- What's New
- Service Overview
- Getting Started
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User Guide
- Function Overview
- Permissions Management
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Instance Management
- Buying a DDM Instance
- Splitting Read-only and Read-Write Services
- Changing Class of a DDM Node
- Scaling Out a DDM Instance
- Scaling In a DDM Instance
- Changing Billing Mode of a DDM Instance
- Renewing a DDM Instance
- Restarting a DDM Instance
- Unsubscribing from a DDM Instance
- Deleting a DDM Instance
- Modifying Parameters of a DDM Instance
- Splitting Read and Write Requests
- Configuring a Parameter Template
- Connection Management
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Parameter Template Management
- Creating a Parameter Template
- Editing a Parameter Template
- Comparing Two Parameter Templates
- Viewing Parameter Change History
- Replicating a Parameter Template
- Applying a Parameter Template
- Viewing Application Records of a Parameter Template
- Modifying the Description of a Parameter Template
- Deleting a Parameter Template
- Task Center
- Schema Management
- Shard Configuration
- Data Node Management
- Account Management
- Backups and Restorations
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Data Migration
- Overview
- Migration Evaluation
- Scenario 1: Migrating Data from Huawei Cloud RDS to DDM
- Scenario 2: Migrating Data from an On-Premises RDS Instance for MySQL to DDM
- Scenario 3: Migrating Data from a Third-Party RDS for MySQL Instance to DDM
- Scenario 4: Migrating Data from a Self-Built MySQL Instance to DDM
- Scenario 5: Migrating Data from Heterogeneous Databases to DDM
- Scenario 6: Exporting Data from a DDM Instance
- Slow Queries
- Monitoring Management
- Auditing
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SQL Syntax
- Introduction
- DDL
- DML
- Functions
- Use Constraints
- Supported SQL Statements
- Global Sequence
- Database Management Syntax
- Advanced SQL Functions
- Quotas
- Change History
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API Reference
- Before You Start
- API Overview
- Calling APIs
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APIs (Recommended)
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DDM Instances
- Buying a DDM instance
- Querying DDM Instances
- Querying Details of a DDM Instance
- Modifying the Name of a DDM Instance
- Modifying the Security Group of a DDM Instance
- Deleting a DDM Instance
- Restarting a DDM Instance
- Reloading Table Data
- Scaling out a DDM instance
- Scaling in a DDM instance
- Modifying the Read Policy of the Associated DB Instance
- Synchronizing Data Node Information
- Querying Nodes of a DDM Instance
- Querying Details of a DDM Instance Node
- Querying Parameters of a Specified DDM Instance
- Modifying Parameters of a DDM Instance
- Querying DDM Engine Information
- Querying DDM Node Classes Available in an AZ
- Changing the Node Class of a DDM Instance
- Schemas
- DDM Accounts
- Monitoring
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DDM Instances
- APIs (Unavailable Soon)
- Appendix
- Change History
- SDK Reference
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Best Practices
- Overview
- Formulating Sharding Rules
- Determining the Number of Shards in a Schema
- Using Broadcast and Unsharded Tables
- Transaction Models
- SQL Standards
- Migrating an Entire RDS Database to DDM
- Migrating an Entire MyCat Database to DDM
- Accessing DDM Using a JDBC Connection Pool
- Logging In to a DDM Instance Using Navicat
- Migrating Data from RDS for MySQL to DDM Using DRS
- Performance White Paper
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FAQs
- General Questions
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DDM Usage
- How Does DDM Perform Sharding?
- What Do I Do If I Fail to Connect to a DDM Instance Using the JDBC Driver?
- What Version and Parameters Should I Select?
- Why It Takes So Long Time to Export Data from MySQL Using mysqldump?
- What Do I Do If a Duplicate Primary Key Error Occurs When Data Is Imported into DDM?
- What Should I Do If an Error Message Is Returned When I Specify an Auto-Increment Primary Key During Migration?
- What Do I Do If an Error Is Reported When Parameter Configuration Does Not Time Out?
- Which Should I Delete First, a Schema or its Associated RDS Instances?
- Can I Manually Delete Databases and Accounts Remained in Data Nodes After a Schema Is Deleted?
- SQL Syntax
- RDS-related Questions
- Connection Management
- Resource Freezing, Release, Deletion, and Unsubscription
- Change History
- Videos
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Overview and Application Scenarios
Overview
Shard configuration is a core function of DDM. With this function, you can increase data nodes or shards to improve database storage and concurrency as services grow. Shard configuration has little impacts on your services, so you do not need to worry about database scaling and subsequent O&M as your services are burst.
Application Scenarios
1. Keep shards unchanged and increase data nodes.
This method does not change the number of shards and only increases the number of data nodes. Some shards are migrated from original data nodes to new data nodes. The shard data is not redistributed, so this method is the fastest one among all three methods is recommended.
This method meets rapid service growth after horizontal sharding and can reduce costs at the beginning stage of services.
It is also suitable if RDS for MySQL instances cannot meet storage space and read/write performance requirements.
2. Increase shards with data nodes unchanged.
This method increases the shards, but not data nodes. It changes total shards, total table shards, and table sharding rules. Data is redistributed to different shards, and broadcast tables are increased.
This method is suitable if the associated RDS for MySQL instance has sufficient storage space but one of its tables contains a large amount of data, with query performance limited.
3. Increase both shards and data nodes.
This method increases both shards and data nodes. It changes total shards, total table shards, and table sharding rules. Data is redistributed to different shards, and broadcast tables are increased.
This method is suitable if RDS for MySQL instances cannot meet storage space and read/write requirements and there is a physical table containing a large amount of data with query performance limited.
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