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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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OceanBase Database

SQL - V4.3.0

  • What's New
  • What is OceanBase Database
    • Overview
    • Differences between the Enterprise Edition and the Community Edition
    • System architecture
    • Compatibility with Oracle
      • Compatibility with Oracle
      • SQL data types
      • Built-in functions
      • System views
    • Compatibility with MySQL
    • Limitations
  • Get Started
    • Video tutorials
    • Try out OceanBase Database Community Edition
    • Try out advanced features of OceanBase Database
      • Scalable OLTP
        • Try out the hot row update capability of OceanBase Database
        • Run the TPC-C benchmark in OceanBase Database
      • Try out operational OLAP
      • Try out parallel import and data compression
      • Try out the multi-tenant feature
    • Build a sample application (Oracle mode)
      • Build a Java application
      • Build a C application
    • Learn OceanBase SQL
      • Basic SQL operations (Oracle mode)
      • Basic SQL operations (MySQL mode)
      • Before you begin
    • Build a sample application (MySQL mode)
      • Build a Python application
      • Build a Java application
      • Build a C application
      • Build a Go application
  • Develop
    • Develop applications (MySQL mode)
      • Sample applications
        • Java
          • Spring Data JDBC
          • Spring Boot
          • Spring Data JPA
          • MyBatis
          • Spring Batch
          • Hibernate
          • Connector/J
          • TestContainers
        • Python
          • mysqlclient
          • PyMySQL
          • MySQL-connector-python
        • C
          • MySQL Connector/C
        • Go
          • GORM
          • Go-SQL-Driver/MySQL
        • PHP
          • EXT
          • MySQLi
          • PDO
      • Write data
        • Delete data
        • Generate test data in batches
        • Update data
        • Insert data
        • Replace data
      • Application errors
        • Common errors and troubleshooting practices
          • Table does not exist, with ERROR 1146 reported
          • Data truncated while being inserted, with ERROR 1265 reported
          • Incorrect user password, with ERROR 1045 reported
          • Transaction timed out, with ERROR 4012 reported
          • User locked, with ERROR 3118 reported
          • Idle transaction timed out, with ERROR 6002 reported
          • Table already exists, with ERROR 1050 reported
          • Duplicate data inserted, with ERROR 1062 reported
          • Disconnected from the server, with ERROR 2013 reported
          • ERROR 1215 reported in foreign key addition
        • Troubleshooting guidelines
          • About error codes
          • Error handling specifications for MySQL-compatible applications
      • Connect to OceanBase Database
        • Connect to an OceanBase tenant by using OBClient
        • Connect to an OceanBase tenant by using the mysql client
        • Connect to OceanBase Database by using ODC
        • Overview
        • Connect to OceanBase Database by using DBeaver
        • Connect to OceanBase Database by using Navicat
        • Use database connection pool
          • HikariCP
          • Proxool
          • DBCP
          • Commons Pool
          • Druid
          • Database connection pool configuration
          • Connect to OceanBase Database by using a Tomcat connection pool
          • c3p0
      • Read data
        • Use a DBLink in queries
        • Single-table queries
        • Set operations
        • Use operators and functions in queries
          • Use aggregate functions in queries
          • Use numerical functions in queries
          • Use the SELECT ... LOCK IN SHARE MODE statement to lock query results
          • Use the CASE conditional operator in queries
          • Use type conversion functions in queries
          • Use datetime functions in queries
          • Use arithmetic operators in queries
          • Use string functions in queries
          • Use string concatenation operators in queries
          • Use NULL-related functions in queries
          • Use the SELECT ... FOR UPDATE statement to lock query results
        • Join tables
          • RIGHT JOIN queries
          • Lateral derived table
          • Subqueries
          • LEFT JOIN queries
          • INNER JOIN queries
          • FULL JOIN queries
      • Plan database objects
        • Create an external table
        • Create an index
        • Create a table group
        • Create a database
        • Create a table
      • Transactions
        • Roll back a transaction
        • Commit a transaction
        • Overview
        • Start a transaction
        • Savepoints
          • Mark a savepoint
          • Release a savepoint
          • Roll back a transaction to a savepoint
    • Develop applications (Oracle mode)
      • Sample applications
        • Java
          • Spring Boot
          • MyBatis
          • JFinal
          • OceanBase Connector/J
          • Spring Data JPA
          • Spring Data JDBC
          • Hibernate
          • Spring Batch
        • C/C++
          • OceanBase Connector/C
          • OceanBase Connector/ODBC
          • SqlSugar
      • Read data
        • Set operations
        • Single-table queries
        • Use a DBLink in queries
        • Join tables
          • INNER JOIN queries
          • RIGHT JOIN queries
          • LEFT JOIN queries
          • Subqueries
          • FULL JOIN queries
        • Use operators and functions in queries
          • Use arithmetic operators in queries
          • Use type conversion functions in queries
          • Use aggregate functions in queries
          • Use numerical functions in queries
          • Use string concatenation operators in queries
          • Use CASE functions in queries
          • Use the SELECT...FOR UPDATE statement to lock query results
          • Use string functions in queries
          • Use NULL-related functions in queries
          • Use datetime functions in queries
      • Connect to OceanBase Database
        • Overview
        • Connect to OceanBase Database by using ODC
        • Connect to an OceanBase tenant by using OBClient
        • Use database connection pool
          • c3p0
          • Database connection pool configuration
          • DBCP
          • HikariCP
          • Druid
          • Proxool
          • Tomcat
          • Commons Pool
      • Application errors
        • Common errors and troubleshooting practices
          • Transaction timed out, with Error ORA-00600 reported
          • Idle transaction timed out, with Error ORA-24761 reported
          • Duplicate data inserted, with Error ORA-00001 reported
          • Table does not exist, with Error ORA-04043 reported
          • Inconsistent data types, with Error ORA-00932 reported
          • User locked, with ERROR 3118 reported
          • Table already exists, with Error ORA-00955 reported
          • Error ORA-00600 reported in foreign key addition
          • Incorrect user password, with ERROR 1045 reported
        • Troubleshooting guidelines
          • Error handling specifications for Oracle-compatible applications
          • About error codes
      • Write data
        • Insert data
        • Update data
        • Delete data
        • Replace data
        • Generate test data in batches
      • Transactions
        • Overview
        • Start a transaction
        • Savepoints
          • Roll back a transaction to a savepoint
          • Mark a savepoint
        • Commit a transaction
        • Roll back a transaction
      • Plan database objects
        • Create a table group
        • Create a table
        • Create an index
        • Create an external table
  • Deploy
    • Delete old clusters
    • Overview
    • High availability deployment solutions for OceanBase clusters
    • Deploy OceanBase Database Community Edition
      • Overview
      • Deploy locally
        • Deploy OceanBase Database in a production environment by using the command line
        • Software and hardware requirements
        • Deploy OceanBase Database by using systemd
        • Before deployment
          • (Optional) Check resources
          • (Optional) Set password-free SSH logon
          • (Optional) Configure the clock source
          • (Optional) Perform disk planning
          • (Optional) Configure limits.conf
          • (Optional) Configure sysctl.conf
          • (Optional) Disable the firewall and SELinux
          • (Optional) Create a user
        • Deploy through GUI
          • Deploy an OceanBase cluster through the GUI of OCP
          • Deploy an OceanBase cluster through the GUI of OBD
      • Deploy OceanBase Database in a Kubernetes cluster
    • Deploy OceanBase Database Enterprise Edition
      • Deployment process
      • Deploy through GUI
        • (Optional) Deploy ODP
        • Deploy OceanBase clusters using OCP
          • Deploy a two-replica OceanBase cluster with the arbitration service by using OCP
          • Deploy a three-replica OceanBase cluster by using OCP
          • Deploy a single-replica OceanBase cluster by using OCP
        • Configure deployment environment using OAT
          • Add a server
        • Deploy OCP
          • Deploy OCP
          • Create MetaDB
          • Upload installation packages
          • Overview
      • Deploy through CLI
        • Configure deployment environment
          • Initialize an OBServer node using oatcli
          • (Optional) Configure the clock source
        • Deploy OceanBase clusters using CLI
          • Deploy an OceanBase cluster with two replicas and arbitration service using the CLI
          • Deploy a three-replica OceanBase cluster using the CLI
          • Deploy a single-replica OceanBase cluster using the CLI
        • (Optional) Deploy ODP
      • Before deployment
        • Deploy OAT
        • Prepare the installation packages
        • Server configuration
        • Prepare servers
  • Migrate
    • Import data from SQL files to OceanBase Database
    • Overview
    • Migrate from DB2 databases to OceanBase Database
      • Use OMS to migrate data from a DB2 LUW database to a MySQL tenant of OceanBase Database
      • Use OMS to migrate data from a DB2 LUW database to an Oracle tenant of OceanBase Database
      • Use DBCAT to migrate table schemas from a DB2 LUW database to OceanBase Database
    • Migrate from Oracle databases to OceanBase Database
      • Use OMS to migrate data from an Oracle database to a MySQL tenant of OceanBase Database
      • Use OMS to migrate data from an Oracle database to an Oracle tenant of 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 MySQL databases
      • Use OMS to migrate data from a MySQL tenant of OceanBase Database to a MySQL database
      • Use OMS to migrate incremental data from an Oracle tenant of OceanBase Database to a MySQL database
      • 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
      • Use Flink CDC to migrate data from OceanBase Database to a MySQL database
      • Migrate data from a MySQL database in OceanBase Database to a MySQL database using ChunJun
    • Migrate data between OceanBase Database
      • Use OBLOADER & OBDUMPER to migrate data from a MySQL tenant to an Oracle tenant in OceanBase Database
      • Use OMS to migrate data from an OceanBase tenant to another of the same type
      • Use OMS to migrate data from an OceanBase tenant to another of the same type in active-active disaster recovery scenarios
      • Use OBLOADER & OBDUMPER to migrate data between Oracle tenants in OceanBase Database
      • Use OBLOADER & OBDUMPER to migrate data between MySQL tenants in OceanBase Database
      • Use OBLOADER & OBDUMPER to migrate data from an Oracle tenant to a MySQL tenant in OceanBase Database
    • Bypass import
      • Import data in bypass mode by using the INSERT INTO SELECT statement
      • Import data in bypass mode by using the LOAD DATA statement
      • Overview
    • Migrate from MySQL databases to OceanBase Database
      • Use Flink CDC to synchronize data from a MySQL database to OceanBase Database
