pre-filtering
A RAG access control technique in which chunk metadata in the vector store is first filtered according to the user's permission scope at query time, before vector similarity retrieval is performed, ensuring that unauthorized content is not recalled.
Timeline (last 90 days)
Production-grade RAG usually adopts 'pre-filtering' rather than 'post-filtering,' because the latter lets unauthorized content enter the model context first, which both wastes tokens and poses a leakage risk.
Storing key dimensions such as plan type as filterable metadata fields allows irrelevant branches to be excluded before retrieval, which is pre-filtering in hybrid retrieval
Enforcing permission control at the retrieval layer means each chunk in the vector store carries access control metadata, and at query time filtering is first done by the current user's permission scope, followed by vector similarity retrieval.
Post-filtering (retrieve first, then filter) may result in insufficient recall when filter conditions are strict, while pre-filtering (filter first, then retrieve) may disrupt index structures and reduce retrieval efficiency.
All Facts (4)
Production-grade RAG usually adopts 'pre-filtering' rather than 'post-filtering,' because the latter lets unauthorized content enter the model context first, which both wastes tokens and poses a leakage risk.
50%UnverifiedStoring key dimensions such as plan type as filterable metadata fields allows irrelevant branches to be excluded before retrieval, which is pre-filtering in hybrid retrieval
50%UnverifiedEnforcing permission control at the retrieval layer means each chunk in the vector store carries access control metadata, and at query time filtering is first done by the current user's permission scope, followed by vector similarity retrieval.
50%UnverifiedPost-filtering (retrieve first, then filter) may result in insufficient recall when filter conditions are strict, while pre-filtering (filter first, then retrieve) may disrupt index structures and reduce retrieval efficiency.
50%