Distributed Database Middleware
Distributed Database Middleware
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" in this service
All results for "
" in this service
What's New
What's New
Product Bulletin
[Discontinuation Notice] Some Node Classes of Huawei Cloud Distributed Database Middleware (DDM) Instances Will Be Going Offline
[Change Notice]DDM Instance Bills Are Changing
Service Overview
Infographics
What Is DDM?
Basic Concepts
Core Functions
Product Specifications
Use Constraints
Network Access
Data Nodes
Unavailable Features and Limitations
High-risk Operations
Regions and AZs
Application Scenarios
Permissions Management
Billing
Billing Overview
Billing Modes
Overview
Yearly/Monthly Billing
Pay-per-Use Billing
Billing Examples
Billing Mode Changes
Overview
Pay-per-Use to Yearly/Monthly
Yearly/Monthly to Pay-per-Use
Renewing Subscriptions
Overview
Manually Renewing a DDM Instance
Auto-renewing a DDM Instance
Bills
Arrears
Billing Termination
Cost Management
Cost Composition
Cost Allocation
Cost Analysis
Cost Optimization
Getting Started
Buying a DDM Instance and Connecting to a Schema Using DAS
Buying a DDM Instance and Connecting to a Schema Using a Linux System
Buying a DDM Instance and Connecting to a Schema Using a Windows System
Common Practices
User Guide
Function Overview
Kernel Version Notes
Permissions Management
Creating a User and Granting Permissions
Creating a Custom Policy
Database Accounts and Permissions
Instance Management
Instance Statuses
Buying a DDM instance
Splitting Read-only and Read-Write Services
What Is Read-only Service Isolation?
How Are Read-only Services Split from Read-Write Services
Changing Node Class
Scaling Out a DDM Instance
Scaling In a DDM Instance
Restarting a DDM Instance or an Instance Node
Deleting Pay-per-Use Instances
Reloading Table Data
Changing a Parameter Template
Modifying Parameters of a DDM Instance
Rolling Back the Version of a DDM Instance
Upgrading the Version of a DDM Instance
Upgrading the DDM Engine and OS
Connection Management
Configuring Access Control
Modifying the Floating IP Address of a DDM Instance and a Group
Binding and Unbinding an EIP
Changing the DDM Service Port
Changing the Security Group of a DDM Instance
Schema Management
Creating a Schema
Exporting Schema Information
Importing Schema Information
Deleting a Schema
Configuring a SQL Blacklist
Viewing Schemas and Logical Table Information
Shard Configuration
Overview and Application Scenarios
Assessment
Pre-check
Operation Guide
Data Nodes
Overview
Synchronizing Data Node Information
Enabling Read/Write Splitting
Configuring Read Weights
Configuring Read/Write Splitting
Parameter Template Management
Instance Parameters
Creating a Parameter Template
Modifying a Custom 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
Account Management
Administrator Account
Creating an Account
Modifying an account
Deleting an Account
Resetting the Password of an Account
Account Permissions
Overview
Account Requirements
Managing Permissions
Backups and Restorations
Backup Principles
Consistent Backups
Restoring Data to a New Instance
Restoring Metadata
Data Migration
Overview
Migration Evaluation
Scenario 1: Migrating Data from an On-Premises MySQL Instance to DDM
Scenario 2: Migrating Data from a Third-Party Cloud MySQL Instance to DDM
Scenario 3: Migrating Data from an ECS-hosted MySQL Instance on Huawei Cloud to DDM
Scenario 4: Exporting Data from a DDM Instance
Scenario 5: Migrating Data from Heterogeneous Databases to DDM
Scenario 6: Migrating Data from Huawei Cloud RDS for MySQL to DDM
Session Management
Slow Queries
Monitoring and Alarm Reporting
Supported Metrics
DDM Instance Metrics
Network Metrics
Viewing Metrics
Viewing Instance Metrics
Viewing Network Metrics
Creating Monitoring Alarm Rules
Event Monitoring
Overview
Viewing Event Monitoring Data
Creating an Alarm Rule for Event Monitoring
Events Supported by Event Monitoring