      • Use OMS to migrate data from a MySQL database to a MySQL tenant of OceanBase Database
      • Use mydumper and myloader to migrate data from a MySQL database to OceanBase Database
      • Use ChunJun to migrate data from a MySQL database to OceanBase Database
      • Migrate data from a MySQL database to OceanBase Database using CloudCanal
      • Use DataX to migrate table data from a MySQL database to OceanBase Database
      • Use DBCAT to migrate schemas from a MySQL database to OceanBase Database
      • Use Canal to synchronize data from a MySQL database to OceanBase Database
    • Migrate from CSV files to OceanBase Database
      • Import data by using the LOAD DATA statement
      • Use DataX to migrate CSV files 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
      • Use OMS to migrate data from an Oracle tenant of OceanBase Database to an Oracle database
    • Migrate from PostgreSQL databases to OceanBase Database
      • Use OMS to migrate data from a PostgreSQL database to a MySQL tenant of OceanBase Database
    • Migrate data using SQL statements
      • Export data by using OUTFILE statements
      • Migrate resource units
      • Migrate data between tables
    • Migrate from OceanBase Database to DB2 databases
      • Use OMS to migrate data from a MySQL tenant of OceanBase Database to a DB2 LUW database
      • Use OMS to migrate data from an Oracle tenant of OceanBase Database to a DB2 LUW database
    • Migrate from TiDB databases to OceanBase Database
      • Use OMS to migrate data from a TiDB database to a MySQL tenant of OceanBase Database
  • Manage
    • Log on to an OceanBase tenant
    • Manage replicas
      • Overview
      • Replica distribution
        • Locality
        • Common locality operations
          • View locality
          • Adjust the distribution of replicas
          • Remove replicas
          • Add replicas
          • View the locality change history
          • Migrate units
          • Modify locality
      • Traffic distribution
      • Data distribution
    • Performance tuning
      • Overview
      • Identify bottlenecks on the data link
      • Identify bottlenecks within components
        • ODP performance bottlenecks
        • ODP performance analysis
        • OBServer performance bottlenecks
          • Overview
          • Non-optimal plan
            • Non-optimal plan
            • Cardinality
            • Buffer tables
          • Hard parsing
          • Capacity issues
          • Internal wait events
      • SQL tuning
        • SQL tuning system
        • Execution plan optimization
          • Order and limit optimization
            • Overview
            • Optimization in ORDER BY + LIMIT scenarios
            • SORT assignment and optimization
          • Plan management
            • Plan cache
            • Disadvantages of the plan cache and countermeasures
            • Views related to the plan cache
          • Statistical information and row estimation
            • Overview
            • Use statistical information and row estimation
            • Statistical information
              • Query statistics
              • Overview
              • Manage statistical information
                • Overview
                • Lock statistics
                • Configure statistics collection strategies
                • Query historical versions of statistics and roll back to a specified version
                • Delete and set statistics
                • Import and export statistics
              • Collect statistical information
                • Automatic statistics collection
                • Overview
                • Manually collect statistics
            • Row estimation
              • Row estimation based on the selectivity
              • Overview
              • Row estimation based on the storage layer
          • Join order and join algorithm
            • Join order
            • Join types
            • Joins
            • Join algorithm
              • Nested loop joins
              • Common business issues
              • Hash joins
              • Merge joins
          • Index selection
            • Reduce row reads
            • Avoid sorting
            • Overview
            • Avoid table access by index primary key
        • Business logic optimization
          • SQL specifications
          • Schema specifications
        • Locate and analyze slow queries I
        • Locate and analyze slow queries (II)
        • Typical scenarios and cases
    • Daily inspection
      • Deadlock detection
      • Overview
      • Check tenant resource usage
      • Check cluster parameters
      • Check cluster resource usage
      • Check the host status
      • Check the NTP offset
      • Check the OBServer node status
      • End-to-end tracing
        • Show end-to-end tracing information
        • Process
        • Methods
        • Overview
    • Manage clusters
      • Overview
      • Cluster parameters
      • Common cluster operations
        • Delete a zone
        • Isolate a zone
        • Add a zone
        • Reset a cluster parameter
        • Restart a node
        • Delete a node
        • Modify a zone
        • Modify cluster parameters
        • Isolate a node
        • View cluster parameters
        • View a zone
        • Add a node
        • Start a zone
        • View a node
        • Replace a node
      • Troubleshoot common problems
        • Failures of a minority of nodes
        • Failures of the majority of nodes
    • Security and permissions
      • Overview
      • Access control
        • Network security access control
        • Row-level access control
        • RPC connection authentication
        • Overview
        • Users and permissions
          • Overview
          • MySQL mode
            • Privilege delegation
            • Drop a user
            • Lock or unlock a user
            • Grant privileges
            • Modify user privileges
            • Query user privileges
            • Create a user
            • Privilege types in MySQL mode
          • Oracle mode
            • Privilege types in Oracle mode
            • Modify user privileges
            • Grant indirect privileges
            • Query user privileges
            • Create a user
            • Privilege delegation
            • View the information of a user
            • Grant direct privileges
            • Drop a user
            • Lock or unlock a user
            • Manage roles
              • View roles
              • Create a role
              • Grant a role to a user
              • Overview
              • Activate or deactivate roles for a user
              • Revoke a role
              • Drop a role
              • Modify a role
              • Grant a role to another role
      • Transparent data encryption
        • Overview
        • MySQL mode
          • Enable transparent data encryption for existing tables
          • Decrypt a table
          • Enable transparent data encryption for new tables
        • Oracle mode
          • Decrypt a table
          • Enable transparent data encryption for existing tables
          • Enable transparent data encryption for new tables
      • Identification and authentication
        • MySQL mode
          • Identity authentication
          • Password complexity
          • Logon failure processing
        • Oracle mode
          • Identity authentication
          • Password complexity
          • Logon failure processing
      • 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
      • Data transmission encryption
        • ODP transmission encryption
        • OBServer transmission encryption
        • Overview
    • Backup and restore
      • Introduction to physical backup and restore
      • Experience physical backup and restore with simplified deployment
      • Deploy NFS
      • Optimize backup and restore performance
      • Restore by table
        • Preparations
        • Parameters related to table restore
        • View the table restore result
        • Views related to table restore
        • View the table restore progress
        • Restore data by table
        • Cancel table restore
      • 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
      • Log archive
        • Overview
        • Disable ARCHIVELOG
        • Change the log archive destination
        • View information about pieces
        • Views related to log archiving
        • View the archiving progress
        • Prepare for log archiving
        • View the archiving history
        • Suspend archiving
        • View archiving parameter settings
        • Enable ARCHIVELOG
      • Restore data
        • Replay logs to a standby tenant
        • Physical restore parameters
        • Views related to physical restore
        • Convert a standby tenant into primary tenant
        • Cancel physical restore
        • Preparations
        • Upgrade a tenant after restore
        • View the physical restore progress
        • View physical restore results
        • Perform physical restore
      • Data backup
        • Overview
        • Prepare for the backup
        • 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 for monitoring backup progress and results
    • Emergency response
      • Emergency response overview
      • Analysis, diagnosis, and decision-making procedure
      • Common emergency problem handling
        • Capacity issues
          • Node data disk full
          • obproxy thread exhaustion
          • Exceptions of SQL queries
          • Tenant memory full
          • Node network card overload
          • Tenant request queue backlog
          • Node disk I/O high
          • Node clog disk full
        • Hardware issues
          • Other hardware and network issues
          • Node failure
          • ODP failure
          • Network failure
        • Other cluster issues
          • Insufficiency or leakage of system memory
          • sys tenant or RootService exceptions
    • High availability
      • Flashback queries
      • High availability overview
      • Physical standby database disaster recovery
        • Overview
        • Limitations
        • Create a standby tenant
          • Preparations
          • Create an empty standby tenant
          • Create a standby tenant by using the backup and recovery feature
          • Create a standby tenant by using the BACKUP DATABASE PLUS ARCHIVELOG feature
        • Log transmission service
          • Overview
          • Configure log transmission service
            • Configure the log restore source
            • Set the log recovery endpoint
          • View log restore source information
          • View the log synchronization progress
          • Pause or resume log synchronization
          • Optimize the log synchronization performance
          • Set the log synchronization bandwidth limit
          • Set log synchronization compression
        • Log storage service
        • Switch roles
          • Switchover
          • Overview of tenant roles
          • Failover
        • Drop primary and standby tenants
      • Multi-replica disaster recovery
        • Disaster recovery architecture and levels
        • ODP high availability
        • Database-level high availability
        • Data link introduction
      • Arbitration high availability
        • Enable the arbitration service for a tenant
        • Remove the arbitration service for a cluster
        • Disable the arbitration service for a tenant
        • Query log stream upgrade/downgrade information
        • Replace the arbitration service for a cluster
        • Clear residual cluster information
        • Overview
        • Modify the log stream downgrade control time
      • Manage recycle bin
        • Overview
        • Enable or disable the recycle bin
        • View objects in the recycle bin
        • Restore objects from the recycle bin
        • Purge the recycle bin
    • Manage tenants
      • Tenant introduction
      • Tenant capacity
      • Tenant types
      • User tenant introduction
      • Tenant system variables
      • Common tenant operations
        • Create a tenant
        • Resource isolation
          • Resource isolation overview
          • Manage resource isolation (Oracle mode)
