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Start on Cloud

A unified distributed database ready for your transactional, analytical, and AI workloads.

DEPLOY YOUR WAY

OceanBase Cloud

The best way to deploy and scale OceanBase

OceanBase Enterprise

Run and manage OceanBase on your infra

TRY OPEN SOURCE

OceanBase Community Edition

The free, open-source distributed database

OceanBase seekdb

Open source AI native search database

Customer Stories

Real-world success stories from enterprises across diverse industries.

View All
BY USE CASES

Mission-Critical Transactions

Global & Multicloud Application

Elastic Scaling for Peak Traffic

Real-time Analytics

Active Geo-redundancy

Database Consolidation

Comprehensive knowledge hub for OceanBase.

Blog

Live Demos

Training & Certification

Documentation

Official technical guides, tutorials, API references, and manuals for all OceanBase products.

View All
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QUICK START
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OceanBase Database

SQL - V4.1.0Enterprise Edition

  • What is OceanBase Database
    • Overview
    • Differences between the features of the Enterprise Edition and the Community Edition
    • System architecture
    • Compatibility with Oracle
      • Overview
      • SQL data types
      • Built-in functions
      • System views
    • Compatibility with MySQL
    • Limitations
  • Get Started
    • Get started with OceanBase Database
    • Learn OceanBase SQL
      • Before you begin
      • Basic SQL operations (MySQL mode)
      • Basic SQL operations (Oracle mode)
    • Build a sample application (MySQL mode)
      • Build a Python application
      • Build a Java application
      • Build a C application
      • Build a Go application
    • Build a sample application (Oracle mode)
      • Build a Python application
      • Build a Java application
      • Build a C application
    • Try out advanced features of OceanBase Database
      • Scalable OLTP
        • Run the TPC-C benchmark in OceanBase Database
        • Try out the hot row update capability of OceanBase Database
      • Try out operational OLAP
      • Try out parallel import and data compression
      • Try out the multi-tenant feature
      • DDL
        • Try out new DDL features in MySQL mode
        • Try out new DDL features in Oracle mode
    • Video tutorials
  • Develop
    • Develop applications in MySQL mode
      • Connect to OceanBase Database
        • Overview
        • Connect to an OceanBase Database tenant by using the mysql client
        • Connect to an OceanBase Database tenant by using OBClient
        • Connect to OceanBase Database by using ODC
        • Connect to OceanBase Database by using Spring Boot
        • Connect to OceanBase Database by using Spring Batch
        • Connect to OceanBase Database by using Spring JDBC
        • Connect to OceanBase Database by using Spring JPA
        • Connect to OceanBase Database by using Hibernate
        • Use database connection pool
          • Database connection pool configuration
          • Configure a Tomcat connection pool
          • Configure a C3P0 connection pool
          • Configure a Proxool connection pool
          • Configure a HiKariCP connection pool
          • Configure a DBCP connection pool
          • Configure a CommonPool connection pool
          • Configure a JDBC connection pool
      • Create database objects
        • Create a database
        • Create a table
        • Create indexes
      • Write data
        • Insert data
        • Update data
        • Delete data
        • Replace data
      • Read data
        • About queries
        • Single-table queries
        • Conditional queries
        • ORDER BY queries
        • GROUP BY queries
        • Use the LIMIT clause in queries
        • Join tables
          • INNER JOIN queries
          • FULL JOIN queries
          • LEFT JOIN queries
          • RIGHT JOIN queries
          • Subqueries
        • Use operators and functions in queries
          • Use arithmetic operators in queries
          • Use numerical functions in queries
          • Use string concatenation operators in queries
          • Use string functions in queries
          • Use datetime functions in queries
          • Use type conversion functions in queries
          • Use aggregate functions in queries
          • Use NULL-related functions in queries
          • Use the CASE conditional operator in queries
          • Use the SELECT FOR UPDATE statement to lock query results
        • Execution plans
          • View an execution plan
          • Understand an execution plan
        • Use SQL hints in queries
        • Variables of query timeout
      • Transactions
        • Overview
        • Start a transaction
        • Savepoints
          • Mark a savepoint
          • Roll back a transaction to a savepoint
          • Release a savepoint
        • Commit a transaction
        • Roll back a transaction
      • Troubleshoot common errors
        • Disconnected from the server, with ERROR 2013 reported
        • Idle transaction timed out, with ERROR 6002 reported
        • Transaction timed out, with ERROR 4012 reported
        • User locked, with ERROR 3118 reported
        • Incorrect user password, with ERROR 1045 reported
        • Table already exists, with ERROR 1050 reported
        • Table does not exist, with ERROR 1146 reported
        • Duplicate data inserted, with ERROR 1062 reported
        • ERROR 1215 reported in foreign key addition
        • Data truncated while being inserted, with ERROR 1265 reported
    • Develop applications in Oracle mode
      • Connect to OceanBase Database
        • Overview
        • Connect to an OceanBase Database tenant by using OBClient
        • Connect to OceanBase Database by using ODC
        • Connect to OceanBase Database by using Spring Boot
        • Connect to OceanBase Database by using Spring Batch
        • Connect to OceanBase Database by using Spring JDBC
        • Connect to OceanBase Database by using MyBatis
        • Use database connection pool
          • Database connection pool configuration
          • Configure a Tomcat connection pool
          • Configure a C3P0 connection pool
          • Configure a Proxool connection pool
          • Configure a HiKariCP connection pool
          • Example of configuring a DBCP connection pool
          • Configure a CommonPool connection pool
          • Configure a JDBC connection pool
      • Create database objects
        • Create a table
        • Create an index
      • Write data
        • Insert data
        • Update data
        • Delete data
        • Replace data
      • Read data
        • About queries
        • Single-table queries
        • Conditional queries
        • ORDER BY queries
        • GROUP BY queries
        • Use Row_Limiting_Clause in queries
        • Join tables
          • INNER JOIN queries
          • FULL JOIN queries
          • LEFT JOIN queries
          • RIGHT JOIN queries
          • Subqueries
        • Use operators and functions in queries
          • Use arithmetic operators in queries
          • Use numerical functions in queries
          • Use string concatenation operators in queries
          • Use string functions in queries
          • Use datetime functions in queries
          • Use type conversion functions in queries
          • Use aggregate functions in queries
          • Use NULL-related functions in queries
          • Use CASE functions in queries
          • Use the SELECT FOR UPDATE statement to lock query results
        • Execution plans
          • View execution plans of queries
          • Understand an execution plan
        • Use SQL hints in queries
        • About query timeout variables
      • Transactions
        • Overview
        • Start a transaction
        • Savepoints
          • Mark a savepoint
          • Roll back a transaction to a savepoint
        • Commit a transaction
        • Roll back a transaction
      • Troubleshoot common errors
        • Idle transaction timed out, with ORA-24761 error reported
        • Transaction timeout, with ORA-00600 error reported
        • User locked, with ERROR 3118 reported
        • Incorrect user password, with ERROR 1045 reported
        • Table already exists, with ORA-00955 error reported
        • Table does not exist, with ORA-04043 error reported
        • Duplicate data inserted, with ORA-00001 error reported
        • ORA-00600 error reported in foreign key addition
        • Inconsistent data types, with ORA-00932 error reported
  • Deploy
    • Overview
    • OceanBase cluster deployment solutions
    • Deploy OceanBase Database Enterprise Edition
      • Deployment process
      • Before deployment
        • Prepare servers
        • Configure servers
        • Prepare installation packages
      • Deploy through GUI
        • Configure deployment environment
          • Deploy OAT
          • Verify OAT deployment
          • Configure the clock source
          • Upload installation packages
          • Add a server
          • Edit a server
          • Create MetaDB
        • Deploy OCP
          • Overview
          • Deploy OCP
          • Verify OCP deployment
        • Deploy OceanBase clusters
          • Add an OBServer node to the resource pool
          • Create an OceanBase cluster
        • Deploy ODP
          • Overview
          • Deploy ODP
        • Create OceanBase tenant
          • View resources available for a business tenant
          • Create a tenant
          • Verify connectivity after tenant creation
        • Deploy ODC
          • Overview
          • Deploy ODC
          • Verify ODC deployment
      • Deploy through CLI
        • Configure deployment environment
          • Install oat-cli
          • Use oat-cli to configure the deployment environment
          • Configure the clock source
          • Upload installation packages
          • Configure host information
          • Check the environment before deployment
        • Deploy OCP
          • Overview
          • Generate a configuration file
          • Deploy OCP
          • Verify OCP deployment
        • Deploy OceanBase clusters
          • Deploy a single-replica OceanBase cluster
          • Deploy a three-replica OceanBase cluster
        • Deploy ODP
          • Deploy ODP
        • Create OceanBase tenants
          • View resources available for a business tenant
          • Create a tenant
          • Verify connectivity after tenant creation
        • Deploy ODC
          • Overview
          • Modify the configuration file
          • Start deployment
          • Verify deployment
    • Deploy OceanBase Database Community Edition
      • Overview
      • Deploy locally
        • Software and hardware requirements
        • Before deployment
          • Check resources
          • Set password-free SSH logon
          • Configure the clock source
          • Perform disk planning
          • Configure the limits.conf file
          • Configure the sysctl.conf file
          • Disable the firewall and SELinux
          • Create a user
        • Deploy through GUI
          • Deploy an OceanBase cluster by using OCP
        • Deploy OceanBase Database in a production environment by using a CLI
      • Deploy OceanBase Database in a Kubernetes cluster
    • Clean up an old cluster
  • Migrate
    • About data migration
    • Migrate from MySQL databases to OceanBase Database
      • Migrate data from a MySQL database to OceanBase Database by using mydumper and myloader
      • Use DBCAT to migrate schemas from a MySQL database to OceanBase Database
      • Use DataX to migrate table data from a MySQL database to OceanBase Database
      • Use CloudCanal to migrate data from a MySQL database to OceanBase Database
      • Use Canal to synchronize data from a MySQL database to OceanBase Database
      • Use Flink CDC to synchronize data from a MySQL database to OceanBase Database
      • Use ChunJun to migrate data from a MySQL database to OceanBase Database
    • Migrate from OceanBase Database to MySQL databases
      • Use DBCAT to migrate schemas from OceanBase Database to a MySQL database
      • Use DataX to migrate table data from OceanBase Database to a MySQL database
      • Synchronize data from OceanBase Database to a MySQL database using Canal
      • Migrate data from a MySQL OceanBase database to a MySQL database using CloudCanal
      • Migrate data from OceanBase Database to a MySQL database using Flink CDC
      • Migrate data from a MySQL database in OceanBase Database to a MySQL database using ChunJun
    • Migrate from Oracle databases to OceanBase Database
      • Use DBCAT to migrate schemas from an Oracle database to OceanBase Database
      • Use DataX to migrate table data from an Oracle database to OceanBase Database
    • Migrate from OceanBase Database to Oracle databases
      • Use DBCAT to migrate schemas from OceanBase Database to an Oracle database
      • Use DataX to migrate table data from OceanBase Database to an Oracle database
    • Migrate from DB2 databases to OceanBase Database
      • Use DBCAT to migrate DB2 LUW table schemas to OceanBase Database
    • Migrate from CSV files to OceanBase Database
      • Use DataX to migrate CSV files to OceanBase Database
      • Import data by using the LOAD DATA statement
    • Import data from SQL files to OceanBase Database
    • Migrate data between OceanBase Database
      • Use OBLOADER & OBDUMPER to migrate data between MySQL tenants in OceanBase Database clusters
      • Use OBLOADER & OBDUMPER to migrate data from a MySQL tenant to an Oracle tenant in an OceanBase cluster
      • Use OBLOADER & OBDUMPER to migrate data between Oracle tenants in OceanBase Database clusters
      • Use OBLOADER & OBDUMPER to migrate data from an Oracle tenant to a MySQL tenant in OceanBase Database
    • Migrate data using SQL statements
      • Migrate data between tables
      • Migrate resource units
      • Export data by using OUTFILE statements
    • Bypass import
      • Overview
      • Import data in bypass mode by using the LOAD DATA statement
      • Import data in bypass mode by using the INSERT INTO SELECT statement
  • Manage
    • Log on to an OceanBase Database tenant
    • Manage clusters
      • Overview
      • Cluster parameters
      • Common cluster operations
        • View a zone
        • View a node
        • Restart a node
        • Add a node
        • Delete a node
        • Isolate a node
        • Replace a node
        • Start a zone
        • Add a zone
        • Delete a zone
        • Modify a zone
        • Isolate a zone
        • View cluster parameters
        • Modify cluster parameters
        • Online scale-out from standalone deployment to distributed deployment
        • Upgrade clusters
          • Upgrade using CLI
            • Overview
            • Perform an upgrade
            • Check upgrade results
      • Troubleshoot common problems
        • Failures of a minority of nodes
        • Failures of the majority of nodes
    • Manage tenants
      • Tenant introduction
      • Tenant capacity
      • Tenant types
      • User tenants
      • System variables of a tenant
      • Common tenant operations
        • Create a tenant
        • Resource isolation
          • Overview
          • Manage resource isolation (Oracle mode)
            • Configure cgroups
            • Configure user-level resource isolation
            • Configure SQL statement-level resource isolation
            • Update a plan directive
            • Delete a plan directive
            • Delete a resource management plan
            • Delete a resource group
            • Clear cgroup configurations
          • Manage resource isolation (MySQL mode)
            • Configure cgroups
            • Configure user-level resource isolation
            • Configure SQL statement-level resource isolation
            • Update a plan directive
            • Delete a plan directive
            • Delete a resource management plan
            • Delete a resource group
            • Clear cgroup configurations
        • View tenant and resource information
        • Set and modify the tenant allowlist
        • View system variables of a tenant
        • Modify system variables of a tenant
        • Scale in/out
          • Tenant scaling
          • Modify the unit configs for a tenant
          • Modify the number of resource units for a tenant
          • Modify the number of primary zones for a tenant
        • Modify the attributes of a resource pool
        • Modify attributes of a tenant
        • Lock and unlock a tenant
        • Drop a tenant
        • Restore a tenant
        • Drop a resource pool
        • Drop a unit config
    • Manage replicas
      • What is replica
      • Replica distribution
        • Locality
        • Locality common operations
          • View locality
          • Modify locality
          • Add replicas
          • Remove replicas
          • Adjust the distribution of replicas
          • View the locality change history
          • Migrate units
      • Traffic distribution
      • Data distribution
    • High availability
      • What is high availability
      • Multi-replica disaster recovery
        • Data links
        • High availability of ODP
        • Database-level high availability
        • Disaster recovery architecture and levels
      • Physical standby database disaster recovery
        • Overview
        • Limitations
        • Create a standby tenant
        • Change the restore source of a standby tenant
        • Monitor the log synchronization status of a standby tenant
        • Adjust the log synchronization performance of a standby tenant
        • Adjust the log archiving speed of the primary tenant
        • Switch roles
          • Overview
          • Switchover
          • Failover
        • Drop a primary or standby tenant
      • Arbitration high availability
        • Overview
        • Enable the arbitration service
        • Disable the arbitration service
        • Modify the downgrade timeout period
        • Replace the arbitration service
        • Remove the arbitration service
      • Manage recycle bin
        • Recycle bin
        • Enable or disable the recycle bin
        • View objects in the recycle bin
        • Restore objects from the recycle bin
        • Purge the recycle bin
      • Flashback queries
    • Security and permissions
      • Overview
      • Identification and authentication
        • MySQL mode
          • Authentication
          • Password complexity
          • Login failure processing
        • Oracle mode
          • Authentication
          • Password complexity
          • Login failure processing
      • Access control
        • Overview
        • Users and permissions
          • Overview
          • MySQL mode
            • Privilege types in MySQL mode
            • Grant privileges
            • Privilege delegation
            • View user privileges
            • Modify user privileges
          • Oracle mode
            • Privilege types in Oracle mode
            • Direct privileges
            • Privilege delegation
            • Manage roles
            • Indirect privileges
            • View user privileges
            • Modify user privileges
        • Network security access control
        • Row-level access control
      • Data transmission encryption
        • Overview
        • OBServer transmission encryption
        • ODP transmission encryption
      • Transparent data encryption
        • Overview
        • MySQL mode
          • Enable transparent data encryption for new tables
          • Enable transparent data encryption for existing tables
          • Decrypt a table
        • Oracle mode
          • Enable transparent data encryption for a new table
          • Enable transparent data encryption for an existing table
          • Decrypt a table
      • Security audit
        • Overview
        • Enable security audit
        • Set and view audit rules
        • View audit records
        • Audit user logon operations
        • Audit user operations
        • Audit specified database objects
    • Backup and restore
      • Introduction to physical backup and restore
      • Deploy NFS
      • Log archive
        • Overview
        • Prepare for log archiving
        • Enable log archiving
        • Disable log archiving
