cohere_rerank_simple()

Rerank search results by semantic relevance with a simplified response

Rerank a list of documents by semantic relevance to a query. This function returns a simplified table format with just the document index, text, and relevance score.

Samples

Rerank search results

Improve search relevance by reordering results:

SELECT *
FROM ai.cohere_rerank_simple(
    'rerank-english-v3.0',
    'What is a database?',
    ARRAY[
        'PostgreSQL is a relational database',
        'Python is a programming language',
        'A database stores and manages data',
        'JavaScript is used for web development'
    ]
)
ORDER BY relevance_score DESC;

Returns:

 index |              document              | relevance_score
-------+------------------------------------+-----------------
     2 | A database stores and manages data |        0.95
     0 | PostgreSQL is a relational database|        0.89
     1 | Python is a programming language   |        0.12
     3 | JavaScript is used for web dev     |        0.08

Limit results with top_n

Return only the most relevant documents:

SELECT *
FROM ai.cohere_rerank_simple(
    'rerank-english-v3.0',
    'time-series databases',
    ARRAY[
        'TimescaleDB extends PostgreSQL for time-series data',
        'MongoDB is a document database',
        'Time-series data has temporal ordering',
        'Redis is an in-memory cache'
    ],
    top_n => 2
)
ORDER BY relevance_score DESC;

Use in a search pipeline

Combine vector search with reranking:

WITH vector_results AS (
    SELECT content, embedding <=> query_embedding AS distance
    FROM documents
    ORDER BY embedding <=> query_embedding
    LIMIT 20
)
SELECT content, relevance_score
FROM vector_results
CROSS JOIN LATERAL ai.cohere_rerank_simple(
    'rerank-english-v3.0',
    'user query here',
    ARRAY_AGG(content) OVER (),
    top_n => 5
) AS reranked
WHERE content = document
ORDER BY relevance_score DESC;

Arguments

Name	Type	Default	Required	Description
model	TEXT	-	✔	The Cohere reranking model (e.g., rerank-english-v3.0)
query	TEXT	-	✔	The search query
documents	TEXT[]	-	✔	Array of documents to rerank
api_key	TEXT	NULL	✖	Cohere API key. If not provided, uses configured secret
api_key_name	TEXT	NULL	✖	Name of the secret containing the API key
top_n	INT	NULL	✖	Return only the top N most relevant documents
max_tokens_per_doc	INT	NULL	✖	Maximum tokens per document (for truncation)
verbose	BOOLEAN	FALSE	✖	Enable verbose logging for debugging

Returns

TABLE: A table with the following columns:

Column	Type	Description
index	INT	Original index of the document in the input array (0-based)
document	TEXT	The document text
relevance_score	FLOAT8	Relevance score (0.0 to 1.0, higher is more relevant)

Related functions

• cohere_rerank(): full API response with additional metadata
• cohere_embed(): generate embeddings for vector search