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User Guide
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Instance Management
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Parameter Template Management
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Data Migration
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- Scenario 4: Exporting Data from a DDM Instance
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SQL Syntax
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API Reference
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APIs (Recommended)
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DDM Instances
- Buying a DDM instance
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- 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
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DDM Instances
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- Appendix
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Best Practices
- Overview
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- Using Broadcast and Unsharded Tables
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- Migrating an Entire RDS Database to DDM
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- 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
- Sharding Database and Table Data of an RDS for MySQL Instance
- 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?
- 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
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RDS-related Questions
- Is the Name of a Database Table Case-Sensitive?
- What Risky Operations on RDS for MySQL Will Affect DDM?
- How Do I Handle Data with Duplicate Primary Keys in a Table?
- How Can I Query RDS for MySQL Information by Running Command show full innodb status?
- What Should I Pay Attention to When Selecting RDS for MySQL Instance Specifications?
- Connection Management
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- Videos
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More Documents
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User Guide (ME-Abu Dhabi Region)
- Service Overview
- Getting Started
- Function Overview
- Instance 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
- Account Management
- Backup Management
- Monitoring Management
- Auditing
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SQL Syntax
- Introduction
- DDL
- DML
- Functions
- Unsupported Items
- Supported SQL Statements
- Global Sequence
- Database Management Syntax
- Advanced SQL Functions
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FAQs
- General Questions
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DDM Usage
- How Can I Rectify a Fault in Accessing DDM by Using the JDBC Driver?
- What Version and Parameters Should I Select?
- Why It Takes So Long Time to Export Data from MySQL Using mysqldump?
- How Should I Handle the Duplicate Primary Key Error Occurring After Data Is Imported into DDM?
- What Should I Do If an Error Message Is Returned After I Specify an Auto-Increment Primary Key?
- How Do I Handle the Error Reported When Parameter Configuration Does Not Time Out?
- Which Should I Delete First, Schema or Associated RDS DB Instances?
- Should I Manually Delete Databases and Accounts Remained in the Associated RDS DB Instances After a Schema Is Deleted?
- SQL Syntax
- RDS-related Questions
- Connection Management
-
User Guide (Kuala Lumpur Region)
- Service Overview
- Getting Started
- Function Overview
- Instance 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
- Account Management
- Backup Management
- Monitoring Management
- Auditing
-
SQL Syntax
- Introduction
- DDL
- DML
- Functions
- Unsupported Items
- Supported SQL Statements
- Global Sequence
- Database Management Syntax
- Advanced SQL Functions
-
FAQs
- General Questions
-
DDM Usage
- How Can I Rectify a Fault in Accessing DDM by Using the JDBC Driver?
- What Version and Parameters Should I Select?
- Why It Takes So Long Time to Export Data from MySQL Using mysqldump?
- How Should I Handle the Duplicate Primary Key Error Occurring After Data Is Imported into DDM?
- What Should I Do If an Error Message Is Returned After I Specify an Auto-Increment Primary Key?
- How Do I Handle the Error Reported When Parameter Configuration Does Not Time Out?
- Which Should I Delete First, Schema or Associated RDS DB Instances?
- Should I Manually Delete Databases and Accounts Remained in the Associated RDS DB Instances After a Schema Is Deleted?
- SQL Syntax
- RDS-related Questions
- Connection Management
-
API Reference (Kuala Lumpur Region)
- Before You Start
- API Overview
- Calling APIs
-
DDM Instance Management
- Querying DDM Engine
- Querying the Quota of Classes Available in Each AZ
- Creating a DDM Instance
- Querying DDM Instances
- Viewing 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 DB Instance Data
- 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
- Schema Management
- Account Management
- Monitoring Management
- Permissions Policies and Supported Actions
- Appendix
- Change History
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User Guide (ME-Abu Dhabi Region)
- General Reference
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Using Broadcast and Unsharded Tables
Unsharded Table
The DDM console does not allow creation of unsharded tables. To create unsharded tables, you can log in to your DDM instance using a MySQL client or an application.
If a table contains fewer than 10 million data records and has no requests for JOIN operations with other sharded tables for query, set the table type to Unsharded Table to store data in the default shard.
The following is an example SQL statement for creating an unsharded table:
CREATE TABLE single( id int NOT NULL AUTO_INCREMENT COMMENT 'Primary key ID', name varchar(128), PRIMARY KEY(id) );
Broadcast Table
In business databases, some tables have a small amount of data and are not frequently updated, but they are often used for JOIN operations.
- The broadcast table stores the same data in each shard. Data insertion, update, and deletion in broadcast tables are executed in each shard in real time.
- Queries of broadcast tables are only executed in one shard.
- Any tables can JOIN with broadcast tables.
- Before using any broadcast hint, ensure that there are available tables.
Example:
When the order management system of an e-commerce enterprise needs to query and collect statistics on order data in Guangdong province (China), JOIN query is performed for a regional table and an order flow table. The order data volume is large and the order flow table needs to be sharded. In this scenario, you can set the regional table as a broadcast table to avoid cross-database JOIN.
The following is an example SQL statement for creating a broadcast table:
CREATE TABLE broadcast_tbl ( id int NOT NULL AUTO_INCREMENT COMMENT 'Primary key ID', name varchar(128), PRIMARY KEY(id) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci BROADCAST;
Operate broadcast tables or perform full table scanning operations during off-peak hours, such as executing SQL statements that do not contain sharding conditions. Otherwise, an error may occur, indicating that the number of backend RDS connections is insufficient.
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