Task Center
Tags
Auditing
Key Operations Recorded by CTS
Querying Traces
SQL Syntax
Introduction
DDL
Overview
Creating a Table
Sharding Algorithm Overview
Sharding Algorithms
MOD_HASH
MOD_HASH_CI
RIGHT_SHIFT
MM
DD
WEEK
MMDD
YYYYMM
YYYYDD
YYYYWEEK
HASH
Range
DML
INSERT
REPLACE
DELETE
UPDATE
SELECT
SELECT JOIN Syntax
SELECT UNION Syntax
SELECT Subquery Syntax
Unsupported DML Statements
Supported System Schema Queries
Online DDL
Functions
Unsupported Objects and Use Constraints
Supported SQL Statements
CHECK TABLE
Checking DDL Consistency of Physical Tables in All Logical Tables
Checking DDL Consistency of All Physical Tables Corresponding to One Logical Table
SHOW RULE
SHOW TOPOLOGY
SHOW DATA NODE
TRUNCATE TABLE
HINT-DB
HINT-TABLE
HINT-DB/TABLE
Additional Information
HINT- ALLOW_ALTER_RERUN
LOAD DATA
SHOW PHYSICAL PROCESSLIST
Customized Hints for Read/Write Splitting
Setting a Hint to Skip the Cached Execution Plan
Specifying a Shard Using a Hint When You Execute a SQL Statement
Global Sequence
Overview
Using NEXTVAL or CURRVAL to Query Global Sequence Numbers
Using Global Sequences in INSERT or REPLACE Statements
Database Management Syntax
Advanced SQL Functions
Quotas
API Reference
Before You Start
Overview
API Calling
Endpoints
Constraints
Concepts
API Overview
Calling APIs
Making an API Request
Authentication
Returned Values
APIs (Recommended)
DDM Instances
Buying a DDM instance
Querying DDM Instances
Querying Details of a DDM Instance
Modifying the Name of a DDM Instance
Changing 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
Obtaining the Instance Group Information
Creating an Instance Group
Schemas
Creating a Schema
Querying Schemas
Querying Details of a Schema
Deleting a Schema
Querying DB Instances Available for Creating a Schema
Accounts
Creating a DDM Account
Querying DDM Accounts
Modifying a DDM Account
Deleting a DDM Account
Resetting the Password of a DDM Account
Managing the Administrator Password
Validating Password Strength
Monitoring
Monitoring Slow Query Logs
Session Management
Querying Logical Sessions
Killing Logical Sessions
Querying Physical Sessions
Killing Physical Sessions
Querying Audit Logs of Killing Sessions
Application Examples
Querying DDM Instances
Modifying the Name of a DDM Instance
Deleting a DDM instance
Permissions Policies and Supported Actions
Introduction
Instance Management
Schema Management
Account Management
Reloading Table Data
Appendix
Abnormal Request Results
Status Codes
Error Codes
Instance Specifications
Obtaining a Project ID
Status Description
SDK Reference
SDK Overview
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
Overview
Resource and Cost Planning
Operation Process
Preparing for the Source RDS for MySQL Instance
Creating a VPC and Security Group
Creating an RDS for MySQL Instance
Creating a VPN for the Source
Preparing for the Destination DDM Instance
Creating a VPC and Security Group
Creating a DDM Instance
Creating an RDS for MySQL Instance
Creating a Schema and Associating It with the RDS for MySQL Instance
Creating a DDM Account
Creating Table Structures in the Destination Database
Creating a VPN for the Destination
Creating a VPN Connection
Creating a DRS Migration Task
Checking Migration Results
Sharding Database and Table Data of an RDS for MySQL Instance
Overview
Preparing an RDS for MySQL Instance
Preparing a DDM Instance
Creating a DDM Instance
Creating a Schema and Associating It with the Prepared RDS for MySQL Instance
Creating a DDM Account
Creating Table Structures in the DDM Instance
Creating a DRS Migration Task
Creating a DRS Migration Task
Checking Migration Results
Cross-Shard Complex SQL Tuning
Performance White Paper
Test Method
FAQs
General Questions
What High-Reliability Mechanisms Does DDM Provide?
How Do I Select and Configure a Security Group?
What Do I Do If My Database Time Is 13 or 14 Hours Later than Beijing Time?
Can Data Nodes Associated with a DDM Instance Share Data?
