Infino
About
Infino — keyword, vector, hybrid, and SQL retrieval over data on object storage, for AI agents.
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- Author
- infino-ai
- Categories
- Database, Other, File Management
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Setup
Install Infino in your MCP client (Claude Desktop, Cursor, Windsurf, and others).
Repository: https://github.com/infino-ai/infino
Follow the installation instructions in the repository README, then restart your MCP client.
infino is a fast retrieval engine that runs SQL, full-text search, and vector search over a single copy of your data on object storage.Data stays in Parquet on S3 (or Azure, GCS, or local disk) and you can query it at scale.
- Speed per dollar— infino optimizes for speed per dollar, making tradeoffs to achieve object-storage economics at search engine speeds. On a 1-million-document index, warm BM25 queries return in the microsecond range — seebenchmarks.
- Multi-modal queries— keyword (BM25), vector, and SQL queries over the same rows, offering flexible query paths for agents.
- Object-storage-native— data lives on S3, Azure, GCS, or local disk, with snapshot-isolated reads and atomic commits.
- Open format, no lock in— text and numeric data is stored as spec-compliant Parquet, so anything that reads Parquet can read your data.
- Install
- Quickstart
- Cloud storage
- Architecture
- SQL joins across tables
- Hybrid search
- Stability
- Development
- Performance
- Tests
pip install infino # Or with uv (https://docs.astral.sh/uv/): uv pip install infino
The full Rust API reference is ondocs.rs/infino.
import infino import pyarrow as pa # A knowledge base your agent retrieves over. "memory://" is in-process; # use "./data" or "s3://bucket/prefix" to persist. db = infino.connect("memory://") # Tiny stand-in for your embedding model so this runs as-is — a 16-dim # one-hot by topic. Real embeddings are dense and higher-dimensional. def embed(topic): # 0 = billing, 1 = appearance v = [0.0] 16 v[topic] = 1.0 return v schema = pa.schema([ pa.field("source", pa.large_utf8(), nullable=False), pa.field("body", pa.large_utf8(), nullable=False), pa.field("embedding", pa.list_(pa.float32(), 16), nullable=False), ]) docs = db.create_table( "docs", schema, infino.IndexSpec().fts("body").vector("embedding", 16, "cosine"), ) docs.append([ {"source": "help-center", "body": "To cancel a subscription, open Settings then Billing.", "embedding": embed(0)}, {"source": "help-center", "body": "Refunds return to the original payment method.", "embedding": embed(0)}, {"source": "blog", "body": "Enable dark mode under Settings then Appearance.", "embedding": embed(1)}, ]) # Retrieve context to ground the agent's next answer: keyword = docs.bm25_search("body", "cancel subscription", 5) # BM25 semantic = docs.vector_search("embedding", embed(0), 5) # vector kNN # vector kNN, restricted to rows whose body matches a keyword (pushdown filter): filtered = docs.vector_search("embedding", embed(0), 5, filter_column="body", filter_query="billing") billing = db.query_sql("SELECT body FROM docs WHERE source = 'help-center'") # SQL filter
