⚡️ [us-east-1] RAG chat knowledge not refreshing after S3 file deletion

Thanks for the chatbot response.　 Thank you for your kindness and support, chatbot 😄🤖 At 10:09 a.m. (Japan time) on 2025/10/23, I tested it again, and the syncing succeeded.

Have a nice day! If I have more questions, I’ll write them down below. Anyway.

When you delete files from your S3 bucket that's connected to an Amazon Bedrock Knowledge Base, you need to explicitly sync the data source again for those changes to be reflected in your RAG application.

Syncing in Bedrock Knowledge Base works incrementally, which means it only processes added, modified, or deleted documents since the last sync. However, simply putting files in or removing them from the S3 folder connected to Bedrock does not automatically trigger synchronization.

To refresh your RAG knowledge after deleting files from S3, you need to:

1. Go to your Knowledge Base in the Bedrock console
2. Navigate to the Data Source tab
3. Click the "Sync" button to initiate a new ingestion job

If you've clicked the sync button and nothing appears to happen (no indication of sync starting or failure), there could be several issues:

• The Knowledge Base might not be fully available yet (the sync button may appear active but won't actually trigger a sync until the KB is active)
• There might be permission issues with your S3 bucket
• You might need to check CloudWatch logs for any error messages related to the ingestion job
• You may need to verify you have access to the embedding model being used (often Titan)
• You may also check the sync history of the Data Source for details on - Added/Deleted/Modified files, Source files, Metadata files, Failed files, or Metadata files modified.

If you have already attempted to sync but the issue persists, for troubleshooting, you can check if there's a history of "StartIngestionJob" API execution in CloudTrail event history, which would indicate if the API is running. You can also check CloudWatch for more detailed information about any failures or successful ingestions (given that logging is enabled for your Knowledge base).

If the issue persists, kindly consider contacting AWS Support for further assistance and provide the Knowledge Base ID and the associated Data Source ID.

Sources
[1] Bedrock knowledge base data source sync is not working | AWS re:Post

[2] Data sync in bedrock knowledge base | AWS re:Post

[3] Monitor knowledge bases using CloudWatch Logs

[4] Sync your data with your Amazon Bedrock knowledge base