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https://github.com/timescale/pgvectorscale

A complement to pgvector for high performance, cost efficient vector search on large workloads.
https://github.com/timescale/pgvectorscale

Last synced: 3 months ago
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A complement to pgvector for high performance, cost efficient vector search on large workloads.

Host: GitHub
URL: https://github.com/timescale/pgvectorscale
Owner: timescale
License: postgresql
Created: 2023-07-01T01:05:05.000Z (over 1 year ago)
Default Branch: main
Last Pushed: 2024-07-25T09:07:30.000Z (4 months ago)
Last Synced: 2024-07-25T16:16:02.770Z (4 months ago)
Language: Rust
Homepage:
Size: 479 KB
Stars: 713
Watchers: 12
Forks: 31
Open Issues: 25
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: .github/CODE_OF_CONDUCT.md
- Codeowners: .github/CODEOWNERS

Awesome Lists containing this project

awesome-repositories - timescale/pgvectorscale - A complement to pgvector for high performance, cost efficient vector search on large workloads. (Rust)
awesome - timescale/pgvectorscale - A complement to pgvector for high performance, cost efficient vector search on large workloads. (Rust)
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README

# pgvectorscale

pgvectorscale builds on pgvector with higher performance embedding search and cost-efficient storage for AI applications.

[![Discord](https://img.shields.io/badge/Join_us_on_Discord-black?style=for-the-badge&logo=discord&logoColor=white)](https://discord.gg/KRdHVXAmkp)
[![Try Timescale for free](https://img.shields.io/badge/Try_Timescale_for_free-black?style=for-the-badge&logo=timescale&logoColor=white)](https://tsdb.co/gh-pgvector-signup)

pgvectorscale complements [pgvector][pgvector], the open-source vector data extension for PostgreSQL, and introduces the following key innovations for pgvector data:
- A new index type called StreamingDiskANN, inspired by the [DiskANN](https://github.com/microsoft/DiskANN) algorithm, based on research from Microsoft.
- Statistical Binary Quantization: developed by Timescale researchers, This compression method improves on standard Binary Quantization.

On benchmark dataset of 50 million Cohere embeddings (768 dimensions each), PostgreSQL with pgvector and pgvectorscale achieves **28x lower p95 latency** and **16x higher query throughput** compared to Pinecone's storage optimized (s1) index for approximate nearest neighbor queries at 99% recall, all at 75% less cost when self-hosted on AWS EC2.

![Benchmarks](https://assets.timescale.com/docs/images/benchmark-comparison-pgvectorscale-pinecone.png)

PostgreSQL with pgvector and pgvectorscale extensions outperformed Pinecone’s storage optimized (s1) and performance-optimized (p2) pod-based index types.

To learn more about the performance impact of pgvectorscale, and details about benchmark methodology and results, see the [pgvector vs Pinecone comparison blog post](http://www.timescale.com/blog/pgvector-vs-pinecone).

In contrast to pgvector, which is written in C, pgvectorscale is developed in [Rust][rust-language] using the [PGRX framework](https://github.com/pgcentralfoundation/pgrx),
offering the PostgreSQL community a new avenue for contributing to vector support.

**Application developers or DBAs** can use pgvectorscale with their PostgreSQL databases.
* [Install pgvectorscale](#installation)
* [Get started using pgvectorscale](#get-started-with-pgvectorscale)

If you **want to contribute** to this extension, see how to [build pgvectorscale from source in a developer environment](./DEVELOPMENT.md).

For production vector workloads, get **private beta access to vector-optimized databases** with pgvector and pgvectorscale on Timescale. [Sign up here for priority access](https://timescale.typeform.com/to/H7lQ10eQ).

## Installation

The fastest ways to run PostgreSQL with pgvectorscale are:

* [Using a pre-built Docker container](#using-a-pre-built-docker-container)
* [Installing from source](#installing-from-source)
* [Enable pgvectorscale in a Timescale Cloud service](#enable-pgai-in-a-timescale-cloud-service)

### Using a pre-built Docker container

1. [Run the TimescaleDB Docker image](https://docs.timescale.com/self-hosted/latest/install/installation-docker/).

1. Connect to your database:
```bash
psql -d "postgres://:@:/"
```

1. Create the pgvectorscale extension:

```sql
CREATE EXTENSION IF NOT EXISTS vectorscale CASCADE;
```

The `CASCADE` automatically installs `pgvector`.

### Installing from source

You can install pgvectorscale from source and install it in an existing PostgreSQL server

1. Compile and install the extension

```
# install prerequisites
## rust
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
## pgrx
cargo install --locked cargo-pgrx
cargo pgrx init --pg16 pg_config

#download, build and install pgvectorscale
cd /tmp
git clone --branch https://github.com/timescale/pgvectorscale
cd pgvectorscale/pgvectorscale
cargo pgrx install --release
```

You can also take a look at our [documentation for extension developers](./DEVELOPMENT.md) for more complete instructions.

1. Connect to your database:
```bash
psql -d "postgres://:@:/"
```

1. Create the pgvectorscale extension:

```sql
CREATE EXTENSION IF NOT EXISTS vectorscale CASCADE;
```

The `CASCADE` automatically installs `pgvector`.

