PolarDB:DynamoDB compatibility

How it works

PolarDB for PostgreSQL achieves compatibility with the DynamoDB API through the interaction between the database proxy layer and compute nodes.

• Database ProxyThis proxy layer is the key to protocol compatibility. It accepts DynamoDB HTTP requests from clients and performs identity authentication, protocol parsing, and request routing. The proxy layer then converts DynamoDB operations into JSONB search statements that PostgreSQL can recognize and intelligently dispatches these statements to the most appropriate backend compute nodes. This design completely decouples the compatibility logic from the database kernel, which ensures the underlying PostgreSQL kernel remains unmodified and stable, and allows for the reuse of PolarDB's mature connection pooling, load balancing, and read/write splitting capabilities.

• Compute node

  The compute nodes use a high availability (HA) architecture with one primary node and multiple read-only nodes (up to 15 for Enterprise Edition and 7 for Standard Edition). The primary node handles all write operations, while the read-only nodes offload read requests. The compute node is based on the standard PostgreSQL kernel and uses only built-in plugins to adapt to the subtle differences in DynamoDB behavior, such as collation, operators, and data types. This minimal approach ensures the feature is easy to maintain and stays current with new PostgreSQL versions. For you, the database abstracts away traditional database and schema concepts, providing a table management experience identical to DynamoDB.

Advantages

• Seamless migration: Connect existing applications directly to PolarDB without refactoring code.

• Unified data platform: Use the NoSQL API for fast key-value access and standard SQL for complex analysis on the same data.

• Elasticity in seconds and cost-effectiveness: Compute and storage are separate. Storage is pay-as-you-go, and compute nodes scale in minutes for significant cost savings.

• Enterprise-grade Reliability: Built on PolarDB's mature high-availability architecture to ensure data security and business continuity.

Prerequisites

Before you use this feature, make sure your cluster meets the following version requirements:

• Kernel version: PostgreSQL 14, and the revision version must be 2.0.14.17.35.0 or later.

• Database proxy version: 2.3.59 or later.

• The DynamoDB compatibility feature is not supported by PolarDB for PostgreSQL Distributed Edition or serverless clusters.

Billing

The DynamoDB compatibility feature itself does not incur additional costs. Only the related fees for the PolarDB for PostgreSQL cluster apply.

The DynamoDB compatibility feature does not have an additional cost. You only pay the related fees for your PolarDB for PostgreSQL cluster.

Next steps

1. Get started: After you review the feature overview, follow the Instructions to create a cluster, configure an account, and verify the initial connection.

2. Compatibility and limitations: This feature is highly compatible with the DynamoDB API, but some differences in behavior and limitations exist. For example, some deprecated parameters are not supported, and the error behavior for failed transactions differs from that of native DynamoDB. For more information, see Compatibility and limitations.

3. (Optional) Data migration: To migrate data from an existing Amazon DynamoDB instance, see the Migrate from Amazon DynamoDB to PolarDB for PostgreSQL for detailed steps and information about tool usage.

Performance testing

PolarDB used the standard Yahoo! Cloud Serving Benchmark (YCSB) tool for comprehensive performance benchmark tests. The test results show that the feature demonstrates stable and excellent performance across different data volumes and read/write models. For more information, see the Performance Testing Report.