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Documentation Index

Fetch the complete documentation index at: https://docs.turso.tech/llms.txt

Use this file to discover all available pages before exploring further.

Turso supports vector search as a native feature — no extensions required. Store vector embeddings alongside your relational data and query them using built-in distance functions for similarity search.

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Vector Types

Turso supports dense, sparse, quantized, and binary vector representations, each suited to different workloads.

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Dense Vectors

Dense vectors store a value for every dimension. Turso provides two precision levels:
FunctionPrecisionStorage per dimensionBest for
vector3232-bit float4 bytesMost ML embeddings (OpenAI, sentence transformers)
vector6464-bit float8 bytesApplications requiring higher precision

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Sparse Vectors

Sparse vectors only store non-zero values and their indices, making them memory-efficient for high-dimensional data with many zero values.
FunctionStorageBest for
vector32_sparseNon-zero values + indicesTF-IDF, bag-of-words, high-dimensional sparse data

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Quantized Vectors

FunctionStorage per dimensionBest for
vector81 byte (+8 bytes overhead)Large-scale search where ~4x compression vs Float32 is worth minimal precision loss
Values are linearly quantized to the 0-255 range using min/max scaling. Dequantization: f_i = alpha * q_i + shift.

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Binary Vectors

FunctionStorage per dimensionBest for
vector1bit1 bitBinary hashing, approximate nearest neighbor search (~32x compression vs Float32)
Positive values become 1, non-positive values become 0. Extracted values are displayed as +1/-1.
For most applications, vector32 is a good starting point. Explore more compact types if your table has a large number of rows.

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Storing Vectors

Create a table with a BLOB column to store embeddings alongside your relational data: 
CREATE TABLE documents (
    id INTEGER PRIMARY KEY,
    title TEXT,
    content TEXT,
    embedding BLOB
);
Insert rows with vector embeddings using the appropriate conversion function: 
INSERT INTO documents (title, content, embedding) VALUES
    ('Machine learning basics', 'An introduction to ML concepts...', vector32('[0.2, 0.5, 0.1, 0.8]')),
    ('Database fundamentals', 'How relational databases work...', vector32('[0.1, 0.3, 0.9, 0.2]')),
    ('Neural networks guide', 'Deep learning architectures...', vector32('[0.3, 0.6, 0.2, 0.7]'));
For sparse vectors, zero values are automatically compressed: 
INSERT INTO documents (title, content, embedding) VALUES
    ('Sparse example', 'A document with sparse features...', vector32_sparse('[0.0, 1.5, 0.0, 2.3, 0.0]'));
Use distance functions to find the most similar vectors. All distance functions require both vectors to have the same type and dimensionality. Lower values indicate greater similarity.

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Cosine Distance

Measures the angle between vectors, ignoring magnitude. Returns a value between 0 (identical direction) and 2 (opposite direction). 
SELECT title,
       vector_distance_cos(embedding, vector32('[0.25, 0.55, 0.15, 0.75]')) AS distance
FROM documents
ORDER BY distance
LIMIT 5;
Best for text embeddings and document similarity where direction matters more than magnitude.

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Euclidean (L2) Distance

Measures straight-line distance in n-dimensional space. Not supported for vector1bit vectors. 
SELECT title,
       vector_distance_l2(embedding, vector32('[0.25, 0.55, 0.15, 0.75]')) AS distance
FROM documents
ORDER BY distance
LIMIT 5;
Best for image embeddings, spatial data, and unnormalized embeddings where absolute differences matter.

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Dot Product Distance

Computes the negative dot product: -sum(v1[i] * v2[i]). Lower (more negative) values indicate higher similarity. 
SELECT title,
       vector_distance_dot(embedding, vector32('[0.25, 0.55, 0.15, 0.75]')) AS distance
FROM documents
ORDER BY distance
LIMIT 5;
Best for normalized embeddings (equivalent to cosine distance when vectors are unit-length) and maximum inner product search (MIPS).

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Jaccard Distance

Computes weighted Jaccard distance based on the ratio of minimum to maximum values across dimensions. For vector1bit vectors, computes binary Jaccard distance. 
SELECT title,
       vector_distance_jaccard(embedding, vector32_sparse('[0.0, 1.0, 0.0, 2.0]')) AS distance
FROM documents
ORDER BY distance
LIMIT 5;
Best for sparse vectors, set-like comparisons, TF-IDF representations, and binary similarity with vector1bit.

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Utility Functions

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vector_extract

Convert a vector BLOB back to a readable JSON representation: 
SELECT vector_extract(embedding) FROM documents WHERE id = 1;
-- [0.200000,0.500000,0.100000,0.800000]

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vector_concat

Concatenate two vectors into one: 
SELECT vector_extract(
    vector_concat(vector32('[1.0, 2.0]'), vector32('[3.0, 4.0]'))
);
-- [1.000000,2.000000,3.000000,4.000000]

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vector_slice

Extract a contiguous portion of a vector (zero-based, end exclusive): 
SELECT vector_extract(
    vector_slice(vector32('[1.0, 2.0, 3.0, 4.0, 5.0]'), 1, 4)
);
-- [2.000000,3.000000,4.000000]

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Limitations

  • Euclidean distance is not supported for vector1bit vectors
  • Maximum vector dimensionality is 65,536
  • vector1bit cosine distance returns Hamming distance (number of differing bits) instead of standard cosine distance
A complete end-to-end example combining vector storage and similarity search: 
-- Create a table with vector embeddings
CREATE TABLE articles (
    id INTEGER PRIMARY KEY,
    title TEXT NOT NULL,
    content TEXT,
    embedding BLOB
);

-- Insert articles with precomputed embeddings
INSERT INTO articles (title, content, embedding) VALUES
    ('Introduction to Machine Learning', 'ML is a subset of AI...', vector32('[0.12, -0.34, 0.56, 0.78]')),
    ('Database Design Patterns', 'Relational databases organize...', vector32('[0.82, 0.15, -0.44, 0.23]')),
    ('Neural Networks Explained', 'Neural networks are computing...', vector32('[0.14, -0.28, 0.62, 0.71]')),
    ('SQL Query Optimization', 'Efficient queries start with...', vector32('[0.75, 0.22, -0.38, 0.19]'));

-- Find the 3 most similar articles to a query vector
SELECT
    title,
    content,
    vector_distance_cos(embedding, vector32('[0.10, -0.30, 0.50, 0.80]')) AS distance
FROM articles
ORDER BY distance
LIMIT 3;
Similarity searches use a linear scan over the table. For large datasets, consider limiting the search to a subset of rows with a WHERE clause.

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See Also