Milvus

Milvus is an open-source vector database that has garnered significant attention in the fields of data science and machine learning. One of its standout features lies in its robust support for vector indexing and querying. Milvus employs state-of-the-art, cutting-edge algorithms to accelerate the search process, making it exceptionally efficient at retrieving similar vectors, even when handling extensive datasets.

Prerequisites

  • A running Milvus instance. The following options are available:

  • If required, an API key for the EmbeddingModel to generate the embeddings stored by the MilvusVectorStore.

Dependencies

Then add the Milvus VectorStore boot starter dependency to your project:

<dependency>
	<groupId>org.springframework.ai</groupId>
	<artifactId>spring-ai-milvus-store-spring-boot-starter</artifactId>
</dependency>

or to your Gradle build.gradle build file.

dependencies {
    implementation 'org.springframework.ai:spring-ai-milvus-store-spring-boot-starter'
}
Refer to the Dependency Management section to add the Spring AI BOM to your build file. Refer to the Repositories section to add Milestone and/or Snapshot Repositories to your build file.

The vector store implementation can initialize the requisite schema for you, but you must opt-in by specifying the initializeSchema boolean in the appropriate constructor or by setting …​initialize-schema=true in the application.properties file.

this is a breaking change! In earlier versions of Spring AI, this schema initialization happened by default.

The Vector Store, also requires an EmbeddingModel instance to calculate embeddings for the documents. You can pick one of the available EmbeddingModel Implementations.

To connect to and configure the MilvusVectorStore, you need to provide access details for your instance. A simple configuration can either be provided via Spring Boot’s application.yml

spring:
	ai:
		vectorstore:
			milvus:
				client:
					host: "localhost"
					port: 19530
					username: "root"
					password: "milvus"
				databaseName: "default"
				collectionName: "vector_store"
				embeddingDimension: 1536
				indexType: IVF_FLAT
				metricType: COSINE
Check the list of configuration parameters to learn about the default values and configuration options.

Now you can Auto-wire the Milvus Vector Store in your application and use it

@Autowired VectorStore vectorStore;

// ...

List <Document> documents = List.of(
    new Document("Spring AI rocks!! Spring AI rocks!! Spring AI rocks!! Spring AI rocks!! Spring AI rocks!!", Map.of("meta1", "meta1")),
    new Document("The World is Big and Salvation Lurks Around the Corner"),
    new Document("You walk forward facing the past and you turn back toward the future.", Map.of("meta2", "meta2")));

// Add the documents to Milvus Vector Store
vectorStore.add(documents);

// Retrieve documents similar to a query
List<Document> results = this.vectorStore.similaritySearch(SearchRequest.query("Spring").withTopK(5));

Manual Configuration

Instead of using the Spring Boot auto-configuration, you can manually configure the MilvusVectorStore. To add the following dependencies to your project:

<dependency>
	<groupId>org.springframework.ai</groupId>
	<artifactId>spring-ai-milvus-store</artifactId>
</dependency>
Refer to the Dependency Management section to add the Spring AI BOM to your build file.

To configure MilvusVectorStore in your application, you can use the following setup:

	@Bean
	public VectorStore vectorStore(MilvusServiceClient milvusClient, EmbeddingModel embeddingModel) {
		MilvusVectorStoreConfig config = MilvusVectorStoreConfig.builder()
			.withCollectionName("test_vector_store")
			.withDatabaseName("default")
			.withIndexType(IndexType.IVF_FLAT)
			.withMetricType(MetricType.COSINE)
			.build();
		return new MilvusVectorStore(milvusClient, embeddingModel, config);
	}

	@Bean
	public MilvusServiceClient milvusClient() {
		return new MilvusServiceClient(ConnectParam.newBuilder()
			.withAuthorization("minioadmin", "minioadmin")
			.withUri(milvusContainer.getEndpoint())
			.build());
	}

Metadata filtering

You can leverage the generic, portable metadata filters with the Milvus store.

For example, you can use either the text expression language:

vectorStore.similaritySearch(
    SearchRequest.defaults()
    .withQuery("The World")
    .withTopK(TOP_K)
    .withSimilarityThreshold(SIMILARITY_THRESHOLD)
    .withFilterExpression("author in ['john', 'jill'] && article_type == 'blog'"));

or programmatically using the Filter.Expression DSL:

FilterExpressionBuilder b = new FilterExpressionBuilder();

vectorStore.similaritySearch(SearchRequest.defaults()
    .withQuery("The World")
    .withTopK(TOP_K)
    .withSimilarityThreshold(SIMILARITY_THRESHOLD)
    .withFilterExpression(b.and(
        b.in("author","john", "jill"),
        b.eq("article_type", "blog")).build()));
These filter expressions are converted into the equivalent Milvus filters.