            • Configure SQL statement-level resource isolation
            • Update a resource management plan config
            • Configure cgroups
            • Delete a resource management plan
            • Configure user-level resource isolation
            • Delete a resource management plan config
            • Clear cgroup configurations
            • Calibrate the disk performance
            • Delete a resource group
          • Manage resource isolation (MySQL mode)
            • Configure cgroups
            • Calibrate the disk performance
            • Configure user-level resource isolation
            • Configure SQL statement-level resource isolation
            • Update a resource management plan config
            • Delete a resource management plan config
            • Delete a resource management plan
            • Delete a resource group
            • Clear cgroup configurations
        • View tenant and resource information
        • View and set the tenant allowlist
        • View tenant system variables
        • Modify system variables of a tenant
        • Scale in/out
          • Introduction to scaling in/out
          • 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 attributes of a resource pool
        • Modify attributes of a tenant
        • Lock and unlock a tenant
        • Clone a tenant
        • Cancel tenant cloning
        • Drop a tenant
        • Recover a tenant
        • Rename a tenant
        • Manage resource pools
          • View resource pool information
          • Allocate a resource pool to a tenant
          • Remove resource pools from a tenant
          • Merge and split resource pools
          • Drop a resource pool
        • Manage unit configs
          • Query unit configs
          • Modify unit configs
          • Drop unit configs
    • Troubleshooting
      • Overview
      • Bootstrap
      • Storage
        • Migration, replication, and rebuild tasks
        • Minor compaction and major compaction
        • Memory-related errors
      • Election
        • Election
        • Leader switchover exceptions
        • Absence of the leader
      • Transaction
        • Suspended transactions
        • Long-running transactions
        • Transaction-related errors
        • Transaction rollbacks
        • Idle transactions
      • Log synchronization-related errors
      • Physical standby database
        • Switchover failures
        • Log synchronization stuck for the physical standby database
      • Backup and restore
        • Physical restore failures
        • Data backup failures
      • Troubleshoot SQL execution errors
      • Application exception -- error message does not contain OceanBase error code
      • Application exception -- error message contains an OceanBase error code
    • Monitor
      • Overview
      • Cases
      • Metrics
        • System monitoring
          • Wait events
          • Metrics
          • Latch events
          • Overview
        • SQL monitoring
          • Overview
          • SQL audit
          • Execution plans
    • Logs
      • Overview
      • Log levels
      • Log stability
      • Log control
      • Log metrics
      • View logs
        • Query the log of a previous SQL request by using the SQL Trace feature
        • Search for the logs of a specific SQL request
  • Reference
    • SQL reference
      • Reserved keywords (Oracle mode)
      • Reserved keywords (MySQL mode)
      • SQL syntax
        • User tenants (MySQL mode)
          • Basic elements
            • Data types
              • SET type
              • Overview
              • ENUM type
              • Datetime types
                • TIME type
                • DATE, DATETIME, and TIMESTAMP types
                • Overview
                • YEAR type
              • Numeric types
                • Overview
                • Integer data types
                • Fixed-point data types
                • Floating-point data types
                • Bit value data type
              • Spatial data types
                • Overview
                • SRS
                • Create a spatial column
                • Create a spatial index
                • Spatial data formats
              • Large objects and text types
                • TEXT types
                • LOB type
                • Overview
                • BLOB types
              • JSON data types
                • Overview
                • Create a JSON value
                • Query and modify JSON values
                • Convert a JSON data type
              • String types
                • Overview
                • CHAR and VARCHAR
                • BINARY and VARBINARY
            • Expressions
              • Convert data types in expression evaluation
              • Expression syntax
              • Overview
            • 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
            • Literals
              • Overview
              • Strings
              • NULLs
              • Boolean values
              • Bit values
              • Numbers
              • Datetime values
            • Schema object names
            • User-defined variables
            • Comments
          • Operators
            • Bitwise operators
            • Date and time operators
            • CASE conditional operator
            • Operator precedence
            • Logical operators
            • BINARY operator
            • Assignment operators
            • Arithmetic operators
            • Overview
            • Concatenation operators
            • Comparison operators
          • Sequence pseudocolumns
          • Functions
            • Overview
            • Single-row functions
              • Mathematical functions
                • COS
                • GENERATOR
                • ZIPF
                • RANDOM
                • ACOS
                • CONV
                • ABS
                • LOG2
                • TAN
                • EXP
                • LOG10
                • ATAN
                • RAND
                • DEGREES
                • FLOOR
                • ATAN2
                • BIT_COUNT
                • LOG
                • POWER
                • CEIL
                • SIGN
                • PI
                • MOD
                • TRUNCATE
                • RADIANS
                • NEG
                • UNIFORM
                • NORMAL
                • SQRT
                • LN
                • ASIN
                • CRC32
                • RANDSTR
                • CEILING
                • POW
                • SIN
                • ROUND
                • COT
              • Datetime functions
                • FROM_DAYS
                • CURRENT_TIMESTAMP
                • TIME
                • SUBTIME
                • DATE_FORMAT
                • FROM_UNIXTIME
                • UTC_DATE
                • DATE_ADD
                • LOCALTIME
                • GET_FORMAT
                • USEC_TO_TIME
                • SECOND
                • TIME_TO_SEC
                • QUARTER
                • LAST_DAY
                • TIME_FORMAT
                • SEC_TO_TIME
                • MICROSECOND
                • CURRENT_DATE
                • YEARWEEK
                • TO_SECONDS
                • MINUTE
                • MAKEDATE
                • TIMESTAMPADD
                • YEAR
                • PERIOD_DIFF
                • SUBDATE
                • DAYOFYEAR
                • SYSDATE
                • UTC_TIMESTAMP
                • HOUR
                • CURDATE
                • DAYOFWEEK
                • TIMEDIFF
                • STR_TO_DATE
                • MONTH
                • WEEK
                • EXTRACT
                • MAKETIME
                • DAY
                • UNIX_TIMESTAMP
                • WEEKDAY
                • ADDTIME
                • CURTIME
                • DAYNAME
                • DAYOFMONTH
                • DATE_SUB
                • TIMESTAMPDIFF
                • CURRENT_TIME
                • UTC_TIME
                • PERIOD_ADD
                • WEEKOFYEAR
                • NOW
                • DATEDIFF
                • TO_DAYS
                • MONTHNAME
                • CONVERT_TZ
                • ADDDATE
                • DATE
                • LOCALTIMESTAMP
                • TIMESTAMP
                • TIME_TO_USEC
              • String functions
                • UNHEX
                • RTRIM
                • UCASE
                • REPLACE
                • LOWER
                • CONCAT_WS
                • REGEXP_SUBSTR
                • OCTET_LENGTH
                • LEFT
                • REGEXP_REPLACE
                • REGEXP_LIKE
                • WEIGHT_STRING
                • CONCAT
                • IP2INT
                • LPAD
                • BIN
                • RPAD
                • SUBSTRING
                • SPACE
                • FORMAT
                • MAKE_SET
                • REPEAT
                • ASCII
                • LOCATE
                • FROM_BASE64
                • SOUNDEX
                • INSERT
                • TO_BASE64
                • OCT
                • FIELD
                • QUOTE
                • CHARACTER_LENGTH
                • HEX
                • RLIKE
                • POSITION
                • REVERSE
                • REGEXP
                • STRCMP
                • EXPORT_SET
                • INSTR
                • SUBSTR
                • SUBSTRING_INDEX
                • BIT_LENGTH
                • REGEXP_INSTR
                • MID
                • LCASE
                • UPPER
                • ORD
                • ELT
                • LENGTH
                • CHAR
                • TRIM
                • CHAR_LENGTH
                • RIGHT
                • FIND_IN_SET
                • INT2IP
                • LTRIM
              • Comparison functions
                • INTERVAL
                • LEAST
                • GREATEST
                • ISNULL
              • Conversion functions
                • CAST
                • CONVERT
                • SCN_TO_TIMESTAMP
                • TIMESTAMP_TO_SCN
              • Process control functions
                • IF
                • NULLIF
                • IFNULL
                • ORA_DECODE
                • CASE
            • Aggregate functions
              • VAR_POP
              • GROUPING
              • GROUP_CONCAT
              • STD
              • COUNT
              • VARIANCE
              • STDDEV_POP
              • MIN
              • BIT_AND
              • SUM
              • BIT_XOR
              • AVG
              • STDDEV
              • APPROX_COUNT_DISTINCT
              • VAR_SAMP
              • MAX
              • BIT_OR
              • STDDEV_SAMP
            • 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
              • RANDOM_BYTES
              • DES_ENCRYPT
              • COMPRESS
              • UNCOMPRESS
              • SHA1
              • SHA2
              • AES_ENCRYPT
              • DES_DECRYPT
              • ENCODE
              • UNCOMPRESSED_LENGTH
              • ENCRYPT
              • MD5
              • DECODE
              • SHA
              • VALIDATE_PASSWORD_STRENGTH
            • Information functions
              • SESSION_USER
              • SCHEMA
              • BENCHMARK
              • LAST_INSERT_ID
              • SYSTEM_USER
              • ICU_VERSION
              • CONNECTION_ID
              • COERCIBILITY
              • FOUND_ROWS
              • VERSION
              • CURRENT_USER
              • USER
              • COLLATION
              • CHARSET
              • ROW_COUNT
              • DATABASE
              • OB_VERSION
              • OB_TRANSACTION_ID
            • JSON functions
              • Overview
              • JSON_TABLE
              • Search JSON text functions
                • JSON_OVERLAPS
                • JSON_EXTRACT
                • JSON_KEYS
                • JSON_CONTAINS
                • JSON_CONTAINS_PATH
                • MEMBER OF
                • JSON_SEARCH
                • JSON_VALUE
              • Return JSON text property functions
                • JSON_DEPTH
                • JSON_LENGTH
