Azure AI Search: Newly Added Filterable Fields Not Populating After Indexer Run

Question

I recently added two new fields to my Azure AI Search index and marked them as filterable. After updating the index schema and running the indexer, the new fields are still not populated in the index.

Steps Taken So Far:

• Ran the indexer to pull in the new data from the data source.
• Verified that the data source contains values for these fields.
• Checked the index definition in Azure Portal, and the fields appear correctly.

Questions:

• Do I need to reset or delete the indexer before the new fields can populate?
• Is there a way to force Azure Search to re-index only the new fields?
• Could this be due to indexer caching or an issue with field mappings?

Any guidance on troubleshooting this issue would be greatly appreciated!

I also tried an alternative approach by creating a new index. This time, the fields are populated, but they are no longer filterable.

This is the first Index where I have added new fields manually

This is the newly added index with auto mapping fields

Answer 1

Hello @Anonymous ,

The issue isn’t related to field caching or mappings. Instead, it’s about keeping the AI Search index structure consistent over time. Once an index is created, most field definitions (except for "Retrievable") are locked in and cannot be changed. Adding new fields is possible, but modifying existing ones requires rebuilding the index.

Because of this, developers often use the Azure portal for quick tests and simple index setups. However, for frequent changes or iterations, a code-based approach is recommended, as it allows you to rebuild the index more efficiently.

• Do I need to reset or delete the indexer before the new fields appear? → Yes, you need to rebuild the index.
• Can I force Azure Search to update only the new fields? → No, new fields must follow the original index schema.
• Could this be caused by indexer caching or field mappings? → No, that’s not the issue.

You can refer to the Azure Search documentation for more details.

Hope this helps!

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