- Release Notes and Announcements
- Release Notes
- Announcements
- 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
- Emergency Fix for Certain Monitoring Metrics
- Monitoring Metric Optimization
- Some AZs Are Sold Out
- Change to Database Audit Resource ID
- Ops Change
- Storage Price Adjustment Notification
- Product Introduction
- Kernel 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
- 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)
- 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
- Best Practices
- White Paper
- API Documentation
- History
- Introduction
- API Category
- Making API Requests
- Instance APIs
- CloseClusterPasswordComplexity
- CopyClusterPasswordComplexity
- DescribeClusterPasswordComplexity
- ModifyClusterPasswordComplexity
- OpenClusterPasswordComplexity
- UpgradeClusterVersion
- UpgradeInstance
- SetRenewFlag
- OfflineCluster
- ModifyMaintainPeriodConfig
- IsolateInstance
- IsolateCluster
- DescribeMaintainPeriod
- DescribeInstanceSpecs
- DescribeClusters
- DescribeClusterDetail
- 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
- Billing APIs
- Serverless APIs
- ResourcePackage APIs
- Other APIs
- CloseWan
- CreateClusterDatabase
- DeleteClusterDatabase
- DescribeClusterDetailDatabases
- ModifyClusterDatabase
- OpenWan
- OpenClusterReadOnlyInstanceGroupAccess
- OpenReadOnlyInstanceExclusiveAccess
- ModifyDBInstanceSecurityGroups
- DescribeProjectSecurityGroups
- DescribeDBSecurityGroups
- SwitchProxyVpc
- DescribeFlow
- DescribeZones
- SwitchClusterVpc
- ModifyVipVport
- Data Types
- Error Codes
- FAQs
- TDSQL-C Policy
- Glossary
- Contact Us
- Release Notes and Announcements
- Release Notes
- Announcements
- 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
- Emergency Fix for Certain Monitoring Metrics
- Monitoring Metric Optimization
- Some AZs Are Sold Out
- Change to Database Audit Resource ID
- Ops Change
- Storage Price Adjustment Notification
- Product Introduction
- Kernel 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
- 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)
- 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
- Best Practices
- White Paper
- API Documentation
- History
- Introduction
- API Category
- Making API Requests
- Instance APIs
- CloseClusterPasswordComplexity
- CopyClusterPasswordComplexity
- DescribeClusterPasswordComplexity
- ModifyClusterPasswordComplexity
- OpenClusterPasswordComplexity
- UpgradeClusterVersion
- UpgradeInstance
- SetRenewFlag
- OfflineCluster
- ModifyMaintainPeriodConfig
- IsolateInstance
- IsolateCluster
- DescribeMaintainPeriod
- DescribeInstanceSpecs
- DescribeClusters
- DescribeClusterDetail
- 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
- Billing APIs
- Serverless APIs
- ResourcePackage APIs
- Other APIs
- CloseWan
- CreateClusterDatabase
- DeleteClusterDatabase
- DescribeClusterDetailDatabases
- ModifyClusterDatabase
- OpenWan
- OpenClusterReadOnlyInstanceGroupAccess
- OpenReadOnlyInstanceExclusiveAccess
- ModifyDBInstanceSecurityGroups
- DescribeProjectSecurityGroups
- DescribeDBSecurityGroups
- SwitchProxyVpc
- DescribeFlow
- DescribeZones
- SwitchClusterVpc
- ModifyVipVport
- Data Types
- Error Codes
- FAQs
- TDSQL-C Policy
- Glossary
- Contact Us
Overview
DDL statements support
NO_WAIT and WAIT options. If a DDL statement with WAIT enabled fails to obtain an MDL lock, it will wait for WAIT seconds before it directly returns the query result. If a DDL statement with NO_WAIT enabled, it will directly return the query result without waiting for the MDL lock.SELECT FOR UPDATE statement supports
NOWAIT and SKIP LOCKED options. If target rows are locked by another transaction, a SELECT FOR UPDATE statement is supposed to wait for the transaction to release the lock. But in some use cases like flash sales, you do not want to wait for a lock. You can use SKIP LOCKED to skip locked rows (as a result, the locked rows won't be returned in the query result set) or NOWAIT to return an error without waiting for the lock.Note that
NO_WAIT and NOWAIT are different keywords.Supported Versions
TDSQL-C for MySQL 5.7 (kernel version 2.0.23/2.1.9) or later.
TDSQL-C for MySQL 8.0 (kernel version 3.1.10) or later.
Use Cases
Currently, DevAPI/XPlugin does not support using
SKIP LOCKED or NOWAIT in SELECT FOR UPDATE/SHARE statements. Note that NO_WAIT in DDL statements and NOWAIT in SELECT FOR UPDATE statements are different keywords for historical reasons.
Yes
No
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