                • JSON_TYPE
                • JSON_VALID
              • Modify JSON text functions
                • JSON_REPLACE
                • JSON_MERGE_PATCH
                • JSON_MERGE
                • JSON_SET
                • JSON_UNQUOTE
                • JSON_REMOVE
                • JSON_INSERT
                • JSON_ARRAY_INSERT
                • JSON_ARRAY_APPEND
                • JSON_MERGE_PRESERVE
              • Create JSON text functions
                • JSON_OBJECT
                • JSON_QUOTE
                • JSON_ARRAY
              • JSON aggregate functions
                • JSON_ARRAYAGG
                • JSON_OBJECTAGG
              • JSON utility functions
                • JSON_PRETTY
                • JSON_STORAGE_SIZE
            • Spatial functions
              • Spatial relation functions
              • Functions that create geometry values
              • Geometry property functions
              • Geometry format conversion functions
              • Spatial operation functions
            • Performance schema functions
              • FORMAT_BYTES
              • FORMAT_PICO_TIME
            • 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
          • Queries and subqueries
            • Joins
            • Overview
            • Subqueries
          • SQL statements
            • General syntax
            • Common Table Expressions
            • ALTER DATABASE
            • ALTER OUTLINE
            • ALTER EXTERNAL TABLE
            • ALTER SEQUENCE
            • MAJOR and MINOR
            • ALTER TABLE
            • ALTER TABLEGROUP
            • ALTER TABLEGROUP
            • ALTER USER
            • ALTER VIEW
            • ANALYZE
            • CREATE DATABASE
            • CREATE DATABASE LINK
            • CREATE INDEX
            • CREATE EXTERNAL TABLE
            • CREATE MATERIALIZED VIEW
            • CREATE MATERIALIZED VIEW LOG
            • CREATE OUTLINE
            • CREATE RESTORE POINT
            • CREATE SEQUENCE
            • CREATE TABLE
            • CREATE TABLEGROUP
            • CREATE TABLESPACE
            • CREATE USER
            • CREATE VIEW
            • DEALLOCATE PREPARE
            • DROP DATABASE LINK
            • DELETE
            • DESCRIBE
            • DROP DATABASE
            • DROP INDEX
            • DROP MATERIALIZED VIEW
            • DROP MATERIALIZED VIEW LOG
            • DROP OUTLINE
            • DROP TABLE
            • DROP TABLEGROUP
            • DROP TABLESPACE
            • 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 statement
              • OVER clause
              • JOIN clause
              • UNION clause
            • SET
            • SET CHARSET
            • SET NAMES
            • SET PASSWORD
            • SET TRANSACTION
            • SHOW
            • TRANSACTION
            • TRUNCATE TABLE
            • UPDATE
            • USE
            • VALUES
          • DDL feature
            • Column type change rules
            • Generated column operations
            • Column operations
            • Foreign key operations
            • Partition operations
            • Overview
            • Online and offline DDL operations
            • Primary key operations
            • Index operations
            • Conversion rules for numeric data types
            • Table operations
        • User tenants (Oracle mode)
          • Introduction to SQL
          • Pseudo columns
            • Sequence pseudocolumns
            • Overview
            • ORA_ROWSCN pseudocolumn
            • ROWNUM pseudocolumn
            • Hierarchical query pseudocolumns
            • ROWID pseudocolumn
          • Basic elements
            • Character sets and collations
            • Built-in data types
              • Rowid data types
              • Any types
              • RAW data type
              • Overview
              • User-defined data types
              • Numeric data types
                • Precedence of numeric data types
                • NUMBER data type
                • FLOAT data type
                • Overview
                • Floating-point numbers
              • Datetime and interval data types
                • INTERVAL YEAR TO MONTH data type
                • TIMESTAMP data type
                • TIMESTAMP WITH TIME ZONE data type
                • DATE data type
                • INTERVAL DAY TO SECOND data type
                • Calculation of dates, timestamps, and intervals
                • TIMESTAMP WITH LOCAL TIME ZONE data type
                • Overview
              • Large object data types
                • CLOB data type
                • BLOB data type
                • Overview
              • JSON data types
                • Create JSON columns
                • Query JSON data
                • Overview
                • Conversion rules for JSON data types
              • Character data types
                • CHAR data type
                • Overview
                • NVARCHAR2 data type
                • NCHAR data type
                • VARCHAR2 data type
                • VARCHAR data type
              • XML data types
                • Query XMLType data
                • XML data definition
                • Convert XMLType data
                • Create an XMLType column
                • Overview
            • Database objects
              • Schema objects
              • Non-schema objects
            • Database naming conventions
              • Suggestions on schema object names
              • Overview
            • Annotations
              • Overview
              • Comments within SQL statements
              • Comments on schema and non-schema objects
              • Hints
                • 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 object reference methods
              • Reference an attribute or method of an object type
              • Overview
              • Reference partitioned tables and indexes
              • Reference schema objects
              • Reference objects in a remote database
                • Create a DBLink
                • Reference a DBLink
            • Literals
              • Overview
              • Text literals
              • Numeric literals
              • Datetime literals
                • Date literals
                • Timestamp literals
              • Interval literals
            • Data type comparison rules
              • Data type conversion rules
              • Date value comparison rules
              • Overview
              • Security considerations for data conversion
              • Numeric value comparison rules
              • Data type precedence
              • Character value comparison rules
            • Format model
              • Number format models
              • RR datetime format element
              • Datetime format models
              • Overview
              • String-to-date conversion rules
            • NULL value
              • Overview
              • NULLs in comparison conditions
              • NULLs in SQL functions
              • NULLs in conditional expressions
          • Operators
            • Arithmetic operators
            • Set operators
            • COLLATE operator
            • Operator precedence
            • Overview
            • Hierarchical query operators
            • Concatenation operator
          • Functions
            • Overview
            • Single-row functions
              • Numeric functions
                • ABS
                • ACOS
                • ASIN
                • ATAN
                • ATAN2
                • BITAND
                • CEIL
                • COS
                • COSH
                • EXP
                • FLOOR
                • LN
                • GENERATOR
                • LOG
                • MOD
                • NANVL
                • NORMAL
                • POWER
                • REMAINDER
                • ROUND
                • RANDOM
                • RANDSTR
                • SIGN
                • SIN
                • SINH
                • SQRT
                • TAN
                • TANH
                • TRUNC
                • UNIFORM
                • WIDTH_BUCKET
                • ZIPF
              • String functions that return a string
                • CONCAT
                • INITCAP
                • CHR
                • NLS_LOWER
                • REPLACE
                • LPAD
                • SUBSTR
                • LTRIM
                • NLSSORT
                • TRANSLATE ... USING
                • TRIM
                • UPPER
                • REGEXP_REPLACE
                • TRANSLATE
                • RTRIM
                • RPAD
                • LOWER
                • NLS_UPPER
                • REGEXP_SUBSTR
              • String functions that return numbers
                • INSTR
                • LENGTH
                • ASCII
                • REGEXP_COUNT
                • REGEXP_INSTR
              • Datetime functions
                • 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
                • TO_CHAR(number)
                • TO_TIMESTAMP
                • RAWTOHEX
                • ASCIISTR
                • TO_DATE
                • TO_NCHAR(character)
                • TO_NCHAR(number)
                • TO_YMINTERVAL
                • TO_MULTI_BYTE
                • SCN_TO_TIMESTAMP
                • TO_BLOB
                • CHARTOROWID
                • CONVERT
                • TO_BINARY_DOUBLE
                • ROWIDTONCHAR
                • TO_DSINTERVAL
                • TO_NUMBER
                • TIMESTAMP_TO_SCN
                • TO_CHAR(datetime)
                • TO_BINARY_FLOAT
                • NUMTOYMINTERVAL
                • TO_CLOB
                • NUMTODSINTERVAL
                • UNISTR
                • HEXTORAW
                • TO_CHAR(character)
                • ROWIDTOCHAR
                • TO_NCHAR(datetime)
                • TO_TIMESTAMP_TZ
                • CAST
                • TO_SINGLE_BYTE
              • Encoding and decoding functions
                • ORA_HASH
                • DECODE
                • VSIZE
                • DUMP
              • Null value related functions
                • NULLIF
                • NVL2
                • COALESCE
                • NANVL
                • NVL
                • LNNVL
              • Environment and identifier functions
                • SYS_CONTEXT
                • SYS_GUID
                • UID
                • USER
                • USERENV
                • OB_VERSION
              • Hierarchical functions
                • SYS_CONNECT_BY_PATH
              • JSON functions
                • Overview
                • Modify JSON text functions
                  • JSON_MERGEPATCH
                • Create JSON text functions
                  • JSON_ARRAY
                  • JSON_OBJECTAGG
                  • JSON_ARRAYAGG
                  • JSON_OBJECT
                • Query JSON text functions
                  • JSON_VALUE
                  • JSON_QUERY
                  • JSON_EXISTS
                  • JSON_TABLE
                • Validate JSON text functions
                  • JSON_EQUAL
              • XML functions
                • Overview
                • Construct XMLType data functions
                  • XMLAGG
                  • XMLATTRIBUTES
                  • XMLPARSE
                  • XMLELEMENT
                • Modify XMLType data functions
                  • UPDATEXML
                • Query XMLType data functions
                  • EXTRACTVALUE
                  • XMLSERIALIZE
                  • XMLCAST
                  • EXTRACT
            • Aggregate functions
              • WMSYS.WM_CONCAT/WM_CONCAT
              • GROUPING
              • COVAR_POP
              • GROUPING_ID
              • PERCENTILE_DISC
              • LISTAGG
              • ROLLUP
              • VAR_SAMP
              • GROUP_ID
              • STDDEV_POP
              • SUM
              • MAX
              • VAR_POP
              • CORR
              • AVG
              • STDDEV_SAMP
              • STDDEV
              • MIN
              • PERCENT_RANK
              • VARIANCE
              • CUME_DIST
