Milvus Architecture and Internals

Milvus Architecture

Milvus is a purpose-built vector database optimized for similarity search and AI workloads. Its architecture is distinct from traditional RDBMS like PostgreSQL and MySQL, as it is designed to handle high-dimensional vector data (e.g., embeddings) rather than traditional structured data. Below is an overview of the Milvus architecture and how it differs from traditional relational database systems.


1. Milvus Architecture Overview

Core Components:

  • Query Node • Handles search queries and retrieves relevant vector data. • Uses vector search algorithms like IVF_FLAT, HNSW, or ANNOY for similarity search. • Performs distributed query processing in a cluster setup.
  • Data Node • Handles data ingestion and storage. • Writes vector and metadata to persistent storage. • Manages data replication and erasure coding for fault tolerance.
  • Index Node • Builds and manages vector indices (e.g., IVF, HNSW). • Offloads compute-intensive indexing tasks from the query and data nodes.
  • Root Coordinator • Serves as the central control plane for the cluster. • Manages metadata, task scheduling, and node coordination. • Ensures data consistency across distributed nodes.
  • Proxy • Acts as the entry point for client applications. • Routes requests to appropriate query or data nodes. • Performs authentication and API handling.
  • Storage Layer • Supports various storage backends like local SSDs, HDFS, or cloud object storage (e.g., S3, GCS). • Handles the separation of hot (frequently accessed) and cold (archived) data for optimal performance.
  • Cache Layer • Provides in-memory caching for frequently accessed data and indices. • Reduces query latency for read-heavy workloads.
  • Monitoring and Logging • Integrates with Prometheus and Grafana for metrics and visualizations. • Provides detailed logs for troubleshooting and performance tuning.

2. Differences from Traditional RDBMS

Aspect Milvus Traditional RDBMS (PostgreSQL/MySQL)
Data Model Vector-based: Focuses on storing and querying high-dimensional vectors for similarity search. Relational: Uses tables with rows and columns for structured data.
Query Types Nearest neighbor search, vector similarity queries. SQL-based CRUD operations, joins, aggregations, and analytical queries.
Indexing Vector-specific indices like IVF_FLAT, HNSW, ANNOY for fast similarity search. B-tree, hash, or GIN indices for efficient querying of relational data.
Workload Type Optimized for AI/ML workloads (e.g., recommendation systems, image search, NLP). Transactional and analytical workloads, including OLTP and OLAP.
Scaling Designed for horizontal scaling with distributed nodes for query, data, and indexing. Supports vertical scaling and limited sharding.

3. Unique Features of Milvus

  • Vectorized Query Processing: Optimized for nearest neighbor searches and similarity computations.
  • GPU Acceleration: Supports GPU-based indexing and query execution for high-speed vector computations.
  • Distributed Architecture: Built from the ground up for distributed scalability, handling petabyte-scale vector data.
  • Integration with AI Workflows: Seamlessly works with embeddings generated by AI models.

4. Use Case Comparison

Use Case Milvus PostgreSQL/MySQL
Image or Video Search Efficient vector similarity search Not suitable; requires additional frameworks
Recommender Systems High-speed similarity search in vector space Limited; needs custom algorithms
Relational Data Management Not ideal; lacks SQL support Well-suited with normalized table designs

 


5. When to Choose Milvus vs. RDBMS

Milvus complements traditional RDBMS by addressing AI/ML and vector-based workloads. While PostgreSQL and MySQL excel at structured data management and transactional processing, Milvus focuses on the unique demands of similarity search and large-scale AI-driven applications.

Requirement Choose Milvus Choose PostgreSQL/MySQL
High-dimensional vector search Most suitable - optimized for vector operations Limited capabilities, requires extensions
AI/ML model integration Native support for embeddings and similarity search Requires additional frameworks
Relational data handling Limited SQL support Excellent with complex relationships
Query performance Optimized for vector similarity queries Optimized for structured data queries
Scalability approach Built-in horizontal scaling Primarily vertical scaling

6. Conclusion

Understanding the architectural differences between Milvus and traditional RDBMS is crucial for making informed technology choices. While Milvus excels in vector similarity search and AI-driven applications, traditional RDBMS remain essential for structured data management. The key is recognizing that these systems serve different purposes and can coexist in modern data architectures.

Organizations should evaluate their specific needs - whether they require efficient vector search capabilities for AI applications (Milvus) or robust relational data management (RDBMS). In many cases, a hybrid approach might be optimal, leveraging both systems' strengths to build comprehensive data solutions that can handle both traditional and AI-driven workloads effectively.

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About Shiv Iyer 496 Articles
Open Source Database Systems Engineer with a deep understanding of Optimizer Internals, Performance Engineering, Scalability and Data SRE. Shiv currently is the Founder, Investor, Board Member and CEO of multiple Database Systems Infrastructure Operations companies in the Transaction Processing Computing and ColumnStores ecosystem. He is also a frequent speaker in open source software conferences globally.