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14 changes: 14 additions & 0 deletions docs/navigation/standard.md
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- label: 'Creating sequence tables'
slug: '/docs/sharding/sequence-tables'

- label: 'Vectors'
icon: 'vectors'
items:
- label: 'Vectors overview'
slug: '/docs/vectors/overview'
- label: 'Concepts and terminology'
slug: '/docs/vectors/terminology-and-concepts'
- label: 'Use cases'
slug: '/docs/vectors/use-cases'
- label: 'Using with an ORM'
slug: '/docs/vectors/using-with-an-orm'
- label: 'Reference'
slug: '/docs/vectors/reference'

- label: 'Security and access'
icon: 'security'
items:
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111 changes: 20 additions & 91 deletions docs/concepts/vectors.md → docs/vectors/overview.md
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---
title: 'Vector search and storage'
subtitle: 'Learn how to use PlanetScale vector search and storage.'
date: '2024-09-30'
date: '2024-10-29'
---

Welcome to the PlanetScale vectors beta! The goal of this private beta period is to get the product in the hands of our customers so you can build alongside us while we continue to improve the feature — with your feedback.
Welcome to the PlanetScale vectors beta! The goal of this beta period is to get the product in the hands of our customers so you can build alongside us while we continue to improve the feature — with your feedback.

If at any point you experience issues with vectors while using the beta, we highly encourage you to get in touch. Your feedback is extremely valuable during this beta period, so don’t hesitate to reach out. You can [submit a support ticket](/contact) to relay any feedback or issues. We also have a private [Discord](https://discord.com/invite/pDUGAAFEJx) channel for the vectors beta. If you'd like to added, fill out our [contact form](/contact).
If at any point you experience issues with vectors while using the beta, we highly encourage you to get in touch. Your feedback is extremely valuable during this beta period, so don’t hesitate to reach out. You can [submit a support ticket](/contact) to relay any feedback or issues. We also have a vectors channel in our [Discord](https://discord.com/invite/pDUGAAFEJx) where you can ask questions and share feedback.

{% callout type="warning" %}
This feature is still beta quality and is not intended for use in production workloads. We recommend limiting use of PlanetScale vector search and storage to testing and evaluation purposes only. PlanetScale vectors is considered a Beta Feature as noted in our Agreement with you, and any use of PlanetScale vectors is in accordance with the Agreement.
{% /callout %}

This documentation outlines how to get started with vectors, known issues and limitations, some example usage, and how to share feedback.

## Known issues and limitations

- Building a **one-shot** **index** (an index built in bulk on an existing set of vectors) requires enough RAM to fit all of the vectors in memory simultaneously. This limitation will be lifted by the time the beta is complete.
- **Incremental indexes** (indexes that begin empty and update as new vectors are added) function correctly, but are significantly slower to build compared to a one-shot index. Disk usage is much higher due to potentially very high InnoDB blob fragmentation issues, so it's much easier to run out of disk space.
- **Online DDL** and deploy requests do not work well yet, because they build incremental indexes. Please use direct DDL for now. We plan to improve this significantly during the beta.
- Since this is a beta, there may be bugs, performance, and security issues that have not yet been uncovered. We also may need to change query or DDL syntax before the feature is generally available. Don’t run this on a production database.
- Once you opt a branch into the vectors feature, that branch must continue to run a vectors-enabled version of MySQL. You can remove your vector columns/tables, but you cannot downgrade that branch to its prior version of MySQL.

## Overview

Vectors are a data structure that captures opaque semantic meaning about something and allows a database to search for resources by similarity based on this opaque meaning. As a data type, a vector is just an array of floating-point numbers. Those numbers are generated by submitting some resource — a word, a string, a document, an image, audio, etc — to an *embedding*¹, which converts the resource to a vector.
Vectors are a data structure that captures opaque semantic meaning about something and allows a database to search for resources by similarity based on this opaque meaning. As a data type, a vector is just an array of floating-point numbers. Those numbers are generated by submitting some resource — a word, a string, a document, an image, audio, etc. — to an _embedding model_ which converts the resource to a vector.

A vector database stores those vector embeddings alongside other relational data. In practice, that might look like a table with columns for ID (a primary key), content (as a BLOB or VARCHAR), and a vector. Then it becomes possible to perform queries that find content similar to a search query, like so:
A vector database stores those vector embeddings alongside other relational data. In practice, that might look like a table with columns for ID (a primary key), content (as a BLOB or VARCHAR), and a vector. Then it becomes possible to perform queries that find content similar to a search vector, like so:

```sql
SELECT id
Expand All @@ -35,17 +25,15 @@ SELECT id
LIMIT 10;
```

Possible applications include recommendation engines that show products similar to a user's purchase history, or search engines that find documents or other resources based on natural-language queries.
Possible applications include recommendation engines that show products similar to a user's purchase history, or search engines that find documents or other resources based on natural-language queries. Read our [applications of vector databases](/docs/vectors/use-cases) docs to learn more about how vector databases can be applied in the real world.