import { connect, IndexSpec } from "@infino-ai/infino"; // A knowledge base your agent retrieves over. "memory://" is in-process; // use "./data" or "s3://bucket/prefix" to persist. const db = connect("memory://"); // Tiny stand-in for your embedding model so this runs as-is — a 16-dim // one-hot by topic. Real embeddings are dense and higher-dimensional. const embed = (topic) => { const v = Array(16).fill(0.0); v[topic] = 1.0; return v; }; const docs = db.createTable( "docs", { source: "large_utf8", body: "large_utf8", embedding: { vector: 16 } }, new IndexSpec().fts("body").vector("embedding", 16, "cosine"), ); docs.append([ { source: "help-center", body: "To cancel a subscription, open Settings then Billing.", embedding: embed(0) }, { source: "help-center", body: "Refunds return to the original payment method.", embedding: embed(0) }, { source: "blog", body: "Enable dark mode under Settings then Appearance.", embedding: embed(1) }, ]); // Retrieve context to ground the agent's next answer: const keyword = docs.bm25Search("body", "cancel subscription", 5); // BM25 const semantic = docs.vectorSearch("embedding", embed(0), 5); // vector kNN // vector kNN, restricted to rows whose body matches a keyword (pushdown filter): const filtered = docs.vectorSearch("embedding", embed(0), 5, { filter: { column: "body", query: "billing" } }); const billing = db.querySql("SELECT body FROM docs WHERE source = 'help-center'"); // SQL filter
use std::sync::Arc; use infino::arrow_array::{FixedSizeListArray, Float32Array, LargeStringArray, RecordBatch}; use infino::arrow_schema::{DataType, Field, Schema}; use infino::{connect, BoolMode, IndexSpec, Metric, VectorFilter, VectorSearchOptions}; // Tiny stand-in for your embedding model so this runs as-is — a 16-dim // one-hot by topic. Real embeddings are dense and higher-dimensional. fn embed(topic: usize) -> Vec<f32> { let mut v = vec![0.0_f32; 16]; v[topic] = 1.0; v } # fn main() -> Result<(), Box<dyn std::error::Error>> { // A knowledge base your agent retrieves over. "memory://" is in-process; // use "./data" or "s3://bucket/prefix" to persist. let db = connect("memory://")?; let item = Arc::new(Field::new("item", DataType::Float32, true)); let schema = Arc::new(Schema::new(vec![ Field::new("source", DataType::LargeUtf8, false), Field::new("body", DataType::LargeUtf8, false), Field::new("embedding", DataType::FixedSizeList(item.clone(), 16), false), ])); let docs = db.create_table( "docs", schema.clone(), IndexSpec::new().fts("body").vector("embedding", 16, Metric::Cosine), )?; let flat: Vec<f32> = [0usize, 0, 1].iter().flat_map(|&t| embed(t)).collect(); docs.append(&RecordBatch::try_new( schema, vec![ Arc::new(LargeStringArray::from(vec!["help-center", "help-center", "blog"])), Arc::new(LargeStringArray::from(vec![ "To cancel a subscription, open Settings then Billing.", "Refunds return to the original payment method.", "Enable dark mode under Settings then Appearance.", ])), Arc::new(FixedSizeListArray::new(item, 16, Arc::new(Float32Array::from(flat)), None)), ], )?)?; // Retrieve context to ground the agent's next answer: let keyword = docs.bm25_search("body", "cancel subscription", 5, BoolMode::Or, None)?; let semantic = docs.vector_search("embedding", &embed(0), 5, VectorSearchOptions::new(), None, None)?; // vector kNN, restricted to rows whose body matches a keyword (pushdown filter): let filtered = docs.vector_search( "embedding", &embed(0), 5, VectorSearchOptions::new(), Some(VectorFilter { column: "body", query: "billing", mode: BoolMode::Or }), None, )?; let billing = db.query_sql("SELECT body FROM docs WHERE source = 'help-center'")?; assert_eq!(keyword.iter().map(|b| b.num_rows()).sum::<usize>(), 1); // BM25 assert!(semantic.iter().map(|b| b.num_rows()).sum::<usize>() >= 1); // vector kNN assert_eq!(filtered.iter().map(|b| b.num_rows()).sum::<usize>(), 1); // vector + keyword filter assert_eq!(billing.iter().map(|b| b.num_rows()).sum::<usize>(), 2); // SQL filter # Ok(()) # }
Bindings live ininfino-python/(PyO3 + maturin) andinfino-node/; see their READMEs to build from source. The Node API is synchronous — objects in, plain records out, with_idreturned as a JavaScriptbigint.
