- Release Notes and Announcements
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- Announcement on the Rule-Based Audit Feature for Database Audit
- Announcement on Some APIs with CAM Authentication Integrated
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- Notice on Elimination of Some Indicators in Event Alarms
- Commercial Billing for Database Proxy
- TencentDB for MySQL Audit Upgrade
- Added Authentication APIs
- API Authentication Upgrade
- TencentDB for MySQL API 2.0 Discontinuation
- Monitoring Module Upgrade in Shanghai Region
- Monitoring Metric Optimization
- Network Architecture Upgrade
- Change of APIs for Querying the Specifications of Purchasable Database Instances
- Replacement of Certain Old Database Proxy APIs
- Added Advanced Monitoring Metrics
- Change of Calculation Formula for Memory Utilization
- Monitoring Module Upgrade and Optimization in Guangzhou and Shanghai Regions
- Monitoring Module Upgrade
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- Configuring Automatic Application Reconnection
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- Limits on Automatic Conversion from MyISAM to InnoDB
- Creating VPCs for TencentDB for MySQL
- Enhancing Business Load Capacity with TencentDB for MySQL
- Setting up 2-Region-3-DC Disaster Recovery Architecture
- Improving TencentDB for MySQL Performance with Read/Write Separation
- Migrating Data from InnoDB to RocksDB with DTS
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- Database Proxy APIs
- AdjustCdbProxy
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- CloseCdbProxyAddress
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- CreateCdbProxyAddress
- DescribeCdbProxyInfo
- DescribeProxyCustomConf
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- ReloadBalanceProxyNode
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- Security APIs
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- ModifyBackupDownloadRestriction
- ModifyLocalBinlogConfig
- ModifyRemoteBackupConfig
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- Database APIs
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- Data Types
- Error Codes
- FAQs
- Service Agreement
- Reference
- Glossary
- Contact Us
- Preset Plugin List
- Release Notes and Announcements
- Release Notes
- Announcements
- Announcement on the Rule-Based Audit Feature for Database Audit
- Announcement on Some APIs with CAM Authentication Integrated
- Announcement on Some APIs with CAM Authentication Integrated
- Notice on Elimination of Some Indicators in Event Alarms
- Commercial Billing for Database Proxy
- TencentDB for MySQL Audit Upgrade
- Added Authentication APIs
- API Authentication Upgrade
- TencentDB for MySQL API 2.0 Discontinuation
- Monitoring Module Upgrade in Shanghai Region
- Monitoring Metric Optimization
- Network Architecture Upgrade
- Change of APIs for Querying the Specifications of Purchasable Database Instances
- Replacement of Certain Old Database Proxy APIs
- Added Advanced Monitoring Metrics
- Change of Calculation Formula for Memory Utilization
- Monitoring Module Upgrade and Optimization in Guangzhou and Shanghai Regions
- Monitoring Module Upgrade
- Parameter Template and Instance Purchase Process Optimization
- Binlog Will Take up Disk Space
- User Tutorial
- Product Introduction
- Tencent Kernel TXSQL
- Overview
- Kernel Version Release Notes
- Functionality Features
- Performance Features
- Security Features
- Stability Features
- TXRocks Engine
- Purchase Guide
- Billing Overview
- Selection Guide
- Purchase Methods
- Renewal
- Payment Overdue
- Refund
- Pay-as-You-Go to Monthly Subscription
- Instance Adjustment Fee
- Backup Space Billing
- Database Audit Billing Overview
- Commercial Billing and Activity Description for Database Proxy
- Description of the Database Proxy Billing Cycle
- Viewing Bills
- Getting Started
- Database Audit
- MySQL Cluster Edition
- Operation Guide
- Use Limits
- Operation Overview
- Instance Management and Maintenance
- Instance Upgrade
- CPU Elastic Expansion
- Read-Only/Disaster Recovery Instances
- Database Proxy
- Account Management
- Database Management Center (DMC)
- Parameter Configuration
- Network and Security
- Backup and Rollback
- Data Migration
- Monitoring and Alarms
- Operation Logs
- Tag
- Practical Tutorial
- Usage Specifications of TencentDB for MySQL
- Configuring Automatic Application Reconnection
- Impact of Modifying MySQL Source Instance Parameters
- Limits on Automatic Conversion from MyISAM to InnoDB
- Creating VPCs for TencentDB for MySQL
- Enhancing Business Load Capacity with TencentDB for MySQL
- Setting up 2-Region-3-DC Disaster Recovery Architecture
- Improving TencentDB for MySQL Performance with Read/Write Separation
- Migrating Data from InnoDB to RocksDB with DTS
- Building LAMP Stack for Web Application
- Building Drupal Website
- Building All-Scenario High-Availability Architecture
- Calling MySQL APIs in Python
- White Paper
- Troubleshooting
- API Documentation
- History
- Introduction
- API Category
- Data Import APIs
- Rollback APIs
- Parameter APIs
- Making API Requests
- Instance APIs
- StopCpuExpand
- StartCpuExpand
- DescribeCpuExpandStrategy
- AddTimeWindow
- BalanceRoGroupLoad
- CloseWanService
- CreateRoInstanceIp
- DeleteTimeWindow
- DescribeCdbZoneConfig
- DescribeDBFeatures
- DescribeDBInstanceCharset
- DescribeDBInstanceConfig
- DescribeDBInstanceGTID
- DescribeDBInstanceInfo
- DescribeDBInstanceRebootTime
- DescribeDBSwitchRecords
- DescribeRoGroups
- DescribeRoMinScale
- DescribeTagsOfInstanceIds
- DescribeTimeWindow
- IsolateDBInstance
- ModifyAutoRenewFlag
- ModifyDBInstanceName
- ModifyDBInstanceProject
- ModifyDBInstanceVipVport
- ModifyInstanceTag
- ModifyNameOrDescByDpId
- ModifyRoGroupInfo
- ModifyTimeWindow
