

PUT my-index-000001
{
  "settings": {
    "index.mapping.ignore_above": 256
  }
}

In this example, all applicable fields in my-index-000001 will ignore any strings longer than 256 characters.