A superfileisa spec-compliant Parquet file. The embedded BM25 and vector index regions are spliced in ahead of a standard Parquet footer and pointed at byinf.key/value metadata keys, which any conformant Parquet reader ignores. So the columnar body opens in DuckDB, pandas, pyarrow, or DataFusion withno infino in the read pathand no export step:
import infino, pyarrow as pa, glob, duckdb db = infino.connect("./data") # persist to disk (not "memory://") docs = db.create_table( "docs", pa.schema([ pa.field("source", pa.large_utf8(), nullable=False), pa.field("body", pa.large_utf8(), nullable=False), ]), infino.IndexSpec().fts("body"), ) docs.append([ {"source": "help-center", "body": "To cancel a subscription, open Settings then Billing."}, {"source": "help-center", "body": "Refunds return to the original payment method."}, {"source": "blog", "body": "Enable dark mode under Settings then Appearance."}, ]) # The superfiles are ordinary files on disk (one write can shard into # several, so read them as a set): files = glob.glob("data//.sf.parquet", recursive=True) print(files[0]) # e.g. data/docs-18bc4051eb6a9468-0/data/seg-....sf.parquet # Read them with a third-party engine, no infino in this line: duckdb.sql("SELECT source, count() FROM read_parquet('data//.sf.parquet') GROUP BY source").show() # ┌─────────────┬──────────────┐ # │ source │ count_star() │ # ├─────────────┼──────────────┤ # │ help-center │ 2 │ # │ blog │ 1 │ # └─────────────┴──────────────┘
Read-only openness.Standard toolsreada superfile's columns with no export step. Rewriting it through a generic Parquet writer (e.g.pyarrow.parquet.write_table) produces valid Parquet that has silently dropped the embedded BM25/vector indexes, so it's no longer a superfile. The compatibility is one-directional.
The shortest end-to-end demo (write a corpus, run BM25 + vector + SQL/hybrid retrieval against it, then read the very same file back with DuckDBandpyarrow) isinfino-python/examples/parquet_interop.py.
The backend is chosen by the URI scheme —s3://bucket/prefix,az://container/prefix,gs://bucket/prefix,file://path, a bare path, ormemory://. Credentials go throughConnectOptions, keyed byobject_store's config strings (aws_/azure_/google_— the names the AWS/Azure/GCS SDKs use). Infino reads no credentials from the environment; omit them to use ambient cloud identity (IAM instance role / managed identity / workload-identity ADC).
use infino::{connect_with, ConnectOptions}; // S3 let db = connect_with("s3://bucket/prefix", ConnectOptions::new() .with_storage_option("aws_access_key_id", "…") .with_storage_option("aws_secret_access_key", "…") .with_storage_option("aws_region", "us-east-1"))?; // Azure let db = connect_with("az://container/prefix", ConnectOptions::new() .with_storage_option("azure_storage_account_name", "…") .with_storage_option("azure_storage_account_key", "…"))?; // GCS let db = connect_with("gs://bucket/prefix", ConnectOptions::new() .with_storage_option("google_service_account_key", "…"))?; # Ok::<(), Box<dyn std::error::Error>>(())
The full set is whateverobject_storeaccepts for the backend; an unknown or cross-backend key is rejected at connect.with_validate(true)opts into a connect-time reachability probe, so bad credentials fail atconnectrather than on the first query. The same options exist in the config file (storage.storage_options) and both bindings (storage_options+validate).
Three docs cover the design, from the high-level tour down to the on-disk bytes:
- Overview →— the plain-language tour: what infino is, the mental model, and how it compares to other systems.
- Superfile format →— the single-file superfile format: a valid Parquet file with embedded full-text and vector indexes. Covers the layout, Parquet compatibility, and the full-text and vector index design.
- Supertable layer →— the table layer over many superfiles: manifest snapshots, the commit/publish path, pluggable storage, query fan-out with manifest-only skip pruning, and reader/writer concurrency.
