Hybrid RAG on PostgreSQL

Answers grounded in your data, with sources

Hybrid retrieval combines vector search, keyword search and structured filters so answers come from the right documents. We build it on PostgreSQL with pgvector where that fits.

Overview

How we approach it

Vector search alone misses exact terms, codes and names; keyword search alone misses meaning. Hybrid retrieval merges both, re-ranks the results and passes the best passages to the model with their sources.

Where relationships matter, we add a lightweight knowledge graph in the same database, so questions about people, products and dependencies can follow links instead of guessing.

Retrieval quality decides answer quality

Most hallucination in enterprise assistants is a retrieval failure. We measure retrieval separately from generation.

  • Fresh data via incremental re-indexing.
  • Clear behaviour when the answer is not in the data.
  • Evaluation sets built from your real questions.
Delivery

Step by step

Ingest

Parse, chunk and enrich documents with metadata.

Retrieve

Vector plus keyword plus filters.

Re-rank

Order candidates by relevance to the question.

Answer with sources

Citations the user can open.

Deliverables

What you receive

Hybrid retrieval

pgvector with full-text search and structured filters.

Access control

Retrieval respects who may see what.

Citations

Every answer links back to the passages used.

Retrieval evaluation

Measure recall and precision on real questions.

FAQ

Common questions

Do we need a separate vector database?

Often not. PostgreSQL with pgvector handles many workloads and keeps data in one place. We recommend a dedicated store when scale or latency requires it.

How do you prevent leaking restricted documents?

Permissions are enforced at retrieval time, not only in the prompt.

Can it handle PDFs and scans?

Yes, with parsing and OCR as part of the ingestion pipeline.

Scope your agent system with an engineer

Bring the process you want to automate. We will talk through the architecture, the risks and a realistic first release.