        • View information about pieces
        • View the archiving progress
        • View the archiving history
        • View the archiving parameter settings
        • Change the destination of log archiving
        • Views related to log archiving
      • Data backup
        • Preparations
        • Initiate a full data backup job
        • Initiate an incremental data backup job
        • Stop a backup job
        • View the data backup progress
        • View the data backup history
        • View data backup parameter settings
        • Change the backup destination
        • Views related to data backup
      • Clear backup data
        • Automatic cleanup of expired backups
        • Stop backup cleanup
        • Query the backup cleanup progress
        • Query the backup cleanup history
        • Backup cleanup parameter
        • Views related to backup cleanup
      • Restore data
        • Preparations before the restore
        • Perform physical restore
        • Cancel the restore
        • Query the restore progress
        • Query the restore result
        • Change the role of a standby tenant to PRIMARY
        • Replay logs to a standby tenant
        • Parameters related to physical restore
        • Views related to physical restore
    • Monitoring
      • Overview
      • Metrics
        • System monitoring
          • Overview
          • Metrics
          • Wait events
          • Latch events
        • SQL monitoring
          • Overview
          • SQL Audit
          • Execution plans
      • Cases
    • Logs
      • Overview
      • Log levels
      • Log stability
      • Log control
      • Log metrics
      • View logs
        • Search for the logs of a specific SQL request
    • Performance tuning
      • SQL tuning
        • Execution plan optimization
          • Statistical information and row estimation
            • Statistical information
              • Collect statistical information
                • Automatic statistics collection
        • Business logic optimization
          • Schema specifications
    • Troubleshooting
      • Troubleshoot SQL execution errors
  • Reference
    • Concepts
      • Overall architecture of OceanBase Database
      • Database objects
        • Oracle mode
          • Tables
            • Overview
        • MySQL mode
          • Tables
            • Data type
              • Date and time data types
      • Data reliability and high availability
        • High availability architecture
          • Automatic handling of node failures
    • Administrator guide
      • Database connection and routing
        • Overview
        • Manage ODP
          • Overview
          • Manage ODP clusters
            • Create an ODP cluster
            • Manage ODP cluster parameters
            • Delete an ODP cluster
            • Upgrade all ODPs in an ODP cluster
            • Restart all ODPs in an ODP cluster
            • Manage OceanBase clusters connected to an ODP
            • Monitor ODP cluster performance
          • Manage ODP
            • Add an ODP
            • Start an ODP
            • Refresh ODP configurations
            • Stop an ODP
            • Restart an ODP
            • Delete an ODP
            • Upgrade one or more ODPs
          • ODP startup parameters
        • Physical connections
        • Logical connection
          • Query all sessions
          • Query the details of a session
          • Query the metrics of a session
          • Query session variables
          • Terminate a server session
        • Manage routing
          • Table-based routing of ODP
          • LDC-based routing
          • ODP routing policy
            • Read/Write splitting
            • Follower-first read
            • Blocklist mechanism
            • Transaction routing
      • Cluster and multi-tenant management
        • Manage clusters
          • Create a cluster
          • Manage clusters
          • Manage cluster parameters
            • Overview
            • Query cluster parameters
            • Modify cluster-level parameters
          • Manage zones in clusters
            • Overview of zone management
            • Add or delete a zone
            • Start or stop a zone
            • Modify the configurations of a zone
            • Restart a zone
            • Isolate a failed zone
          • Manage nodes
            • Add nodes
            • View the status of a node
            • Stop or start a node
            • Restart a node
            • Isolate a failed node
            • Delete a node
            • Replace a node
          • View the topology of a cluster
          • Overview of cluster tenant management
          • Monitor cluster performance
          • Cluster performance report
          • View resource information of a cluster
        • Manage configurations
          • Overview of configuration management
          • Set parameters
          • Set variables
          • General system parameters
          • Default production parameters
          • Minimum resource configurations
        • Manage resources
          • Overview
          • Create a resource unit configuration
          • Manage resource units
            • View resource unit configurations
            • Modify configurations of a resource unit
            • Drop a resource unit
          • Create a resource pool
          • Manage resource pools
            • View resource pools
            • Allocate a resource pool to a tenant
            • Modify a resource pool
            • Merge resource pools
            • Split a resource pool
            • Remove a resource pool from a tenant
            • Delete a resource pool
          • View resource allocation
        • Manage tenants
          • Overview of tenant management
          • Create a tenant
          • Create a user tenant
          • View tenant information
          • Copy a tenant
          • Modify a tenant
          • Rename a tenant
          • Drop a tenant
          • Manage users and permissions
            • Introduction
              • Overview
              • sys tenant
              • Oracle tenants
              • MySQL tenants
            • Oracle mode
              • Create a user
              • Set password complexity rules
              • Handle logon failures
              • View user privileges
              • Modify user privileges
              • Change the password of a user
              • Lock and unlock a user
              • Drop a user
              • Manage roles
                • Overview
                • Create a role
                • Assign a role to another role
                • Assign a role to a user
                • Specify valid or invalid roles for a user
                • View roles
                • Modify a role
                • Revoke a role
                • Drop a role
            • MySQL mode
              • Create a user
              • Set password complexity rules
              • Handle logon failures
              • View user privileges
              • Modify user privileges
              • Change the password of a user
              • Lock and unlock a user
              • Drop a user
          • Set and view the tenant allowlist
          • View the topology of a tenant
          • View the resource configurations of a tenant
          • Modify the resource configurations of a tenant
          • View the performance metrics of a tenant
          • View tenant sessions
          • Terminate a tenant session
          • Set the maximum number of connections for a tenant
          • Manage tenant parameters
            • Overview
            • Query tenant-level parameters
            • Modify tenant-level parameters
          • Manage tenant variables
        • Manage data storage
          • Dump management
            • Overview
            • Automatically trigger a minor compaction
            • Manually initiate a minor compaction
            • View minor compaction information
            • Modify minor compaction settings
          • Merge management
            • Overview
            • Automatically trigger a major compaction
            • Configure scheduled major compactions
            • Adaptive major compaction
            • Manually initiate a major compaction
            • Manually control a major compaction
            • View the major compaction process
            • Modify major compaction settings
          • Data compression
            • Overview
            • Data encoding and compression
        • Manage memory
          • Overview
          • Memory structure
          • Set the maximum memory for an OceanBase database
          • Manage internal system memory
          • Manage internal tenant memory
          • Manage the memory of the plan cache
          • Memleak-based regular memory leak diagnostics mechanism
          • Query memory usage information
          • Common memory issues
        • Manage processes
          • Overview
          • Multi-tenant threads of OceanBase Database
          • FAQ about multi-tenant threads
          • Background threads of OceanBase Database
        • Manage logs
          • Log overview
          • Log print level
            • Log generation levels
            • Set a log generation level
          • Manage size and quantity of log files
            • Use the log file splitting feature
            • Control the number of log files
          • View logs
            • Query the log of an SQL request
            • Query the log of a previous SQL request by using the SQL Trace feature
      • Manage database objects
        • Overview
        • MySQL mode
          • Manage databases
            • Create a database
            • View databases
            • Modify a database
            • Drop a database
          • Manage tables
            • Overview
            • Create a table
            • Define an auto-increment column
            • Define column constraints
            • Query the definition of a table
            • Modify a table
            • Empty a table
            • Drop a table
            • Lock a table
          • Manage indexes
            • Overview
            • Create an index
            • Query indexes
            • Drop an index
          • Manage views
          • Manage sequence
            • Create a sequence
            • Query sequences
            • Reference a sequence
            • Modify a sequence
            • Drop a sequence
          • Manage triggers
            • Overview
            • Create a DML trigger
            • Query trigger information
            • Drop a trigger
        • Oracle mode
          • Manage tables
            • Overview
            • Create a table
            • Define column constraints
            • Query the definition of a table
            • Modify a table
            • Empty a table
            • Drop a table
            • Lock a table
          • Manage indexes
            • Overview
            • Create an index
            • Query indexes
            • Drop an index
          • Manage views
          • Manage sequences
          • Manage synonyms
          • Manage triggers
            • Overview
            • Create a DML trigger
            • Create an INSTEAD OF trigger
            • Create a composite trigger
            • Modify and drop a trigger
            • Disable or enable a trigger
            • Query trigger information
          • Manage directory objects
          • Manage DBLink
            • Create a DBLink
            • View existing DBLinks
            • Use a DBLink to access data in a remote database
            • Use a DBLink to modify data in a remote database
            • Drop a DBLink
      • Manage replicas
        • Manage partitions
          • Oracle mode
            • Overview
            • Create a partitioned table
            • Modify partitioning rules
            • Add a partition
            • Drop partitions
            • Truncate a partition
            • Partition pruning
            • Query data in specified partitions
            • Create partitioned table index
              • Overview
              • Local indexes
              • Global indexes
          • MySQL mode
            • Overview
            • Create a partitioned table
            • Modify partitioning rules
            • Add a partition
            • Drop partitions
            • Truncate a partition
            • Partition pruning
            • Query data in specified partitions
            • Create partitioned table index
              • Overview
              • Local indexes
              • Global indexes
        • Manage replicas
          • Overview
          • Create a replica
          • Edit a tenant replica in a zone
          • Delete a tenant replica from a zone
        • Manage locality
          • Overview
          • Modify tenant locality
      • O&M
        • Scaling
          • Overview
          • Overview
            • Scale out
              • Add zones to a cluster
              • Add OBServer nodes to zones
            • Scale in
              • Delete zones from a cluster
              • Delete OBServer nodes from zones
          • Tenant resource scaling
            • Modify unit_config
            • Modify UNIT_NUM
        • Monitoring and alerting
          • Overview
          • Monitoring
            • Status monitoring
            • Performance monitoring
            • SQL monitoring
          • Alerting
            • Configure an alert channel
            • Alert push
            • Perform alert management
            • Manage general alert rules
        • Performance diagnosis
          • ASH report
            • ASH
            • Generate ASH reports
            • Analyze ASH reports
        • Emergency handling
          • Analysis, diagnostics, and decision-making process
          • Common emergency problem handling
            • Issues related to capacity changes
              • High disk I/O on the node
              • Tenant memory full
    • Performance tuning guide
      • Overview
      • Performance related tools
        • System tools
          • General tool Top
          • CPU tools
          • Memory tools
          • Disk I/O tools
          • Network tools
        • Internal tables
          • GV$SYSSTAT
          • GV$OB_SQL_AUDIT
          • GV$OB_TRANSACTION_PARTICIPANTS
        • Logs
          • slow trans
          • dump tenant info
          • trace log
        • OCP
      • System tuning
        • OS parameter tuning
        • Database parameter tuning
          • CPU parameters
          • I/O parameters
          • Memory-related parameters
          • Network transmission parameters
        • OBProxy parameter tuning
          • CPU parameters
          • Network transmission parameters
          • Route parameters on nodes
      • Business model tuning
        • Load balancing
        • SQL diagnostics
        • Distributed transactions
      • SQL optimization guide
        • SQL request execution process
        • SQL execution plan
          • Introduction to SQL execution plans
          • Execution plan operator
            • TABLE SCAN
            • JOIN
            • COUNT
            • GROUP BY
            • WINDOW FUNCTION
            • SUBPLAN FILTER
            • DISTINCT
            • SEQUENCE
            • MATERIAL
            • SORT
            • LIMIT
            • FOR UPDATE
            • SELECT INTO
            • SUBPLAN SCAN
            • UNION
            • INTERSECT
            • EXCEPT/MINUS
            • INSERT
            • DELETE
            • UPDATE
            • MERGE
            • EXCHANGE
            • GI
          • Plan cache
          • Fast parameterization
          • Real-time execution plan display
        • Distributed execution plan
          • Perform distributed execution and parallel queries
          • Generate a distributed plan
          • Schedule distributed execution plans
          • Manage distributed execution plans
          • Execute parallel queries
          • Perform parameter tuning for a parallel query
          • Parallel DML
        • SQL optimization
          • Overview
          • General procedure of SQL tuning
          • SQL execution performance monitoring
            • GV$OB_SQL_AUDIT
            • SQL Trace
            • Plan cache views
            • SQL performance analysis example
              • Use SQL Audit to analyze wait events in a query
              • Analyze SQL queries that cause an abrupt RT jitter
              • View and analyze the shape of an execution plan
              • Analyze slow SQL queries
              • Query SQL traffic distribution and QPS
              • Check whether SQL queries are balanced across servers in a cluster
              • Find the TOP N SQL queries
              • Analyze whether an unusually large number of remote execution requests exist in the system or the execution of an SQL statement
              • Find full table scan SQL statements in a tenant
              • Find the TOP N queries with the longest execution time within a specified period
              • Analyze queries related to distributed plans
              • Check whether the RPC execution count of a distributed subplan is balanced across servers in a cluster
          • Optimizer statistics
            • Overview of statistics
            • Statistics conllection methods
              • Overview
              • Histograms
              • Manual statistics collection
              • Automatic statistics collection
              • Online statistics collection
            • Statistics management
              • Overview
              • Deletion
              • Setting
              • Import and export
              • Locking and unlocking
              • History management
              • Collection strategy prefs management
            • Examples
          • Query rewrite
            • Overview
            • Rule-based query rewrite
            • Cost-based query rewrite
          • Query optimization
            • Access path
              • Overview
              • Rule-based path selection
              • Cost-based path selection
            • Join algorithm
              • Overview
              • Join algorithms
              • Join order
          • Manage execution plans
            • Optimizer hints
            • Plan binding
            • SQL plan management
        • Glossary
        • General issues in SQL tuning
      • Performance testing
        • Run the TPC-H benchmark on OceanBase Database
        • TPC-H benchmark report of OceanBase Database
        • Run the Sysbench benchmark on OceanBase Database
        • Sysbench benchmark report of OceanBase Database
        • Run the TPC-C benchmark on OceanBase Database
        • TPC-C benchmark report of OceanBase Database
    • Application development reference
      • SQL syntax
        • System tenants
          • Overview
          • ALTER SYSTEM
            • BACKUP
            • Log archive
            • BALANCE TASK
            • CANCEL MIGRATE UNIT
            • CHANGE TENANT
            • DELETE BACKUPSET
            • DELETE OBSOLETE BACKUP
            • FAILOVER
            • FLUSH
            • JOB
            • MERGE
            • MIGRATE UNIT
            • PARAMETER
            • RECOVER
            • REFRESH
            • REPLICA
            • RESTORE
            • SERVER
            • SWITCHOVER
            • THROTTLE
            • ZONE
          • ALTER RESOURCE POOL
          • ALTER RESOURCE TENANT
          • ALTER RESOURCE UNIT
          • ALTER TENANT
          • CREATE RESOURCE POOL
          • CREATE RESOURCE UNIT
          • CREATE TENANT
          • DROP RESOURCE POOL
          • DROP RESOURCE UNIT
          • DROP TENANT
          • SET DECRYPTION
          • SET ENCRYPTION
        • Common tenant (MySQL mode)
          • Basis elements
            • Data types
              • Overview
              • Numeric types
                • Overview
                • Integer data types
                • Fixed-point data types
                • Floating-point data types
                • Bit value data type
              • Date and time types
                • Overview
                • DATE, DATETIME, and TIMESTAMP types
                • TIME type
                • YEAR type
              • Character types
                • Overview
                • CHAR and VARCHAR
                • BINARY and VARBINARY
              • Large objects and text types
                • Overview
                • BLOB types