Milvus VectorStore properties

You can use the following properties in your Spring Boot configuration to customize the Milvus vector store.

Property Description Default value

spring.ai.vectorstore.milvus.database-name

The name of the Milvus database to use.

default

spring.ai.vectorstore.milvus.collection-name

Milvus collection name to store the vectors

vector_store

spring.ai.vectorstore.milvus.initialize-schema

whether to initialize Milvus' backend

false

spring.ai.vectorstore.milvus.embedding-dimension

The dimension of the vectors to be stored in the Milvus collection.

1536

spring.ai.vectorstore.milvus.index-type

The type of the index to be created for the Milvus collection.

IVF_FLAT

spring.ai.vectorstore.milvus.metric-type

The metric type to be used for the Milvus collection.

COSINE

spring.ai.vectorstore.milvus.index-parameters

The index parameters to be used for the Milvus collection.

{"nlist":1024}

spring.ai.vectorstore.milvus.id-field-name

The ID field name for the collection

doc_id

spring.ai.vectorstore.milvus.is-auto-id

Boolean flag to indicate if the auto-id is used for the ID field

false

spring.ai.vectorstore.milvus.content-field-name

The content field name for the collection

content

spring.ai.vectorstore.milvus.metadata-field-name

The metadata field name for the collection

metadata

spring.ai.vectorstore.milvus.embedding-field-name

The embedding field name for the collection

embedding

spring.ai.vectorstore.milvus.client.host

The name or address of the host.

localhost

spring.ai.vectorstore.milvus.client.port

The connection port.

19530

spring.ai.vectorstore.milvus.client.uri

The uri of Milvus instance

-

spring.ai.vectorstore.milvus.client.token

Token serving as the key for identification and authentication purposes.

-

spring.ai.vectorstore.milvus.client.connect-timeout-ms

Connection timeout value of client channel. The timeout value must be greater than zero .

10000

spring.ai.vectorstore.milvus.client.keep-alive-time-ms

Keep-alive time value of client channel. The keep-alive value must be greater than zero.

55000

spring.ai.vectorstore.milvus.client.keep-alive-timeout-ms

The keep-alive timeout value of client channel. The timeout value must be greater than zero.

20000

spring.ai.vectorstore.milvus.client.rpc-deadline-ms

Deadline for how long you are willing to wait for a reply from the server. With a deadline setting, the client will wait when encounter fast RPC fail caused by network fluctuations. The deadline value must be larger than or equal to zero.

0

spring.ai.vectorstore.milvus.client.client-key-path

The client.key path for tls two-way authentication, only takes effect when "secure" is true

-

spring.ai.vectorstore.milvus.client.client-pem-path

The client.pem path for tls two-way authentication, only takes effect when "secure" is true

-

spring.ai.vectorstore.milvus.client.ca-pem-path

The ca.pem path for tls two-way authentication, only takes effect when "secure" is true

-

spring.ai.vectorstore.milvus.client.server-pem-path

server.pem path for tls one-way authentication, only takes effect when "secure" is true.

-

spring.ai.vectorstore.milvus.client.server-name

Sets the target name override for SSL host name checking, only takes effect when "secure" is True. Note: this value is passed to grpc.ssl_target_name_override

-

spring.ai.vectorstore.milvus.client.secure

Secure the authorization for this connection, set to True to enable TLS.

false

spring.ai.vectorstore.milvus.client.idle-timeout-ms

Idle timeout value of client channel. The timeout value must be larger than zero.

24h

spring.ai.vectorstore.milvus.client.username

The username and password for this connection.

root

spring.ai.vectorstore.milvus.client.password

The password for this connection.

milvus

Starting Milvus Store

From within the src/test/resources/ folder run:

docker-compose up

To clean the environment:

docker-compose down; rm -Rf ./volumes

Then connect to the vector store on http://localhost:19530 or for management http://localhost:9001 (user: minioadmin, pass: minioadmin)

Troubleshooting

If Docker complains about resources, then execute:

docker system prune --all --force --volumes