              • PERCENTILE_CONT
              • RANK
              • REGR_(Linear Regression)
              • DENSE_RANK
              • APPROX_COUNT_DISTINCT
              • MEDIAN
              • KEEP
              • COVAR_SAMP
              • COUNT
            • 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
            • Information functions
              • OB_TRANSACTION_ID
          • Expressions
            • Function expressions
            • Datetime expressions
            • Column expressions
            • Compound expressions
            • Scalar subquery expressions
            • Overview
            • Case expressions
            • Expression list
            • Interval expressions
            • CURSOR expressions
            • Type constructor expressions
            • Simple expressions
          • 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
            • DUAL table query
            • Simple query
            • Hierarchical query
            • Subquery
            • Join query
            • Compound query
            • Overview
          • SQL statements
            • DDL
              • ALTER EXTERNAL TABLE
              • 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 EXTERNAL TABLE
              • CREATE INDEX
              • CREATE KEYSTORE
              • CREATE MATERIALIZED VIEW
              • CREATE MATERIALIZED VIEW LOG
              • CREATE OUTLINE
              • CREATE PROFILE
              • CREATE ROLE
              • CREATE SEQUENCE
              • CREATE SYNONYM
              • CREATE TABLE
              • CREATE TABLEGROUP
              • CREATE TABLESPACE
              • CREATE USER
              • CREATE VIEW
              • DROP CONTEXT
              • DROP DATABASE LINK
              • DROP DIRECTORY
              • DROP INDEX
              • DROP MATERIALIZED VIEW
              • DROP MATERIALIZED VIEW LOG
              • DROP OUTLINE
              • DROP PROFILE
              • DROP ROLE
              • DROP SEQUENCE
              • DROP SYNONYM
              • DROP TABLE
              • DROP TABLEGROUP
              • DROP TABLESPACE
              • DROP USER
              • DROP VIEW
              • RENAME
              • TRUNCATE TABLE
              • MAJOR and MINOR
            • DML
              • UPDATE
              • MERGE
              • PURGE
              • EXPLAIN
              • INSERT
              • DELETE
              • SELECT
                • Set-based SELECT
                • SIMPLE SELECT
                • WITH clause
            • DCL
              • SET PASSWORD
              • TRANSACTION
              • GRANT
              • SHRINK
              • SET VARIABLE
              • SET NAMES
              • AUDIT
              • ANALYZE
              • FLASHBACK TABLE BEFORE DROP
              • ALTER SYSTEM KILL SESSION
              • LOAD DATA
              • LOCK TABLE
              • COMMENT
              • COMMIT
              • REVOKE
              • SAVEPOINT
              • KILL
              • ROLLBACK
              • SHOW
              • SET ROLE
          • DDL feature
            • Overview
            • Online and offline DDL operations
            • Index operations
            • Primary key operations
            • Column operations
            • Generated column operations
            • Foreign key operations
            • Table operations
            • Partition operations
            • Column type change rules
            • Conversion rules for numeric data types
        • System tenants
          • ALTER RESOURCE UNIT
          • CREATE RESOURCE POOL
          • SET DECRYPTION
          • DROP RESOURCE UNIT
          • CREATE TENANT
          • CREATE RESOURCE UNIT
          • SET ENCRYPTION
          • ALTER RESOURCE POOL
          • ALTER RESOURCE TENANT
          • CREATE STANDBY TENANT
          • DROP TENANT
          • ALTER TENANT
          • DROP RESOURCE POOL
          • Overview
          • ALTER SYSTEM
            • ACTIVATE STANDBY
            • SET LOG_ARCHIVE_DEST
            • SET LOG_ARCHIVE_DEST_STATE
            • ARCHIVELOG
            • NOARCHIVELOG
            • ARBITRATION
            • BOOTSTRAP
            • BACKUP KEY
            • BACKUP
            • BALANCE TASK
            • CANCEL BACKUP
            • CANCEL CLONE
            • CANCEL DELETE BACKUP
            • CANCEL MIGRATE UNIT
            • CHANGE TENANT
            • CANCEL RESTORE
            • CANCEL RECOVER TABLE
            • MAJOR and MINOR
            • MIGRATE UNIT
            • DELETE BACKUP POLICY
            • FLUSH PLAN CACHE
            • JOB
            • SET LOG_RESTORE_SOURCE
            • PARAMETER
            • RECOVER STANDBY
            • RECOVER STANDBY CANCEL
            • REFRESH
            • RESTORE
            • RECOVER TABLE
            • SET DATA_BACKUP_DEST
            • SERVER
            • SWITCHOVER
            • THROTTLE
            • WASH MEMORY FRAGMENTATION
            • ZONE
      • PL reference
        • PL reference (Oracle mode)
          • Reserved PL keywords
          • DDL operations on stored PL units
            • Overview
            • DROP FUNCTION
            • CREATE PACKAGE BODY
            • CREATE TRIGGER
            • DROP TYPE BODY
            • CREATE FUNCTION
            • CREATE PACKAGE
            • CREATE PROCEDURE
            • DROP TYPE
            • DROP PROCEDURE
            • DROP TRIGGER
            • ALTER PACKAGE
            • CREATE TYPE
            • DROP PACKAGE
            • ALTER TRIGGER
            • ALTER PROCEDURE
            • CREATE TYPE BODY
            • ALTER TYPE
            • ALTER FUNCTION
          • PL static SQL
            • Transaction processing and control
            • Overview
            • Cursors
              • Overview
              • Cursor attributes
              • Implicit cursors
              • Explicit cursors
              • Cursor variables
              • Traverse cursor data by using the FOR loop
              • Modify and drop a cursor
            • Autonomous transactions
              • Call autonomous functions from SQL statements
              • Autonomous triggers
              • Control autonomous transactions
              • Overview
          • PL stored procedures and functions
            • Overview
            • Create a stored procedure
            • Create a function
            • Manage stored procedures and functions
            • Privilege control
            • Pipeline functions
              • Overview
              • Application
              • Create a pipelined table function
            • User-defined functions
              • Use user-defined aggregate functions
              • Overview
              • Interface for user-defined aggregate functions
              • Create user-defined aggregate functions
            • Collection of stored procedure information and its impact on parallel execution of SQL statements
            • PL DBLinks
          • 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
              • CLEAN_AUDIT_TRAIL
              • SET_LAST_ARCHIVE_TIMESTAMP
              • SET_PURGE_JOB_STATUS
              • Overview
              • CREATE_PURGE_JOB
              • DROP_PURGE_JOB
            • 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
              • RUN
              • Overview
              • SUBMIT
              • INTERVAL
              • BROKEN
              • ZONE
              • WHAT
              • USER_EXPORT
              • REMOVE
              • NEXT_DATE
              • CHANGE
            • DBMS_LOB
              • Overview
              • APPEND
              • CLOSE
              • COPY
              • CREATETEMPORARY
              • ERASE
              • FREETEMPORARY
              • GETLENGTH
              • ISOPEN
              • INSTR
              • ISTEMPORARY
              • OPEN
              • READ
              • SUBSTR
              • TRIM
              • WRITE
              • WRITEAPPEND
            • DBMS_LOCK
              • REQUEST
              • SLEEP
              • ALLOCATE_UNIQUE
              • ALLOCATE_UNIQUE_AUTONOMOUS
              • Overview
            • DBMS_METADATA
              • Overview
              • GET_DDL
            • DBMS_MVIEW
              • Overview
              • PURGE_LOG
              • REFRESH
            • DBMS_MONITOR
              • Overview
              • OB_SESSION_TRACE_ENABLE
              • OB_SESSION_TRACE_DISABLE
              • OB_CLIENT_ID_TRACE_ENABLE
              • OB_CLIENT_ID_TRACE_DISABLE
              • OB_MOD_ACT_TRACE_ENABLE
              • OB_MOD_ACT_TRACE_DISABLE
              • OB_TENANT_TRACE_ENABLE
              • OB_TENANT_TRACE_DISABLE
            • DBMS_MVIEW_STAT
              • Overview
              • PURGE_REFRESH_STATS
              • SET_MVREF_STATS_PARAMS
              • SET_SYSTEM_DEFAULT
            • DBMS_OUTPUT
              • Overview
              • DISABLE
              • ENABLE
              • GET_LINE
              • GET_LINES
              • NEW_LINE
              • PUT
              • PUT_LINE
            • DBMS_PLAN_CACHE
              • PURGE
              • Overview
            • DBMS_RANDOM
              • TERMINATE
              • STRING
              • Overview
              • RANDOM
              • NORMAL
              • SEED
              • INITIALIZE
              • VALUE
            • DBMS_RESOURCE_MANAGER
              • CREATE_PLAN
              • CREATE_PLAN_DIRECTIVE
              • DELETE_CONSUMER_GROUP
              • DELETE_PLAN
              • Overview
              • UPDATE_PLAN_DIRECTIVE
              • CREATE_CONSUMER_GROUP
              • DELETE_PLAN_DIRECTIVE
              • SET_CONSUMER_GROUP_MAPPING
            • DBMS_SCHEDULER
              • Overview
              • SET_ATTRIBUTE
              • DROP_JOB
              • DISABLE
              • SET_JOB_ARGUMENT_VALUE
              • GENERATE_JOB_NAME
              • ENABLE
              • RUN_JOB
              • DROP_PROGRAM
              • CREATE_PROGRAM
              • DEFINE_PROGRAM_ARGUMENT
              • CREATE_JOB
            • DBMS_SESSION
              • SET_CONTEXT
              • CLEAR_CONTEXT
              • SET_IDENTIFIER
              • CLEAR_IDENTIFIER
              • CLEAR_ALL_CONTEXT
              • Overview
              • RESET_PACKAGE
            • DBMS_SQL
              • DEFINE_ARRAY
              • EXECUTE_AND_FETCH
              • DESCRIBE_COLUMNS
              • Overview
              • BIND_VARIABLE
              • OPEN_CURSOR
              • EXECUTE
              • COLUMN_VALUE
              • CLOSE_CURSOR
              • LAST_ERROR_POSITION
              • IS_OPEN
              • DEFINE_COLUMN
              • PARSE
              • FETCH_ROWS
              • VARIABLE_VALUE
            • DBMS_STATS
              • GET_PARAM
              • LOCK_SCHEMA_STATS
              • LOCK_PARTITION_STATS
              • RESET_PARAM_DEFAULTS
              • UNLOCK_PARTITION_STATS
              • IMPORT_COLUMN_STATS
              • CREATE_STAT_TABLE
              • EXPORT_INDEX_STATS
              • EXPORT_SCHEMA_STATS
              • SET_SYSTEM_STATS
              • GATHER_INDEX_STATS
              • SET_GLOBAL_PREFS
              • GATHER_SCHEMA_STATS
              • COPY_TABLE_STATS
              • EXPORT_TABLE_STATS
              • RESET_GLOBAL_PREF_DEFAULTS
              • SET_PARAM
              • GATHER_SYSTEM_STATS
              • FLUSH_DATABASE_MONITORING_INFO
              • IMPORT_TABLE_STATS
              • UNLOCK_TABLE_STATS
              • IMPORT_SCHEMA_STATS
              • EXPORT_COLUMN_STATS
              • RESTORE_TABLE_STATS
              • GATHER_TABLE_STATS
              • PURGE_STATS
              • DELETE_SCHEMA_STATS
              • DELETE_TABLE_STATS
              • DELETE_TABLE_PREFS
              • GET_PREFS
              • SET_INDEX_STATS
              • DELETE_INDEX_STATS
              • DELETE_COLUMN_STATS
              • UNLOCK_SCHEMA_STATS
              • SET_TABLE_STATS
              • SET_TABLE_PREFS
              • ALTER_STATS_HISTORY_RETENTION
              • DELETE_SCHEMA_PREFS
              • RESTORE_SCHEMA_STATS
              • SET_COLUMN_STATS
              • DELETE_SYSTEM_STATS
              • Overview
              • DROP_STAT_TABLE