                • TEXT types
              • ENUM data type
              • SET data type
              • JSON data types
                • Overview
                • Create a JSON value
                • Query and modify JSON values
                • Convert a JSON data type
              • Spatial data types
                • Overview
                • SRS
                • Create a spatial column
                • Create a spatial index
                • Spatial data formats
            • Expressions
              • Overview
              • Expression syntax
              • Convert data types in expression evaluation
            • Character set and collation
              • Overview
              • Character sets
              • Collations
              • Database-level character sets and collations
              • Table-level character sets and collations
              • Column-level character sets and collations
              • Character sets and collations for character expressions
              • Character sets and collations for client connection
            • Literal
              • Overview
              • Strings
              • Value
              • Datetime values
              • Bit values
              • Boolean
              • NULLs
            • Schema object names
            • User-defined variables
            • Comments
          • Operator
            • Overview
            • Operator precedence
            • Arithmetic operators
            • Bitwise operators
            • Comparison operators
            • Logical operators
            • Assignment operators
            • Datetime operators
            • Concatenation operators
            • BINARY operator
            • CASE conditional operator
          • Sequence pseudocolumns
          • Function
            • Overview
            • Single-row functions
              • Date and time functions
                • ADDDATE
                • CONVERT_TZ
                • CURDATE
                • CURRENT_DATE
                • CURRENT_TIME
                • CURRENT_TIMESTAMP
                • CURTIME
                • DATE
                • DATE_ADD
                • DATE_FORMAT
                • DATE_SUB
                • DATEDIFF
                • DAYOFMONTH
                • DAYOFWEEK
                • DAYOFYEAR
                • EXTRACT
                • FROM_DAYS
                • FROM_UNIXTIME
                • GET_FORMAT
                • HOUR
                • LAST_DAY
                • LOCALTIME
                • LOCALTIMESTAMP
                • MAKEDATE
                • MAKETIME
                • MICROSECOND
                • MINUTE
                • MONTH
                • MONTHNAME
                • NOW
                • PERIOD_ADD
                • PERIOD_DIFF
                • QUARTER
                • SEC_TO_TIME
                • SECOND
                • STR_TO_DATE
                • SUBDATE
                • SUBTIME
                • SYSDATE
                • TIME
                • TIME_FORMAT
                • TIME_TO_SEC
                • TIME_TO_USEC
                • TIMEDIFF
                • TIMESTAMP
                • TIMESTAMPADD
                • TIMESTAMPDIFF
                • TO_DAYS
                • TO_SECONDS
                • UNIX_TIMESTAMP
                • USEC_TO_TIME
                • UTC_DATE
                • UTC_TIME
                • UTC_TIMESTAMP
                • WEEK
                • WEEKDAY
                • WEEKOFYEAR
                • YEARWEEK
                • YEAR
                • ADDTIME
                • DAYNAME
                • DAY
              • String functions
                • ASCII
                • BIN
                • BIT_LENGTH
                • CHAR
                • CHAR_LENGTH
                • CHARACTER_LENGTH
                • CONCAT
                • CONCAT_WS
                • ELT
                • EXPORT_SET
                • FIELD
                • FIND_IN_SET
                • FORMAT
                • HEX
                • INSERT
                • INSTR
                • INT2IP
                • IP2INT
                • LCASE
                • LEFT
                • LENGTH
                • LOCATE
                • LOWER
                • LPAD
                • LTRIM
                • MAKE_SET
                • MID
                • OCT
                • OCTET_LENGTH
                • ORD
                • POSITION
                • QUOTE
                • REGEXP
                • REGEXP_INSTR
                • REGEXP_LIKE
                • REGEXP_REPLACE
                • REGEXP_SUBSTR
                • REPEAT
                • REPLACE
                • REVERSE
                • RIGHT
                • RLIKE
                • RPAD
                • RTRIM
                • SPACE
                • STRCMP
                • SUBSTR
                • SUBSTRING
                • SUBSTRING_INDEX
                • TRIM
                • UCASE
                • UNHEX
                • UPPER
                • WEIGHT_STRING
                • TO_BASE64
                • FROM_BASE64
                • SOUNDEX
              • Conversion functions
                • CAST
                • CONVERT
                • SCN_TO_TIMESTAMP
                • TIMESTAMP_TO_SCN
              • Mathematical functions
                • ABS
                • ACOS
                • ASIN
                • ATAN
                • ATAN2
                • BIT_COUNT
                • CEIL
                • CEILING
                • CONV
                • COS
                • COT
                • CRC32
                • DEGREES
                • EXP
                • FLOOR
                • LN
                • LOG
                • LOG10
                • LOG2
                • MOD
                • NEG
                • PI
                • POW
                • POWER
                • RADIANS
                • RAND
                • ROUND
                • SIGN
                • SIN
                • SQRT
                • TAN
                • TRUNCATE
              • Comparison functions
                • GREATEST
                • INTERVAL
                • ISNULL
                • LEAST
              • Process control functions
                • CASE
                • IF
                • IFNULL
                • NULLIF
                • ORA_DECODE
            • Aggregation functions
              • APPROX_COUNT_DISTINCT
              • AVG
              • BIT_AND
              • BIT_OR
              • BIT_XOR
              • COUNT
              • GROUP_CONCAT
              • GROUPING
              • MAX
              • MIN
              • STD
              • STDDEV
              • STDDEV_POP
              • STDDEV_SAMP
              • SUM
              • VAR_POP
              • VAR_SAMP
              • VARIANCE
            • Analysis functions
              • APPROX_COUNT_DISTINCT
              • AVG
              • BIT_AND
              • BIT_OR
              • BIT_XOR
              • COUNT
              • CUME_DIST
              • DENSE_RANK
              • FIRST_VALUE
              • LAG
              • LAST_VALUE
              • LEAD
              • MAX
              • MIN
              • NTH_VALUE
              • NTILE
              • PERCENT_RANK
              • RANK
              • ROW_NUMBER
              • STD
              • STDDEV
              • STDDEV_POP
              • STDDEV_SAMP
              • SUM
              • VAR_POP
              • VAR_SAMP
              • VARIANCE
            • Encryption functions
              • AES_DECRYPT
              • AES_ENCRYPT
              • COMPRESS
              • DECODE
              • DES_DECRYPT
              • DES_ENCRYPT
              • ENCODE
              • ENCRYPT
              • MD5
              • UNCOMPRESS
              • UNCOMPRESSED_LENGTH
              • RANDOM_BYTES
              • SHA
              • SHA1
              • SHA2
              • VALIDATE_PASSWORD_STRENGTH
            • Information functions
              • BENCHMARK
              • CHARSET
              • COERCIBILITY
              • COLLATION
              • CONNECTION_ID
              • CURRENT_USER
              • DATABASE
              • FOUND_ROWS
              • LAST_INSERT_ID
              • ICU_VERSION
              • ROW_COUNT
              • SCHEMA
              • SESSION_USER
              • SYSTEM_USER
              • USER
              • VERSION
              • OB_VERSION
            • JSON functions
              • Create JSON text
                • JSON_ARRAY
                • JSON_OBJECT
                • JSON_QUOTE
              • Search JSON text
                • JSON_CONTAINS
                • JSON_CONTAINS_PATH
                • JSON_EXTRACT
                • JSON_KEYS
                • JSON_OVERLAPS
                • JSON_SEARCH
                • JSON_VALUE
                • MEMBER OF
              • Modify JSON text
                • JSON_ARRAY_APPEND
                • JSON_ARRAY_INSERT
                • JSON_INSERT
                • JSON_MERGE
                • JSON_MERGE_PATCH
                • JSON_MERGE_PRESERVE
                • JSON_REMOVE
                • JSON_REPLACE
                • JSON_SET
                • JSON_UNQUOTE
              • Return JSON text properties
                • JSON_DEPTH
                • JSON_LENGTH
                • JSON_TYPE
                • JSON_VALID
              • JSON utility functions
                • JSON_PRETTY
                • JSON_STORAGE_SIZE
              • JSON aggregation functions
                • JSON_ARRAYAGG
                • JSON_OBJECTAGG
            • Spatial functions
              • Create a geometric function
              • Spatial operation functions
              • Spatial relation functions
              • Geometry property functions
              • Geometric format conversion functions
          • Queries and subqueries
            • Overview
            • Subquery
            • JOIN
          • SQL statements
            • General syntax
            • CTE
            • ALTER DATABASE
            • ALTER OUTLINE
            • ALTER SEQUENCE
            • MERGE
            • ALTER TABLE
            • ALTER TABLEGROUP
            • ALTER USER
            • ALTER VIEW
            • ANALYZE
            • CREATE DATABASE
            • CREATE INDEX
            • CREATE OUTLINE
            • CREATE SEQUENCE
            • CREATE TABLE
            • CREATE TABLEGROUP
            • CREATE USER
            • CREATE VIEW
            • DEALLOCATE PREPARE
            • DELETE
            • DESCRIBE
            • DROP DATABASE
            • DROP INDEX
            • DROP OUTLINE
            • DROP TABLE
            • DROP TABLEGROUP
            • DROP SEQUENCE
            • DROP USER
            • DROP VIEW
            • EXECUTE
            • EXPLAIN
            • FLASHBACK
            • GRANT
            • HELP
            • INSERT
            • KILL
            • LOAD DATA
            • LOCK TABLES
            • MERGE
            • OPTIMIZE
            • PREPARE
            • PURGE
            • PURGE RECYCLEBIN
            • RENAME USER
            • RENAME TABLE
            • REPLACE
            • REVOKE
            • SAVEPOINT
            • SCHEMA
            • SELECT INTO
            • SELECT
              • SELECT
              • JOIN clause
              • OVER clause
              • UNION clause
            • SET
            • SET CHARSET
            • SET NAMES
            • SET PASSWORD
            • SET TRANSACTION
            • SHOW
            • TRANSACTION
            • TRUNCATE TABLE
            • UPDATE
            • USE
          • DDL features
            • Overview
            • Index operations
            • Primary key operations
            • Column operations
            • Column generation operations
            • Foreign key operations
            • Table operations
            • Partition operations
            • Column type change rules
          • Performance schema functions
            • FORMAT_BYTES
            • FORMAT_PICO_TIM
          • Other functions
            • ANY_VALUE
            • BIN_TO_UUID
            • COALESCE
            • DEFAULT
            • NAME_CONST
            • INET_ATON
            • INET_NTOA
            • INET6_ATON
            • INET6_NTOA
            • IS_IPV4
            • IS_IPV4_COMPAT
            • IS_IPV6
            • IS_UUID
            • NVL
            • UUID_TO_BIN
            • SLEEP
            • UUID
            • UUID_SHORT
            • VALUES
        • Common tenant (Oracle mode)
          • Introduction to SQL
          • Pseudo column
            • Overview
            • Hierarchical query pseudocolumns
            • Sequence pseudocolumns
            • ORA_ROWSCN pseudocolumn
            • ROWNUM pseudocolumn
            • ROWID pseudocolumn
          • Basic elements
            • Built-in data types
              • Overview
              • Character data types
                • Overview
                • CHAR data type
                • NCHAR data type
                • NVARCHAR2 data type
                • VARCHAR2 data type
                • VARCHAR data type
              • Numeric data types
                • Overview
                • NUMBER data type
                • FLOAT data type
                • Floating-point numbers
                • Precedence of numeric data types
              • Date and time and interval data types
                • Overview
                • DATE type
                • TIMESTAMP type
                • TIMESTAMP WITH TIME ZONE date type
                • TIMESTAMP WITH LOCAL TIME ZONE data type
                • INTERVAL YEAR TO MONTH data type
                • INTERVAL DAY TO SECOND data type
                • Calculation of dates, timestamps, and intervals
              • RAW data type
              • Large object data types
                • Overview
                • BLOB data type
                • CLOB data type
              • Rowid data types
              • User-defined data types
              • Any type
              • JSON data types
                • Overview
                • Create JSON columns
                • Query JSON data
                • Conversion rules for JSON data types
            • Data type comparison rules
              • Overview
              • Numeric value comparison rules
              • Date value comparison rules
              • Character value comparison rules
              • Data type precedence
              • Data type conversion rules
              • Security considerations for data conversion
            • Literal
              • Overview
              • Text literals
              • Numeric literals
              • Date and time literal
                • Date literals
                • Timestamp literals
              • Interval literals
            • Format model
              • Overview
              • Number format models
              • Datetime format models
              • RR datetime format element
              • String-to-date conversion rules
            • Null value
              • Overview
              • Nulls in SQL functions
              • Nulls in comparison conditions
              • Nulls in conditional expressions
            • Annotation
              • Overview
              • Comments within SQL statements
              • Comments on schema and nonschema objects
              • Hint
                • Overview
                • Hint list
                  • Hints related to access path
                  • Hints related to join orders
                  • Hints related to joins
                  • Hints related to parallel execution
                  • Hints related to query strategy
                  • Hints related to query conversion
                  • Other hints
            • Database objects
              • Schema objects
              • Non-schema objects
            • Database naming conventions
              • Overview
              • Suggestions on schema object names
            • Database object reference method
              • Overview
              • Reference to schema objects
              • Reference objects in remote databases
                • Create a database link
                • Reference a database link
              • Reference to partition tables and indexes
              • Reference an attribute or method of an object type
          • Operator
            • Overview
            • Operator precedence
            • Arithmetic operators
            • Concatenation operator
            • Hierarchical query operators
            • Set operators
            • COLLATE operator
          • Function
            • Overview
            • Single-row functions
              • Numeric functions
                • ABS
                • ACOS
                • ASIN
                • ATAN
                • ATAN2
                • BITAND
                • CEIL
                • COS
                • COSH
                • EXP
                • FLOOR
                • LN
                • LOG
                • MOD
                • NANVL
                • POWER
                • REMAINDER
                • ROUND
                • SIGN
                • SIN
                • SINH
                • SQRT
                • TAN
                • TANH
                • TRUNC
                • WIDTH_BUCKET
              • String functions returning strings
                • CHR
                • CONCAT
                • INITCAP
                • LOWER
                • LPAD
                • LTRIM
                • NLS_LOWER
                • NLS_UPPER
                • REGEXP_REPLACE
                • REGEXP_SUBSTR
                • REPLACE
                • RPAD
                • RTRIM
                • SUBSTR
                • TRANSLATE
                • TRANSLATE ... USING
                • TRIM
                • UPPER
              • String functions returning numbers
                • ASCII
                • INSTR
                • LENGTH
                • REGEXP_COUNT
                • REGEXP_INSTR
              • Date and time
                • ADD_MONTHS
                • CURRENT_DATE
                • CURRENT_TIMESTAMP
                • DBTIMEZONE
                • EXTRACT(datetime)
                • FROM_TZ
                • LAST_DAY
                • LOCALTIMESTAMP
                • MONTHS_BETWEEN
                • NEXT_DAY
                • NUMTODSINTERVAL
                • NUMTOYMINTERVAL
                • ROUND (date)
                • SESSIONTIMEZONE
                • SYS_EXTRACT_UTC
                • SYSDATE
                • SYSTIMESTAMP
                • TO_CHAR (datetime)
                • TO_DSINTERVAL
                • TO_TIMESTAMP
                • TO_TIMESTAMP_TZ
                • TO_YMINTERVAL
                • TRUNC (date)
                • TZ_OFFSET
              • Generic comparison functions
                • GREATEST
                • LEAST
              • Conversion functions
                • ASCIISTR
                • CAST
                • CHARTOROWID
                • CONVERT
                • HEXTORAW
                • NUMTODSINTERVAL
                • NUMTOYMINTERVAL
                • RAWTOHEX
                • ROWIDTOCHAR
                • ROWIDTONCHAR
                • SCN_TO_TIMESTAMP
                • TIMESTAMP_TO_SCN
                • TO_BINARY_DOUBLE
                • TO_BINARY_FLOAT
                • TO_BLOB
                • TO_CHAR (character)
                • TO_CHAR (datetime)
                • TO_CHAR (number)
                • TO_CLOB
                • TO_DATE
                • TO_DSINTERVAL
                • TO_MULTI_BYTE
                • TO_NUMBER
                • TO_NCHAR (character)
                • TO_NCHAR (datetime)
                • TO_NCHAR (number)
                • TO_SINGLE_BYTE
                • TO_TIMESTAMP
                • TO_TIMESTAMP_TZ
                • TO_YMINTERVAL
                • UNISTR
              • Encoding and decoding functions
                • DECODE
                • DUMP
                • ORA_HASH
                • VSIZE
              • Null value related functions
                • COALESCE
                • LNNVL
                • NANVL
                • NULLIF
                • NVL
                • NVL2
              • Environment and identifier functions
                • SYS_CONTEXT
                • SYS_GUID
                • UID
                • USER
                • USERENV
                • OB_VERSION
              • Hierarchical functions