PlanetScale has added support for vector columns, vector distance functions, and vector indexes, as described below.

[¹]: PlanetScale does not currently provide an embedding service. You can find several good cloud-based options like OpenAI or AWS Titan, or local options like Python sentence_transformers.
[¹]: PlanetScale does not currently provide an embedding service. You can find several good cloud-based options like OpenAI or AWS Titan, or local options like Python `sentence_transformers`.

## Enrolling in the PlanetScale vectors beta

This is currently a closed beta. To access the beta, you must have received an invite. If you did not receive an invite and wish to join, or you would like to enroll a different organization, please fill out our [contact form](/contact).

PlanetScale has a series of MySQL images that have been extended with vector support. Vector support can be enabled on a per-branch basis, however, you have to first opt-in to the beta from your database settings page. After that, you will choose which branch(es) you’d like to opt-in to the vectors beta. The branch will be updated to the vectors-enabled version of MySQL at the time of opting the branch in.
PlanetScale has a custom version of MySQL that has been extended with vector support. Vector support can be enabled on a per-branch basis, however, you have to first opt-in to the beta from your database settings page. After that, you will choose which branch(es) you’d like to opt-in to the vectors beta. The branch will be updated to the vectors-enabled version of MySQL at the time of opting the branch in.
To enable the vector support on a branch:

1. Click on the database that you’d like to enroll in the vectors beta.
Expand All @@ -56,7 +44,7 @@ To enable the vector support on a branch:
6. Click on the small gear icon underneath the “Connect” button on the right.
7. Click the toggle next to “Enable vectors”.
8. Click “Save branch settings”.
9. The branch will upgrade asynchronously to the correct version of MySQL, which may take 30-60 minutes. You can confirm when this process is complete by executing a “SELECT @@version” query. The vector-enabled version is 8.0.37.
9. The branch will upgrade asynchronously to the correct version of MySQL, which may take 30-60 minutes. While this happens, the database dashboard will show an "Enabling vectors" badge, which changes to a "Vector-enabled" badge when the upgrade is complete.

## Adding vector columns

Expand Down Expand Up @@ -88,12 +76,12 @@ SELECT id, DISTANCE(TO_VECTOR('[3, 3, 3, 3]'), embedding, 'L2_SQUARED') AS d

Use an `EXPLAIN` query to confirm that the query uses the new index. This query actually won’t use the index until the table has around 50 rows in it.

Note that vector indexes provide approximate results. An unindexed query with LIMIT 100 returns exactly the 100 rows closest to the reference vector, after performing a full table scan and a sort. An indexed query returns, on average, about 100 of the top 105 (around 95%) of the rows closest to the reference vector, but much faster than a full table scan. This is expected, because all efficient vector indexes, including PlanetScale’s vector indexes, perform approximate nearest neighbor (ANN) searches.
Vector indexes provide approximate results. An unindexed query with LIMIT 100 returns exactly the 100 rows closest to the reference vector, after performing a full table scan and a sort. An indexed query returns, on average, about 100 of the top 105 (around 95%) of the rows closest to the reference vector, but much faster than a full table scan. This is expected, because all efficient vector indexes, including PlanetScale’s vector indexes, perform approximate nearest neighbor (ANN) searches.

If you are adding vectors from an app, you may want to use prepared statements, although we do not recommend it. `TO_VECTOR` works in that setting, but serializing the vectors on the client side and uploading them as binary is faster. The serialized format is IEEE-754 32-bit floats, which you can serialize with code like this:
If you are adding vectors to your database from an application, you may want to use prepared statements, although we do not recommend it. `TO_VECTOR` works in that setting, but serializing the vectors on the client side and uploading them as binary is faster. The serialized format is IEEE-754 32-bit floats, which you can serialize with code like this:

- Python: `struct.pack('ffff', *float_array)`
- Ruby: `float_array.pack(“ffff”)`
- Python: `struct.pack(f'{len(float_array)}f', *float_array)`
- Ruby: `float_array.pack(“f*”)`
- Rust: `float_array.map(|f| f.to_ne_bytes()).flatten().collect()`

You can use the resulting blob (which will be 4 bytes times the number of dimensions in the vector) in an `INSERT` statement like this:
Expand Down Expand Up @@ -147,76 +135,17 @@ This query selects the ten products from a given seller that are closest to some

The MySQL query planner chooses whether to use the vector index or some other index automatically based on the query and based on the contents of the table, to maximize query performance. Use `EXPLAIN` on any given query to see how it will execute.

