Milvus

Overview

Milvus is an open-source vector database built for scalable similarity search and AI applications. It supports billions of vectors with millisecond search performance.

Installation

npm install @llamaindex/milvus @zilliz/milvus2-sdk-node

Basic Usage

import { MilvusVectorStore } from "@llamaindex/milvus";
import { VectorStoreIndex, Document } from "llamaindex";

const vectorStore = new MilvusVectorStore({
  params: {
    configOrAddress: "http://localhost:19530"
  },
  collection: "my_collection"
});

const documents = [
  new Document({ text: "LlamaIndex is a data framework." }),
  new Document({ text: "Milvus is a vector database." })
];

const index = await VectorStoreIndex.fromDocuments(documents, {
  storageContext: { vectorStore }
});

const queryEngine = index.asQueryEngine();
const response = await queryEngine.query({
  query: "What is Milvus?"
});

Constructor Options

milvusClient

MilvusClient

Existing Milvus client instance

params.configOrAddress

ClientConfig | string

Milvus server address (defaults to MILVUS_ADDRESS env var)

params.ssl

boolean

Enable SSL connection (defaults to MILVUS_SSL env var)

params.username

string

Milvus username (defaults to MILVUS_USERNAME env var)

params.password

string

Milvus password (defaults to MILVUS_PASSWORD env var)

collection

string

default:"llamacollection"

Collection name for storing vectors

idKey

string

default:"id"

Field name for storing node IDs

contentKey

string

default:"content"

Field name for storing text content

metadataKey

string

default:"metadata"

Field name for storing metadata (as JSON)

embeddingKey

string

default:"embedding"

Field name for storing embedding vectors

Configuration

Environment Variables

MILVUS_ADDRESS=http://localhost:19530
MILVUS_USERNAME=username  # Optional
MILVUS_PASSWORD=password  # Optional
MILVUS_SSL=false          # Optional

With Custom Client

import { MilvusClient } from "@zilliz/milvus2-sdk-node";
import { MilvusVectorStore } from "@llamaindex/milvus";

const milvusClient = new MilvusClient({
  address: "localhost:19530",
  username: "username",
  password: "password"
});

const vectorStore = new MilvusVectorStore({
  milvusClient,
  collection: "my_collection"
});

Running Milvus

Docker Compose

version: '3.5'

services:
  etcd:
    container_name: milvus-etcd
    image: quay.io/coreos/etcd:v3.5.5
    environment:
      - ETCD_AUTO_COMPACTION_MODE=revision
      - ETCD_AUTO_COMPACTION_RETENTION=1000
      - ETCD_QUOTA_BACKEND_BYTES=4294967296
    volumes:
      - etcd:/etcd

  minio:
    container_name: milvus-minio
    image: minio/minio:RELEASE.2023-03-20T20-16-18Z
    environment:
      MINIO_ACCESS_KEY: minioadmin
      MINIO_SECRET_KEY: minioadmin
    volumes:
      - minio:/minio_data
    command: minio server /minio_data

  milvus:
    container_name: milvus-standalone
    image: milvusdb/milvus:v2.3.3
    command: ["milvus", "run", "standalone"]
    environment:
      ETCD_ENDPOINTS: etcd:2379
      MINIO_ADDRESS: minio:9000
    volumes:
      - milvus:/var/lib/milvus
    ports:
      - "19530:19530"
      - "9091:9091"
    depends_on:
      - etcd
      - minio

volumes:
  etcd:
  minio:
  milvus:

Docker

docker run -d --name milvus \
  -p 19530:19530 \
  -p 9091:9091 \
  milvusdb/milvus:latest

Zilliz Cloud

const vectorStore = new MilvusVectorStore({
  params: {
    configOrAddress: "https://your-cluster.api.gcp-us-west1.zillizcloud.com",
    username: process.env.ZILLIZ_USERNAME,
    password: process.env.ZILLIZ_PASSWORD,
    ssl: true
  },
  collection: "my_collection"
});