                • SYS_CONNECT_BY_PATH
              • JSON functions
                • Overview
                • Create JSON text
                  • JSON_ARRAY
                  • JSON_OBJECT
                  • JSON_ARRAYAGG
                  • JSON_OBJECTAGG
                • Query JSON text
                  • JSON_VALUE
                  • JSON_QUERY
                  • JSON_EXISTS
                  • JSON_TABLE
                • Validate JSON text
                  • JSON_EQUAL
                • Modify JSON text
                  • JSON_MERGEPATCH
            • Aggregation functions
              • APPROX_COUNT_DISTINCT
              • AVG
              • CORR
              • COUNT
              • COVAR_POP
              • COVAR_SAMP
              • CUME_DIST
              • DENSE_RANK
              • GROUPING
              • KEEP
              • LISTAGG
              • MAX
              • MEDIAN
              • MIN
              • PERCENT_RANK
              • PERCENTILE_CONT
              • PERCENTILE_DISC
              • RANK
              • REGR_ (Linear Regression)
              • ROLLUP
              • STDDEV
              • STDDEV_POP
              • STDDEV_SAMP
              • SUM
              • VAR_POP
              • VAR_SAMP
              • VARIANCE
              • WMSYS.WM_CONCAT/WM_CONCAT
            • Analysis functions
              • Analytic functions
              • AVG
              • CORR
              • COUNT
              • COVAR_POP
              • COVAR_SAMP
              • CUME_DIST
              • DENSE_RANK
              • FIRST_VALUE
              • KEEP
              • LAG
              • LAST_VALUE
              • LEAD
              • LISTAGG
              • MAX
              • MEDIAN
              • MIN
              • NTILE
              • NTH_VALUE
              • PERCENT_RANK
              • PERCENTILE_CONT
              • PERCENTILE_DISC
              • RANK
              • RATIO_TO_REPORT
              • REGR_ (Linear Regression)
              • ROW_NUMBER
              • STDDEV
              • STDDEV_POP
              • STDDEV_SAMP
              • SUM
              • VAR_POP
              • VAR_SAMP
              • VARIANCE
              • WMSYS.WM_CONCAT/WM_CONCAT
          • Expressions
            • Overview
            • Simple expressions
            • Compound expressions
            • Case expressions
            • Column expressions
            • CURSOR expressions
            • Datetime expressions
            • Function expressions
            • Interval expressions
            • Scalar subquery expressions
            • Type constructor expressions
            • Expression list
          • Conditions
            • Overview
            • Condition precedence
            • Comparison conditions
            • Floating-point conditions
            • Logical conditions
            • Pattern-matching conditions
            • Null conditions
            • Compound conditions
            • BETWEEN condition
            • EXISTS condition
            • IN condition
          • Queries and subqueries
            • Overview
            • Simple query
            • Hierarchical query
            • Compound query
            • Join queries
            • Subqueries
            • DUAL table query
          • SQL statements
            • DDL
              • ALTER INDEX
              • ALTER KEYSTORE
              • ALTER OUTLINE
              • ALTER PROFILE
              • ALTER ROLE
              • ALTER SEQUENCE
              • ALTER SESSION
              • ALTER SYSTEM FLUSH PLAN CACHE
              • ALTER SYSTEM PARAMETER
              • ALTER TABLE
              • ALTER TABLEGROUP
              • ALTER USER
              • CREATE CONTEXT
              • CREATE DIRECTORY
              • CREATE DATABASE LINK
              • CREATE INDEX
              • CREATE KEYSTORE
              • CREATE OUTLINE
              • CREATE PROFILE
              • CREATE ROLE
              • CREATE SEQUENCE
              • CREATE SYNONYM
              • CREATE TABLE
              • CREATE TABLEGROUP
              • CREATE TABLESPACE
              • CREATE USER
              • CREATE VIEW
              • DROP CONTEXT
              • DROP DIRECTORY
              • DROP INDEX
              • DROP OUTLINE
              • DROP PROFILE
              • DROP ROLE
              • DROP SEQUENCE
              • DROP SYNONYM
              • DROP TABLE
              • DROP TABLEGROUP
              • DROP TABLESPACE
              • DROP USER
              • DROP VIEW
              • RENAME
              • TRUNCATE TABLE
              • ALTER SYSTEM MAJOR FREEZE
            • DML
              • DELETE
              • INSERT
              • MERGE
              • PURGE
              • SELECT
                • SIMPLE SELECT
                • Set-based SELECT
                • WITH CLAUSE
              • UPDATE
            • DCL
              • ANALYZE
              • AUDIT
              • COMMENT
              • COMMIT
              • EXPLAIN
              • FLASHBACK TABLE BEFORE DROP
              • GRANT
              • KILL
              • LOAD DATA
              • LOCK TABLE
              • REVOKE
              • ROLLBACK
              • SAVEPOINT
              • SET NAMES
              • SET PASSWORD
              • SET ROLE
              • SET VARIABLE
              • SHOW
              • SHRINK
              • TRANSACTION
          • DDL features
            • Overview
            • Index operations
            • Primary key operations
            • Column operations
            • Column generation operations
            • Foreign key operations
            • Table operations
            • Partition operations
            • Column type change rules
      • SQL practices and suggestions
        • Limits on writing SQL statements
        • SQL writing guidelines
          • SELECT statements
          • DML statements
          • Multi-table join statements
          • Table scan
          • Transactions
          • Cache
          • Hint
          • Other specifications
        • SQL statement examples
          • Implicit data type conversion
          • JOIN tables
          • Weak consistency read
          • Pagination queries
      • PL reference
        • What is PL
          • Overview
          • Main features of PL
          • PL architecture
        • MySQL mode
          • Syntax of PL stored programs
          • PL stored procedure
            • Overview
            • Variables in stored programs
            • Stored procedures
            • Stored functions
            • Trigger
            • Limitations on stored programs
          • PL cursor
            • Overview
            • Cursor execution process
            • Limitations on server cursors
          • PL conditional control statements
            • CASE
            • IF
            • ITERATE
            • LEAVE
            • LOOP
            • REPEAT
            • RETURN
            • WHILE
          • PL DML statements
            • CALL
            • DO
          • PL DDL statements
            • ALTER FUNCTION
            • ALTER PROCEDURE
            • CREATE FUNCTION
            • CREATE PROCEDURE
            • CREATE TRIGGER
            • DROP FUNCTION
            • DROP PROCEDURE
            • DROP TRIGGER
          • PL database management statements
            • SHOW CREATE FUNCTION
            • SHOW CREATE PROCEDURE
            • SHOW CREATE TRIGGER
            • SHOW FUNCTION STATUS
            • SHOW PROCEDURE STATUS
            • SHOW TRIGGERS
          • PL related dictionary views
            • INFORMATION_SCHEMA PARAMETERS
            • INFORMATION_SCHEMA ROUTINES
            • INFORMATION_SCHEMA TRIGGERS
          • PL exception handling
            • Overview
            • DECLARE ... CONDITION
            • DECLARE ... HANDLER
            • GET DIAGNOSTICS
            • RESIGNAL
            • SIGNAL
            • Effective scope of an exception handler
            • Diagnostics area
            • Exception handling and OUT/INOUT parameters
            • Limitations on exception handling
          • PL system package
            • Overview
            • DBMS_RESOURCE_MANAGER
              • Overview
              • CREATE_CONSUMER_GROUP
              • CREATE_PLAN
              • CREATE_PLAN_DIRECTIVE
              • DELETE_CONSUMER_GROUP
              • DELETE_PLAN
              • DELETE_PLAN_DIRECTIVE
              • SET_CONSUMER_GROUP_MAPPING
              • UPDATE_PLAN_DIRECTIVE
            • DBMS_STATS
              • Overview
              • ALTER_STATS_HISTORY_RETENTION
              • CREATE_STAT_TABLE
              • DELETE_COLUMN_STATS
              • DELETE_INDEX_STATS
              • DELETE_TABLE_STATS
              • DELETE_SCHEMA_STATS
              • DELETE_SCHEMA_PREFS
              • DELETE_TABLE_PREFS
              • DROP_STAT_TABLE
              • EXPORT_COLUMN_STATS
              • EXPORT_INDEX_STATS
              • EXPORT_TABLE_STATS
              • EXPORT_SCHEMA_STATS
              • FLUSH_DATABASE_MONITORING_INFO
              • GATHER_INDEX_STATS
              • GATHER_TABLE_STATS
              • GATHER_SCHEMA_STATS
              • GET_STATS_HISTORY_AVAILABILITY
              • GET_STATS_HISTORY_RETENTION
              • GET_PARAM
              • GET_PREFS
              • IMPORT_INDEX_STATS
              • IMPORT_COLUMN_STATS
              • IMPORT_TABLE_STATS
              • IMPORT_SCHEMA_STATS
              • LOCK_PARTITION_STATS
              • LOCK_SCHEMA_STATS
              • LOCK_TABLE_STATS
              • RESTORE_TABLE_STATS
              • RESTORE_SCHEMA_STATS
              • RESET_GLOBAL_PREF_DEFAULTS
              • RESET_PARAM_DEFAULTS
              • PURGE_STATS
              • SET_COLUMN_STATS
              • SET_INDEX_STATS
              • SET_TABLE_STATS
              • SET_GLOBAL_PREFS
              • SET_PARAM
              • SET_SCHEMA_PREFS
              • SET_TABLE_PREFS
              • UNLOCK_PARTITION_STATS
              • UNLOCK_SCHEMA_STATS
              • UNLOCK_TABLE_STATS
            • DBMS_UDR
              • Overview
              • CREATE_RULE
              • DISABLE_RULE
              • ENABLE_RULE
              • REMOVE_RULE
            • DBMS_XPLAN
              • Overview
              • DISABLE_OPT_TRACE
              • ENABLE_OPT_TRACE
              • SET_OPT_TRACE_PARAMETER
          • Reserved and non-reserved PL keywords
        • Oracle mode
          • PL language basics
            • Character sets
            • Lexical units
            • Declaration
            • Reference identifiers
            • Scope and visibility of identifiers
            • Assign values
            • Expressions
            • PL blocks
            • Subprograms
            • Error-reporting functions
          • PL data types
            • Overview
            • SQL data types
            • LOB data types
            • BOOLEAN type
            • User-defined subtypes
            • PLS_INTEGER and BINARY_INTEGER
            • Arrays
            • PL JSON data types
          • PL process control
            • Overview
            • Conditional control
            • Loop control
            • Sequential control
          • PL collections and records
            • Overview
            • Collections
            • Associative arrays
            • Varrays
            • Nested tables
            • Collection constructor function
            • Collection methods
              • Overview of collection methods
              • DELETE method
              • TRIM method
              • EXTEND method
              • EXISTS method
              • FIRST and LAST methods
              • COUNT method
              • LIMIT method
              • PRIOR and NEXT methods
            • Records
            • Insert records into a table and update a table by using records
            • Create and call a subprogram with record type parameters
          • PL static SQL
            • Overview
            • Cursor
              • Overview
              • Cursor attributes
              • Implicit cursors
              • Explicit cursors
              • Cursor variables
              • Traverse cursor data by using the FOR loop
              • Modify and drop a cursor
            • Transaction processing and control
            • Autonomous transactions
              • Overview
              • Control autonomous transactions
              • Autonomous triggers
              • Call autonomous functions from SQL statements
          • PL dynamic SQL
            • Overview
            • Execute dynamic SQL statements
            • DBMS_SQL system package
          • PL stored procedure and functions
            • Overview
            • Create a stored procedure
            • Create a function
            • Manage stored procedures and functions
            • Privilege control
            • Pipeline functions
              • Overview
              • Create a pipelined table function
              • Application
            • User defined functions
              • Overview
              • Interface for user-defined aggregate functions
              • Create user-defined aggregate functions
              • Use user-defined aggregate functions
          • PL trigger
            • Overview
            • Create a DML trigger
            • Modify and drop a trigger
            • Disable or enable a trigger
            • Query trigger information
            • INSTEAD OF DML trigger
            • Compound DML trigger
          • PL package
            • Overview
            • Create a program package
            • Overloaded programs in a package
            • Manage program packages
            • Definition of the PL environment by the STANDARD package
          • PL exception handling
            • Overview
            • Compile-Time alerts
            • Exception types
            • Exception handling processes
          • DDL operations on stored PL units
            • Overview
            • ALTER FUNCTION
            • ALTER PACKAGE
            • ALTER PROCEDURE
            • ALTER TRIGGER
            • ALTER TYPE
            • CREATE FUNCTION
            • CREATE PACKAGE
            • CREATE PACKAGE BODY
            • CREATE PROCEDURE
            • CREATE TRIGGER
            • CREATE TYPE
            • CREATE TYPE BODY
            • DROP FUNCTION
            • DROP PACKAGE
            • DROP PROCEDURE
            • DROP TRIGGER
            • DROP TYPE
            • DROP TYPE BODY
          • PL label security package
            • Overview of label security PL packages
            • SA_SYSDBA
              • SA_SYSDBA overview
              • SA_SYSDBA.ALTER_POLICY
              • SA_SYSDBA.CREATE_POLICY
              • SA_SYSDBA.DROP_POLICY
            • SA_COMPONENTS
              • SA_COMPONENTS overview
              • SA_COMPONENTS.ALTER_LEVEL
              • SA_COMPONENTS.CREATE_LEVEL
              • SA_COMPONENTS.DROP_LEVEL
            • SA_LABEL_ADMIN
              • SA_LABEL_ADMIN overview
              • SA_LABEL_ADMIN.ALTER_LABEL
              • SA_LABEL_ADMIN.CREATE_LABEL
              • SA_LABEL_ADMIN.DROP_LABEL
            • SA_POLICY_ADMIN
              • SA_POLICY_ADMIN overview
              • SA_POLICY_ADMIN.APPLY_TABLE_POLICY
              • SA_POLICY_ADMIN.DISABLE_TABLE_POLICY
              • SA_POLICY_ADMIN.ENABLE_TABLE_POLICY
              • SA_POLICY_ADMIN.REMOVE_TABLE_POLICY
            • SA_USER_ADMIN
              • SA_USER_ADMIN overview
              • SA_USER_ADMIN.SET_LEVELS
            • SA_SESSION
              • SA_SESSION overview
              • SA_SESSION.LABEL
              • SA_SESSION.RESTORE_DEFAULT_LABELS
              • SA_SESSION.ROW_LABEL
              • SA_SESSION.SET_LABEL
              • SA_SESSION.SET_ROW_LABEL
          • PL system package (Oracle mode)
            • Overview
            • DBMS_APPLICATION_INFO
              • Overview
              • READ_CLIENT_INFO
              • READ_MODULE
              • SET_ACTION
              • SET_CLIENT_INFO
              • SET_MODULE
            • DBMS_AUDIT_MGMT
              • Overview
              • CLEAN_AUDIT_TRAIL
              • CREATE_PURGE_JOB
              • DROP_PURGE_JOB
              • SET_LAST_ARCHIVE_TIMESTAMP
              • SET_PURGE_JOB_STATUS
            • DBMS_CRYPTO
              • Overview
              • ENCRYPT
              • DECRYPT
              • HASH
            • DBMS_DEBUG
              • Overview
              • ATTACH_SESSION
              • CONTINUE
              • DEBUG_ON
              • DEBUG_OFF
              • DETACH_SESSION
              • DELETE_BREAKPOINT
              • DISABLE_BREAKPOINT
              • ENABLE_BREAKPOINT
              • GET_VALUE
              • GET_VALUES
              • GET_RUNTIME_INFO
              • GET_TIMEOUT_BEHAVIOUR
              • INITIALIZE
              • PROBE_VERSION
              • PRINT_BACKTRACE
              • SET_TIMEOUT
              • SET_TIMEOUT_BEHAVIOUR
              • SET_BREAKPOINT
              • SHOW_BREAKPOINTS
            • DBMS_DESCRIBE
              • Overview
              • DESCRIBE_PROCEDURE
            • DBMS_JOB
              • Overview
              • BROKEN
              • CHANGE
              • ZONE
              • INTERVAL
              • NEXT_DATE
              • REMOVE
              • RUN
              • SUBMIT
              • USER_EXPORT
              • WHAT
            • DBMS_LOB
              • Overview
              • APPEND
              • CLOSE
              • COPY
              • CREATETEMPORARY
              • ERASE
              • FREETEMPORARY
              • GETLENGTH
              • ISOPEN
              • INSTR
              • OPEN
              • READ
              • SUBSTR
              • TRIM
              • WRITE
              • WRITEAPPEND
            • DBMS_LOCK
              • Overview
              • SLEEP
            • DBMS_METADATA
              • Overview
              • GET_DDL
            • DBMS_OUTPUT
              • Overview
              • DISABLE
              • ENABLE
              • GET_LINE
              • GET_LINES
              • NEW_LINE
              • PUT
              • PUT_LINE
            • DBMS_PLAN_CACHE
              • Overview
              • PURGE
            • DBMS_RANDOM
              • Overview
              • INITIALIZE
              • NORMAL
              • RANDOM
              • SEED
              • STRING
              • TERMINATE
              • VALUE
            • DBMS_RESOURCE_MANAGER
              • Overview
              • CREATE_CONSUMER_GROUP
              • CREATE_PLAN
              • CREATE_PLAN_DIRECTIVE
              • DELETE_CONSUMER_GROUP
              • DELETE_PLAN
              • DELETE_PLAN_DIRECTIVE
              • SET_CONSUMER_GROUP_MAPPING
              • UPDATE_PLAN_DIRECTIVE
            • DBMS_SCHEDULER
              • Overview
              • CREATE_JOB
              • CREATE_PROGRAM
              • DEFINE_PROGRAM_ARGUMENT
              • DISABLE
              • DROP_JOB
              • DROP_PROGRAM
              • ENABLE
              • GENERATE_JOB_NAME
              • RUN_JOB
              • SET_ATTRIBUTE
              • SET_JOB_ARGUMENT_VALUE
            • DBMS_SESSION
              • Overview
              • CLEAR_ALL_CONTEXT
              • CLEAR_CONTEXT
              • CLEAR_IDENTIFIER
              • SET_CONTEXT
              • SET_IDENTIFIER
            • DBMS_SQL
              • Overview
              • BIND_VARIABLE
              • CLOSE_CURSOR
              • COLUMN_VALUE
              • DEFINE_COLUMN
              • DEFINE_ARRAY
              • DESCRIBE_COLUMNS
              • EXECUTE
              • EXECUTE_AND_FETCH
              • FETCH_ROWS
              • IS_OPEN
              • OPEN_CURSOR
              • PARSE
            • DBMS_STATS
              • Overview
              • ALTER_STATS_HISTORY_RETENTION
              • CREATE_STAT_TABLE
              • DELETE_COLUMN_STATS
              • DELETE_INDEX_STATS
              • DELETE_TABLE_STATS
              • DELETE_SCHEMA_STATS
              • DELETE_SCHEMA_PREFS
              • DELETE_TABLE_PREFS
              • DROP_STAT_TABLE
              • EXPORT_COLUMN_STATS
              • EXPORT_INDEX_STATS
              • EXPORT_TABLE_STATS
              • EXPORT_SCHEMA_STATS
              • FLUSH_DATABASE_MONITORING_INFO
              • GATHER_INDEX_STATS
              • GATHER_TABLE_STATS
              • GATHER_SCHEMA_STATS
              • GET_STATS_HISTORY_AVAILABILITY
