DynamoDB vs PostgreSQL - Key Differences

Comparing SQL databases with NoSQL databases presents a fascinating challenge in modern data architecture, where the choice between systems like DynamoDB and PostgreSQL can determine whether your application scales gracefully or struggles under growth. Recent industry analysis reveals that organizations using polyglot persistence architectures—combining multiple database technologies strategically—achieve significantly better performance outcomes than those constrained to single-database approaches. The evolution of both DynamoDB and PostgreSQL has transformed them from simple storage solutions into sophisticated platforms supporting complex modern workloads, making the selection decision more nuanced than ever before.

Among these databases, two popular choices are DynamoDB and PostgreSQL. However, they differ significantly, which might cause confusion when selecting one over the other.

This guide will help you understand the key differences between DynamoDB vs PostgreSQL and select the optimal solution for your daily tasks.

What Is DynamoDB and How Does It Work?

Offered by Amazon Web Services (AWS), DynamoDB is a serverless, cloud-based NoSQL database service. It enables you to efficiently handle large volumes of semi-structured and unstructured data while providing low latency. Supporting a schema-less architecture, DynamoDB offers flexibility in handling different formats and data structures.

With its fully managed nature, DynamoDB allows you to scale your applications automatically without infrastructure management. This feature is an essential factor that separates this tool from others, especially when you don't want to spend your time managing the database.

DynamoDB has undergone remarkable evolution, now handling more than 10 trillion requests per day and supporting peaks exceeding 20 million requests per second. The platform's introduction of multi-region strong consistency capabilities represents a significant advancement for distributed applications requiring strict consistency guarantees across geographic regions, eliminating the traditional trade-off between global availability and strong consistency.

Key Features of DynamoDB

• Multi-active Replication: Global tables let you replicate data across regions, ensuring high availability and low-latency local access.
• ACID Transactions: Supports ACID compliance for mission-critical workloads.
• Secondary Indexes: Global and local secondary indexes let you query data with attributes other than the primary key.
• Caching: DynamoDB Accelerator (DAX) can deliver up to 10× performance improvement for millions of requests per second.
• Security: Integrated with AWS IAM, encryption, key management, and fine-grained access control.
• Advanced Streaming: DynamoDB Streams provide real-time change data capture for building event-driven architectures and enabling sophisticated integration patterns with downstream systems.

What Is PostgreSQL and What Makes It Unique?

PostgreSQL is an open-source object-relational database management system (RDBMS) that enables you to handle structured data in tabular form. Developed at UC Berkeley, this platform is compliant with ACID properties to support concurrency and SQL standards. By offering robust plugins like PostGIS, PostgreSQL extends its capabilities to store, index, and query geospatial data.

To efficiently handle increasing workloads, PostgreSQL offers vertical scaling. Although PostgreSQL doesn't natively support horizontal scaling, features like partitioning and replication can help you enhance scalability.

PostgreSQL 18 introduces groundbreaking asynchronous I/O support that promises 2-3x performance improvements for read-heavy workloads, especially in high-latency environments. The database has evolved into a versatile platform supporting both transactional and analytical workloads within unified architectures, positioning it as a strong competitor in modern data engineering environments.

Key Features of PostgreSQL

• Concurrency Control: Multiversion concurrency control (MVCC) maintains data integrity in a multi-user environment.
• Replication: Built-in streaming and logical replication improve availability through redundancy.
• Indexing: Supports B-tree, Hash, GIN, BRIN, GiST, SP-GiST, and more for fast queries.
• Partitioning: Range, list, and hash partitioning improve performance on large tables.
• Security: SSL encryption, role-based access control, LDAP auth, and row-level security protect data.
• Advanced Analytics: Enhanced parallel processing capabilities and sophisticated query optimization make PostgreSQL suitable for complex analytical workloads alongside traditional transactional processing.

What Are the Key Differences Between DynamoDB and PostgreSQL?

The main difference between DynamoDB and PostgreSQL is that DynamoDB is a NoSQL database optimized for high-speed, scalable, low-latency access to unstructured data, while PostgreSQL is a relational database known for its advanced features and ACID compliance.

