Functions

Horizontal sharding

Select a sharding key when creating a distributed database. DDM will generate a sharding rule and horizontally shard data.

Scaling

DDM supports both compute and storage scaling. You can scale up or out a DDM instance dynamically with zero downtime. Compute scaling is undetectable to your applications, and storage scaling minimizes service interruption to seconds.

Storage scaling can be actualized with two methods: rebalancing or resharding.

• Rebalancing keeps the total database shards unchanged.
• Resharding doubles the number of database shards.

Distributed transactions

DDM processes three types of transactions, including single-shard, FREE, and Extended Architecture (XA).

• Single-shard: Transactions cannot be committed across shards.
• FREE: Transactions are committed across shards. A transaction is not rolled back when it fails to be committed by any shard, causing data inconsistency.
• XA: Transactions are committed in two phases. If a transaction fails to be committed by any shard, all work done will be rolled back to ensure data consistency.

Data import and export

External data can be imported into DDM to help you migrate databases to the cloud, and DDM instance data can be exported based on requirements.

SQL syntax

DDM is highly compatible with the MySQL licenses and syntaxes.

Read and write splitting

Read and write requests can be split without modifying the application code, and this is totally transparent to applications. You only need to create read replicas for a MySQL DB instance associated with your DDM instance and configure a read policy, so a large number of concurrent requests can read data from those read replicas.

Global sequence

DDM allows you to use globally unique, distributed, and ascending SNs as primary or unique keys or to meet your requirements in specific scenarios.

DDM console

The DDM console enables you to manage and maintain DDM instances and schemas.