- Release Notes and Announcements
- Release Notes
- Announcements
- Announcement on Release of New Upgrade Mechanism for Kernel Minor Version
- Announcement on Optimization of Instance Storage Capacity, IOPS, and I/O Bandwidth
- Announcement on Some APIs with CAM Authentication Integrated
- Announcement on Sales Suspension of Some General Specifications
- Announcement on Some APIs Integrated with CAM Authentication
- Announcement on Some APIs with CAM Authentication Integrated
- Announcement on Change of Part of Parameters
- Announcement on Update of Database Audit Feature
- Announcement on Authentication of a Newly Added API Interface of Database Audit
- Announcement on Change of Public Network Linkage
- TDSQL-C for MySQL Audit Service Update
- Announcement on Supplementary Charge for Clusters with Pay-as-You-Go Storage Billing Mode
- Announcement on New APIs Integrated with CAM Permissions
- Announcement on the Release of New Version of Database Proxy
- Emergency Fix for Certain Monitoring Metrics
- Monitoring Metric Optimization
- Change to Database Audit Resource ID
- Ops Change
- Storage Price Adjustment Notification
- Beginner's Guide
- Product Introduction
- Kernel Features
- Kernel Overview
- Kernel Version Release Notes
- Optimized Kernel Version
- Functionality Features
- Performance Features
- Columns Syntax
- Correlated Subquery Result Cache
- Global Index
- Binlog Write Optimization
- Large Transaction Binlog Optimization
- Binlog Purging Performance Optimization
- Optimization of Plan Caching Point Query
- Auto-Increment Column Persistence
- Invisible Index
- Computation Pushdown
- Parallel Initialization of InnoDB Buffer Pool
- Security Features
- Stability Feature
- Analysis Engine Features
- Purchase Guide
- Getting Started
- Database Audit
- Serverless Service
- Operation Guide
- Switching Cluster Page View in Console
- Database Connection
- Instance Management
- Configuration Adjustment
- Cluster Management
- Scaling Instance
- Database Proxy
- Database Proxy Overview
- Use Limits
- Database Proxy Kernel Features
- Managing Database Proxy
- Enabling Database Proxy
- Setting Database Proxy Address
- Modifying or Deleting Connection Addresses
- Viewing and Changing the Access Policy
- Rebalancing the Load
- Transaction Split Feature
- Momentary Disconnection Prevention Feature
- Access Mode
- Adjusting Database Proxy Configuration
- Switching Database Proxy Network
- Viewing Database Proxy Monitoring Data
- Disabling Database Proxy
- Automatic Read/Write Separation
- Connection Pool Feature
- Other Features
- Account Management
- Database Management
- Database Management Tool
- Columnar Storage Index (CSI)
- Read-Only Analysis Engine
- Overview
- Feature Limits and Compatibility
- Compatibility and Use Limits
- Data Loading Limitations
- Description of Functions and Operators
- Description of Supported Bitwise Operations
- Description of Supported Arithmetic
- Description of Supported Comparison Operations
- Description of Supported Logical Operations
- Description of Supported String Functions
- Description of Supported Mathematical Operation Functions
- Description of Supported Date Functions
- Description of Supported Aggregation Functions
- Description of Supported Type Conversion Functions
- Data Types
- Read-Only Analysis Engine Management
- Data Loading
- Executing Queries
- Performance Optimization
- Performance White Paper
- Parameter Configuration
- Multi-AZ Deployment
- Backup and Restoration
- Operation Log
- Data Migration
- Parallel Query
- Database Security and Encryption
- Monitoring and Alarms
- Basic SQL Operations
- Connecting to TDSQL-C for MySQL Through SCF
- Tag
- Practical Tutorial
- Classified Protection Practice for Database Audit of TDSQL-C for MySQL
- Upgrading Database Version from MySQL 5.7 to 8.0 Through DTS
- Usage Instructions for TDSQL-C MySQL
- New Version of Console
- Implementing Multiple RO Groups with Multiple Database Proxy Connection Addresses
- Strengths of Database Proxy
- Selecting Billing Mode for Storage Space
- Creating Remote Disaster Recovery by DTS
- Creating VPC for Cluster
- Data Rollback
- Solution to High CPU Utilization
- How to Authorize Sub-Users to View Monitoring Data
- White Paper
- API Documentation
- History
- Introduction
- API Category
- Making API Requests
- Billing APIs
- Instance APIs
- CloseClusterPasswordComplexity
- CopyClusterPasswordComplexity
- DescribeClusterDetail
- DescribeClusterPasswordComplexity
- ModifyClusterPasswordComplexity
- OpenClusterPasswordComplexity
- UpgradeClusterVersion
- UpgradeInstance
- SetRenewFlag
- OfflineCluster
- ModifyMaintainPeriodConfig
- IsolateInstance
- IsolateCluster
- DescribeMaintainPeriod
- DescribeInstanceSpecs
- DescribeClusters
- CreateClusters
- AddInstances
- OfflineInstance
- DescribeInstanceDetail
- DescribeClusterInstanceGrps
- DescribeInstances
- ActivateInstance
- ModifyInstanceName
- ModifyClusterName
- SearchClusterTables
- SearchClusterDatabases
