[Enhancement] Auto Upgrade Mappings for system indices in ML-Commons

[Zhangxunmt]

What is the bug? When we add a field to the system index’s mapping (e.g. ml-model, ml-connector, etc), we should update the mapping proactively in the backend if the mapping changed before indexing. Currently, indexing a document which contains new fields will cause dynamic mapping, resulting in a text+keyword field and some Term/Query Search may not work properly anymore which is not expected. We should set dynamic to false for them to resolve this issue.

This problem occurs after the Memory index mapping is updated in the refactoring and the "memory_id" field is set to "text" through dynamic mapping. So the term search query doesn't return correct results based on the "memory_id".

Also, in this issue https://github.com/opensearch-project/ml-commons/issues/1860, updating the mapping for ml-models triggered some issues once the .plugins-ml-model is manually deleted in some edge cases.

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1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

What is the expected behavior? A clear and concise description of what you expected to happen.

What is your host/environment?

• OS: [e.g. iOS]
• Version [e.g. 22]
• Plugins

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[ylwu-amzn]

This problem occurs after the Memory index mapping is updated in the refactoring and the "memory_id" field is set to "text" through dynamic mapping. So the term search query doesn't return correct results based on the "memory_id".

@Zhangxunmt why this will happen? looks like a bug