For concepts, quickstart, guides, and examples (Python, Node.js, and Rust), see the full documentation atinfino.ai/docs.
query_sqlresolves every table the query names through the catalog into one engine, and thebm25_search/vector_search/hybrid_searchtable functions are relations too — so a single query can fuse keyword and vector retrieval and join the result to an ordinary table. This is the canonical agent retrieval, end to end: hybrid-search a knowledge base, fuse the two rankings (reciprocal-rank fusion), and join provenance — one snapshot, no client-side stitching.
use std::sync::Arc; use infino::arrow_array::{FixedSizeListArray, Float32Array, Int64Array, LargeStringArray, RecordBatch}; use infino::arrow_schema::{DataType, Field, Schema}; use infino::{connect, IndexSpec, Metric}; // Tiny stand-in for your embedding model so this runs as-is; real // embeddings are dense and higher-dimensional (e.g. 1536). fn embed(topic: usize) -> Vec<f32> { let mut v = vec![0.0_f32; 16]; v[topic] = 1.0; v } # fn main() -> Result<(), Box<dyn std::error::Error>> { let db = connect("memory://")?; // docs: text (BM25) + embedding (vector) + the source it came from. let item = Arc::new(Field::new("item", DataType::Float32, true)); let docs_schema = Arc::new(Schema::new(vec![ Field::new("source", DataType::LargeUtf8, false), Field::new("body", DataType::LargeUtf8, false), Field::new("embedding", DataType::FixedSizeList(item.clone(), 16), false), ])); let docs = db.create_table( "docs", docs_schema.clone(), IndexSpec::new().fts("body").vector("embedding", 16, Metric::Cosine), )?; let flat: Vec<f32> = [0usize, 0, 1].iter().flat_map(|&t| embed(t)).collect(); docs.append(&RecordBatch::try_new( docs_schema, vec![ Arc::new(LargeStringArray::from(vec!["help-center", "help-center", "blog"])), Arc::new(LargeStringArray::from(vec![ "To cancel a subscription, open Settings then Billing.", "Refunds return to the original payment method.", "Enable dark mode under Settings then Appearance.", ])), Arc::new(FixedSizeListArray::new(item, 16, Arc::new(Float32Array::from(flat)), None)), ], )?)?; // sources: a plain table — where each source came from, and its trust. let sources_schema = Arc::new(Schema::new(vec![ Field::new("source", DataType::LargeUtf8, false), Field::new("url", DataType::LargeUtf8, false), Field::new("trust", DataType::Int64, false), ])); let sources = db.create_table("sources", sources_schema.clone(), IndexSpec::new())?; sources.append(&RecordBatch::try_new( sources_schema, vec![ Arc::new(LargeStringArray::from(vec!["help-center", "blog"])), Arc::new(LargeStringArray::from(vec![ "https://help.example.com", "https://blog.example.com", ])), Arc::new(Int64Array::from(vec![2, 1])), ], )?)?; // The agent's question, embedded like the corpus. The vector TVF takes // the query vector as a comma-separated string, so build the SQL with it. let qvec = embed(0).iter().map(|x| x.to_string()).collect::<Vec<_>>().join(","); let sql = format!( "WITH lexical AS ( -- BM25 candidates, ranked SELECT _id, source, body, ROW_NUMBER() OVER (ORDER BY score DESC) AS rank FROM bm25_search('docs', 'body', 'how do I cancel my subscription?', 50) ), semantic AS ( -- vector candidates (nearer = lower score) SELECT _id, source, body, ROW_NUMBER() OVER (ORDER BY score ASC) AS rank FROM vector_search('docs', 'embedding', '{qvec}', 50) ) SELECT s.url, COALESCE(l.body, v.body) AS chunk, COALESCE(1.0/(60+l.rank), 0.0) + COALESCE(1.0/(60+v.rank), 0.0) AS relevance FROM lexical l FULL OUTER JOIN semantic v ON l._id = v._id -- fuse lexical + semantic JOIN sources s ON s.source = COALESCE(l.source, v.source) -- + provenance WHERE s.trust >= 1 ORDER BY relevance DESC LIMIT 5" ); let context = db.query_sql(&sql)?; assert!(context.iter().map(|b| b.num_rows()).sum::<usize>() >= 1); # Ok(()) # }
Making it real.embed()here is a 16-dim toy so the example runs as written; swap in your embedding model and raisedimto match (e.g. 1536 / 256). The vector TVF takes the query vector as a comma-separated string — that's the only reason the query is built withformat!. The SQL itself is identical from Python and Node; only table creation and embedding differ.