              • SET_SCHEMA_PREFS
              • GET_STATS_HISTORY_AVAILABILITY
              • LOCK_TABLE_STATS
              • GET_STATS_HISTORY_RETENTION
              • IMPORT_INDEX_STATS
            • DBMS_UDR
              • DISABLE_RULE
              • ENABLE_RULE
              • REMOVE_RULE
              • Overview
              • CREATE_RULE
            • DBMS_UTILITY
              • IS_CLUSTER_DATABASE
              • OLD_CURRENT_SCHEMA
              • GET_SQL_HASH
              • FORMAT_ERROR_BACKTRACE
              • DB_VERSION
              • FORMAT_ERROR_STACK
              • GET_ENDIANNESS
              • ACTIVE_INSTANCES
              • Overview
              • GET_HASH_VALUE
              • GET_PARAMETER_VALUE
              • PORT_STRING
              • TABLE_TO_COMMA
              • NAME_RESOLVE
              • GET_TIME
              • IS_BIT_SET
              • OLD_CURRENT_USER
              • FORMAT_CALL_STACK
              • NAME_TOKENIZE
              • CURRENT_INSTANCE
            • DBMS_WORKLOAD_REPOSITORY
              • Overview
              • ASH_REPORT
            • DBMS_XA
              • DBMS_XA_XID object type
              • XA_RECOVER
              • DBMS_XA constants
              • XA_PREPARE
              • XA_SETTIMEOUT
              • XA_GETLASTOER
              • XA_START
              • XA_END
              • XA_ROLLBACK
              • XA_FORGET
              • Overview
              • DIST_TXN_SYNC
              • XA_COMMIT
            • DBMS_XMLGEN
              • Overview
              • CONVERT
            • DBMS_XPLAN
              • Overview
              • DISPLAY_ACTIVE_SESSION_PLAN
              • DISPLAY_CURSOR
              • DISPLAY
              • DISABLE_OPT_TRACE
              • DISPLAY_SQL_PLAN_BASELINE
              • ENABLE_OPT_TRACE
              • SET_OPT_TRACE_PARAMETER
            • ODCIConst
              • ODCIStatsOptions.Options
              • ODCIIndexInfo.IndexParaDegree
              • ODCIEnv.CallProperty
              • Overview
              • ODCIIndexInfo.IndexInfoFlags
              • ODCIIndexAlter
              • ODCIStatsOptions.Flags
              • ScnFlg
              • ODCIIndexAlter parameter alter_option
              • ODCIArgDesc.ArgType
              • ODCIPredInfo.Flags
              • ODCIQueryInfo.Flags
              • Return Status
              • ODCIEnv.Envflags
            • 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
              • BIT_AND
              • CAST_TO_VARCHAR2
              • CAST_TO_BINARY_FLOAT
              • Overview
              • CAST_TO_RAW
              • CAST_FROM_BINARY_DOUBLE
              • BIT_OR
              • REVERSE
              • CAST_FROM_BINARY_FLOAT
              • CAST_TO_BINARY_DOUBLE
              • COMPARE
              • CONCAT
              • CAST_FROM_BINARY_INTEGER
              • BIT_XOR
              • CAST_FROM_NUMBER
              • CAST_TO_BINARY_INTEGER
              • SUBSTR
              • BIT_COMPLEMENT
              • COPIES
              • LENGTH
              • CAST_TO_NUMBER
            • ANYDATA TYPE
              • ENDCREATE member procedure
              • SET* member procedures
              • GETTYPE member function
              • Overview
              • GET* member functions
              • PIECEWISE member procedure
              • BEGINCREATE static procedure
              • GETTYPENAME member function
            • XMLType
              • CREATEXML
              • XMLTYPE
              • GETSTRINGVAL
              • Overview
              • TRANSFORM
              • GETCLOBVAL
          • PL triggers
            • Query trigger information
            • INSTEAD OF DML trigger
            • Create a DML trigger
            • Overview
            • Disable or enable a trigger
            • Modify and drop a trigger
            • Compound DML trigger
          • PL label security package
            • Overview
            • SA_SESSION session management package
              • Overview
              • SA_SESSION.LABEL
              • SA_SESSION.RESTORE_DEFAULT_LABELS
              • SA_SESSION.ROW_LABEL
              • SA_SESSION.SET_LABEL
              • SA_SESSION.SET_ROW_LABEL
            • SA_LABEL_ADMIN label management package
              • SA_LABEL_ADMIN.ALTER_LABEL
              • SA_LABEL_ADMIN.CREATE_LABEL
              • SA_LABEL_ADMIN.DROP_LABEL
              • Overview
            • SA_POLICY_ADMIN policy management package
              • Overview
              • SA_POLICY_ADMIN.APPLY_TABLE_POLICY
              • SA_POLICY_ADMIN.DISABLE_TABLE_POLICY
              • SA_POLICY_ADMIN.REMOVE_TABLE_POLICY
              • SA_POLICY_ADMIN.ENABLE_TABLE_POLICY
            • SA_USER_ADMIN user label management package
              • SA_USER_ADMIN.SET_LEVELS
              • Overview
            • SA_SYSDBA policy management package
              • Overview
              • SA_SYSDBA.ALTER_POLICY
              • SA_SYSDBA.DROP_POLICY
              • SA_SYSDBA.CREATE_POLICY
            • SA_COMPONENTS label component package
              • Overview
              • SA_COMPONENTS.ALTER_LEVEL
              • SA_COMPONENTS.CREATE_LEVEL
              • SA_COMPONENTS.DROP_LEVEL
          • PL collections and records
            • Overview
            • Collections
            • Associative arrays
            • Varrays
            • Nested tables
            • Collection constructor function
            • Collection methods
              • COUNT method
              • EXISTS method
              • EXTEND method
              • FIRST and LAST methods
              • Overview
              • DELETE method
              • TRIM 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 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 language basics
            • Subprograms
            • Scope and visibility of identifiers
            • Lexical units
            • Error-reporting functions
            • Character sets
            • Declare
            • Expressions
            • PL blocks
            • Reference identifiers
            • Assign values
          • PL exception handling
            • Exception handling processes
            • Exception types
            • Overview
            • Compile-Time alerts
          • PL process control
            • Overview
            • Sequential control
            • Loop control
            • Conditional control
          • PL dynamic SQL
            • DBMS_SQL system package
            • Execute dynamic SQL statements
            • Overview
          • PL packages
            • Create a program package
            • Manage program packages
            • Definition of the PL environment by the STANDARD package
            • Overview
            • Overloaded programs in a package
        • PL reference (MySQL mode)
          • Syntax of PL stored programs
          • PL stored procedures
            • Overview
            • Variables in stored programs
            • Stored procedures
            • Stored functions
            • Trigger
            • Limitations on stored programs
          • PL cursors
            • Overview
            • Cursor execution process
            • Limitations on server cursors
          • PL conditional control statements
            • REPEAT
            • LEAVE
            • IF
            • RETURN
            • WHILE
            • LOOP
            • CASE
            • ITERATE
          • PL data manipulation statements
            • CALL
            • DO
          • PL data definition statements
            • ALTER FUNCTION
            • ALTER PROCEDURE
            • CREATE FUNCTION
            • CREATE PROCEDURE
            • CREATE TRIGGER
            • DROP FUNCTION
            • DROP PROCEDURE
            • DROP TRIGGER
          • PL database management statements
            • SHOW TRIGGERS
            • SHOW CREATE TRIGGER
            • SHOW FUNCTION STATUS
            • SHOW CREATE FUNCTION
            • SHOW PROCEDURE STATUS
            • SHOW CREATE PROCEDURE
          • PL related dictionary views
            • INFORMATION_SCHEMA ROUTINES
            • INFORMATION_SCHEMA PARAMETERS
            • INFORMATION_SCHEMA TRIGGERS
          • PL exception handling
            • Exception handling and OUT/INOUT parameters
            • DECLARE ... CONDITION
            • Limitations on exception handling
            • DECLARE ... HANDLER
            • RESIGNAL
            • Diagnostics area
            • GET DIAGNOSTICS
            • Overview
            • Effective scope of an exception handler
            • SIGNAL
          • PL system packages
            • Overview
            • DBMS_RESOURCE_MANAGER
              • CREATE_PLAN
              • DELETE_PLAN_DIRECTIVE
              • DELETE_CONSUMER_GROUP
              • SET_CONSUMER_GROUP_MAPPING
              • CREATE_CONSUMER_GROUP
              • DELETE_PLAN
              • Overview
              • CREATE_PLAN_DIRECTIVE
              • UPDATE_PLAN_DIRECTIVE
            • DBMS_STATS
              • GET_PREFS
              • GATHER_INDEX_STATS
              • DROP_STAT_TABLE
              • GET_STATS_HISTORY_AVAILABILITY
              • CREATE_STAT_TABLE
              • SET_TABLE_STATS
              • GATHER_SCHEMA_STATS
              • DELETE_SYSTEM_STATS
              • DELETE_COLUMN_STATS
              • UNLOCK_SCHEMA_STATS
              • SET_PARAM
              • IMPORT_SCHEMA_STATS
              • RESET_PARAM_DEFAULTS
              • GET_PARAM
              • SET_TABLE_PREFS
              • GET_STATS_HISTORY_RETENTION
              • DELETE_TABLE_STATS
              • DELETE_INDEX_STATS
              • LOCK_PARTITION_STATS
              • FLUSH_DATABASE_MONITORING_INFO
              • EXPORT_INDEX_STATS
              • UNLOCK_PARTITION_STATS
              • UNLOCK_TABLE_STATS
              • SET_GLOBAL_PREFS
              • DELETE_TABLE_PREFS
              • ALTER_STATS_HISTORY_RETENTION
              • SET_COLUMN_STATS
              • SET_INDEX_STATS
              • SET_SYSTEM_STATS
              • IMPORT_TABLE_STATS
              • EXPORT_TABLE_STATS
              • IMPORT_COLUMN_STATS
              • DELETE_SCHEMA_PREFS
              • IMPORT_INDEX_STATS
              • LOCK_TABLE_STATS
              • SET_SCHEMA_PREFS
              • GATHER_SYSTEM_STATS
              • RESET_GLOBAL_PREF_DEFAULTS
              • EXPORT_COLUMN_STATS
              • LOCK_SCHEMA_STATS
              • RESTORE_SCHEMA_STATS
              • EXPORT_SCHEMA_STATS
              • PURGE_STATS
              • GATHER_TABLE_STATS
              • DELETE_SCHEMA_STATS
              • Overview
              • RESTORE_TABLE_STATS
            • DBMS_XPLAN
              • DISPLAY_ACTIVE_SESSION_PLAN
              • DISABLE_OPT_TRACE
              • DISPLAY
              • DISPLAY_CURSOR
              • ENABLE_OPT_TRACE
              • SET_OPT_TRACE_PARAMETER
              • Overview
              • DISPLAY_SQL_PLAN_BASELINE
            • DBMS_UDR
              • CREATE_RULE
              • DISABLE_RULE
              • Overview
              • ENABLE_RULE
              • REMOVE_RULE
            • DBMS_MVIEW_STAT
              • Overview
              • SET_SYSTEM_DEFAULT
              • SET_MVREF_STATS_PARAMS
              • PURGE_REFRESH_STATS
            • DBMS_WORKLOAD_REPOSITORY
              • Overview
              • ASH_REPORT
              • CREATE_SNAPSHOT
              • DROP_SNAPSHOT_RANGE
              • MODIFY_SNAPSHOT_SETTINGS
            • DBMS_MVIEW
              • PURGE_LOG
              • REFRESH
              • Overview
            • DBMS_TRUSTED_CERTIFICATE_MANAGER
              • DELETE_TRUSTED_CERTIFICATE
              • Overview
              • ADD_TRUSTED_CERTIFICATE
              • UPDATE_TRUSTED_CERTIFICATE
          • Reserved and non-reserved PL keywords
        • What is PL
          • PL architecture
          • Overview
          • Main features of PL
      • SQL specifications and practices
        • Limitations on writing SQL statements
        • SQL writing specifications
          • Transactions
          • Table scan
          • SELECT statements
          • Multi-table join specifications
          • Cache
          • Hint
          • DML statements
          • Others
        • SQL statement examples