Performance

• DynamoD: In-memory cache (DAX) can boost read performance up to 10× and serves millions of requests per second. Its request router also optimizes query latency. The platform's adaptive capacity feature automatically redistributes throughput to handle uneven access patterns, enabling applications to handle traffic spikes of 10x to 100x without manual intervention.
• PostgreSQL: Rerformance depends on hardware and tuning. Features such as advanced indexing and Just-in-Time (JIT) compilation accelerate queries. The introduction of asynchronous I/O capabilities in recent versions has fundamentally improved resource utilization efficiency, particularly benefiting read-heavy workloads that constitute a significant portion of many application profiles.

Scalability

• DynamoDB: Auto-scales horizontally by partitioning and replicating data across availability zones. The introduction of warm throughput capabilities allows organizations to proactively manage performance during peak events, addressing one of the few remaining unpredictabilities in DynamoDB's performance model.
• PostgreSQL: No native horizontal scaling, but partitioning and replication improve capacity and availability. Recent logical replication enhancements provide sophisticated options for horizontal scaling, including failover control and improved upgrade procedures that maintain replication during major version updates.

Flexibility

• DynamoDB: No predefined schema; ideal for semi-structured/unstructured data, but with limited data-modeling functions. The platform now supports sophisticated single-table design patterns that can handle complex relationships while maintaining optimal performance characteristics.
• PostgreSQL: Requires schema up-front, yet supports user-defined functions and stored procedures for rich data modeling. Enhanced JSON support and virtual generated columns provide greater flexibility for handling semi-structured data within relational frameworks.

Cost

• DynamoDB: Pay-as-you-go pricing for storage, read/write capacity, backups, etc. Recent pricing reductions—50% for on-demand throughput and up to 67% for global tables' replicated writes—have made variable workloads significantly more cost-effective.
• PostgreSQL: Free and open-source; total cost is driven by hardware and in-house expertise. Serverless PostgreSQL offerings now provide usage-based pricing models that align costs with actual utilization.

Use Cases

DynamoDB: Game development, real-time analytics, IoT, event-driven architectures requiring consistent low-latency performance at massive scale.

PostgreSQL: CMS, banking, data warehousing, e-commerce, analytical workloads requiring complex queries and sophisticated data relationships.

How Do Event-Driven Architectures and Change Data Capture Work with DynamoDB vs. PostgreSQL?

Modern applications increasingly rely on event-driven architectures that can capture and process data changes in real-time, enabling sophisticated workflow orchestration and real-time analytics. Both DynamoDB and PostgreSQL provide powerful change data capture mechanisms, though they approach this capability from different architectural perspectives.

DynamoDB

DynamoDB Streams serves as the foundation for event-driven patterns, capturing all item-level changes, including inserts, updates, and deletes, in time-ordered sequences. When enabled on a table, DynamoDB Streams records data modification events and makes this information available for up to 24 hours. Stream records can be configured to capture different levels of information, from keys only to complete before-and-after images of modified items, providing flexibility for various integration and processing requirements.

The integration of DynamoDB Streams with AWS Lambda enables sophisticated real-time processing architectures that can handle massive volumes of change events with automatic scaling capabilities. Lambda functions can process stream events to calculate aggregates, update materialized views, trigger downstream workflows, and propagate changes to integrated systems. This serverless approach to change processing eliminates infrastructure management overhead while providing the scalability needed for high-velocity applications.

PostgreSQL

PostgreSQL's logical replication capabilities provide comprehensive change data capture through Write-Ahead Log processing and replication slots. Modern PostgreSQL versions offer robust logical replication that captures all database changes in structured formats suitable for downstream processing. The system supports selective replication based on tables and schemas, enabling fine-grained control over what changes are captured and distributed. For row and column-level filtering, extensions like pglogical are required.

The PostgreSQL approach to change data capture often integrates with streaming platforms like Apache Kafka to create sophisticated data pipelines that can capture database changes and distribute them to multiple downstream systems with guaranteed delivery and ordering semantics. These pipelines support complex transformation and enrichment operations that adapt data formats for different consuming systems while maintaining consistency guarantees.

