- What's New
- Service Overview
- Getting Started
-
User Guide
- Function Overview
- Permissions Management
-
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
-
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
-
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
-
SQL Syntax
- Introduction
- DDL
- DML
- Functions
- Use Constraints
- Supported SQL Statements
- Global Sequence
- Database Management Syntax
- Advanced SQL Functions
- Quotas
- Change History
-
API Reference
- Before You Start
- API Overview
- Calling APIs
-
APIs (Recommended)
-
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
-
DDM Instances
- APIs (Unavailable Soon)
- Appendix
- Change History
- SDK Reference
-
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
-
FAQs
- General Questions
-
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
Show all
Creating a Parameter Template
A database parameter template acts as a container for parameter configurations that can be applied to one or more DDM instances. You can manage configurations of a DDM instance by managing parameters in the parameter template applied to the instance.
If you do not specify a parameter template when creating a DDM instance, the system uses the default parameter template for your instance. The default parameter template contains multiple default values, which are determined based on the computing level and the storage space allocated to the instance. You cannot modify parameter settings of a default parameter template. You must create your own parameter template to change parameter settings.
If you want to use your custom parameter template, you simply create a parameter template and select it when you create a DDM instance or apply it to an existing DDM instance following the instructions provided in Applying a Parameter Template.
When you have already created a parameter template and want to provide most of its custom parameters and values in a new parameter template, you can replicate the template you created following the instructions provided in Replicating a Parameter Template.
The following are the key points you should know when using parameters from a parameter template:
- When you change a parameter value in a parameter template that has been applied to a DB instance, the change applies only to the current DB instance and does not affect other DB instances.
- When you change a parameter value in a parameter template and save the change, the change will take effect only after you apply the parameter template to a DDM instance and manually restart the instance.
- Improper parameter settings may have unintended adverse effects, including degraded performance and system instability. Exercise caution when modifying parameters and you need to back up data before modifying parameters in a parameter template. Before applying parameter template changes to a production DDM instance, you should try out these changes on a test DDM instance.
Procedure
- Log in to the management console.
- Click
in the upper left corner and select a region and a project.
- Click
in the upper left corner of the page and choose Databases > Distributed Database Middleware.
- Choose Parameter Templates and click Create Parameter Template.
- In the displayed dialog box, enter a template name and description and click OK.
- The template name is case-sensitive and consists of 1 to 64 characters. It can contain only letters, digits, hyphens (-), underscores (_), and periods (.).
- The template description consists of a maximum of 256 characters and cannot include carriage return characters and the following special characters: >!<"&'=
NOTE:
Each user can create up to 100 parameter templates.
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