Zvec

Zvec is a lightweight, in-process vector database meant to be embedded into applications ("SQLite for vectors").

Quick navigation

• Overview: references/overview.md
• Concepts: references/concepts.md
• Quickstart (first operations): references/quickstart.md
• Installation (only if needed): references/installation.md
• Index types & quantization: references/indexing.md
• Embedding pipelines: references/embedding.md
• Reranking pipelines: references/reranker.md
• Data modeling & collections: references/collections.md
• CRUD / search operations: references/data-operations.md
• Configuration & persistence: references/configuration.md

Operator recipes (high signal)

• Minimal “embed Zvec” checklist

- (Optional) Configure globals once at startup via zvec.init(...) (logging, querythreads). - Create a collection on disk with createand_open(path=..., schema=..., option=...). - Ingest documents as Doc(id=..., fields=..., vectors=...) via insert() or upsert(). - Query via collection.query(vectors=VectorQuery(...), topk=...). - Call collection.optimize() periodically after heavy ingestion.

• Bulk ingest + keep query latency stable

- Prefer batched insert() / upsert(). - Monitor collection.stats and run optimize() when flat buffers grow.

• Hybrid retrieval patterns

- Filter-only: collection.query(filter=..., topk=...). - Vector + filter: pass both vectors=... and filter=.... - Multi-vector fusion: pass multiple VectorQuery items and rerank using WeightedReRanker or RRF.

• Memory-sensitive ANN on x86_64

- Prefer HNSW-RaBitQ when HNSW-quality recall matters but memory is the limiting factor. - Start with the documented defaults (totalbits=7, numclusters=16) and tune query-time ef before changing quantization bits.

• Safe evolution of live collections

- Add/drop/alter scalar columns via addcolumn(), dropcolumn(), altercolumn(). - Manage indexes via createindex() / drop_index() (scalar). Vector indexes cannot be dropped.

Critical prohibitions

• Do not mirror vendor docs verbatim; summarize in your own words.
• Do not assume a client/server deployment model: Zvec is in-process.
• Do not add project-specific paths, secrets, or environment assumptions.
• Do not choose HNSW-RaBitQ on unsupported hardware; current docs limit it to x86_64 with AVX2 or better.

Release Highlights (0.7.0)

• C++ API is now snake_case (breaking). Index, Collection and methods like Open(), Search(), Query(), Insert() moved to index, collection, open(), search(), query(), insert(). C and Python API names are unchanged. See references/data-operations.md for migration notes.
• Wider DiskANN platform support. DiskANN indexes now run on Linux ARM64 and macOS ARM64 (Apple Silicon), auto-selecting the best I/O backend.
• New index and quantization options. IVF RaBitQ, uniform uint7/uint8 quantizers, a Turbo PQ-INT8 quantizer (L2/Cosine/IP), Turbo record quantizers with portable scalar distance kernels, and an optional Fast Hadamard Transform (FHT) preprocessor before quantization.
• RaBitQ runtime SIMD dispatch. HNSW-RaBitQ selects AVX2 or AVX512 at runtime from the host CPU, so no instruction set needs to be hard-coded at build time.
• Better HNSW graph quality. Optional Vamana two-pass graph build, and building the graph from the original (unquantized) vectors while search still runs against the stored lossy vectors.
• FTS ngram tokenizer. A character-level tokenizer for short text, code, or pinyin, configured via the index extra_params.
• DocIterator. Stream the full collection as a snapshot without loading it into memory; exposed across the C++, C, and Python bindings.
• Concurrent optimize(). Reads and writes now proceed while optimization runs, so long optimizations no longer stall ingest or retrieval.