          • Implicit data type conversion
          • Join tables
          • Weak consistency read
          • Pagination queries
    • System views
      • Overview of system views
      • Changes in views in OceanBase Database V3.x and V4.x
      • Common statistical events
      • General wait events
      • Overview
      • SYS tenant views
        • Dictionary views
          • oceanbase.DBA_OB_BALANCE_TASKS
          • oceanbase.DBA_SUBPART_COL_STATISTICS
          • mysql.time_zone_name
          • oceanbase.DBA_RSRC_PLAN_DIRECTIVES
          • oceanbase.CDB_OB_RESTORE_HISTORY
          • oceanbase.DBA_OB_LS_LOCATIONS
          • oceanbase.DBA_SUBPART_KEY_COLUMNS
          • oceanbase.DBA_OB_TENANTS
          • oceanbase.DBA_OB_TABLEGROUP_TABLES
          • oceanbase.CDB_OB_IMPORT_TABLE_TASK_HISTORY
          • information_schema.PARTITIONS
          • DBA_MVREF_STMT_STATS
          • oceanbase.DBA_WR_SQLTEXT
          • oceanbase.CDB_OB_BACKUP_PARAMETER
          • oceanbase.DBA_OB_TENANT_EVENT_HISTORY
          • oceanbase.CDB_OB_BACKUP_DELETE_JOBS
          • oceanbase.CDB_OB_LS
          • oceanbase.DBA_RSRC_GROUP_MAPPINGS
          • oceanbase.CDB_OB_TABLET_CHECKSUM_ERROR_INFO
          • oceanbase.DBA_OB_RESTORE_HISTORY
          • oceanbase.DBA_OB_ARCHIVELOG_SUMMARY
          • DBA_OB_CLONE_PROGRESS
          • oceanbase.DBA_OB_TRANSFER_PARTITION_TASK_HISTORY
          • oceanbase.CDB_OB_BALANCE_JOBS
          • oceanbase.DBA_OB_SERVER_JOBS
          • information_schema.GLOBAL_STATUS
          • oceanbase.DBA_OB_LS_REPLICA_TASKS
          • oceanbase.CDB_OB_TRANSFER_PARTITION_TASKS
          • oceanbase.CDB_WR_CONTROL
          • oceanbase.DBA_OB_USER_DEFINED_RULES
          • oceanbase.CDB_OB_TABLE_LOCATIONS
          • oceanbase.CDB_WR_SQLTEXT
          • oceanbase.CDB_OB_KV_TTL_TASKS
          • oceanbase.DBA_OB_CONCURRENT_LIMIT_SQL
          • oceanbase.CDB_TAB_COLS_V$
          • DBA_MVREF_STATS_SYS_DEFAULTS
          • CDB_MVREF_STATS_PARAMS
          • oceanbase.DBA_OB_OUTLINE_CONCURRENT_HISTORY
          • oceanbase.DBA_RSRC_CONSUMER_GROUPS
          • oceanbase.DBA_WR_STATNAME
          • oceanbase.DBA_SEQUENCES
          • oceanbase.DBA_OB_FREEZE_INFO
          • oceanbase.DBA_OB_ZONE_MAJOR_COMPACTION
          • oceanbase.DBA_OB_ROOTSERVICE_EVENT_HISTORY
          • oceanbase.DBA_WR_SNAPSHOT
          • oceanbase.DBA_OB_USERS
          • oceanbase.CDB_OB_RECOVER_TABLE_JOBS
          • oceanbase.CDB_OB_ARCHIVELOG_PIECE_FILES
          • oceanbase.DBA_OB_TABLE_STAT_STALE_INFO
          • DBA_INDEX_USAGE
          • oceanbase.DBA_OB_CLUSTER_EVENT_HISTORY
          • oceanbase.DBA_OB_RESOURCE_POOLS
          • oceanbase.CDB_OB_LS_ARB_REPLICA_TASKS
          • oceanbase.DBA_OB_TABLEGROUP_PARTITIONS
          • oceanbase.CDB_TABLES
          • oceanbase.DBA_IND_PARTITIONS
          • oceanbase.CDB_OB_TABLET_REPLICAS
          • mysql.help_category
          • oceanbase.DBA_DB_LINKS
          • oceanbase.CDB_OB_COLUMN_CHECKSUM_ERROR_INFO
          • information_schema.CONNECTION_CONTROL_FAILED_LOGIN_ATTEMPTS
          • oceanbase.DBA_OB_TASK_OPT_STAT_GATHER_HISTORY
          • oceanbase.CDB_WR_SYS_TIME_MODEL
          • oceanbase.DBA_OB_IMPORT_TABLE_JOB_HISTORY
          • oceanbase.DBA_WR_ACTIVE_SESSION_HISTORY
          • oceanbase.CDB_OB_BACKUP_JOBS
          • oceanbase.CDB_PART_KEY_COLUMNS
          • oceanbase.DBA_OB_IMPORT_TABLE_TASK_HISTORY
          • oceanbase.CDB_OB_TRANSFER_TASK_HISTORY
          • oceanbase.DBA_OB_EXTERNAL_TABLE_FILES
          • oceanbase.DBA_OB_BALANCE_TASK_HISTORY
          • oceanbase.CDB_OB_TABLET_TO_LS
          • mysql.time_zone_transition
          • DBA_OB_AUX_STATISTICS
          • CDB_OB_AUX_STATISTICS
          • information_schema.CHECK_CONSTRAINTS
          • oceanbase.CDB_OB_BACKUP_DELETE_POLICY
          • oceanbase.DBA_PART_TABLES
          • oceanbase.DBA_OB_AUTO_INCREMENT
          • oceanbase.DBA_OB_SERVERS
          • oceanbase.CDB_OB_DEADLOCK_EVENT_HISTORY
          • oceanbase.DBA_OB_DATABASE_PRIVILEGE
          • oceanbase.DBA_OB_TABLEGROUPS
          • oceanbase.DBA_OB_RESTORE_PROGRESS
          • oceanbase.DBA_PART_INDEXES
          • oceanbase.DBA_OB_KV_TTL_TASK_HISTORY
          • oceanbase.DBA_OB_LS_ARB_REPLICA_TASKS
          • oceanbase.CDB_OB_DATABASES
          • CDB_MVIEWS
          • mysql.db
          • oceanbase.CDB_OB_ARCHIVE_DEST
          • oceanbase.CDB_OB_TABLEGROUP_TABLES
          • oceanbase.CDB_OB_IMPORT_TABLE_TASKS
          • oceanbase.DBA_PART_COL_STATISTICS
          • DBA_OB_CLONE_HISTORY
          • oceanbase.DBA_TAB_COL_STATISTICS
          • mysql.user
          • CDB_MVREF_STMT_STATS
          • oceanbase.DBA_WR_SYSTEM_EVENT
          • information_schema.SCHEMA_PRIVILEGES
          • CDB_MVREF_STATS_SYS_DEFAULTS
          • oceanbase.DBA_OB_DEADLOCK_EVENT_HISTORY
          • oceanbase.DBA_WR_CONTROL
          • oceanbase.DBA_OB_LS
          • information_schema.TABLES
          • oceanbase.CDB_OB_USERS
          • information_schema.ENGINES
          • oceanbase.DBA_OB_BALANCE_JOB_HISTORY
          • oceanbase.DBA_OB_ACCESS_POINT
          • oceanbase.DBA_SCHEDULER_WINDOWS
          • oceanbase.CDB_OB_BALANCE_TASKS
          • oceanbase.CDB_OB_DATABASE_PRIVILEGE
          • oceanbase.CDB_OB_BALANCE_TASK_HISTORY
          • oceanbase.DBA_OBJECTS
          • information_schema.SESSION_VARIABLES
          • DBA_MVREF_CHANGE_STATS
          • information_schema.COLUMNS
          • oceanbase.CDB_OB_LS_ARB_REPLICA_TASK_HISTORY
          • oceanbase.DBA_OB_LS_LOG_ARCHIVE_PROGRESS
          • oceanbase.CDB_OB_BACKUP_DELETE_TASK_HISTORY
          • oceanbase.CDB_OB_LS_LOCATIONS
          • oceanbase.CDB_WR_ACTIVE_SESSION_HISTORY
          • oceanbase.CDB_OB_TENANT_EVENT_HISTORY
          • oceanbase.DBA_SUBPARTITION_TEMPLATES
          • oceanbase.CDB_IND_PARTITIONS
          • information_schema.TABLE_PRIVILEGES
          • oceanbase.CDB_OB_BACKUP_STORAGE_INFO_HISTORY
          • oceanbase.DBA_TAB_STATISTICS
          • mysql.help_topic
          • oceanbase.DBA_OB_TABLEGROUP_SUBPARTITIONS
          • oceanbase.DBA_OB_TRANSFER_TASK_HISTORY
          • information_schema.CHARACTER_SETS
          • oceanbase.CDB_OB_BACKUP_TASK_HISTORY
          • oceanbase.DBA_TAB_STATS_HISTORY
          • oceanbase.DBA_OB_TRANSFER_TASKS
          • mysql.help_relation
          • mysql.help_keyword
          • oceanbase.CDB_OB_TABLEGROUP_PARTITIONS
          • oceanbase.DBA_IND_SUBPARTITIONS
          • oceanbase.CDB_OB_AUTO_INCREMENT
          • oceanbase.CDB_OB_BALANCE_JOB_HISTORY
          • oceanbase.CDB_OB_BACKUP_JOB_HISTORY
          • oceanbase.DBA_TAB_MODIFICATIONS
          • information_schema.USER_PRIVILEGES
          • oceanbase.CDB_OB_SYS_VARIABLES
          • oceanbase.DBA_OB_ZONES
          • oceanbase.DBA_OB_SEQUENCE_OBJECTS
          • oceanbase.DBA_OB_TABLET_TO_LS
          • oceanbase.CDB_OB_ARCHIVELOG_SUMMARY
          • DBA_MVREF_STATS_PARAMS
          • DBA_MVIEW_LOGS
          • oceanbase.CDB_SUBPART_KEY_COLUMNS
          • information_schema.ROUTINES
          • oceanbase.CDB_OB_TABLEGROUPS
          • oceanbase.DBA_SUBPART_HISTOGRAMS
          • information_schema.QUERY_RESPONSE_TIME
          • oceanbase.DBA_OB_UNITS
          • oceanbase.DBA_OB_RSRC_IO_DIRECTIVES
          • oceanbase.DBA_SQL_PLAN_BASELINES
          • oceanbase.DBA_TAB_HISTOGRAMS
          • oceanbase.DBA_WR_SQLSTAT
          • oceanbase.DBA_TAB_PARTITIONS
          • CDB_MVREF_STATS
          • oceanbase.DBA_OB_IMPORT_TABLE_TASKS
          • oceanbase.DBA_OB_RECOVER_TABLE_JOBS
          • oceanbase.DBA_OB_UNIT_JOBS
          • oceanbase.CDB_OB_ARCHIVELOG
          • oceanbase.CDB_OB_RESTORE_PROGRESS
          • oceanbase.DBA_OB_ARBITRATION_SERVICE
          • information_schema.SCHEMATA
          • oceanbase.CDB_OB_LS_LOG_ARCHIVE_PROGRESS
          • oceanbase.CDB_OB_ZONE_MAJOR_COMPACTION
          • oceanbase.DBA_OB_DATA_DICTIONARY_IN_LOG
          • oceanbase.CDB_OB_FREEZE_INFO
          • oceanbase.CDB_OB_BACKUP_STORAGE_INFO
          • oceanbase.DBA_OB_BACKUP_DELETE_TASK_HISTORY
          • information_schema.VIEWS
          • CDB_MVREF_CHANGE_STATS
          • oceanbase.DBA_OB_BACKUP_DELETE_TASKS
          • oceanbase.CDB_WR_EVENT_NAME
          • oceanbase.CDB_OB_BACKUP_SET_FILES
          • oceanbase.CDB_OB_TRANSFER_TASKS
          • oceanbase.DBA_OB_BACKUP_TASKS
          • oceanbase.CDB_TAB_PARTITIONS
          • oceanbase.DBA_SQL_MANAGEMENT_CONFIG
          • oceanbase.DBA_OB_ARCHIVELOG
          • oceanbase.CDB_INDEXES
          • oceanbase.CDB_WR_SYSSTAT
          • information_schema.COLLATIONS
          • oceanbase.DBA_OB_BACKUP_STORAGE_INFO
          • oceanbase.CDB_OB_TRANSFER_PARTITION_TASK_HISTORY
          • oceanbase.DBA_WR_SYS_TIME_MODEL
          • oceanbase.DBA_OB_BACKUP_DELETE_JOBS
          • oceanbase.DBA_OB_BACKUP_DELETE_POLICY
          • information_schema.REFERENTIAL_CONSTRAINTS
          • mysql.time_zone_transition_type
          • oceanbase.CDB_OB_IMPORT_TABLE_JOB_HISTORY
          • oceanbase.CDB_PART_TABLES
          • information_schema.KEY_COLUMN_USAGE
          • CDB_MVREF_RUN_STATS
          • oceanbase.DBA_PART_KEY_COLUMNS
          • DBA_MVIEWS
          • mysql.time_zone
          • oceanbase.DBA_OB_TABLET_REPLICAS
          • information_schema.PARAMETERS
          • DBA_MVREF_STATS
          • oceanbase.CDB_TAB_COLS
          • oceanbase.CDB_IND_COLUMNS
          • oceanbase.DBA_OB_TABLE_LOCATIONS
          • oceanbase.CDB_OB_LOG_RESTORE_SOURCE
          • oceanbase.DBA_OB_TENANT_JOBS
          • oceanbase.DBA_OB_BACKUP_JOBS
          • oceanbase.DBA_OB_BACKUP_TASK_HISTORY
          • information_schema.COLUMN_PRIVILEGES
          • oceanbase.CDB_SUBPARTITION_TEMPLATES
          • oceanbase.DBA_OB_UNIT_CONFIGS
          • oceanbase.CDB_TAB_SUBPARTITIONS
          • oceanbase.CDB_IND_SUBPARTITIONS
          • oceanbase.CDB_OB_RECOVER_TABLE_JOB_HISTORY
          • oceanbase.DBA_OB_BALANCE_JOBS
          • CDB_MVIEW_LOGS
          • information_schema.SESSION_STATUS
          • oceanbase.DBA_OB_IMPORT_TABLE_JOBS
          • oceanbase.DBA_OB_OUTLINES
          • oceanbase.DBA_WR_SYSSTAT
          • CDB_INDEX_USAGE
          • oceanbase.DBA_OB_TRANSFER_PARTITION_TASKS
          • oceanbase.DBA_OB_ARCHIVE_DEST
          • oceanbase.CDB_OB_KV_TTL_TASK_HISTORY
          • oceanbase.DBA_RSRC_PLANS
          • oceanbase.DBA_OB_MAJOR_COMPACTION
          • oceanbase.DBA_OB_RECOVER_TABLE_JOB_HISTORY
          • oceanbase.CDB_OB_TABLEGROUP_SUBPARTITIONS
          • information_schema.STATISTICS
          • oceanbase.CDB_OBJECTS
          • oceanbase.CDB_OB_IMPORT_TABLE_JOBS
          • oceanbase.DBA_OB_BACKUP_SET_FILES
          • oceanbase.DBA_OB_TABLE_OPT_STAT_GATHER_HISTORY
          • oceanbase.DBA_IND_STATISTICS
          • oceanbase.CDB_OB_DATA_DICTIONARY_IN_LOG
          • oceanbase.CDB_WR_SYSTEM_EVENT
          • DBA_OB_TRUSTED_ROOT_CERTIFICATE
          • oceanbase.CDB_OB_LS_HISTORY
          • oceanbase.CDB_PART_INDEXES
          • oceanbase.CDB_OB_LS_REPLICA_TASKS
          • oceanbase.CDB_OB_ACCESS_POINT
          • oceanbase.DBA_WR_EVENT_NAME
          • information_schema.GLOBAL_VARIABLES
          • oceanbase.CDB_OB_BACKUP_DELETE_TASKS
          • oceanbase.DBA_OB_LS_ARB_REPLICA_TASK_HISTORY
          • information_schema.PROCESSLIST
          • oceanbase.DBA_OB_ARCHIVELOG_PIECE_FILES
          • oceanbase.CDB_OB_EXTERNAL_TABLE_FILES
          • information_schema.TABLE_CONSTRAINTS
          • mysql.proc
          • oceanbase.DBA_OB_DATABASES
          • oceanbase.DBA_SCHEDULER_JOBS
          • oceanbase.DBA_OB_BACKUP_JOB_HISTORY
          • oceanbase.CDB_OB_BACKUP_TASKS
          • oceanbase.DBA_TAB_SUBPARTITIONS
          • oceanbase.CDB_TAB_COL_STATISTICS
          • oceanbase.CDB_WR_SNAPSHOT
          • oceanbase.DBA_OB_BACKUP_STORAGE_INFO_HISTORY
          • oceanbase.DBA_OB_BACKUP_PARAMETER
          • oceanbase.DBA_OB_BACKUP_DELETE_JOB_HISTORY
          • oceanbase.DBA_OB_SERVER_EVENT_HISTORY
          • oceanbase.CDB_OB_BACKUP_DELETE_JOB_HISTORY
          • oceanbase.CDB_OB_MAJOR_COMPACTION
          • oceanbase.DBA_OB_LS_HISTORY
          • oceanbase.ALL_OB_EXTERNAL_TABLE_FILES
          • DBA_MVREF_RUN_STATS
          • information_schema.VIEW_TABLE_USAGE