As part of the private beta, we’re looking for feedback on how well MySQL plans vector queries. If you believe you’ve hit an edge case or something looks wrong, please [open a support ticket](/contact) and let us know.

## Vector function reference

**`TO_VECTOR(string)`**
Converts a text string to a binary vector value. The text string is an array of floating point numbers in JSON format.

- alias `STRING_TO_VECTOR(string)`
- Example: `SELECT TO_VECTOR('[1, 2.78, 3.14]');`

`-> 0x0000803F85EB3140C3F54840`

**`FROM_VECTOR(string)`**
Converts a binary vector to a human-readable string.

- alias `VECTOR_TO_STRING(vector)`
- Example: `SELECT FROM_VECTOR(0x0000803F85EB3140C3F54840);`

`-> [1.00000e+00,2.78000e+00,3.14000e+00]`

**`VECTOR_DIM(string)`**
Calculates the dimension of a vector

- Example: `SELECT VECTOR_DIM(TO_VECTOR('[1,2,3]')); -> 3`

**`DISTANCE(vector1, vector2, [metric])`**
Calculates the distance between two vectors. The optional third parameter specifies which distance metric is to be used: `DOT`, `COSINE`, L2 (`EUCLIDEAN)`, or L2_SQUARED (`EUCLIDEAN_SQUARED)`. If the distance metric is omitted, it defaults to `DOT`.

- `DOT` means the dot product. Example:
As part of the beta, we’re looking for feedback on how well MySQL plans vector queries. If you believe you’ve hit an edge case or something looks wrong, please [open a support ticket](/contact) and let us know.

`SELECT DISTANCE(TO_VECTOR('[1,2]'), TO_VECTOR('[5,4]'), 'DOT');`
## Known issues and limitations for the beta

`-> 13`

- `COSINE` means the cosine of the angle between the two vectors, which is the same as the dot product divided by the magnitude of the two vectors. Example:

`SELECT DISTANCE(TO_VECTOR('[1,2]'), TO_VECTOR('[5,4]'), 'COSINE');`

`-> 0.09204061549954834`

- `L2` (or `EUCLIDEAN`) means the length of a line between the ends of the vectors. Example:

`SELECT DISTANCE(TO_VECTOR('[1,2]'), TO_VECTOR('[5,4]'), 'L2');`

`-> 4.47213595499958`

- `L2_SQUARED` (or `EUCLIDEAN_SQUARED`) is the square of the Euclidean distance

`SELECT DISTANCE(TO_VECTOR('[1,2]'), TO_VECTOR('[5,4]'), 'L2_SQUARED');`

`-> 20`

**`DISTANCE_DOT(vector1, vector2)`**
Is the same as `DISTANCE(vector1, vector2, 'DOT')`

**`DISTANCE_COSINE(vector1, vector2)`**
Is the same as `DISTANCE(vector1, vector2, 'COSINE')`

**`DISTANCE_L2(vector1, vector2)`**
Is the same as `DISTANCE(vector1, vector2, 'L2')`

- alias: `DISTANCE_EUCLIDEAN(vector1, vector2)`

**`DISTANCE_L2_SQUARED(vector1, vector2)`**
Is the same as `DISTANCE(vector1, vector2, 'L2_SQUARED')`

- alias: `DISTANCE_EUCLIDEAN_SQUARED(vector1, vector2)`
- Building a **one-shot** **index** (an index built in bulk on an existing set of vectors) requires enough RAM to fit roughly half of all the vector dataset in memory simultaneously. This will be improved throughout the beta.
- **Incremental indexes** (indexes that begin empty and update as new vectors are added) function correctly, but are significantly slower to build compared to a one-shot index. Disk usage is much higher due to potentially very high InnoDB blob fragmentation issues, so it's much easier to run out of disk space.
- Since this is a beta, there may be bugs, performance, and security issues that have not yet been uncovered. We also may need to change query or DDL syntax before the feature is generally available. Don’t run this on a production database.
- Once you opt a branch into the vectors feature, that branch must continue to run a vectors-enabled version of MySQL. You can remove your vector columns/tables, but you cannot downgrade that branch to its prior version of MySQL.

## Feedback

We want to make our vectors offering as reliable, fast, and feature-rich as possible. Feedback from our early users will help make this possible. If you encounter any issues, crashes, unexpected errors or poor performance, please [submit a support ticket](/contact). You are also welcome to reach out with general feedback and suggestions.

We also have a private [Discord](https://discord.com/invite/pDUGAAFEJx) channel for the vectors beta where you can ask questions, share feedback, and discuss what you’re working on. If you'd like to added, please fill out the [contact form](/contact).
We also have a [Discord](https://discord.com/invite/pDUGAAFEJx) channel for the vectors beta where you can ask questions, share feedback, and discuss what you’re working on.
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