How to Increase index.max_regex_length in OpenSearch – Source: socprime.com

The error index.max.regex_length in OpenSearch is related to the maximum length of regular expressions that can be used in index settings. This setting controls the maximum length of a regular expression used during index creation or mapping, and when a regex pattern exceeds this length, you will encounter an error.

To fix this, you can adjust the index.max.regex_length setting. Here’s how to resolve it.

Solution

• Increase the index.max.regex_length setting: If your regular expression is large, you might need to increase the allowed regex length. You can do this by adding the following setting to your OpenSearch index settings:

PUT /your_index/_settings {   "settings": {     "index.max.regex_length": 10000   } }

In this example, the limit is set to 10,000 characters, but you can adjust this value according to the complexity of your regular expression.

• Update Index Template (for new indices): If you’re using index templates and want to apply this setting to newly created indices, you can add this setting to your index template as well.

PUT /_template/your_template {   "index_patterns": ["your_index_pattern*"],   "settings": {     "index.max.regex_length": 10000   } }

• Check Regular Expressions: Ensure that the regular expression you are using is not unnecessarily long or complex. Try simplifying or optimizing the regex if possible.

Example

Here’s how you can check the current setting and modify it:

• Check the current value:

GET /your_index/_settings

• Update the setting if needed:

PUT /your_index/_settings {   "settings": {     "index.max.regex_length": 10000   } }

This should allow you to avoid running into the error with larger regular expressions.

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