pgvector "operator does not exist: vector <=>" Error

How to fix it

// try these in order, the most common fix is first

1. FIX 1Cast in SQL

   Copy steps
   1. 01Write embedding <=> $1::vector
   2. 02Or CAST($1 AS vector)
   Did this fix it? Yes No

2. FIX 2Python

   Copy steps
   1. 01Call register_vector(conn) from pgvector-python right after connecting
   2. 02Convert numpy arrays with .tolist() for psycopg2
   Did this fix it? Yes No

3. FIX 3Match types

   Copy steps
   1. 01If the column is halfvec cast the query to halfvec
   2. 02Compare vector with vector
   Did this fix it? Yes No

Symptoms

operator does not exist: vector <=> unknown (or real[], numeric[]).

Why it happens

• C-01Untyped query parameter
• C-02Plain array passed from a driver or ORM
• C-03halfvec column queried with vector
• C-04numpy array not converted

// this guide also covers

• operator does not exist vector <=>
• operator does not exist vector <=> unknown
• pgvector cast to vector

The same problem in other apps

All not loading, error messages & connection guides →

• Pinecone 429 Too Many Requests Error (Pinecone)
• Weaviate Error: Vector Lengths Don't Match (Weaviate)
• Chroma "Your system has an unsupported version of sqlite3" Error (Chroma)
• Milvus "collection not loaded" Error (Milvus)
• Qdrant "Wrong input: Vector dimension error: expected dim, got" (Qdrant)

Other pgvector errors

• pgvector Error: extension "vector" is not available
• pgvector HNSW Index Build Slow
• pgvector Dimension Limit: Cannot Index More Than 2000 Dimensions
• pgvector "different vector dimensions" Error
• pgvector Query Returns Fewer Results Than LIMIT With Filter
• pgvector Index Not Being Used
• pgvector HNSW Build Out of Memory or Shared Memory Error
• How to Enable pgvector on Supabase