              • GET_STATS_HISTORY_RETENTION
              • GET_PARAM
              • GET_PREFS
              • IMPORT_INDEX_STATS
              • IMPORT_COLUMN_STATS
              • IMPORT_TABLE_STATS
              • IMPORT_SCHEMA_STATS
              • LOCK_PARTITION_STATS
              • LOCK_SCHEMA_STATS
              • LOCK_TABLE_STATS
              • RESTORE_TABLE_STATS
              • RESTORE_SCHEMA_STATS
              • RESET_GLOBAL_PREF_DEFAULTS
              • RESET_PARAM_DEFAULTS
              • PURGE_STATS
              • SET_COLUMN_STATS
              • SET_INDEX_STATS
              • SET_TABLE_STATS
              • SET_GLOBAL_PREFS
              • SET_PARAM
              • SET_SCHEMA_PREFS
              • SET_TABLE_PREFS
              • UNLOCK_PARTITION_STATS
              • UNLOCK_SCHEMA_STATS
              • UNLOCK_TABLE_STATS
            • DBMS_UDR
              • Overview
              • CREATE_RULE
              • DISABLE_RULE
              • ENABLE_RULE
              • REMOVE_RULE
            • DBMS_UTILITY
              • Overview
              • ACTIVE_INSTANCES
              • COMMA_TO_TABLE
              • CURRENT_INSTANCE
              • DB_VERSION
              • FORMAT_CALL_STACK
              • FORMAT_ERROR_BACKTRACE
              • FORMAT_ERROR_STACK
              • GET_ENDIANNESS
              • GET_HASH_VALUE
              • GET_PARAMETER_VALUE
              • GET_SQL_HASH
              • GET_TIME
              • IS_BIT_SET
              • IS_CLUSTER_DATABASE
              • NAME_RESOLVE
              • NAME_TOKENIZE
              • OLD_CURRENT_SCHEMA
              • OLD_CURRENT_USER
              • PORT_STRING
              • TABLE_TO_COMMA
            • DBMS_WORKLOAD_REPOSITORY
              • Overview
              • ASH_REPORT
            • DBMS_XA
              • Overview
              • DBMS_XA constants
              • DBMS_XA_XID object type
              • DIST_TXN_SYNC
              • XA_COMMIT
              • XA_END
              • XA_FORGET
              • XA_GETLASTOER
              • XA_PREPARE
              • XA_RECOVER
              • XA_ROLLBACK
              • XA_SETTIMEOUT
              • XA_START
            • DBMS_XMLGEN
              • Overview
              • CONVERT
            • DBMS_XPLAN
              • Overview
              • DISABLE_OPT_TRACE
              • ENABLE_OPT_TRACE
              • SET_OPT_TRACE_PARAMETER
            • ODCIConst
              • Overview
              • ODCIArgDesc.ArgType
              • ODCIEnv.CallProperty
              • ODCIEnv.Envflags
              • ODCIIndexAlter
              • ODCIIndexAlter parameter alter_option
              • ODCIIndexInfo.IndexInfoFlags
              • ODCIIndexInfo.IndexParaDegree
              • ODCIPredInfo.Flags
              • ODCIQueryInfo.Flags
              • ODCIStatsOptions.Flags
              • ODCIStatsOptions.Options
              • Return Status
              • ScnFlg
            • UTL_ENCODE
              • Overview
              • BASE64_DECODE
              • BASE64_ENCODE
            • UTL_FILE
              • Overview
              • FCLOSE
              • FFLUSH
              • FOPEN
              • FGETPOS
              • FREMOVE
              • FRENAME
              • FSEEK
              • NEW_LINE
              • GET_LINE
              • PUT
              • PUT_LINE
            • UTL_I18N
              • Overview
              • RAW_TO_CHAR
              • STRING_TO_RAW
            • UTL_RAW
              • Overview
              • BIT_AND
              • BIT_COMPLEMENT
              • BIT_OR
              • BIT_XOR
              • CAST_FROM_BINARY_DOUBLE
              • CAST_FROM_BINARY_FLOAT
              • CAST_FROM_BINARY_INTEGER
              • CAST_FROM_NUMBER
              • CAST_TO_BINARY_DOUBLE
              • CAST_TO_BINARY_FLOAT
              • CAST_TO_BINARY_INTEGER
              • CAST_TO_NUMBER
              • CAST_TO_RAW
              • CAST_TO_VARCHAR2
              • COMPARE
              • CONCAT
              • COPIES
              • LENGTH
              • REVERSE
              • SUBSTR
            • ANYDATA TYPE
              • Overview
              • BEGINCREATE static procedure
              • ENDCREATE member procedure
              • GET* member functions
              • GETTYPE member function
              • GETTYPENAME member function
              • PIECEWISE member procedure
              • SET* member procedures
            • XMLType
              • Overview
              • CREATEXML
              • GETCLOBVAL
              • GETSTRINGVAL
              • TRANSFORM
              • XMLTYPE
          • Reserved PL keywords
      • Database design guidelines
        • Object naming conventions
          • Overview
          • Tenant naming conventions
          • User naming conventions
          • Table naming conventions
          • Field naming conventions
          • Other naming conventions
        • Object structure design guidelines
          • Field design
          • Table structure design
          • Partitioned table design
          • Index design
          • Other structural designs
        • Character set specifications
        • Database connection specifications
        • Use of comments
        • ORM conventions
        • Exception handling
      • TableAPI
        • Introduction to TableAPI implementation
          • Implementation of TableAPI
          • Differences between replace and insert_or_update
          • TableAPI data models
        • Using TableAPI client
          • Introduction to the client and instructions for use
          • Set client parameters
          • An example of client use
        • Troubleshooting
      • HBaseAPI
        • HBaseAPI solution introduction
        • HBaseAPI storage model
        • Usage instructions of the HBaseAPI client
    • System reference
      • System parameters
        • Overview
        • Summary of system parameters
        • Cluster level
          • all_cluster_list
          • all_server_list
          • auto_broadcast_location_cache_rate_limit
          • auto_leader_switch_interval
          • auto_refresh_location_cache_rate_limit
          • autoinc_cache_refresh_interval
          • backup_backup_dest
          • backup_backup_dest_option
          • backup_dest_option
          • backup_concurrency
          • backup_dest
          • backup_data_file_size
          • backup_log_archive_option
          • backup_net_limit
          • backup_recovery_window
          • backup_region
          • backup_zone
          • balance_blacklist_failure_threshold
          • balance_blacklist_retry_interval
          • balancer_emergency_percentage
          • balancer_idle_time
          • balancer_log_interval
          • balancer_task_timeout
          • balancer_timeout_check_interval
          • balancer_tolerance_percentage
          • bf_cache_miss_count_threshold
          • bf_cache_priority
          • builtin_db_data_verify_cycle
          • cache_wash_threshold
          • clog_disk_utilization_threshold
          • clog_expire_days
          • clog_cache_priority
          • clog_disk_usage_limit_percentage
          • clog_sync_time_warn_threshold
          • clog_transport_compress_func
          • cpu_reserved
          • cluster
          • cluster_id
          • config_additional_dir
          • cpu_count
          • data_copy_concurrency
          • data_dir
          • data_disk_usage_limit_percentage
          • data_storage_error_tolerance_time
          • data_storage_warning_tolerance_time
          • datafile_disk_percentage
          • datafile_size
          • dead_socket_detection_timeout
          • debug_sync_timeout
          • default_compress
          • default_compress_func
          • default_transport_compress_func
          • default_row_format
          • devname
          • disk_io_thread_count
          • dtl_buffer_size
          • election_cpu_quota
          • election_blacklist_interval
          • enable_auto_refresh_location_cache
          • enable_auto_refresh_location_cache
          • enable_auto_leader_switch
          • enable_ddl
          • enable_global_freeze_trigger
          • enable_log_archive
          • enable_election_group
          • enable_major_freeze
          • enable_merge_by_turn
          • enable_manual_merge
          • enable_ob_ratelimit
          • enable_one_phase_commit
          • enable_perf_event
          • enable_pg
          • enable_rebalance
          • enable_record_trace_id
          • enable_record_trace_log
          • enable_rereplication
          • enable_rich_error_msg
          • enable_separate_sys_clog
          • enable_smooth_leader_switch
          • enable_rootservice_standalone
          • enable_sql_audit
          • enable_sql_operator_dump
          • enable_sys_table_ddl
          • enable_sys_unit_standalone
          • enable_syslog_recycle
          • enable_syslog_wf
          • enable_tcp_keepalive
          • fast_recovery_concurrency
          • enable_upgrade_mode
          • flush_log_at_trx_commit
          • gc_wait_archive
          • fuse_row_cache_priority
          • global_index_build_single_replica_timeout
          • global_major_freeze_residual_memory
          • get_leader_candidate_rpc_timeout
          • global_write_halt_residual_memory
          • high_priority_net_thread_count
          • ignore_replay_checksum_error
          • ignore_replica_checksum_error
          • index_clog_cache_priority
          • index_info_block_cache_priority
          • index_cache_priority
          • ilog_index_expire_time
          • internal_sql_execute_timeout
          • large_query_threshold
          • large_query_worker_percentage
          • leak_mod_to_check
          • lease_time
          • location_cache_cpu_quota
          • location_cache_priority
          • location_cache_expire_time
          • location_cache_refresh_min_interval
          • location_cache_refresh_rpc_timeout
          • location_cache_refresh_sql_timeout
          • location_fetch_concurrency
          • location_refresh_thread_count
          • log_archive_batch_buffer_limit
          • log_archive_checkpoint_interval
          • max_kept_major_version_number
          • max_px_worker_count
          • max_string_print_length
          • max_syslog_file_count
          • memory_chunk_cache_size
          • memory_limit
          • memory_limit_percentage
          • memory_reserved
          • memstore_limit_percentage
          • merge_stat_sampling_ratio
          • merge_thread_count
          • merger_completion_percentage
          • merger_switch_leader_duration_time
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          • # rootservice_list
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          • server_check_interval
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      • System variables
        • Overview
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      • System views (MySQL mode)
        • Overview
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          • Dictionary views overview
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          • information_schema.ENGINES
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          • information_schema.SCHEMATA
          • information_schema.SESSION_STATUS
          • information_schema.SESSION_VARIABLES
          • information_schema.STATISTICS
          • information_schema.TABLES
          • information_schema.TABLE_CONSTRAINTS
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          • information_schema.VIEW_TABLE_USAGE
          • information_schema.VIEWS
          • mysql.db
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          • mysql.user
          • oceanbase.DBA_IND_PARTITIONS
          • oceanbase.DBA_IND_SUBPARTITIONS
          • oceanbase.DBA_OB_DATABASES
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          • oceanbase.DBA_OB_SERVERS
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          • oceanbase.DBA_OB_TABLEGROUP_SUBPARTITIONS
          • oceanbase.DBA_OB_TABLEGROUP_TABLES
          • oceanbase.DBA_OB_TABLEGROUPS
          • oceanbase.DBA_OB_TABLET_TO_LS
          • oceanbase.DBA_OB_TENANT_JOBS
          • oceanbase.DBA_OB_TENANTS
          • oceanbase.DBA_OB_UNIT_JOBS
          • oceanbase.DBA_OB_UNIT_CONFIGS
          • oceanbase.DBA_OB_UNITS
          • oceanbase.DBA_OB_ZONE_MAJOR_COMPACTION
          • oceanbase.DBA_OB_ZONES
          • oceanbase.DBA_OBJECTS
          • oceanbase.DBA_PART_INDEXES
          • oceanbase.DBA_PART_KEY_COLUMNS
          • oceanbase.DBA_PART_TABLES
          • oceanbase.DBA_OB_SEQUENCE_OBJECTS
          • oceanbase.DBA_SUBPART_KEY_COLUMNS
          • oceanbase.DBA_SUBPARTITION_TEMPLATES
          • oceanbase.DBA_TAB_PARTITIONS
          • oceanbase.DBA_TAB_SUBPARTITIONS
          • oceanbase.CDB_IND_COLUMNS
          • oceanbase.CDB_IND_PARTITIONS
          • oceanbase.CDB_IND_SUBPARTITIONS
          • oceanbase.CDB_INDEXES
          • oceanbase.CDB_OB_ARCHIVELOG_PIECE_FILES
          • oceanbase.CDB_OB_DATABASES
          • oceanbase.CDB_OB_LS_LOCATIONS
          • oceanbase.CDB_OB_MAJOR_COMPACTION
          • oceanbase.CDB_OB_RESTORE_HISTORY
          • oceanbase.CDB_OB_RESTORE_PROGRESS
          • oceanbase.CDB_OB_TABLEGROUP_PARTITIONS
          • oceanbase.CDB_OB_TABLEGROUP_SUBPARTITIONS
          • oceanbase.CDB_OB_TABLEGROUP_TABLES
          • oceanbase.CDB_OB_TABLEGROUPS
          • oceanbase.CDB_OB_TABLET_REPLICAS
          • oceanbase.CDB_OB_TABLET_TO_LS
          • oceanbase.CDB_OB_ZONE_MAJOR_COMPACTION
          • oceanbase.CDB_OBJECTS
          • oceanbase.CDB_PART_INDEXES
          • oceanbase.CDB_PART_KEY_COLUMNS
          • oceanbase.CDB_PART_TABLES
          • oceanbase.CDB_SUBPART_KEY_COLUMNS
          • oceanbase.CDB_SUBPARTITION_TEMPLATES
          • oceanbase.CDB_TAB_COL_STATISTICS
          • oceanbase.CDB_TAB_COLS
          • oceanbase.CDB_TAB_COLS_V$
          • oceanbase.CDB_TAB_PARTITIONS
          • oceanbase.CDB_TAB_SUBPARTITIONS
          • oceanbase.CDB_TABLES
          • oceanbase.CDB_OB_BACKUP_SET_FILES
          • oceanbase.DBA_OB_BACKUP_SET_FILES
          • oceanbase.CDB_OB_BACKUP_JOBS
          • oceanbase.DBA_OB_BACKUP_JOBS
          • oceanbase.CDB_OB_BACKUP_JOB_HISTORY
          • oceanbase.DBA_OB_BACKUP_JOB_HISTORY
          • oceanbase.CDB_OB_BACKUP_TASKS
          • oceanbase.DBA_OB_BACKUP_TASKS
          • oceanbase.CDB_OB_BACKUP_TASK_HISTORY
          • oceanbase.DBA_OB_BACKUP_TASK_HISTORY
          • oceanbase.DBA_OB_ARCHIVELOG_PIECE_FILES
          • oceanbase.DBA_OB_RESTORE_PROGRESS
          • oceanbase.DBA_OB_RESTORE_HISTORY
          • oceanbase.CDB_OB_ARCHIVE_DEST
          • oceanbase.DBA_OB_ARCHIVE_DEST
          • oceanbase.CDB_OB_ARCHIVELOG
          • oceanbase.DBA_OB_ARCHIVELOG
          • oceanbase.CDB_OB_ARCHIVELOG_SUMMARY
          • oceanbase.DBA_OB_ARCHIVELOG_SUMMARY
          • oceanbase.CDB_OB_BACKUP_PARAMETER
          • oceanbase.DBA_OB_BACKUP_PARAMETER
          • oceanbase.DBA_OB_OUTLINE_CONCURRENT_HISTORY
          • oceanbase.DBA_OB_OUTLINES
          • oceanbase.DBA_OB_CONCURRENT_LIMIT_SQL
          • oceanbase.CDB_OB_SYS_VARIABLES
          • oceanbase.CDB_OB_BACKUP_DELETE_JOBS
          • oceanbase.DBA_OB_BACKUP_DELETE_JOBS
          • oceanbase.CDB_OB_BACKUP_DELETE_JOB_HISTORY
          • oceanbase.DBA_OB_BACKUP_DELETE_JOB_HISTORY
          • oceanbase.CDB_OB_BACKUP_DELETE_TASKS
          • oceanbase.DBA_OB_BACKUP_DELETE_TASKS
          • oceanbase.CDB_OB_BACKUP_DELETE_TASK_HISTORY
          • oceanbase.DBA_OB_BACKUP_DELETE_TASK_HISTORY
          • oceanbase.CDB_OB_BACKUP_STORAGE_INFO
          • oceanbase.DBA_OB_BACKUP_STORAGE_INFO
          • oceanbase.CDB_OB_BACKUP_STORAGE_INFO_HISTORY
          • oceanbase.DBA_OB_BACKUP_STORAGE_INFO_HISTORY
          • oceanbase.CDB_OB_BACKUP_DELETE_POLICY
          • oceanbase.DBA_OB_BACKUP_DELETE_POLICY
          • oceanbase.CDB_OB_DEADLOCK_EVENT_HISTORY
          • oceanbase.DBA_OB_DEADLOCK_EVENT_HISTORY
          • oceanbase.CDB_OB_COLUMN_CHECKSUM_ERROR_INFO
          • oceanbase.CDB_OB_TABLET_CHECKSUM_ERROR_INFO
          • oceanbase.DBA_TAB_STATISTICS
          • oceanbase.DBA_TAB_COL_STATISTICS
          • oceanbase.DBA_PART_COL_STATISTICS
          • oceanbase.DBA_SUBPART_COL_STATISTICS
          • oceanbase.DBA_TAB_HISTOGRAMS
          • oceanbase.DBA_PART_HISTOGRAMS
          • oceanbase.DBA_SUBPART_HISTOGRAMS
          • oceanbase.DBA_TAB_STATS_HISTORY
          • oceanbase.DBA_SCHEDULER_JOBS
          • oceanbase.DBA_IND_STATISTICS
          • oceanbase.DBA_TAB_MODIFICATIONS
          • oceanbase.DBA_SQL_PLAN_BASELINES
          • oceanbase.DBA_SQL_MANAGEMENT_CONFIG
          • information_schema.QUERY_RESPONSE_TIME
          • oceanbase.CDB_OB_LS
          • oceanbase.DBA_OB_LS
          • oceanbase.CDB_OB_TABLE_LOCATIONS
          • oceanbase.DBA_OB_TABLE_LOCATIONS
          • oceanbase.DBA_OB_SERVER_EVENT_HISTORY
          • oceanbase.CDB_OB_FREEZE_INFO
          • oceanbase.DBA_OB_FREEZE_INFO
          • oceanbase.DBA_OB_LS_REPLICA_TASKS
          • oceanbase.CDB_OB_LS_REPLICA_TASKS
          • oceanbase.DBA_OB_AUTO_INCREMENT
          • oceanbase.CDB_OB_AUTO_INCREMENT
          • oceanbase.DBA_SEQUENCES
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          • oceanbase.DBA_OB_USERS
          • oceanbase.CDB_OB_USERS
          • oceanbase.DBA_OB_DATABASE_PRIVILEGE
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          • oceanbase.DBA_OB_USER_DEFINED_RULES
          • oceanbase.DBA_OB_TENANTS
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          • oceanbase.DBA_OB_LS_LOG_ARCHIVE_PROGRESS
          • oceanbase.DBA_OB_ARBITRATION_SERVICE
          • oceanbase.CDB_OB_LS_ARB_REPLICA_TASKS
          • oceanbase.DBA_OB_LS_ARB_REPLICA_TASKS
          • oceanbase.CDB_OB_LS_ARB_REPLICA_TASK_HISTORY
          • oceanbase.DBA_OB_LS_ARB_REPLICA_TASK_HISTORY
          • information_schema.ST_GEOMETRY_COLUMNS
          • information_schema.ST_SPATIAL_REFERENCE_SYSTEMS
          • oceanbase.DBA_OB_CLUSTER_EVENT_HISTORY
          • oceanbase.DBA_OB_RSRC_IO_DIRECTIVES
          • oceanbase.DBA_RSRC_PLANS
          • oceanbase.DBA_RSRC_PLAN_DIRECTIVES
          • oceanbase.DBA_RSRC_GROUP_MAPPINGS
          • oceanbase.DBA_RSRC_CONSUMER_GROUPS
        • Performance views
          • Overview
          • GV$OB_COMPACTION_DIAGNOSE_INFO
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          • GV$SESSION_EVENT
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          • GV$OB_SERVER_SCHEMA_INFO
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          • GV$OB_SSTABLES
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          • V$OB_TRANSACTION_PARTICIPANTS
          • V$OB_UNITS
          • V$STATNAME
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          • V$SESSION_WAIT_HISTORY
          • V$SESSTAT
          • V$SYSTEM_EVENT
          • V$OB_MEMORY
          • V$OB_MEMSTORE
          • V$OB_PLAN_CACHE_STAT
          • V$OB_PLAN_CACHE_PLAN_STAT
          • V$OB_PLAN_CACHE_PLAN_EXPLAIN
          • V$OB_SQL_AUDIT
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          • V$SQL_PLAN_MONITOR
          • V$SESSION_LONGOPS
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          • V$OB_PX_WORKER_STAT
          • V$OB_PS_STAT
          • V$OB_PS_ITEM_INFO
          • V$SQL_WORKAREA
          • V$SQL_WORKAREA_ACTIVE
          • V$SQL_WORKAREA_HISTOGRAM
          • V$OB_SQL_WORKAREA_MEMORY_INFO
          • V$OB_SERVER_SCHEMA_INFO
          • V$OB_MERGE_INFO
          • V$SQL_MONITOR_STATNAME
          • V$OB_ENCRYPTED_TABLES
          • V$ENCRYPTED_TABLESPACES
          • V$OB_SSTABLES
          • V$OB_TENANT_MEMORY
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          • GV$OB_MEMSTORE_INFO
          • V$OB_MEMSTORE_INFO
          • GV$OB_IO_CALIBRATION_STATUS
          • V$OB_IO_CALIBRATION_STATUS
          • GV$OB_IO_BENCHMARK
          • V$OB_IO_BENCHMARK
          • GV$SYSSTAT
          • V$SYSSTAT
          • V$SESSION_EVENT
          • GV$ACTIVE_SESSION_HISTORY
          • V$ACTIVE_SESSION_HISTORY
          • GV$DML_STATS
          • V$DML_STATS
          • GV$OB_LOG_STAT
          • V$OB_LOG_STAT
          • GV$OB_DTL_INTERM_RESULT_MONITOR
          • V$OB_DTL_INTERM_RESULT_MONITOR
          • V$OB_LS_REPLICA_TASK_PLAN
          • V$OB_ARCHIVE_DEST_STATUS
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OceanBase Database Enterprise Edition V2.2.77