What Data Nodes Can Be Associated with a DDM Instance?
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
Does DDM Support Distributed JOINs?
How Do I Optimize SQL Statements?
Does DDM Support Forced Conversion of Data Types?
What Should I Do If an Error Is Reported When Multiple Data Records Are Inserted into Batches Using the INSERT Statement?
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
How Can I Handle Garbled Characters Generated When I Connect a MySQL Instance to a DDM Instance?
Resource Freezing, Release, Deletion, and Unsubscription
Videos
More Documents
User Guide (ME-Abu Dhabi Region)
Service Overview
Overview
Basic Concepts
Product Architecture
Functions
DDM Instance Classes
Restrictions
Network Access
MySQL DB Instances
SQL Syntax
Regions and AZs
Application Scenarios
Getting Started
Overview
Step 1: Log In to the DDM Console
Step 2: Create a DDM Instance
Step 3: Create an RDS DB Instance
Step 4: Create a Schema
Step 5: Create a DDM Account
Step 6: Log In to the DDM Instance or Schema
Function Overview
Instance Management
Creating a DDM Instance
Node Groups
Group Introduction
Group Management
Changing Class of a DDM Instance
Scaling Out a DDM Instance
Scaling In a DDM Instance
Configuring Access Control
Restarting a DDM Instance
Deleting a DDM Instance
Reloading Table Data
Parameter Management
Read/Write Splitting
Configuring a Parameter Template
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
Creating a Schema
Exporting Schema Information
Importing Schema Information
Deleting a Schema
Configuring the SQL Blacklist
Scaling Out a Schema
Rebalancing Shards Across All DB Instances
Doubling Shards and Resharding Data Records
Account Management
Creating an Account
Modifying an Account
Deleting an Account
Resetting the Password of an Account
Backup Management
Restoring from Current Instance
Creating a Consistent Backup
Creating a Backup
Restoring from a Backup
Monitoring Management
Metrics
Viewing Metrics
Auditing
Key Operations Recorded by CTS
Querying Traces
SQL Syntax
Introduction
DDL
Creating a Table
Sharding Algorithm Overview
Sharding Algorithms
MOD_HASH
MOD_HASH_CI
UNI_HASH
RIGHT_SHIFT
YYYYMM
YYYYDD
YYYYWEEK
HASH
Range
MM
DD
MMDD
WEEK
DML
INSERT
REPLACE
DELETE
UPDATE
SELECT
SELECT JOIN Syntax
SELECT UNION Syntax
SELECT Subquery Syntax
Functions
Unsupported Items
Supported SQL Statements
CHECK TABLE
Checking DDL Consistency of Table Shards in All Logical Tables
Checking DDL Consistency of Table Shards in One Logical Table
SHOW RULE
SHOW TOPOLOGY
SHOW DATA NODE
TRUNCATE TABLE
HINT-DB
HINT-TABLE
HINT-DB/TABLE
HINT- ALLOW_ALTER_RERUN
LOAD DATA
SHOW PHYSICAL PROCESSLIST
Customized Hints for Read/Write Isolation
Setting a Hint to Skip the Cached Execution Plan
Global Sequence
Using NEXTVAL and CURRVAL to Query Global Sequence Numbers
Using Global Sequences in INSERT or REPLACE Statements
Database Management Syntax
Advanced SQL Functions
FAQs
General Questions
What High-Reliability Mechanisms Does DDM Provide?
Does DDM Store Service-Related Data?
How Do I Select and Configure a Security Group?
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
Does DDM Support Cross-Database Access of SQL?
Does DDM Support Distributed JOIN?
How Do I Optimize SQL Statements?
Does DDM Support Forced Data Type Conversion?
What Should I Do If an Error Is Reported When Multiple Data Records Are Inserted into Batches Using the INSERT Statement?
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 Information by Running Command show full innodb status?
Connection Management
Can I Connect to DDM Instances from My Local Environment?
What Should I Do If Garbled Characters Are Displayed When I Connect to DDM Using MySQL?