How Can You Streamline Data Movement Between DynamoDB and PostgreSQL with Airbyte?

Airbyte is an open-source data integration platform that enables you to migrate data between different systems, including DynamoDB and PostgreSQL. It offers a library of 600+ pre-built connectors, and its Connector Development Kit enables you to build custom connectors efficiently when specialized integration requirements arise.

The platform addresses the fundamental challenges organizations face when implementing polyglot persistence architectures by providing reliable, scalable data movement capabilities that maintain consistency across different database technologies. Airbyte's approach combines the flexibility of open-source development with enterprise-grade security and governance capabilities, making it suitable for organizations ranging from fast-growing startups to Fortune 500 enterprises.

Key features that make Airbyte particularly effective for DynamoDB and PostgreSQL integration include:

• Developer-Friendly Pipelines: PyAirbyte enables Python-based data pipeline development with seamless integration into existing development workflows and data processing frameworks.
• Advanced Schema Management: Automatic schema detection and configurable handling of source schema changes ensure data pipeline reliability as database structures evolve over time.
• Real-time Change Data Capture: Comprehensive CDC capabilities replicate source changes in near real-time, enabling event-driven architectures and keeping integrated systems synchronized with minimal latency.
• Enterprise Security: Full compliance with SOC 2 and ISO 27001, and supporting features for GDPR and HIPAA, help ensure that data integration can meet regulatory requirements across different industries and jurisdictions, depending on customer configuration and use.
• Flexible Deployment Options: Support for cloud, hybrid, and on-premises deployments enables organizations to maintain control over data residency while accessing modern integration capabilities.

Key Takeaways

Choose DynamoDB for highly scalable NoSQL workloads requiring predictable low-latency and serverless infrastructure. Select PostgreSQL when you need complex queries, analytical capabilities, and strict ACID compliance for sophisticated data modeling. Consider polyglot persistence architectures that strategically combine both databases for optimal performance across different workload types. After finalizing your database strategy, use Airbyte to simplify data migration and integration between your systems.

Frequently Asked Questions

What are the main factors to consider when choosing between DynamoDB vs PostgreSQL?

The choice between DynamoDB and PostgreSQL primarily depends on your data model requirements, scalability needs, and operational preferences. Choose DynamoDB for applications requiring predictable low-latency performance at massive scale with flexible schema requirements, particularly for IoT, gaming, or real-time analytics use cases. Select PostgreSQL for complex relational data models requiring sophisticated queries, analytical capabilities, and strong consistency guarantees, especially in financial services, e-commerce, or data warehousing scenarios.

Can DynamoDB and PostgreSQL be used together in the same application architecture?

Yes, many modern applications implement polyglot persistence architectures that combine DynamoDB and PostgreSQL strategically. This approach leverages DynamoDB for high-velocity operational workloads and PostgreSQL for complex analytical queries and reporting. Integration patterns using change data capture, event-driven architectures, and specialized data integration platforms enable seamless coordination between both databases while maintaining data consistency.

How do the cost models of DynamoDB vs PostgreSQL compare for different workload patterns?

DynamoDB uses a consumption-based pricing model with costs based on storage, read/write capacity, and additional features, making it cost-effective for variable workloads but potentially expensive for consistent high-volume usage. PostgreSQL is open-source with costs driven by infrastructure and operational expertise, making it more predictable for steady workloads but requiring more upfront investment in management capabilities.

What are the performance characteristics of DynamoDB vs PostgreSQL for different query types?

DynamoDB excels at key-value lookups and simple range queries with consistent single-digit millisecond latency regardless of dataset size, but struggles with complex analytical queries or cross-partition operations. PostgreSQL provides excellent performance for complex queries, joins, and analytical workloads when properly indexed and configured, but performance varies based on query complexity and data size.

How do the backup and disaster recovery capabilities compare between DynamoDB vs PostgreSQL?

DynamoDB provides automated backup and point-in-time recovery capabilities with cross-region replication through Global Tables, offering enterprise-grade disaster recovery with minimal configuration. PostgreSQL offers flexible backup options, including logical and physical backups, streaming replication, and point-in-time recovery, but requires more configuration and management.