Open Source Databases: The Complete Guide | JusDB

August 24, 2025

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Open Source Databases: The Complete Guide

Open source databases have become the foundation of modern application development. From startups building SaaS platforms to Fortune 500 enterprises managing mission-critical workloads, open source options like MySQL, PostgreSQL, and MongoDB dominate the market. They combine flexibility, scalability, and community-driven innovation with the cost advantages of open source licensing.

At JusDB, we specialize in migrations, performance optimization, high availability, and backup & DR across all major open source engines. This guide acts as a complete resource for understanding, comparing, and implementing open source databases effectively.

1. Why Choose Open Source Databases?

The shift toward open source databases is driven by:

Cost Efficiency: Avoids proprietary licensing fees (Oracle, SQL Server).
Community Innovation: Thousands of contributors continuously improve features.
Cloud-Native Deployments: First-class support across AWS, Azure, GCP.
Flexibility: Choose relational, document, or hybrid models based on workload.
Enterprise Adoption: Major companies like Apple, Uber, Netflix rely on them.

📊 Gartner estimates that by 2026, 80% of all new applications will run on open source databases.

2. The Open Source Database Landscape in 2025

The database ecosystem is evolving rapidly. While proprietary systems still dominate legacy enterprises, open source databases have surpassed them in new adoption. The key players:

MySQL – Best for transactional workloads and web apps.
PostgreSQL – Advanced analytics, hybrid relational + JSON.
MongoDB – Flexible schemas and large-scale scalability.
Cassandra – Wide-column store for distributed workloads.
ClickHouse – Columnar analytics engine.
StarRocks – HTAP workloads with sub-second queries.

In this guide, we’ll focus on the “big three” — MySQL, PostgreSQL, and MongoDB.

3. MySQL

MySQL is the most widely used relational database in the world. Known for reliability, performance, and ease of use, it powers everything from WordPress blogs to large-scale e-commerce platforms like Shopify.

MySQL Strengths

ACID-compliant with the InnoDB engine.
Excellent for structured, transactional data.
Wide adoption and community support.
Supported by all major clouds (AWS RDS, GCP, Azure).

When to Use MySQL

Web and e-commerce platforms.
Financial transactions and billing systems.
CMS systems (WordPress, Drupal).

📖 Deep dive: MySQL Explained: A Complete Guide

4. PostgreSQL

PostgreSQL (or Postgres) is often called the “world’s most advanced open source database.” It shines in analytics-heavy workloads, hybrid relational/JSON environments, and compliance-focused industries.

PostgreSQL Strengths

Strict ACID compliance with MVCC.
Rich indexing (GIN, GiST, BRIN).
Extensions like PostGIS (GIS) and TimescaleDB (time-series).
Highly standards-compliant and extensible.

When to Use PostgreSQL

Analytics-heavy or BI applications.
Hybrid workloads combining relational + JSONB.
Time-series and geospatial data.

📖 Deep dive: PostgreSQL Explained: A Complete Guide

5. MongoDB

MongoDB is the most popular NoSQL database, designed for flexible schema, massive write throughput, and distributed scalability. It powers applications like Uber, Netflix, and Forbes.

MongoDB Strengths

Schema flexibility with BSON documents.
Horizontal scalability with sharding.
Powerful aggregation framework.
Replica sets for high availability.

When to Use MongoDB

Rapidly evolving product catalogs.
IoT and real-time event processing.
Cloud-native microservices.

📖 Deep dive: MongoDB Explained: A Complete Guide

6. Comparing MySQL, PostgreSQL, and MongoDB

Each database is optimized for different workloads. Choosing the right one depends on schema requirements, scaling needs, and query patterns.

Aspect	MySQL	PostgreSQL	MongoDB
Model	Relational (tables)	Relational + JSONB	NoSQL Document
Schema	Rigid	Rigid + Extensible	Flexible
Transactions	ACID (InnoDB)	ACID (MVCC)	ACID (document-level, distributed since v4.0)
Scaling	Vertical + Replication	Vertical + Extensions (Citus)	Horizontal Sharding
Best For	Transactional workloads, CMS, e-commerce	Analytics, hybrid data, compliance	Flexible catalogs, IoT, microservices

📊 Visual Comparison:

MySQL vs PostgreSQL vs MongoDB Comparison

7. Real-World Use Cases

Facebook: MySQL for core transactional workloads.
Instagram: PostgreSQL for media metadata and analytics.
Uber: MongoDB for geospatial ride-matching.
Netflix: Combination of MySQL + Cassandra + MongoDB for mixed workloads.

8. Best Practices for Open Source Databases

Design schemas around query patterns, not just data models.
Enable monitoring and observability with tools like JusDB Monitor.
Plan sharding/partitioning strategies early.
Implement robust backup and DR plans.
Leverage high availability solutions (replication, failover).

9. The Future of Open Source Databases

Open source databases are converging with cloud-native and AI-driven architectures:

HTAP Systems: Engines like StarRocks offer hybrid transactional/analytical capabilities.
Serverless Databases: Pay-as-you-go models reduce operational overhead.
AI-driven Tuning: Automated query optimization and anomaly detection.
Polyglot Persistence: Using multiple databases for different workloads within the same application.

10. How JusDB Helps

At JusDB, we provide end-to-end support for open source databases:

11. Conclusion

MySQL, PostgreSQL, and MongoDB form the core of today’s open source database ecosystem. Each has unique strengths, and the best choice depends on your workload. Increasingly, organizations embrace polyglot architectures that combine multiple engines for optimal performance, scalability, and cost efficiency.

Whether you need MySQL migration, PostgreSQL tuning, or MongoDB support, JusDB’s Database Reliability Engineers ensure your systems are reliable, fast, and future-ready.

Author: JusDB Database Reliability Engineering Team