### Enable pgvectorscale in a Timescale Cloud service

Note: the instructions below are for Timescale's standard compute instance. For production vector workloads, we’re offering **private beta access to vector-optimized databases** with pgvector and pgvectorscale on Timescale. [Sign up here for priority access](https://timescale.typeform.com/to/H7lQ10eQ).

To enable pgvectorscale:

1. Create a new [Timescale Service](https://console.cloud.timescale.com/signup?utm_campaign=vectorlaunch).

If you want to use an existing service, pgvectorscale is added as an available extension on the first maintenance window
after the pgvectorscale release date.

1. Connect to your Timescale service:
```bash
psql -d "postgres://:@:/"
```

1. Create the pgvectorscale extension:

```postgresql
CREATE EXTENSION IF NOT EXISTS vectorscale CASCADE;
```

The `CASCADE` automatically installs `pgvector`.

## Get started with pgvectorscale

1. Create a table with an embedding column. For example:

```postgresql
CREATE TABLE IF NOT EXISTS document_embedding (
id BIGINT PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
metadata JSONB,
contents TEXT,
embedding VECTOR(1536)
)
```

1. Populate the table.

For more information, see the [pgvector instructions](https://github.com/pgvector/pgvector/blob/master/README.md#storing) and [list of clients](https://github.com/pgvector/pgvector/blob/master/README.md#languages).
1. Create a StreamingDiskANN index on the embedding column:
```postgresql
CREATE INDEX document_embedding_idx ON document_embedding
USING diskann (embedding);
```
1. Find the 10 closest embeddings using the index.

```postgresql
SELECT *
FROM document_embedding
ORDER BY embedding <=> $1
LIMIT 10
```

Note: pgvectorscale currently support cosine distance (`<=>`) queries. If you would like additional distance types,
[create an issue](https://github.com/timescale/pgvectorscale/issues).

## Tuning

The StreamingDiskANN index comes with **smart defaults** but also the ability to customize it's behavior. There are two types of parameters: index build-time parameters that are specified when an index is created and query-time parameters that can be tuned when querying an index.

We suggest setting the index build-time paramers for major changes to index operations while query-time parameters can be used to tune the accuracy/performance tradeoff for individual queries.

We expect most people to tune the query-time parameters (if any) and leave the index build time parameters set to default.

### StreamingDiskANN index build-time parameters

These parameters can be set when an index is created.

| Parameter name | Description | Default value |
|------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------|
| `storage_layout` | `memory_optimized` which uses SBQ to compress vector data or `plain` which stores data uncompressed | memory_optimized
| `num_neighbors` | Sets the maximum number of neighbors per node. Higher values increase accuracy but make the graph traversal slower. | 50 |
| `search_list_size` | This is the S parameter used in the greedy search algorithm used during construction. Higher values improve graph quality at the cost of slower index builds. | 100 |
| `max_alpha` | Is the alpha parameter in the algorithm. Higher values improve graph quality at the cost of slower index builds. | 1.2 |
| `num_dimensions` | The number of dimensions to index. By default, all dimensions are indexed. But you can also index less dimensions to make use of [Matryoshka embeddings](https://huggingface.co/blog/matryoshka) | 0 (all dimensions)
| `num_bits_per_dimension` | Number of bits used to encode each dimension when using SBQ | 2 for less than 900 dimensions, 1 otherwise

An example of how to set the `num_neighbors` parameter is:

```sql
CREATE INDEX document_embedding_idx ON document_embedding
USING diskann (embedding) WITH(num_neighbors=50);
```

#### StreamingDiskANN query-time parameters

You can also set two parameters to control the accuracy vs. query speed trade-off at query time. We suggest adjusting `diskann.query_rescore` to fine-tune accuracy.

You can set the value by using `SET` before executing a query. For example:

```sql
SET diskann.query_rescore = 400;
```

Note the [SET command](https://www.postgresql.org/docs/current/sql-set.html) applies to the entire session (database connection) from the point of execution. You can use a transaction-local variant using `LOCAL` which will
be reset after the end of the transaction:

```sql
BEGIN;
SET LOCAL diskann.query_search_list_size= 10;
SELECT * FROM document_embedding ORDER BY embedding <=> $1 LIMIT 10
COMMIT;
```

## Get involved

pgvectorscale is still at an early stage. Now is a great time to help shape the
direction of this project; we are currently deciding priorities. Have a look at the
list of features we're thinking of working on. Feel free to comment, expand
the list, or hop on the Discussions forum.

## About Timescale

Timescale is a PostgreSQL cloud company. To learn more visit the [timescale.com](https://www.timescale.com).

[Timescale Cloud](https://console.cloud.timescale.com/signup?utm_campaign=vectorlaunch) is a high-performance, developer focused, cloud platform that provides PostgreSQL services for the most demanding AI, time-series, analytics, and event workloads. Timescale Cloud is ideal for production applications and provides high availability, streaming backups, upgrades over time, roles and permissions, and great security.

[pgvector]: https://github.com/pgvector/pgvector/blob/master/README.md
[rust-language]: https://www.rust-lang.org/