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sidebar_class_name: node-only
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import CodeBlock from "@theme/CodeBlock";

# SingleStore

[SingleStoreDB](https://singlestore.com/) is a high-performance distributed SQL database that supports deployment both in the [cloud](https://www.singlestore.com/cloud/) and on-premise. It provides vector storage, as well as vector functions like [dot_product](https://docs.singlestore.com/managed-service/en/reference/sql-reference/vector-functions/dot_product.html) and [euclidean_distance](https://docs.singlestore.com/managed-service/en/reference/sql-reference/vector-functions/euclidean_distance.html), thereby supporting AI applications that require text similarity matching.

:::tip Compatibility
Only available on Node.js.
:::

LangChain.js requires the `mysql2` library to create a connection to a SingleStoreDB instance.

## Setup

1. Establish a SingleStoreDB environment. You have the flexibility to choose between [Cloud-based](https://docs.singlestore.com/managed-service/en/getting-started-with-singlestoredb-cloud.html) or [On-Premise](https://docs.singlestore.com/db/v8.1/en/developer-resources/get-started-using-singlestoredb-for-free.html) editions.
2. Install the mysql2 JS client

```bash npm2yarn
npm install -S mysql2
```

## Usage

`SingleStoreVectorStore` manages a connection pool. It is recommended to call `await store.end();` before terminating your application to assure all connections are appropriately closed and prevent any possible resource leaks.

### Standard usage

import UsageExample from "@examples/indexes/vector_stores/singlestore.ts";

Below is a straightforward example showcasing how to import the relevant module and perform a base similarity search using the `SingleStoreVectorStore`:

<CodeBlock language="typescript">{UsageExample}</CodeBlock>

### Metadata Filtering

import UsageExampleWithMetadata from "@examples/indexes/vector_stores/singlestore_with_metadata_filter.ts";

If it is needed to filter results based on specific metadata fields, you can pass a filter parameter to narrow down your search to the documents that match all specified fields in the filter object:

<CodeBlock language="typescript">{UsageExampleWithMetadata}</CodeBlock>