Last Updated:2023-07-28 02:53:17  Updated
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What is on this page
V2.2.77
Version information
Overview
Enhanced features
Fixed issues
V2.2.77 BP1
Version information
Enhanced features
Fixed issues
Upgrade and limits
V2.2.77 BP2
Version information
Enhanced features
Fixed issues
Upgrade and limits
V2.2.77 BP3
Version information
Enhanced features
Fixed issues
Upgrade and limits
V2.2.77 BP4
Version information
Enhanced features
Fixed issues
Upgrade and limits
V2.2.77 BP5
Version information
Enhanced features
Compatibility changes
Fixed issues
Upgrade and limits
V2.2.77 BP6
Version information
Fixed issues
Upgrade and limits
V2.2.77 BP7
Version information
Enhanced features
Fixed issues
Upgrade and limits
V2.2.77 BP8
Version information
Enhanced features
Fixed issues
Upgrade and limits
V2.2.77 BP9
Version information
Fixed issues
Upgrade and limits
V2.2.77 BP10
Version information
Enhanced features
Compatibility changes
Fixed issues
Upgrade and limits
V2.2.77 BP11
Version information
Enhanced features
Fixed issues
Upgrade and limits
V2.2.77 BP12
Version information
Fixed issues
Upgrade and limits
V2.2.77 BP13
Version information
Enhanced features
Upgrade and limits
V2.2.77 BP14
Version information
Enhanced features
Fixed issues
Upgrade and limitations
V2.2.77 BP15
Version information
Enhanced features
Compatibility changes
Fixed issues
Upgrade and limitations
V2.2.77 BP16
Version information
Enhanced features
Fixed issues
Upgrade and limitations