Infino also wires indexes into SQL execution asphysical access paths:
-- The text predicate is answered from the FTS index — inverted index → -- candidate rows → decode only those rows — never a full column scan. SELECT category, AVG(rating) FROM reviews WHERE title = 'battery life' GROUP BY category;
Equality,IN, and boolean combinations on an indexed text column resolve through the index to an exact candidate row set before any column data is read. Superfiles that can't match are never opened at all: term blooms, value ranges, and vector centroids live side by side in the manifest, so scalar, keyword, and vector signals prune through one shared layer.
Retrieval composes the same way. The rankedbm25_search/vector_search/hybrid_searchand the unrankedtoken_match/exact_matchare table functions so a candidate set is thefirst stage of a planrather than its result:
-- Rank first; join and aggregate over just the candidates. SELECT a.name, COUNT(*) AS hits FROM bm25_search('posts', 'body', 'rust async', 100) p JOIN authors a ON a.author_id = p.author_id GROUP BY a.name ORDER BY hits DESC; -- Set algebra over index-bounded candidate sets: "rust but not compiler". SELECT _id FROM token_match('posts', 'body', 'rust') EXCEPT SELECT _id FROM token_match('posts', 'body', 'compiler');
One snapshot, one copy of the data: sparse (BM25), dense (vector), and structured (scalar) predicates compose inside the engine — no second system to sync, no client-side result stitching.
The public API is what's re-exported from the crate root —connect/connect_with,Connection,Supertable,IndexSpec,InfinoError, and the value types their signatures name. It is pinned by acargo-public-apisnapshot (public-api.txt); any change to it is reviewed as a contract change in the same pull request.
- Versioning.0.x while the surface soaks; 1.0 once it has shipped without churn for a release or two. Pre-1.0 may break, but every break shows in the snapshot diff and is called out in the release notes.
- #[non_exhaustive]on growable public enums/structs (e.g.InfinoError,MutationStats), so adding a variant or field is not a breaking change.
- Arrow / DataFusion are part of the contract.The API is Arrow-native (RecordBatch,SchemaRef,Expr); a major bump of arrow / datafusion that changes an exposed type is a breaking change to infino. The supported version range is documented and CI-tested.
- MSRV.The minimum supported Rust version is1.95(enforced byrust-versioninCargo.toml). Raising it is a minor bump, never a patch.
- Deprecation.Post-1.0, removals go through#[deprecated]for at least one minor release first.
- Bindings version independently.The Python (pip install infino) and Node (npm install @infino-ai/infino) packages are versioned on their own SemVer lines — each embeds its own copy of the engine, so a binding version need not match this crate's. Seedocs/versioning.md.
git clone git@github.com:infino-ai/infino.git cd infino cargo build cargo run --example demo # end-to-end tour: build, BM25 + vector search, read back as Parquet
The toolchain is pinned byrust-toolchain.toml, sorustupinstalls the right stable Rust on first build. Runcargo test --features test-helpersfor the suite (integration tests useinfino::test_helpers) andmake cibefore opening a pull request. Browse the full API locally withmake doc(cargo doc --no-deps --open— the same docsdocs.rsrenders).
For an enhanced local development experience, install and configurepre-commithooks withpre-commit installto catch formatting and lint issues before committing.
SeeCONTRIBUTING.mdfor the full development guide.
Runcargo test --workspacefor the full suite. It covers the end-to-end full-text, vector, and superfile pipelines, ingestion and commit, and open-format compatibility — DataFusion reads superfiles as plain Parquet, with column projection, GROUP BY, and predicate pushdown all matching the columnar data.
Memory safety.The full-text surface runs clean undermiri(Stacked Borrows + UB detection) andAddressSanitizer; runmake miriandmake asan.
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