User Guide (Kuala Lumpur Region)
Service Overview
Overview
Basic Concepts
Product Architecture
Functions
DDM Instance Classes
Restrictions
Network Access
MySQL DB Instances
SQL Syntax
Regions and AZs
Application Scenarios
Getting Started
Overview
Step 1: Log In to the DDM Console
Step 2: Create a DDM Instance
Step 3: Create an RDS DB Instance
Step 4: Create a Schema
Step 5: Create a DDM Account
Step 6: Log In to the DDM Instance or Schema
Function Overview
Instance Management
Creating a DDM Instance
Node Groups
Group Introduction
Group Management
Changing Class of a DDM Instance
Scaling Out a DDM Instance
Scaling In a DDM Instance
Configuring Access Control
Restarting a DDM Instance
Deleting a DDM Instance
Reloading Table Data
Parameter Management
Read/Write Splitting
Configuring a Parameter Template
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
Creating a Schema
Exporting Schema Information
Importing Schema Information
Deleting a Schema
Configuring the SQL Blacklist
Scaling Out a Schema
Rebalancing Shards Across All DB Instances
Doubling Shards and Resharding Data Records
Account Management
Creating an Account
Modifying an Account
Deleting an Account
Resetting the Password of an Account
Backup Management
Restoring from Current Instance
Creating a Consistent Backup
Creating a Backup
Restoring from a Backup
Monitoring Management
Metrics
Viewing Metrics
Auditing
Key Operations Recorded by CTS
Querying Traces
SQL Syntax
Introduction
DDL
Creating a Table
Sharding Algorithm Overview
Sharding Algorithms
MOD_HASH
MOD_HASH_CI
UNI_HASH
RIGHT_SHIFT
YYYYMM
YYYYDD
YYYYWEEK
HASH
Range
MM
DD
MMDD
WEEK
DML
INSERT
REPLACE
DELETE
UPDATE
SELECT
SELECT JOIN Syntax
SELECT UNION Syntax
SELECT Subquery Syntax
Functions
Unsupported Items
Supported SQL Statements
CHECK TABLE
Checking DDL Consistency of Table Shards in All Logical Tables
Checking DDL Consistency of Table Shards in One Logical Table
SHOW RULE
SHOW TOPOLOGY
SHOW DATA NODE
TRUNCATE TABLE
HINT-DB
HINT-TABLE
HINT-DB/TABLE
HINT- ALLOW_ALTER_RERUN
LOAD DATA
SHOW PHYSICAL PROCESSLIST
Customized Hints for Read/Write Isolation
Setting a Hint to Skip the Cached Execution Plan
Global Sequence
Using NEXTVAL and CURRVAL to Query Global Sequence Numbers
Using Global Sequences in INSERT or REPLACE Statements
Database Management Syntax
Advanced SQL Functions
FAQs
General Questions
What High-Reliability Mechanisms Does DDM Provide?
Does DDM Store Service-Related Data?
How Do I Select and Configure a Security Group?
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
Does DDM Support Cross-Database Access of SQL?
Does DDM Support Distributed JOIN?
How Do I Optimize SQL Statements?
Does DDM Support Forced Data Type Conversion?
What Should I Do If an Error Is Reported When Multiple Data Records Are Inserted into Batches Using the INSERT Statement?
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 Information by Running Command show full innodb status?
Connection Management
Can I Connect to DDM Instances from My Local Environment?
What Should I Do If Garbled Characters Are Displayed When I Connect to DDM Using MySQL?
API Reference (Kuala Lumpur Region)
Before You Start
Overview
API Calling
Endpoints
Constraints
Concepts
API Overview
Calling APIs
Making an API Request
Authentication
Returned Values
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
Creating a Schema
Querying Schemas
Querying Details of a Schema
Deleting a Schema
Querying DB Instances Available for Creating a Schema
Account Management
Creating an Account
Querying Accounts
Modifying a DDM Account
Deleting a DDM Account
Resetting the Password of a DDM Account
Monitoring Management
Monitoring Slow SQL Logs
Monitoring the Read/Write Ratio
Permissions Policies and Supported Actions
Introduction
Instance Management
Schema Management
Account Management
Reloading Table Data
Appendix
Abnormal Request Results
Status Codes
Error Codes
Instance Specifications
Obtaining a Project ID
Status Description
Change History
General Reference
Glossary
Service Level Agreement
White Papers
Endpoints
Permissions