Release Highlights (0.6.0)

• Pluggable Turbo quantizer: the Turbo module now exposes a Quantizer abstraction with a uniform interface, decoupling quantization logic from index builders/searchers so future quantizers (int8 uniform, int8 record, PQ, RaBitQ, and more) can plug in without touching index code. Ships with a first Fp32Quantizer implementation and scalar FP32 distance kernels.
• Random rotation for INT8/INT4 quantization: an optional random orthogonal rotation (enable_rotate) spreads variance evenly across dimensions before quantizing, cutting quantization error. On the cohere-1m benchmark this took HNSW INT8 recall from 0.9285 to 0.9397, Flat INT8 from 0.9695 to 0.9881, and HNSW INT4 recall from 0.2114 to 0.7117 — a large jump that makes INT4 viable in more scenarios.
• Group-by search: query results can now be deduplicated/grouped so you get the top-K per group instead of top-K globally, across Flat, HNSW, HNSW-RaBitQ, and sparse indexes (with fetchvector, islinear, and bf_pks query modes), exposed through the Python API.
• Zero-copy Python vector queries: the Python query path now points VectorViewClause directly at the source numpy buffer instead of memcpy-ing through serialize_vector, removing redundant copies for dense vector queries.
• Richer FTS tokenization: the standard tokenizer now implements Unicode 17 UAX #29 word-boundary rules (Lucene-style handling for alphanumeric, ideographic, hiragana/katakana/hangul, Southeast Asian scripts, and emoji), backed by utf8proc 2.11.3 for Unicode-aware lowercasing and a new ASCII-folding filter. A Snowball-based stemmer token filter (34+ languages, set via stemmer_lang) reduces words to their root form.
• Complete DiskANN C API: the C API now covers DiskANN end to end — index param getters/setters, query param CRUD, and query wiring for vector queries, group-by queries, and sub-queries — matching the existing HNSW/FTS C API patterns.
• Faster FTS conjunction/phrase queries: block-max skip plus score early-exit in the conjunction iterator skip non-competitive 128-doc blocks outright; benchmarked on a 500k-doc dataset this made AND queries 22-38% faster and phrase queries 33% faster.
• Stability fixes: assorted fixes to FTS correctness (segment stats on reopen, zero-match filter semantics, compaction doc-id gaps), index race conditions in DiskANN/HNSW/IVF, SQL engine group-by parameter handling, and collection LOCK-file behavior for read-only collections.

Release Highlights (0.5.1)

• External vector source: ingest and query from external vector sources for more flexible data pipelines without first copying everything into the collection.
• Zero-copy query path: VectorViewClause establishes a zero-copy vector query path with unified query validation, lowering per-query memory overhead.
• Search prefetch tuning: pass prefetch settings (PO, PL) directly through search parameters for finer performance control.
• Index/storage controls: isdirty is exposed on the core Index interface, and copy-on-write MMAP options (with a corrected MMAPPOPULATE placement) are configurable.
• C API FTS sub-queries: full-text search now works inside sub-queries via the C API.

Release Highlights (0.5.0)

• Full-text search (FTS): attach an FTS index to any string field via createindex() / dropindex() and query it with natural-language or structured expressions, alongside vector indexes.
• Hybrid retrieval: the MultiQuery API combines dense vectors, sparse vectors, scalar filters, and text in one query with consistent reranking across Python, Go, Rust, and C++.
• DiskANN index: keeps the bulk of the index on disk instead of RAM, cutting memory use for billion-scale datasets on memory-constrained hosts.
• Output field selection: fetch() accepts an output_fields parameter to control which fields are returned.
• New SDKs and tooling: official Go SDK (cgo, prebuilt Linux/macOS/Windows libs), Rust SDK (RAII, builder APIs), and Zvec Studio (pip install zvec-studio) for visual data browsing and query testing.

Release Highlights (0.3.0 -> 0.4.0)

• Windows support and official Windows packages for Python and Node.js
• HNSW-RaBitQ quantized vector indexing for lower-memory ANN on supported x86_64 hosts
• Stable C API for building or maintaining additional language bindings
• MCP server / agent skills ecosystem for AI-driven collection management and retrieval workflows
• 0.3.1 hotfixes for relaxed collection path restrictions and better Windows cross-drive/path handling
• 0.4.0 adds official Dart/Flutter bindings, iOS build support, a larger topK ceiling, stricter query_params validation, and fixes an SQ8 quantizer recall regression.

Links

• Documentation: https://zvec.org/en/docs/
• GitHub: https://github.com/alibaba/zvec
• Releases: https://github.com/alibaba/zvec/releases
• Issues: https://github.com/alibaba/zvec/issues