Text reranking

Text reranking#

Use the aidb.rerank_text() function to reorder a set of candidate text passages by their relevance to a query. Reranking is typically applied as a post-retrieval step — after an initial set of candidates has been retrieved from a knowledge base — to surface the most relevant results at the top.

Step 1: Register a reranking model

SELECT aidb.create_model(
    my_reranker,
    nim_reranking,
    config => aidb.nim_reranking_config(
        api_key => nvapi-...,
        model   => nvidia/nv-rerankqa-mistral-4b-v3
    )
);

Step 2: Rerank a set of candidates

SELECT * FROM aidb.rerank_text(
    model_name => my_reranker,
    query      => What is retrieval-augmented generation?,
    input      => ARRAY[
        RAG combines retrieval and generation to produce grounded answers.,
        Vector databases store high-dimensional embeddings for similarity search.,
        RAG systems retrieve relevant documents before generating a response.
    ]
) ORDER BY logit_score DESC;

__OUTPUT__
                              text                              | logit_score | id
- ---------------------------------------------------------------+-------------+----
 RAG systems retrieve relevant documents before generating ...  |        0.97 |  2
 RAG combines retrieval and generation to produce grounded ...  |        0.91 |  0
 Vector databases store high-dimensional embeddings for ...     |        0.43 |  1
(3 rows)

The id column is the zero-based index of each string in the input array, so you can join back to the original data.

For the full parameter reference, see Models reference .

Using reranking after knowledge base retrieval#

A typical pattern is to retrieve an initial candidate set from a knowledge base and then rerank the results:

WITH candidates AS (
    SELECT key, value
    FROM aidb.retrieve_text(my_kb, What is RAG?, topk => 20)
)
SELECT c.key, c.value, r.logit_score
FROM candidates c
JOIN aidb.rerank_text(
    model_name => my_reranker,
    query      => What is RAG?,
    input      => ARRAY(SELECT value FROM candidates ORDER BY key)
) r ON r.text = c.value
ORDER BY r.logit_score DESC
LIMIT 5;

!!!Note Reranking models score passages against a query but don’t generate text. To register a reranking model, use the appropriate 모델 설정 도우미 for your provider — for example, aidb.nim_reranking_config() for NVIDIA NIM reranking endpoints.

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