This blog post is based on the YouTube presentation “MariaDB vs PostgreSQL: Technical Deep Dive | Architecture, Performance & Design Trade-offs” by Manoj Vakeel, part of MariaDB Foundation’s ongoing series exploring core database design choices and how they impact modern workloads.

The goal here is not to pick a “winner,” but to provide clear architectural insight for CTOs, database engineers, and system architects making decisions in 2025 and beyond.

“Both are powerful engines — both are proven in production — but they take very different routes to get there.” — Manoj Vakeel, MariaDB plc

Why this matters

PostgreSQL and MariaDB are two of the most widely adopted open-source relational databases. They both offer strong SQL support, active communities, and enterprise-grade capabilities. Yet, they make distinct architectural choices that shape:

• Concurrency and memory efficiency
• Performance at scale
• Operational complexity
• High availability options
• Maintenance lifecycle and tuning needs

For organizations planning data-intensive systems, understanding these differences early can save both engineering effort and operational cost.

1. Process Model: Multi-Process vs Multi-Threaded

PostgreSQL Runs each connection in its own separate OS process. This reduces in-process contention, but increases memory and context-switching overhead.

“Postgres follows a multi-process design; every client connection is handled by its own process.”

MariaDB Uses a multi-threaded architecture with shared memory, designed for high connection volume and more efficient resource management.

**📎 ***Why it matters

• For modern applications — especially microservices and connection-heavy environments — MariaDB’s thread pool handles spikes and concurrency more efficiently.

2. MVCC & Vacuum vs Continuous Purge

Both databases implement MVCC, but differently.

PostgreSQL MVCC relies on a vacuum operation to reclaim storage from old row versions.

• Must tune autovacuum
• Risk of bloat without aggressive maintenance
• Can lead to performance hiccups if neglected

“In Postgres, you need vacuum to clean up old tuples.”

MariaDB (InnoDB) Uses background purge threads, continuously cleaning old versions without heavy maintenance cycles.

📎 Why it matters*

• MariaDB offers more predictable long-term performance without the operational burden of tuning vacuum processes.

3. Memory Management: Shared Buffers vs Unified Buffer Pool

PostgreSQL Uses shared buffers + OS page cache. Efficient when tuned well, but can result in double buffering.

MariaDB / InnoDB Uses a unified buffer pool to manage caching more deterministically.

“…MariaDB tries to serve as much as possible directly from memory.”

📎 Why it matters*

• MariaDB’s design simplifies tuning and improves predictability for mission-critical applications at scale.

4. Query Engines & Flexibility

PostgreSQL Primarily a single storage engine, highly extensible through extensions.

MariaDB Multi-engine architecture — choose engines based on workload:

• InnoDB — OLTP
• ColumnStore — analytical workloads
• MyRocks — write-optimized LSM tree engine
• Aria — crash-safe, non-transactional engine used for temporary tables and situations where read speed matters more than full ACID guarantees
• Spider — a distributed storage engine that allows sharding and horizontal scaling by mapping tables across multiple MariaDB instances

**📎 ***Why it matters

• MariaDB offers architectural flexibility in one platform — operational databases, analytics, and distributed SQL under a single ecosystem.

5. Concurrency & Connection Scaling

PostgreSQL

• Expensive per-connection footprint
• External poolers (e.g., PgBouncer) often required

MariaDB

• Thread pool handles thousands of concurrent connections efficiently
• Built-in prioritization and scheduling

***📎 Why it matters

• High-traffic applications and microservices benefit from MariaDB’s native concurrency model.

6. Replication & High Availability

PostgreSQL

• Streaming replication
• Logical replication maturing
• Clustering requires external projects (Patroni, Citus, etc.)

MariaDB

• Galera-based cluster is a native, first-class option
• Built-in async replication options

“Galera gives you synchronous writes across nodes.”

**📎 ***Why it matters

• MariaDB offers an integrated HA approach vs PostgreSQL’s “assemble-it-yourself” strategy.

7. Operational Complexity & Maintenance

PostgreSQL

• Vacuum tuning
• Connection poolers
• Extension sprawl depending on needs

MariaDB

• Streamlined operations
• High availability and threading built-in
• Familiar MySQL operational patterns

**📎 ***Why it matters

• MariaDB can reduce DBA overhead and tuning requirements — an important factor for teams seeking reliability without specialized PostgreSQL expertise.

8. Governance, Licensing, and Ecosystem

PostgreSQL

• Community-driven, decentralized
• Support via multiple vendors

MariaDB

• Governed by a non-profit foundation
• Optional unified commercial support model

**📎 ***Why it matters

• MariaDB offers transparent governance and a consolidated enterprise support path — without compromising open source principles.

Summary Table

Dimension	PostgreSQL	MariaDB
Connection model	Multi-process	Multi-threaded
MVCC cleanup	VACUUM	Continuous purge
Connection scaling	External poolers	Native thread pool
Storage engines	Single	Multiple
HA	Ecosystem tools	Built-in Galera
Memory	OS cache + shared buffers	Unified buffer pool
Ops complexity	Higher	Lower
Governance	Community	Foundation + open source

Final Thoughts

Both MariaDB and PostgreSQL are excellent platforms with strong communities. They share more in common than not — but their architectural philosophies differ in meaningful ways.

MariaDB emphasizes:

• Efficient concurrency and thread scalability
• Predictable operational behavior
• Built-in clustering and HA
• Flexibility through multiple storage engines

PostgreSQL emphasizes:

• Extensibility
• Strong SQL language depth
• Robust academic/standards lineage

“The goal wasn’t to pick a winner — but to understand the fundamentally different routes they take to get there.”

You can watch the full original presentation here: MariaDB vs PostgreSQL: Technical Deep Dive — Manoj Vakeel