Collection Management

Milvus automatically creates collections with this schema:

{
  fields: [
    {
      name: "id",
      data_type: DataType.VarChar,
      is_primary_key: true,
      max_length: 200
    },
    {
      name: "embedding",
      data_type: DataType.FloatVector,
      dim: 1536
    },
    {
      name: "content",
      data_type: DataType.VarChar,
      max_length: 9000
    },
    {
      name: "metadata",
      data_type: DataType.JSON
    }
  ]
}

Querying

Basic Query

const index = await VectorStoreIndex.fromVectorStore(vectorStore);

const retriever = index.asRetriever({
  similarityTopK: 5
});

const nodes = await retriever.retrieve("query text");

nodes.forEach(node => {
  console.log(`Score: ${node.score}`);
  console.log(`Text: ${node.node.text}`);
});

Metadata Filtering

import { MetadataFilters, FilterCondition } from "@llamaindex/core/vector-store";

const documents = [
  new Document({
    text: "Doc 1",
    metadata: { category: "tech", year: 2023 }
  }),
  new Document({
    text: "Doc 2",
    metadata: { category: "science", year: 2024 }
  })
];

const index = await VectorStoreIndex.fromDocuments(documents, {
  storageContext: { vectorStore }
});

const retriever = index.asRetriever({
  filters: new MetadataFilters({
    filters: [
      { key: "category", value: "tech", operator: "==" },
      { key: "year", value: 2023, operator: ">=" }
    ],
    condition: FilterCondition.AND
  })
});

const nodes = await retriever.retrieve("query");

Supported Filter Operators

Milvus supports:

== - Equal
!= - Not equal
< - Less than
<= - Less than or equal
> - Greater than
>= - Greater than or equal
in - Value in array
nin - Value not in array (converted to multiple != checks)

Managing Data

Add Documents

const newDoc = new Document({ text: "New content" });
await index.insert(newDoc);

Delete by Document ID

await vectorStore.delete(refDocId);

Access Milvus Client

const client = vectorStore.client();

// Get collection info
const collectionInfo = await client.describeCollection({
  collection_name: "my_collection"
});
console.log("Collection info:", collectionInfo);

// Get collection statistics
const stats = await client.getCollectionStatistics({
  collection_name: "my_collection"
});
console.log("Row count:", stats.data.row_count);

Complete Example

import { MilvusVectorStore } from "@llamaindex/milvus";
import { VectorStoreIndex, Document, Settings } from "llamaindex";
import { OpenAI, OpenAIEmbedding } from "@llamaindex/openai";

// Configure settings
Settings.llm = new OpenAI({ model: "gpt-4" });
Settings.embedModel = new OpenAIEmbedding();

// Create vector store
const vectorStore = new MilvusVectorStore({
  params: {
    configOrAddress: process.env.MILVUS_ADDRESS || "http://localhost:19530",
    username: process.env.MILVUS_USERNAME,
    password: process.env.MILVUS_PASSWORD
  },
  collection: "technical_docs"
});

// Load documents
const documents = [
  new Document({
    text: "Milvus is a cloud-native vector database...",
    metadata: { source: "docs", category: "database" }
  }),
  new Document({
    text: "LlamaIndex integrates with Milvus...",
    metadata: { source: "tutorial", category: "integration" }
  })
];

// Build index
const index = await VectorStoreIndex.fromDocuments(documents, {
  storageContext: { vectorStore }
});

// Query with filters
const retriever = index.asRetriever({
  similarityTopK: 3,
  filters: new MetadataFilters({
    filters: [
      { key: "category", value: "database", operator: "==" }
    ]
  })
});

const nodes = await retriever.retrieve("vector database");
console.log(nodes);

Index Types

Milvus supports various index types for different use cases:

FLAT: Exact search (best for small datasets)
IVF_FLAT: Inverted file with flat compression
IVF_SQ8: IVF with scalar quantization
IVF_PQ: IVF with product quantization
HNSW: Hierarchical Navigable Small World graph (best for high recall)
ANNOY: Approximate Nearest Neighbors Oh Yeah