- RestartInstance
- Multi-AZ APIs
- Account APIs
- Audit APIs
- Database Proxy APIs
- Backup and Restoration APIs
- Parameter Management APIs
- Performance Analysis APIs
- Serverless APIs
- ResourcePackage APIs
- Other APIs
- CloseWan
- CreateClusterDatabase
- DeleteClusterDatabase
- DescribeClusterDetailDatabases
- ModifyClusterDatabase
- OpenWan
- SwitchClusterVpc
- OpenReadOnlyInstanceExclusiveAccess
- OpenClusterReadOnlyInstanceGroupAccess
- ModifyDBInstanceSecurityGroups
- DescribeProjectSecurityGroups
- DescribeDBSecurityGroups
- SwitchProxyVpc
- DescribeFlow
- DescribeZones
- ModifyVipVport
- Data Types
- Error Codes
- FAQs
- Service Agreement
- TDSQL-C Policy
- General References
- Glossary
- Contact Us
- Release Notes and Announcements
- Release Notes
- Announcements
- Announcement on Release of New Upgrade Mechanism for Kernel Minor Version
- Announcement on Optimization of Instance Storage Capacity, IOPS, and I/O Bandwidth
- Announcement on Some APIs with CAM Authentication Integrated
- Announcement on Sales Suspension of Some General Specifications
- Announcement on Some APIs Integrated with CAM Authentication
- Announcement on Some APIs with CAM Authentication Integrated
- Announcement on Change of Part of Parameters
- Announcement on Update of Database Audit Feature
- Announcement on Authentication of a Newly Added API Interface of Database Audit
- Announcement on Change of Public Network Linkage
- TDSQL-C for MySQL Audit Service Update
- Announcement on Supplementary Charge for Clusters with Pay-as-You-Go Storage Billing Mode
- Announcement on New APIs Integrated with CAM Permissions
- Announcement on the Release of New Version of Database Proxy
- Emergency Fix for Certain Monitoring Metrics
- Monitoring Metric Optimization
- Change to Database Audit Resource ID
- Ops Change
- Storage Price Adjustment Notification
- Beginner's Guide
- Product Introduction
- Kernel Features
- Kernel Overview
- Kernel Version Release Notes
- Optimized Kernel Version
- Functionality Features
- Performance Features
- Columns Syntax
- Correlated Subquery Result Cache
- Global Index
- Binlog Write Optimization
- Large Transaction Binlog Optimization
- Binlog Purging Performance Optimization
- Optimization of Plan Caching Point Query
- Auto-Increment Column Persistence
- Invisible Index
- Computation Pushdown
- Parallel Initialization of InnoDB Buffer Pool
- Security Features
- Stability Feature
- Analysis Engine Features
- Purchase Guide
- Getting Started
- Database Audit
- Serverless Service
- Operation Guide
- Switching Cluster Page View in Console
- Database Connection
- Instance Management
- Configuration Adjustment
- Cluster Management
- Scaling Instance
- Database Proxy
- Database Proxy Overview
- Use Limits
- Database Proxy Kernel Features
- Managing Database Proxy
- Enabling Database Proxy
- Setting Database Proxy Address
- Modifying or Deleting Connection Addresses
- Viewing and Changing the Access Policy
- Rebalancing the Load
- Transaction Split Feature
- Momentary Disconnection Prevention Feature
- Access Mode
- Adjusting Database Proxy Configuration
- Switching Database Proxy Network
- Viewing Database Proxy Monitoring Data
- Disabling Database Proxy
- Automatic Read/Write Separation
- Connection Pool Feature
- Other Features
- Account Management
- Database Management
- Database Management Tool
- Columnar Storage Index (CSI)
- Read-Only Analysis Engine
- Overview
- Feature Limits and Compatibility
- Compatibility and Use Limits
- Data Loading Limitations
- Description of Functions and Operators
- Description of Supported Bitwise Operations
- Description of Supported Arithmetic
- Description of Supported Comparison Operations
- Description of Supported Logical Operations
- Description of Supported String Functions
- Description of Supported Mathematical Operation Functions
- Description of Supported Date Functions
- Description of Supported Aggregation Functions
- Description of Supported Type Conversion Functions
- Data Types
- Read-Only Analysis Engine Management
- Data Loading
- Executing Queries
- Performance Optimization
- Performance White Paper
- Parameter Configuration
- Multi-AZ Deployment
- Backup and Restoration
- Operation Log
- Data Migration
- Parallel Query
- Database Security and Encryption
- Monitoring and Alarms
- Basic SQL Operations
- Connecting to TDSQL-C for MySQL Through SCF
- Tag
- Practical Tutorial
- Classified Protection Practice for Database Audit of TDSQL-C for MySQL
- Upgrading Database Version from MySQL 5.7 to 8.0 Through DTS
- Usage Instructions for TDSQL-C MySQL
- New Version of Console
- Implementing Multiple RO Groups with Multiple Database Proxy Connection Addresses
- Strengths of Database Proxy
- Selecting Billing Mode for Storage Space
- Creating Remote Disaster Recovery by DTS
- Creating VPC for Cluster
- Data Rollback
- Solution to High CPU Utilization
- How to Authorize Sub-Users to View Monitoring Data
- White Paper
