Which script score and/or painless functionality is supported by OpenSearch Serverless?

Amazon OpenSearch Serverless supports the Painless scripting language, which is one of the scripting plugins included in the service. However, the specific functionality and features available within Painless for OpenSearch Serverless may be more limited compared to standalone OpenSearch or the managed OpenSearch Service.

While Painless is supported, it's important to note that OpenSearch Serverless comes with a pre-packaged set of plugins and features, and not all functionalities available in standalone OpenSearch may be present.

Regarding script_score and specific functions like termFreq, the documentation doesn't explicitly state which exact functions are supported or not supported in the Serverless offering. The errors you've encountered with string fields and termFreq suggest that there might indeed be limitations or differences in the implementation compared to standalone OpenSearch.

Unfortunately, without more detailed documentation or official statements from AWS, it's difficult to provide a comprehensive list of supported script_score and Painless functionalities in OpenSearch Serverless. If you're encountering specific issues or need clarification on particular functions, it would be advisable to reach out to AWS support for more detailed information about the current capabilities and any potential limitations in the Serverless environment.

Keep in mind that AWS regularly updates and expands the features of their services, so it's possible that additional scripting functionalities may be added in the future based on user feedback and requirements.
Sources
Supported operations and plugins in Amazon OpenSearch Serverless - Amazon OpenSearch Service
Introducing Point in Time queries and SQL/PPL support in Amazon OpenSearch Serverless | AWS Big Data Blog

Hi AWS team,
Is there any documentation on which Script score functionality is supported in Serverless. Can you please share the link?