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V2.2.77

Version information

  • Release date: May 8, 2021

  • Version: V2.2.77

Overview

OceanBase Database V2.2.X is a generally available series that provides products of higher availability, compatibility, and security for customers to batch launch multiple projects.

Enhanced features

  • Primary and standby clusters are enhanced.

  • Physical backup and restore are supported.

  • The encryption of an individual log-only replica at the zone level is supported.

  • Template-based and non-template-based subpartitioned tables are supported.

  • Drop and Truncate operations on partitioned tables are supported.

Fixed issues

  • An error is returned for the aligned read of the 4 KB clog offset.

  • An error is returned during the type derivation of an expression that contains NULL.

V2.2.77 BP1

Version information

  • Release date: May 27, 2021.

  • Version: V2.2.77 BP1

Enhanced features

You can specify the maximum memory usage of partitions in a transaction by setting the tenant-level parameter _tenant_max_trx_size.

Fixed issues

  • The observer process unexpectedly exits when the memory is insufficient and the memory request fails.

  • The plan cache has memory leaks.

  • The Nested Loop Join operator may cause the observer process to unexpectedly exit in the TABLE ACCESS BY INDEX PRIMARY KEY operation.

  • When foreign keys exist, the Semi-Join rewrite generates incorrect results.

  • The observer process unexpectedly exits when an intermediate result set is released.

  • In Oracle mode, the WIDTH_BUCKET() function is incompatible with Oracle when min_value is less than expression.

  • In Oracle mode, the RPAD() function is incompatible with Oracle.

Upgrade and limits

  • The primary and standby clusters can be upgraded only in maximum performance mode. If a cluster is in maximum protection mode or maximum availability mode, you must switch the cluster to maximum performance mode before you can upgrade the cluster.

  • PL debugging is supported only for x86 platforms. We recommend that you do not use this feature on an ARM platform.

V2.2.77 BP2

Version information

  • Release date: June 4, 2021

  • Version: V2.2.77 BP2

Enhanced features

  • In MySQL mode, using escape characters such as single quotation marks (' ') in a LIKE statement is supported.

  • You can explicitly disable the enforced routing of a transaction after it is complete by setting the tenant-level parameter ob_proxy_readonly_transaction_routing_policy. This way, all SQL statements in the transaction are forwarded to the same OBServer node.

  • The memory size that can be utilized by sql_audit of an OceanBase Database tenant is increased.

  • The timeout wait for asynchronous I/O is optimized.

Fixed issues

  • The RootServer node of the standby cluster occasionally exits unexpectedly.

  • The parameter that specifies the maximum memory available for sql_audit does not take effect.

  • When the GBK character set is used, two consecutive queries that use Chinese characters return incorrect filed name even if the data is correct.

Upgrade and limits

  • The primary and standby clusters can be upgraded only in maximum performance mode. If a cluster is in maximum protection mode or maximum availability mode, you must switch the cluster to maximum performance mode before you can upgrade the cluster.

  • PL debugging is supported only for x86 platforms. We recommend that you do not use this feature on an ARM platform.

V2.2.77 BP3

Version information

  • Release date: June 18, 2021

  • Version: V2.2.77 BP3

Enhanced features

  • The LOG(), LN(), PI(), RADIANS(), ATAN(), ASIN(), ACOS(), and COT() functions are supported in MySQL mode.

  • The MONTHNAME() function is supported in MySQL mode.

  • The LAST_DAY() function is supported in MySQL mode.

  • The QUARTER() function is supported in MySQL mode.

  • The BIT_LENGTH() function is supported in MySQL mode.

Fixed issues

  • The observer process unexpectedly exits during the packet return process of a query because of network exceptions.

  • The parallel execution framework has memory leaks.

  • The observer process unexpectedly exits during the process of obtaining the partition location because of concurrent memory requests.

  • The observer process unexpectedly exits during the eviction of the plan cache because of the access to a null pointer.

  • The observer process unexpectedly exits because of stack overflow, which is caused by a large number of static SQL statements in the anonymous block when prepared statement is disabled.

  • The execution of the SELF ANTI JOIN statement results in an incorrect estimation of the number of rows because of SQL rewriting.

  • The OB_ARCHIVE_TEMP_MEMORY module has memory leaks during log archiving.

  • The PL statement cannot hit the plan cache.

  • The OBServer retains the session after the client is disconnected.

Upgrade and limits

  • The primary and standby clusters can be upgraded only in maximum performance mode. If a cluster is in maximum protection mode or maximum availability mode, you must switch the cluster to maximum performance mode before you can upgrade the cluster.

  • PL debugging is supported only for x86 platforms. We recommend that you do not use this feature on an ARM platform.

V2.2.77 BP4

Version information

  • Release date: July 13, 2021

  • Version: V2.2.77 BP4

Enhanced features

  • The MAKETIME() function is supported in MySQL mode.

  • The UTC_DATE(), UTC_TIME(), and GET_FORMAT() functions are supported in MySQL mode.

Fixed issues

  • XA transactions in the Active status cannot be rolled back.

  • In Oracle mode, if the index column contains the CHAR data type and values that are less than or equal to 0, the index column cannot be queried.

  • The execution of the ANTI-, SEMI-, and OUTER-JOIN statements with an OR join condition generates incorrect data.

  • The observer process unexpectedly exits because of an OSS SDK bug during the physical backup to the Alibaba Cloud OSS bucket.

  • The observer process unexpectedly exits sometimes because of queries on the gv$sysstat view.

Upgrade and limits

  • The primary and standby clusters can be upgraded only in maximum performance mode. If a cluster is in maximum protection mode or maximum availability mode, you must switch the cluster to maximum performance mode before you can upgrade the cluster.

  • PL debugging is supported only for x86 platforms. We recommend that you do not use this feature on an ARM platform.

V2.2.77 BP5

Version information

  • Release date: July 31, 2021

  • Version: V2.2.77 BP5

Enhanced features

  • You can set the SQL_MODE parameter to NO_ZERO_IN_DATE in MySQL mode.

Compatibility changes

  • The following default actions of the SQL_MODE parameter are changed in MySQL mode:

Fixed issues

  • The observer process unexpectedly exits when an excessive amount of columns are operated by the TRIGGER operation.

  • The query on the generated column in conjunction with the ORDER BY LIMIT action generates an incorrect plan.

  • Incorrect results are generated because no deep copy is performed during a BATCH NESTED LOOP JOIN operation.

  • The observer process unexpectedly exits because no deep copy that allocates the memory is performed when the PL engine executes dynamic SQL statements.

  • The observer process unexpectedly exits because like Number is used as a filter condition.

  • The observer process unexpectedly exits when the redo log module prints logs.

  • An error is returned when the SHOW PROCEDURE STATUS statement is executed after the execution of the DROP USER statement.

  • The plan_type field of the sql_audit parameter displays incorrect plan type.

Upgrade and limits

  • The primary and standby clusters can be upgraded only in maximum performance mode. If a cluster is in maximum protection mode or maximum availability mode, you must switch the cluster to maximum performance mode before you can upgrade the cluster.

  • PL debugging is supported only for x86 platforms. We recommend that you do not use this feature on an ARM platform.

V2.2.77 BP6

Version information

  • Release date: August 25, 2021

  • Version: V2.2.77 BP6

Fixed issues

  • The backup set is marked as Deleted after the secondary backup fails.

  • In a scenario where a tenant recovery operation is performed, if an existing tenant has the same name as the tenant to be recovered, the existing tenant is dropped.

  • In a parallel execution (PX), if a long timeout is set for a tenant by default, the operation of session termination takes a long time to respond.

  • The observer process may fail to start with a small probability after clog compression is enabled.

  • Deadlocks are possible when SECURITY AUDIT is enabled in high concurrency scenarios.

  • The observer process unexpectedly exits in Oracle mode because of the execution of the SELECT FETCH UNION SELECT FETCH syntax.

  • The observer process unexpectedly exits when the memory request fails during the execution of a distributed plan.

Upgrade and limits

  • The primary and standby clusters can be upgraded only in maximum performance mode. If a cluster is in maximum protection mode or maximum availability mode, you must switch the cluster to maximum performance mode before you can upgrade the cluster.

  • PL debugging is supported only for x86 platforms. We recommend that you do not use this feature on an ARM platform.

V2.2.77 BP7

Version information

  • Release date: September 18, 2021

  • Version: V2.2.77 BP7

Enhanced features

  • The eviction mechanism of SQL execution plans for partitioned tables is optimized.

  • Secure Sockets Layer (SSL) communication encryption is supported by ob_admin.

  • The LOAD DATA REPLACE syntax is supported in Oracle mode.

  • The user logon and logoff statistics are collected.

  • The ORDER BY expression is supported in MySQL mode.

  • Automatic load balancing for partitions in a STOP SERVER/ZONE operation is optimized.

  • The routing of temporary tables is optimized.

Fixed issues

  • The creation of a tenant fails if the _enanble_easy_keepalive parameter is set to true.

  • The substr(c1,x,1)='a' query cannot hit the plan cache.

  • The logical recovery fails because the rowkey does not meet the length requirements.

  • The accumulation of clogs causes the OBServer to restart, which results in excessive memory consumption by the sys tenant.

Upgrade and limits

  • The primary and standby clusters can be upgraded only in maximum performance mode. If a cluster is in maximum protection mode or maximum availability mode, you must switch the cluster to maximum performance mode before you can upgrade the cluster.

  • PL debugging is supported only for x86 platforms. We recommend that you do not use this feature on an ARM platform.

V2.2.77 BP8

Version information

  • Release date: October 15, 2021

  • Version: V2.2.77 BP8

Enhanced features

  • The internal __ALL_VIRTUAL_PROCESSLIST table is provided to display the transaction timeout status.

Fixed issues

  • Under the SQL parallel framework, the SELECT FOR UPDATE statement causes the optimizer to return the OB_STATE_NOT_MATCH error.

  • The gv$SQL_PLAN_MONITOR view cannot properly display non-distributed plans.

  • An internal error is returned when the NVL() function is used in the CASE WHEN statement.

  • In Oracle mode, the value of the PARTITION KEY COUNT field in the ALL_PART_TABLES table is not displayed.

  • The tenant recovery operation fails when the tenant is deleted.

  • In MySQL mode, the execution of the SET PASSWORD statement in stored procedures does not take effect.

  • The creation of views in PL fails in MySQL mode.

  • The redo_transport_option parameter of the standby cluster does not take effect.

  • The observer process unexpectedly exits during the conversion from the INT and STRING data types to the DATATIME, DATE, and TIME data types.

  • The observer process unexpectedly exits during the process of setting the PARALLEL_MAX_SERVERS variable.

  • In Oracle mode, the use of TRIGGER causes the SQL EXECUTOR module to have memory leaks.

  • The 4019 error is returned when you create a tenant after a large number of tenants are deleted.

  • The observer process unexpectedly exits during the process of setting the clog_disk_usage_limit_percentage and clog_disk_utilization_threshold parameters.

Upgrade and limits

  • The primary and standby clusters can be upgraded only in maximum performance mode. If a cluster is in maximum protection mode or maximum availability mode, you must switch the cluster to maximum performance mode before you can upgrade the cluster.

  • PL debugging is supported only for x86 platforms. We recommend that you do not use this feature on an ARM platform.

V2.2.77 BP9

Version information

  • Release date: November 19, 2021

  • Version: V2.2.77 BP9

Fixed issues

  • The 4038 error is returned at the close phase of parallel execution.

  • When PL debugging is performed in the OceanBase Developer Center (ODC) console, resources for debugging cannot be quickly released if ODC directly exits.

  • The client session is disconnected when the memory request fails at the SQL PARSE phase.

  • When a temporary table is created and added with constraints, the cluster is hung if a constraint of the temporary table has the same name as that of a non-temporary table.

  • The MERGE INTO (SELECT *) statement is incompatible with Oracle.

  • In Oracle mode, the ALL_TAB_PARTITIONS view displays partitions in an unordered way.

  • The 4016 error is returned during the execution of the REPLACE INTO statement.

  • The gv$sql_audit view displays inaccurate QUEUE_TIME and RETRY_CNT statistics.

  • The incorrect FILE HANDLE is obtained when the NFSv4 protocol is used for backup.

  • The gv$sql_audit view displays the password for user creation in plaintext.

  • If the base table of the gv$sql_audit view does not exist, the value of elapsed_time in the recorded query information is 0.

  • In Oracle mode, the pivot and unpivot clauses are incompatible with Oracle.

  • The restart of the observer process keeps failing because it cannot be replayed after the restart, which is caused by the reuse of old slogs due to insufficient storage space.

  • When the SHOW TABLE STATUS statement is executed to query a partitioned table, the result is NULL.

  • In Oracle mode, the error unknown timezone is returned for the obclient connection after you specify the global time_zone system variable.

  • In MySQL mode, the user privileges on a table remain valid after the table is deleted.

  • Some IP addresses in the gv$sql_audit view are parsed into 0.0.0.0.

  • In Oracle mode, an error is returned when the SELECT * FROM (GENERATED TABLE) statement is executed due to duplicate column names.

  • The BIT data type is incompatible with MySQL.

  • The observer process unexpectedly exits when it reads the configuration file during startup.

  • The observer process unexpectedly exits during the data backup to OSS.

  • The observer process unexpectedly exits during the conversion of the SET/ENUM/LOB data types.

Upgrade and limits

  • The primary and standby clusters can be upgraded only in maximum performance mode. If a cluster is in maximum protection mode or maximum availability mode, you must switch the cluster to maximum performance mode before you can upgrade the cluster.

  • PL debugging is supported only for x86 platforms. We recommend that you do not use this feature on an ARM platform.

V2.2.77 BP10

Version information

  • Release date: January 17, 2022

  • Version: V2.2.77 BP10

Enhanced features

  • The tag cleanup mode is supported in OSS.

  • The USERENV('SID') and USERENV('LANGUAGE') functions are supported in Oracle mode.

  • When the backup space reaches 100%, you can delete obsolete backup files.

  • The stability and performance of the queuing table are improved.

  • The streaming compression algorithm, which is not supported for clog compression, is removed.