Performance Tuning

Custom Collection Configuration

import { MilvusClient, DataType } from "@zilliz/milvus2-sdk-node";

const client = new MilvusClient({ address: "localhost:19530" });

// Create collection with custom schema
await client.createCollection({
  collection_name: "custom_collection",
  fields: [
    {
      name: "id",
      data_type: DataType.VarChar,
      is_primary_key: true,
      max_length: 100
    },
    {
      name: "embedding",
      data_type: DataType.FloatVector,
      dim: 1536
    },
    {
      name: "content",
      data_type: DataType.VarChar,
      max_length: 65535
    },
    {
      name: "metadata",
      data_type: DataType.JSON
    }
  ]
});

// Create index
await client.createIndex({
  collection_name: "custom_collection",
  field_name: "embedding",
  index_type: "HNSW",
  metric_type: "COSINE",
  params: { M: 16, efConstruction: 256 }
});

Best Practices

Choose appropriate index: HNSW for high recall, IVF for speed
Use Zilliz Cloud for production: Managed, scalable solution
Tune index parameters: Adjust M and efConstruction for HNSW
Monitor memory: Milvus loads indexes into memory
Batch operations: Insert documents in batches for better performance
Regular compaction: Run compaction to optimize storage

Troubleshooting

Connection Refused

Ensure Milvus is running:

docker ps | grep milvus

Collection Already Exists

Milvus auto-creates collections. To use existing collection:

const vectorStore = new MilvusVectorStore({
  params: { configOrAddress: "http://localhost:19530" },
  collection: "existing_collection"
});

Dimension Mismatch

Ensure embedding dimensions match:

import { OpenAIEmbedding } from "@llamaindex/openai";

// text-embedding-3-small: 1536 dimensions (default)
const embedModel = new OpenAIEmbedding({
  model: "text-embedding-3-small"
});

// Milvus collection will auto-create with 1536 dimensions

Core Package

Main Package

LLM Providers

Vector Stores

Workflow & Tools

Overview

Installation

Basic Usage

Constructor Options

Configuration

Environment Variables

With Custom Client

Running Milvus

Docker Compose

Docker

Zilliz Cloud

Collection Management

Querying

Basic Query

Metadata Filtering

Supported Filter Operators

Managing Data

Add Documents

Delete by Document ID

Access Milvus Client

Complete Example

Index Types

Performance Tuning

Custom Collection Configuration

Best Practices

Troubleshooting

Connection Refused

Collection Already Exists

Dimension Mismatch

See Also

Build docs developers (and LLMs) love

Core Package

Main Package

LLM Providers

Vector Stores

Workflow & Tools

​Overview

​Installation

​Basic Usage

​Constructor Options

​Configuration

​Environment Variables

​With Custom Client

​Running Milvus

​Docker Compose

​Docker

​Zilliz Cloud

​Collection Management

​Querying

​Basic Query

​Metadata Filtering

​Supported Filter Operators

​Managing Data

​Add Documents

​Delete by Document ID

​Access Milvus Client

​Complete Example

​Index Types

​Performance Tuning

​Custom Collection Configuration

​Best Practices

​Troubleshooting

​Connection Refused

​Collection Already Exists

​Dimension Mismatch

​See Also

Build docs developers (and LLMs) love

Overview

Installation

Basic Usage

Constructor Options

Configuration

Environment Variables

With Custom Client

Running Milvus

Docker Compose

Docker

Zilliz Cloud

Collection Management

Querying

Basic Query

Metadata Filtering

Supported Filter Operators

Managing Data

Add Documents

Delete by Document ID

Access Milvus Client

Complete Example

Index Types

Performance Tuning

Custom Collection Configuration

Best Practices

Troubleshooting

Connection Refused

Collection Already Exists

Dimension Mismatch

See Also