- OfflineIsolatedInstances
- OpenDBInstanceEncryption
- OpenDBInstanceGTID
- OpenWanService
- ReleaseIsolatedDBInstances
- RenewDBInstance
- RestartDBInstances
- StartReplication
- StopReplication
- SwitchDBInstanceMasterSlave
- SwitchDrInstanceToMaster
- SwitchForUpgrade
- UpgradeDBInstanceEngineVersion
- CreateDBInstance
- CreateDBInstanceHour
- DescribeDBInstances
- UpgradeDBInstance
- DescribeDBZoneConfig
- CreateDeployGroup
- DeleteDeployGroups
- DescribeDeployGroupList
- Database Proxy APIs
- AdjustCdbProxy
- AdjustCdbProxyAddress
- CloseCDBProxy
- CloseCdbProxyAddress
- CreateCdbProxy
- CreateCdbProxyAddress
- DescribeCdbProxyInfo
- DescribeProxyCustomConf
- DescribeProxySupportParam
- ModifyCdbProxyAddressDesc
- ModifyCdbProxyAddressVipAndVPort
- ModifyCdbProxyParam
- ReloadBalanceProxyNode
- SwitchCDBProxy
- UpgradeCDBProxyVersion
- Database Audit APIs
- Security APIs
- Task APIs
- Account APIs
- Backup APIs
- CreateBackup
- DeleteBackup
- DescribeBackupDownloadRestriction
- DescribeBackupOverview
- DescribeBackupSummaries
- DescribeBinlogBackupOverview
- DescribeDataBackupOverview
- DescribeLocalBinlogConfig
- DescribeRemoteBackupConfig
- DescribeSlowLogs
- ModifyBackupDownloadRestriction
- ModifyLocalBinlogConfig
- ModifyRemoteBackupConfig
- DescribeBackups
- DescribeBackupConfig
- DescribeBackupDecryptionKey
- DescribeBackupEncryptionStatus
- DescribeBinlogs
- ModifyBackupConfig
- ModifyBackupEncryptionStatus
- Database APIs
- Monitoring APIs
- Log-related API
- Data Types
- Error Codes
- FAQs
- Service Agreement
- Reference
- Glossary
- Contact Us
- Preset Plugin List
Impact of Modifying MySQL Source Instance Parameters
Last updated: 2024-07-23 12:58:20
For TencentDB for MySQL, you can modify the parameters of a source instance in the console. Modifying some crucial parameters in an improper way will lead to exceptions in disaster recovery instances and data inconsistency. This document describes the consequences of modifying the following crucial parameters.
lower_case_table_names
Default value:
0Description: When creating a database or table, you can set whether storage and query operations are case-sensitive. This parameter can be set to 0 (case-sensitive) or 1 (case-insensitive), and the default value is 0.
Impact: After the parameters of the source instance are modified, the parameters of the disaster recovery instance cannot be modified accordingly, as the source instance is set as case-sensitive, but the disaster recovery instance is not; for example, if two tables named "Test" and "TEst" are created in the source instance, then data sync will fail when the disaster recovery instance uses the corresponding logs, because the table name "TEst" already exists.auto_increment_increment
Default value:
1Description: It is used as the increment value of the auto-increment column AUTO_INCREMENT. Its value can range from 1 (default value) to 65,535.
Impact: After the parameters of the source instance are modified, those of the disaster recovery instance cannot be modified accordingly. When binlog_format is set as statement, only statement execution is recorded. In this case, if the increment column value of the source instance is modified but that of the disaster recovery instance is not modified accordingly, the data will be inconsistent between the source and slave instances.auto_increment_offset
Default value:
1Description: It is used as the start value (offset) of the auto-increment column AUTO_INCREMENT. Its value can range from 1 (default value) to 65,535.
Impact: After the parameters of the source instance are modified, the parameters of the disaster recovery instance cannot be modified accordingly. When the offset value is modified for the source instance but not for the disaster recovery instance, source-replica data inconsistency will occur.sql_mode
Default value:
NO_ENGINE_SUBSTITUTIONDescription: TencentDB for MySQL can operate in different SQL modes, which define the SQL syntax and data check that it should support. The default value of this parameter in v5.6 is NO_ENGINE_SUBSTITUTION, which means that if the used storage engine is disabled or not compiled, an error will be reported; in v5.7, the default value is ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE.
,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION.
Here:ONLY_FULL_GROUP_BY means that in a GROUP BY operation, the column in SELECT or the HAVING or ORDER BY subquery must be a function column that appears in or relies on GROUP BY.STRICT_TRANS_TABLES enables strict mode.NO_ZERO_IN_DATE indicates whether the month and day of a date can contain 0 and is subject to the status of the strict mode.NO_ZERO_DATE means that dates in the database cannot contain zero date and are subject to the status of the strict mode.ERROR_FOR_DIVISION_BY_ZERO means that in strict mode, if data is divided by 0 during the INSERT or UPDATE process, an error rather than a warning will be reported, while in non-strict mode, NULL will be returned.NO_AUTO_CREATE_USER prohibits GRANT from creating a user whose password is empty.NO_ENGINE_SUBSTITUTION means that if the used storage engine is disabled or not compiled, an error will be reported.Impact: After the parameters of the source instance are modified, the parameters of the disaster recovery instance cannot be modified accordingly. When the SQL mode is changed for the source instance but not for the disaster recovery instance, for example, if the SQL mode limit of the source instance is smaller than that of the disaster recovery instance, the SQL statements that are successfully executed in the source instance may trigger errors when synced to the disaster recovery instance and thus lead to source-replica data inconsistency.
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