  • The 4 KB aligned writes of disk DIRECT_IO are supported.

Compatibility changes

  • By default, the auto_refresh_location_cache parameter is set to true to enable the balance strategy for partition replicas.

  • By default, the schema_history_recycle_interval parameter is set to true to enable the periodic cleanup of expiry records in the system table by background threads.

Fixed issues

  • The column type in the view of null columns is NULL, but that in the Oracle database is char(0).

  • In the gv$sql_audit view, the maximum length of the QUERY_SQL column is not 64 KB.

  • In Oracle mode, a false positive error is returned, which indicates that the total row length of all columns exceeds the value of the OB_MAX_USER_ROW_LENGTH parameter.

  • The index creation fails when the GBK character set is used.

  • The statistics of a tenant recovered by using the backup and restore feature are not promptly updated.

  • The error not support is returned when you set the secure_file_priv parameter after the connection is created by using the IP address 127.0.0.1.

  • An error is returned for incorrect calculation of string length when the CREATE TABLE statement involves the setting of variable values.

  • The error Column length too big for column is returned during the length check of the LOB columns.

  • An error is returned during the execution of the ALTER TABLE DROP COLUMN statement due to the delayed deletion of physical backups.

  • When the sql_auto_is_null parameter is set to ON, the error Invalid Argument is returned during a query where the auto-increment columns need to be identified.

  • In Oracle mode, no privilege is provided to control the TRUNCATE DLL operation.

  • The creation of a global index fails if the process of an OBServer node exits.

  • The __all_virtual_memory_info table displays incomplete tenant information.

  • The try_cnt column of the gv$sql_audit view shows inaccurate statistics.

  • In Oracle mode, the TO_CHAR() function cannot recognize the date format.

  • An error occurs when checking is conducted for the index created on a column of the CHAR type in Oracle mode.

  • All rows are NULL after the LEFT JOIN UPDATE on multiple tables.

  • In PL mode, the observer process unexpectedly exits due to the existence of the PRINT LOB data type.

  • The observer process unexpectedly exits because the LIKE clause in the SQL statement exceeds 250 KB in length.

Upgrade and limits

  • The primary and standby clusters can be upgraded only in maximum performance mode. If a cluster is in maximum protection mode or maximum availability mode, you must switch the cluster to maximum performance mode before you can upgrade the cluster.

  • PL debugging is supported only for x86 platforms. We recommend that you do not use this feature on an ARM platform.

V2.2.77 BP11

Version information

  • Release date: May 2, 2022

  • Version: V2.2.77 BP11

Enhanced features

  • The integration of the transparent data encryption (TDE) feature with the Alibaba Cloud Key Management Service (KMS) system is supported.

  • The performance of non-blocking Table API queries is improved.

  • The maximum value of the in(values) query is optimized to make it compatible with MySQL.

  • Filtering by tenant is supported by liboblog to synchronize only logs of the specified tenants.

  • Returning the synchronization timestamps of logs is supported by liboblog.

Fixed issues

  • In MySQL mode, an error is returned during the parsing of the GROUP BY expression because of unclear semantics. In this version, the expression from the selection list is used to avoid errors.

  • In MySQL mode, an error is returned for invalid characters generated during the conversion of the GBK character set by calling the CONVERT() function. In this version, the invalid characters are converted to 0x3F, which is compatible with MySQL.

Upgrade and limits

  • The primary and standby clusters can be upgraded only in maximum performance mode. If a cluster is in maximum protection mode or maximum availability mode, you must switch the cluster to maximum performance mode before you can upgrade the cluster.

  • PL debugging is supported only for x86 platforms. We recommend that you do not use this feature on an ARM platform.

V2.2.77 BP12

Version information

  • Release date: June 14, 2022

  • Version: V2.2.77 BP12

Fixed issues

  • In Oracle mode, when you create a stored procedure with the specified character set GBK, the OBServer becomes suspended unexpectedly during the SQL prepare phase.
  • In MySQL mode, an error is returned because the Limit operator does not support character type conversion.
  • When the system performs a follower-to-leader switchover during a major compaction, the SQL statement is rolled back because the cached route is inaccurate. This causes a long execution time.
  • The error code 4007 is returned when the DBMS_LOB.SUBSTR system package is executed in Oracle mode.
  • The queue_time field is displayed as a negative value in the v$sql_audit view.
  • In the sys tenant, the resource specifications are not restored to the default settings after a unit is removed.
  • When the input parameter is converted during the execution of a stored procedure, the following error is returned: value too large for column.
  • In multi-table join queries, the CPU utilization is high when the join key has an index and a ROWNUM or LIMIT operator.
  • When a null condition is used to query the INFORMATION_SCHEMA.COLUMNS view, incorrect results are returned.
  • The observer process unexpectedly exits due to an exception occurring in table access by global index primary key. This is caused because the background thread does not initialize the tenant context.
  • The observer process unexpectedly exits because the cluster is stopped while data is written to Tencent Cloud Object Storage (COS) or Alibaba Cloud Object Storage Service (OSS).
  • A syntax error is returned when the DBMS_LOB system package is executed to insert data.
  • The logs of the Root Service node repeatedly report errors because an exception occurs when an index is created.

Upgrade and limits

  • The primary and standby clusters can be upgraded only in maximum performance mode. If a cluster is in maximum protection mode or maximum availability mode, you must switch the cluster to maximum performance mode before you can upgrade the cluster.
  • PL debugging is supported only for x86 platforms. We recommend that you do not use this feature on an ARM platform.

V2.2.77 BP13

Version information

  • Release date: August 26, 2022

  • Version: V2.2.77 BP13

Enhanced features

  • Adding partitions is supported in specific scenarios. You can add partitions at the beginning or in the middle of RANGE-partitioned tables. When you add a partition, make sure that no data is written to this partition. You can enable this feature by using the tenant-level parameter _enable_add_between_range_partitions.
  • Cluster-level parameters of a specific OBServer can be modified by using ob_admin. However, tenant-level parameters cannot be modified for a specific OBServer.
  • Backup files on Tencent Cloud COS can be tagged to facilitate file management. Fixed issues
  • The cluster restart times out due to an excessive number of schema history records.
  • In MySQL mode, an error is returned for invalid characters generated during the conversion of the GBK character set by calling the CONVERT() function. In this version, the invalid characters are converted to 0x3F, which is compatible with MySQL.
  • In the primary-standby deployment mode, records in the virtual table __all_server_event_history expand fast due to frequent execution of the ALTER SYSTEM CHANGE TENANT operation on the primary database.
  • During the execution of a distributed plan, when one OBServer fails, the execution of SQL statements on other OBServers hangs until timeout.
  • When an equivalent condition is used to detect the case sensitivity of the collation, the returned result set is wrong because an execution plan is incorrectly hit.
  • When a backup task is forcibly canceled, the backup status stays in Stopping.
  • When the INSERT...ON DUPLICATE KEY UPDATE statement is executed, an error indicating duplicated primary keys is returned.
  • An error is returned during the execution of a nested aggregate operator that contains Distinct.
  • Invalid log information about RPC communication between OBServers is deleted.
  • When the __min_full_resource_pool_memory parameter is set to an abnormal value, the OBServer can still be started.
  • When the LAST_INSERT_ID() function is called within a stored procedure, a invalid execution result is generated.
  • The error code 4016 is returned when a partition is truncated.
  • An error occurs for the data of the net_wait_time field in the gv$sql_audit view.
  • When the weak_read_version_refresh_interval parameter is set to 0, the data in partitions is not synchronized.
  • The query timeout hint added to the cursor of a stored procedure does not take effect.
  • In Oracle mode, when a prepared statement is enabled, the return value of the NUMTODSINTERVAL() function is truncated to a specific precision.
  • After a partition is dropped or truncated, the locality change is suspended due to duplicate global indexes.

Upgrade and limits

  • The primary and standby clusters can be upgraded only in maximum performance mode. If a cluster is in maximum protection mode or maximum availability mode, you must switch the cluster to maximum performance mode before you can upgrade the cluster.
  • PL debugging is supported only for x86 platforms. We recommend that you do not use this feature on an ARM platform.

V2.2.77 BP14

Version information

  • Release date: December 04, 2022
  • Version: V2.2.77 BP14

Enhanced features

  • You can change the AccessKey ID and AccessKey Secret during data backup and restore. The backup feature of OceanBase Database allows you to specify an Alibaba Cloud Object Storage Service (OSS), Tencent Cloud Object Storage (COS), or Huawei Object Storage Service (OBS) bucket as the backup destination. However, you cannot modify the access_id or access_key parameter of the backup destination during the backup. If the AccessKey ID or AccessKey Secret is changed, you must stop the log backup and change the backup directory. Therefore, this version provides the ALTER SYSTEM change external_storage_dest PATH[=]'xxx?host=xxx' set ACCESS_INFO[=]'access_id=xxx&access_key=xxx'; command for you to modify the AccessKey ID and AccessKey Secret of the backup destination. The relevant content in GConf is updated and saved accordingly. Observe the following considerations when you use this command:

    • Before you run the command to update the AccessKey ID and AccessKey Secret for accessing the OSS, COS, or OBS bucket, we recommend that you stop the ongoing second backup task. We also recommend that you delete the old AccessKey ID and AccessKey Secret one hour later after you run the command.
    • If you modify the AccessKey ID and AccessKey Secret during a second backup task, and the task is stuck, you must forcibly cancel the task and change the directory to resume the task.
  • The following three fields are added to the v$sysstat view to optimize hotspot row observation.

    • TRANS_ELR_ENABLE_COUNT: the number of transactions for which early lock release (ELR) can be enabled.
    • TRANS_ELR_UNABLE_COUNT: the number of transactions for which ELR is disabled.
    • READ_ELR_ROW_COUNT: the number of rows that support ELR. The number of rows that support ELR is increased.
  • ob_admin supports OBS.

Fixed issues

  • The execution of the to_hex() function during stored procedure debugging causes server failures.
  • When system variables fail to be loaded, the session is abnormally released, and this causes a server failure.
  • The time zone used by the backup logic is different from that used by the restore logic. As a result, the default values of restored table fields lag behind those of the original table by 8 hours.
  • When the _enable_fulltext_index parameter is set to OFF, creating a full-text index succeeds, which is abnormal.
  • When the special characters "+/" are used in a LIKE statement, the query result of an index scan is incorrect.
  • When an inner join subquery is executed, the query results in OceanBase Database and MySQL Database are inconsistent.
  • In an outer join, the number of rewritten rows is inconsistent with the number of queried rows.
  • The number of constraints on the CONCAT() function is negative, which is abnormal.
  • When the batch deletion operation of COS is called, the system cannot determine whether all objects are deleted.
  • When you delete a large number of Fail to erase key from cache entries from the observer.log file, an error is returned.
  • In non-strict mode, the execution result of creating an index is different from that of adding an index.
  • The use_hash_aggregation hint does not take effect.
  • After schema history file recycling is enabled, physical restore may fail.
  • The backup may fail due to an incorrect session count in the independent backup and restore subprocess.
  • During the procedural language (PL) execution by using the OCI_BATCH_ERRORS handle, a data storage error occurs due to primary key conflicts.
  • If slogs and SSTables are located on the same disk, the clog disk is almost full error is returned during slog initialization.

Upgrade and limitations

  • The primary and standby clusters can be upgraded only in maximum performance mode. If a cluster is in maximum protection mode or maximum availability mode, you must switch the cluster to maximum performance mode before you can upgrade the cluster.
  • PL debugging is supported only for x86 platforms. We recommend that you do not use this feature on an ARM platform.
  • If you have enabled the dynamic AccessKey ID/AccessKey Secret setting feature for data backup and restore, an upgrade to V3.x is not supported.

V2.2.77 BP15

Version information

  • Release date: January 10, 2023
  • Version: V2.2.77 BP15

Enhanced features

The FROM_BASE64() and TO_BASE64() functions are supported in MySQL mode.

Compatibility changes

In MySQL mode, the ORDER BY or LIMIT operator cannot be used for multi-table updates, which is consistent with MySQL.

Fixed issues

  • When you use an IN expression to query a partitioned table, the calculated result set is incorrect.
  • The migration of an empty resource unit causes the leader to get stuck.
  • When an execution plan hits the plan cache, the execution result of MERGE INTO is incorrect.
  • Memory leak occurs when indexes are created on JSON generated columns.
  • Backup sets fail to be cleared during automatic backup clearing.
  • In Oracle mode, when a package uses a cursor for loop operations, the error code 4179 is returned.
  • The standby database fails to restart due to an slog replay error.
  • Errors are returned when the LPAD function processes special characters whose ASCII codes are 0x03, 0x04, 0x05, and 0x06.
  • During the clearing of expired backups, the clearing task remains in the DOING state and cannot be stopped.
  • If the execution of a transaction is interrupted, the transaction ID recorded in SQL audit logs is incorrect.

Upgrade and limitations

  • The primary and standby clusters can be upgraded only in maximum performance mode. If a cluster is in maximum protection mode or maximum availability mode, you must switch the cluster to maximum performance mode before you can upgrade the cluster.
  • PL debugging is supported only for x86 platforms. We recommend that you do not use this feature on an ARM platform.
  • If you have enabled the dynamic AccessKey ID/AccessKey Secret setting feature for data backup and restore, an upgrade to V3.x is not supported.

V2.2.77 BP16

Version information

  • Release date: February 14, 2023
  • Version: V2.2.77 BP16

Enhanced features

The GROUP COMMIT capability is supported for OBKV to update hotspot rows. To better handle highly concurrent updates of hotspot rows, the server that supports GROUP COMMIT aggregates concurrent updates to prevent repeated row lock application and release for each operation. This saves the wait time due to row lock contention, and speeds up the hotspot row update.

Fixed issues

  • The execution of the USE DATABASE statement triggers implicit commit of transactions.
  • The SELECT statement in PL cannot read the data that has not been committed.
  • Some indexes are abnormal after a successful physical restore.
  • When you create a view, you must also specify an alias for ROWID in the SELECT clause even if you have specified column names.
  • The BATCH GET request of HBaseAPI takes a long time to complete.
  • The update of a primary key column in a TableAPI operation results in data inconsistency between the primary table and the index table.
  • An error is reported when TableAPI automatically updates fields with default values of CURRENT_TIMESTAMP or ON UPDATE CURRENT_TIMESTAMP.
  • An error is reported when the estimated result length of the REGEXP_REPLACE function is greater than the maximum allowable value because of excessively strict program check.
  • The binary comparison of the FIND_IN_SET(binary 'b','a,B,c,d') function does not take effect in MySQL mode.
  • The execution of the FIND_IN_SET function is slow in MySQL mode.
  • The backup_piece files that are expected to be cleaned up are not deleted in a normally scheduled automatic cleanup task.

Upgrade and limitations

  • The primary and secondary database clusters can be upgraded only in maximum performance mode. If a cluster is in maximum protection mode or maximum availability mode, you must downgrade the cluster to maximum performance mode before you can upgrade the cluster.
  • If you have enabled the dynamic AccessKey ID (AK)/AccessKey secret (SK) setting feature for data backup and restore, you cannot upgrade OceanBase Database to V3.x.
  • PL debugging is supported only for x86 platforms. We recommend that you do not use this feature on an ARM platform.

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V2.2.77
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