- API Documentation
- History
- Introduction
- API Category
- Making API Requests
- Billing APIs
- Instance APIs
- CloseClusterPasswordComplexity
- CopyClusterPasswordComplexity
- DescribeClusterDetail
- DescribeClusterPasswordComplexity
- ModifyClusterPasswordComplexity
- OpenClusterPasswordComplexity
- UpgradeClusterVersion
- UpgradeInstance
- SetRenewFlag
- OfflineCluster
- ModifyMaintainPeriodConfig
- IsolateInstance
- IsolateCluster
- DescribeMaintainPeriod
- DescribeInstanceSpecs
- DescribeClusters
- CreateClusters
- AddInstances
- OfflineInstance
- DescribeInstanceDetail
- DescribeClusterInstanceGrps
- DescribeInstances
- ActivateInstance
- ModifyInstanceName
- ModifyClusterName
- SearchClusterTables
- SearchClusterDatabases
- RestartInstance
- Multi-AZ APIs
- Account APIs
- Audit APIs
- Database Proxy APIs
- Backup and Restoration APIs
- Parameter Management APIs
- Performance Analysis APIs
- Serverless APIs
- ResourcePackage APIs
- Other APIs
- CloseWan
- CreateClusterDatabase
- DeleteClusterDatabase
- DescribeClusterDetailDatabases
- ModifyClusterDatabase
- OpenWan
- SwitchClusterVpc
- OpenReadOnlyInstanceExclusiveAccess
- OpenClusterReadOnlyInstanceGroupAccess
- ModifyDBInstanceSecurityGroups
- DescribeProjectSecurityGroups
- DescribeDBSecurityGroups
- SwitchProxyVpc
- DescribeFlow
- DescribeZones
- ModifyVipVport
- Data Types
- Error Codes
- FAQs
- Service Agreement
- TDSQL-C Policy
- General References
- Glossary
- Contact Us
This document describes the momentary disconnection prevention feature of the TDSQL-C for MySQL database proxy.
Background
During the instance Ops, you may need to make some adjustments, such as configuration modification, planned HA switch, and planned restart. Theses Ops may cause the problems, such as session interruption, momentary disconnection and failed new connections. The TDSQL-C for MySQL database proxy provides the momentary disconnection prevention feature that enables lossless application continuity to prevent disconnection and transaction interruption.
How It Works
The momentary disconnection prevention feature implements TDSQL-C for MySQL’s session track mechanism. When the lossy behavior is perceived, the database proxy will disconnect the client from the source node before the switch, and connect to the source node after the switch. Then the session-related system variables, user variables, and character set encoding information will be transferred to the new backend connection through the session track mechanism, so as to realize the lossless switching on the application side.
Notes
If the statement uses the temp tables associated with each session, the connection cannot be recovered, and an error will be reported.
To use the momentary disconnection prevention feature, you need to upgrade the database proxy kernel version to v1.3.1 or later.
The disconnection prevention feature will stop the transactions over 3 seconds.
When the connection is switched, if the database proxy is receiving the result message from the database, only part of the data will be transferred due to the source/replica switch, and the momentary disconnection prevention feature will be disabled.
If there is a prepared statement in use during the momentary disconnection prevention, the momentary disconnection prevention feature cannot maintain the connection.
Performance Testing
The performance test of the momentary disconnection prevention feature for TDSQL-C for MySQL database proxy is described in the following.
Test environment
Region/AZ: Beijing - Beijing Zone 7
Client: S5.8XLARGE64 (32-core 64 GB Standard S5)
Client operating system: CentOS 8.2 64-bit
Network: Both the CVM and TDSQL-C for MySQL instances are in the same VPC subnet.
The information of the tested TDSQL-C for MySQL instance is as follows:
Storage type: Local SSD disk
Instance type: General
Parameter template: High-performance template
Test tool
SysBench, as the tool for the performance test, is a modular, cross-platform, and multi-threaded benchmark tool for evaluating OS parameters that are important for a system running a database under intensive load. The idea of this benchmark suite is to quickly get an impression about system performance without setting up complex database benchmarks or even without installing a database at all.
Test method
In different Ops scenarios, you can analyze the ratio of momentary disconnections before and after the operation to test whether a database proxy provides momentary disconnection prevention for the TDSQL-C for MySQL instance.
Test Results
In the following Ops scenarios, the TDSQL-C for MySQL instance maintains a 100% connection keep-alive rate by the momentary disconnection prevention capability of the database proxy.
Ops scenario | Keep-alive rate |
Performing source-replica switch | 100% |
Upgrading kernel minor version | 100% |
Adjusting the instance specifications | 100% |
Yes
No
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