# Milvus

## Description

The [Milvus](https://milvus.io/) online store provides support for materializing feature values into Milvus.

* The data model used to store feature values in Milvus is described in more detail [here](https://github.com/feast-dev/feast/blob/0.47-branch/docs/specs/online_store_format.md).

## Getting started

In order to use this online store, you'll need to install the Milvus extra (along with the dependency needed for the offline store of choice). E.g.

`pip install 'feast[milvus]'`

You can get started by using any of the other templates (e.g. `feast init -t gcp` or `feast init -t snowflake` or `feast init -t aws`), and then swapping in Redis as the online store as seen below in the examples.

## Examples

Connecting to a local MilvusDB instance:

{% code title="feature\_store.yaml" %}

```yaml
project: my_feature_repo
registry: data/registry.db
provider: local
online_store:
  type: milvus
  path: "data/online_store.db"
  connection_string: "localhost:6379"
  embedding_dim: 128
  index_type: "FLAT"
  metric_type: "COSINE"
  username: "username"
  password: "password"
```

{% endcode %}

The full set of configuration options is available in [MilvusOnlineStoreConfig](https://rtd.feast.dev/en/latest/#feast.infra.online_stores.milvus.MilvusOnlineStoreConfig).

## Functionality Matrix

The set of functionality supported by online stores is described in detail [here](https://docs.feast.dev/v0.47-branch/reference/overview#functionality).\
Below is a matrix indicating which functionality is supported by the Milvus online store.

|                                                           | Milvus |
| --------------------------------------------------------- | ------ |
| write feature values to the online store                  | yes    |
| read feature values from the online store                 | yes    |
| update infrastructure (e.g. tables) in the online store   | yes    |
| teardown infrastructure (e.g. tables) in the online store | yes    |
| generate a plan of infrastructure changes                 | no     |
| support for on-demand transforms                          | yes    |
| readable by Python SDK                                    | yes    |
| readable by Java                                          | no     |
| readable by Go                                            | no     |
| support for entityless feature views                      | yes    |
| support for concurrent writing to the same key            | yes    |
| support for ttl (time to live) at retrieval               | yes    |
| support for deleting expired data                         | yes    |
| collocated by feature view                                | no     |
| collocated by feature service                             | no     |
| collocated by entity key                                  | no     |
| vector similarity search                                  | yes    |

To compare this set of functionality against other online stores, please see the full [functionality matrix](https://docs.feast.dev/v0.47-branch/reference/overview#functionality-matrix).