Faiss > Sobo Engineering Notes

FAISS empty retrieval sets after tightening RAG metadata filters

August 1, 2026 by Jordan Lee

Problem – Empty Retrieval Sets After Tightening RAG Metadata Filters In a hybrid‑cloud RAG pipeline, the vector store is a FAISS index replicated from an on‑premises cluster to public‑cloud endpoints. After a recent rollout that added stricter boolean filters on the region, category, and source_id metadata fields, a growing number of queries returned zero results … Read more

FAISS RAG pipeline chunk overlap configuration issues

July 15, 2026 by Jordan Lee

Problem – Retrieval Degradation from Improper Chunk Overlap In a local development sandbox a Retrieval‑Augmented Generation (RAG) pipeline builds a FAISS index from a corpus of text documents. The chunk_size and overlap parameters used during document splitting are mis‑configured, causing two distinct symptoms: Excessive overlap (e.g., overlap = 0.9 * chunk_size) produces many near‑duplicate vectors. … Read more

FAISS index access denied after EC2 instance reboot

June 12, 2026 by Jordan Lee

green grass field near brown bare trees during daytime

Problem – FAISS index access denied after EC2 instance reboot During a disaster‑recovery (DR) drill an EC2 instance was launched to replace a failed node. The instance runs a Python service that restores a FAISS index from an S3 bucket using boto3 and then loads the index with faiss.read_index. After the reboot the service crashes … Read more