          • oceanbase.CDB_WR_SQLSTAT
          • oceanbase.DBA_OB_LOG_RESTORE_SOURCE
          • oceanbase.DBA_OB_KV_TTL_TASKS
          • oceanbase.DBA_PART_HISTOGRAMS
          • information_schema.COLLATION_CHARACTER_SET_APPLICABILITY
          • oceanbase.CDB_WR_STATNAME
        • Performance views
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          • V$SYSSTAT
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          • GV$OB_PLAN_CACHE_STAT
          • V$OB_SQL_WORKAREA_MEMORY_INFO
          • V$SESSION_WAIT_HISTORY
          • V$OB_PLAN_CACHE_PLAN_STAT
          • V$OB_IO_BENCHMARK
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          • GV$LATCH
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          • V$OB_IO_CALIBRATION_STATUS
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          • GV$OB_PX_WORKER_STAT
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          • V$OB_LOCKS
          • V$OB_TENANT_RUNTIME_INFO
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          • V$SESSTAT
          • V$OB_ARBITRATION_MEMBER_INFO
          • V$OB_PLAN_CACHE_PLAN_EXPLAIN
          • GV$OB_MEMSTORE_INFO
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          • GV$OB_PX_P2P_DATAHUB
          • GV$OB_PLAN_CACHE_PLAN_STAT
          • V$STATNAME
          • V$OB_SQL_PLAN
          • V$OB_PX_TARGET_MONITOR
          • GV$OB_KVCACHE
          • V$OB_RPC_INCOMING
          • V$OB_DTL_INTERM_RESULT_MONITOR
          • GV$OB_ACTIVE_SESSION_HISTORY
          • GV$OB_PX_TARGET_MONITOR
          • GV$OB_IO_CALIBRATION_STATUS
          • GV$OB_OPT_STAT_GATHER_MONITOR
          • GV$SESSION_EVENT
          • V$OB_SERVERS
          • V$OB_MERGE_INFO
          • GV$OB_ARBITRATION_MEMBER_INFO
          • GV$OB_PS_ITEM_INFO
          • GV$SQL_WORKAREA
          • GV$OB_MEMSTORE
          • GV$OB_SQL_WORKAREA_MEMORY_INFO
          • GV$OB_TENANT_RUNTIME_INFO
          • V$OB_SESS_TIME_MODEL
          • V$OB_SQLSTAT
          • V$LATCH
          • V$OB_PS_STAT
          • V$OB_PX_P2P_DATAHUB
          • V$OB_SESSION
          • V$SQL_WORKAREA_HISTOGRAM
          • V$OB_COMPACTION_SUGGESTIONS
          • GV$OB_COMPACTION_DIAGNOSE_INFO
          • GV$SQL_PLAN_MONITOR
          • GV$SQL_WORKAREA_HISTOGRAM
          • GV$OB_DTL_INTERM_RESULT_MONITOR
          • V$OB_PLAN_CACHE_STAT
          • GV$OB_PLAN_CACHE_PLAN_EXPLAIN
          • V$SQL_WORKAREA_ACTIVE
          • V$SESSION_WAIT
          • GV$OB_LOG_STAT
          • V$OB_TABLET_COMPACTION_PROGRESS
          • V$OB_SERVER_SCHEMA_INFO
          • V$OB_OPT_STAT_GATHER_MONITOR
          • V$OB_SYS_TIME_MODEL
          • V$OB_PARAMETERS
          • V$OB_COMPACTION_DIAGNOSE_INFO
          • GV$OB_SQL_PLAN
          • V$RSRC_PLAN
          • V$OB_LOG_STAT
          • V$OB_ARCHIVE_DEST_STATUS
          • GV$SESSTAT
          • GV$OB_SQLSTAT
          • GV$OB_TABLET_COMPACTION_HISTORY
          • V$EVENT_NAME
          • GV$OB_SSTABLES
          • GV$DML_STATS
          • V$SESSION_EVENT
          • GV$OB_PROCESSLIST
          • V$DML_STATS
          • GV$OB_TABLET_COMPACTION_PROGRESS
          • V$OB_LS_LOG_RESTORE_STATUS
          • GV$OB_THREAD
          • V$OB_ACTIVE_SESSION_HISTORY
          • GV$OB_RPC_OUTGOING
          • GV$SQL_WORKAREA_ACTIVE
          • V$OB_LS_SNAPSHOTS
          • V$OB_PS_ITEM_INFO
          • GV$OB_TENANT_MEMORY
          • GV$SYSTEM_EVENT
          • V$OB_COMPACTION_PROGRESS
          • V$OB_THREAD
          • GV$OB_SESSION
          • GV$OB_SERVER_SCHEMA_INFO
          • V$OB_UNITS
          • V$OB_LS_REPLICA_TASK_PLAN
          • GV$OB_SERVERS
          • GV$OB_FLT_TRACE_CONFIG
          • V$OB_KVCACHE
          • GV$SESSION_WAIT
          • V$OB_MEMSTORE_INFO
          • V$OB_TIMESTAMP_SERVICE
          • GV$OB_SESS_TIME_MODEL
          • V$SESSION_LONGOPS
          • GV$SESSION_WAIT_HISTORY
          • GV$OB_PS_STAT
          • V$ENCRYPTED_TABLESPACES
          • V$SYSTEM_EVENT
          • V$SQL_JOIN_FILTER
          • V$ACTIVE_SESSION_HISTORY
          • V$OB_MEMSTORE
          • V$SQL_MONITOR_STATNAME
          • GV$OB_ARBITRATION_SERVICE_STATUS
          • V$OB_PROCESSLIST
          • GV$OB_MERGE_INFO
          • V$OB_PX_WORKER_STAT
          • V$OB_MEMORY
          • GV$SYSSTAT
          • GV$SQL_JOIN_FILTER
          • GV$SESSION_LONGOPS
          • V$SQL_PLAN_MONITOR
          • V$OB_SQL_AUDIT
          • V$SQL_WORKAREA
      • MySQL tenant views
        • Dictionary views
          • oceanbase.DBA_TAB_STATS_HISTORY
          • DBA_INDEX_USAGE
          • oceanbase.DBA_OB_LS_HISTORY
          • DBA_MVREF_STMT_STATS
          • mysql.time_zone_name
          • information_schema.GLOBAL_STATUS
          • information_schema.PARAMETERS
          • oceanbase.DBA_OB_ZONE_MAJOR_COMPACTION
          • oceanbase.DBA_OB_TASK_OPT_STAT_GATHER_HISTORY
          • oceanbase.DBA_IND_SUBPARTITIONS
          • DBA_MVIEW_LOGS
          • mysql.user
          • oceanbase.DBA_OB_TABLEGROUP_SUBPARTITIONS
          • information_schema.VIEWS
          • oceanbase.DBA_OB_BACKUP_DELETE_TASKS
          • oceanbase.DBA_OB_BALANCE_JOB_HISTORY
          • information_schema.COLUMN_PRIVILEGES
          • oceanbase.DBA_OB_BACKUP_JOB_HISTORY
          • oceanbase.DBA_OB_TENANTS
          • oceanbase.DBA_DB_LINKS
          • oceanbase.DBA_OB_TRANSFER_TASKS
          • oceanbase.DBA_OB_LS_ARB_REPLICA_TASK_HISTORY
          • oceanbase.DBA_OB_ARCHIVELOG_SUMMARY
          • oceanbase.DBA_OB_LS
          • mysql.proc
          • oceanbase.DBA_OB_TABLEGROUPS
          • oceanbase.DBA_OB_LS_LOG_ARCHIVE_PROGRESS
          • mysql.db
          • oceanbase.DBA_RSRC_CONSUMER_GROUPS
          • oceanbase.DBA_OB_LOG_RESTORE_SOURCE
          • information_schema.PARTITIONS
          • oceanbase.DBA_OB_BACKUP_SET_FILES
          • oceanbase.DBA_WR_CONTROL
          • oceanbase.DBA_IND_PARTITIONS
          • oceanbase.DBA_OB_TRANSFER_PARTITION_TASK_HISTORY
          • oceanbase.DBA_PART_HISTOGRAMS
          • oceanbase.DBA_OB_LS_REPLICA_TASKS
          • oceanbase.DBA_OB_BALANCE_TASK_HISTORY
          • oceanbase.DBA_OB_EXTERNAL_TABLE_FILES
          • oceanbase.DBA_OB_TRANSFER_PARTITION_TASKS
          • information_schema.CHARACTER_SETS
          • DBA_MVREF_STATS_SYS_DEFAULTS
          • mysql.time_zone
          • information_schema.VIEW_TABLE_USAGE
          • oceanbase.DBA_OB_RECOVER_TABLE_JOB_HISTORY
          • oceanbase.DBA_WR_SYS_TIME_MODEL
          • oceanbase.DBA_OB_DATABASES
          • oceanbase.DBA_RSRC_PLAN_DIRECTIVES
          • information_schema.QUERY_RESPONSE_TIME
          • information_schema.ST_GEOMETRY_COLUMNS
          • oceanbase.DBA_OB_FREEZE_INFO
          • oceanbase.DBA_OB_BACKUP_JOBS
          • oceanbase.DBA_SCHEDULER_JOBS
          • information_schema.COLLATION_CHARACTER_SET_APPLICABILITY
          • oceanbase.DBA_OB_DEADLOCK_EVENT_HISTORY
          • oceanbase.DBA_OB_BACKUP_PARAMETER
          • oceanbase.DBA_OB_OUTLINES
          • oceanbase.DBA_OB_DATA_DICTIONARY_IN_LOG
          • DBA_MVREF_STATS
          • oceanbase.DBA_OB_KV_TTL_TASKS
          • mysql.time_zone_transition_type
          • information_schema.TABLE_CONSTRAINTS
          • oceanbase.DBA_OB_MAJOR_COMPACTION
          • oceanbase.DBA_SUBPART_HISTOGRAMS
          • oceanbase.DBA_TAB_PARTITIONS
          • oceanbase.DBA_OB_USER_DEFINED_RULES
          • information_schema.PROCESSLIST
          • information_schema.CHECK_CONSTRAINTS
          • oceanbase.DBA_OB_RECOVER_TABLE_JOBS
          • oceanbase.DBA_WR_EVENT_NAME
          • DBA_MVIEWS
          • oceanbase.DBA_OB_BACKUP_DELETE_TASK_HISTORY
          • oceanbase.DBA_SQL_MANAGEMENT_CONFIG
          • oceanbase.DBA_PART_COL_STATISTICS
          • oceanbase.DBA_SQL_PLAN_BASELINES
          • oceanbase.DBA_OB_IMPORT_TABLE_JOB_HISTORY
          • oceanbase.DBA_OB_ARCHIVELOG_PIECE_FILES
          • information_schema.ST_SPATIAL_REFERENCE_SYSTEMS
          • oceanbase.DBA_WR_ACTIVE_SESSION_HISTORY
          • oceanbase.DBA_SUBPART_COL_STATISTICS
          • oceanbase.DBA_OB_TABLE_OPT_STAT_GATHER_HISTORY
          • information_schema.STATISTICS
          • oceanbase.DBA_WR_STATNAME
          • oceanbase.DBA_WR_SNAPSHOT
          • DBA_MVREF_CHANGE_STATS
          • information_schema.ROUTINES
          • information_schema.GLOBAL_VARIABLES
          • oceanbase.DBA_OB_AUTO_INCREMENT
          • information_schema.TABLES
          • oceanbase.DBA_OB_BACKUP_TASK_HISTORY
          • information_schema.REFERENTIAL_CONSTRAINTS
          • oceanbase.DBA_OB_USERS
          • information_schema.COLUMNS
          • oceanbase.DBA_OB_BALANCE_TASKS
          • oceanbase.DBA_IND_STATISTICS
          • oceanbase.DBA_TAB_MODIFICATIONS
          • oceanbase.DBA_OB_BACKUP_DELETE_JOB_HISTORY
          • oceanbase.DBA_OB_ARCHIVE_DEST
          • oceanbase.DBA_OB_ARCHIVELOG
          • oceanbase.DBA_OB_BALANCE_JOBS
          • oceanbase.DBA_OB_TABLET_REPLICAS
          • oceanbase.DBA_OBJECTS
          • oceanbase.DBA_TAB_SUBPARTITIONS
          • oceanbase.DBA_SCHEDULER_WINDOWS
          • DBA_MVREF_STATS_PARAMS
          • oceanbase.DBA_OB_IMPORT_TABLE_TASKS
          • information_schema.COLLATIONS
          • oceanbase.DBA_SUBPART_KEY_COLUMNS
          • information_schema.ENGINES
          • oceanbase.DBA_OB_TENANT_EVENT_HISTORY
          • oceanbase.DBA_WR_SQLSTAT
          • oceanbase.DBA_OB_KV_TTL_TASK_HISTORY
          • DBA_OB_AUX_STATISTICS
          • oceanbase.DBA_SUBPARTITION_TEMPLATES
          • information_schema.KEY_COLUMN_USAGE
          • oceanbase.DBA_PART_KEY_COLUMNS
          • oceanbase.DBA_WR_SYSSTAT
          • information_schema.TABLE_PRIVILEGES
          • information_schema.USER_PRIVILEGES
          • oceanbase.DBA_OB_BACKUP_STORAGE_INFO_HISTORY
          • oceanbase.DBA_OB_TABLE_STAT_STALE_INFO
          • oceanbase.DBA_OB_TABLEGROUP_TABLES
          • oceanbase.DBA_OB_IMPORT_TABLE_TASK_HISTORY
          • oceanbase.DBA_SEQUENCES
          • oceanbase.DBA_OB_RESTORE_PROGRESS
          • oceanbase.DBA_OB_RESTORE_HISTORY
          • DBA_MVREF_RUN_STATS
          • oceanbase.DBA_RSRC_GROUP_MAPPINGS
          • information_schema.SESSION_VARIABLES
          • information_schema.SCHEMA_PRIVILEGES
          • mysql.help_category
          • oceanbase.DBA_TAB_HISTOGRAMS
          • oceanbase.DBA_RSRC_PLANS
          • information_schema.CONNECTION_CONTROL_FAILED_LOGIN_ATTEMPTS
          • oceanbase.DBA_PART_TABLES
          • oceanbase.DBA_OB_DATABASE_PRIVILEGE
          • oceanbase.DBA_OB_BACKUP_DELETE_JOBS
          • mysql.help_keyword
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          • mysql.time_zone_transition
          • oceanbase.DBA_OB_TRANSFER_TASK_HISTORY
          • oceanbase.DBA_OB_LS_ARB_REPLICA_TASKS
          • mysql.help_topic
          • oceanbase.DBA_PART_INDEXES
          • information_schema.SESSION_STATUS
          • oceanbase.DBA_WR_SYSTEM_EVENT
          • oceanbase.DBA_TAB_STATISTICS
          • oceanbase.DBA_OB_LS_LOCATIONS
          • oceanbase.DBA_WR_SQLTEXT
          • oceanbase.DBA_OB_TABLET_TO_LS
          • oceanbase.DBA_OB_BACKUP_TASKS
          • oceanbase.DBA_TAB_COL_STATISTICS
          • information_schema.SCHEMATA
          • oceanbase.DBA_OB_OUTLINE_CONCURRENT_HISTORY
          • oceanbase.ALL_OB_EXTERNAL_TABLE_FILES
          • oceanbase.DBA_OB_RSRC_IO_DIRECTIVES
          • oceanbase.DBA_OB_SEQUENCE_OBJECTS
          • mysql.help_relation
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          • oceanbase.DBA_OB_CONCURRENT_LIMIT_SQL
          • oceanbase.DBA_OB_BACKUP_STORAGE_INFO
          • oceanbase.DBA_OB_BACKUP_DELETE_POLICY
          • oceanbase.DBA_OB_ACCESS_POINT
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        • Performance views
          • V$SESSION_WAIT_HISTORY
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          • GV$SESSTAT
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          • GV$SYSTEM_EVENT
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          • V$SESSION_LONGOPS
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          • GV$LATCH
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          • V$OB_PX_WORKER_STAT
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          • GV$SESSION_EVENT
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          • V$OB_COMPACTION_DIAGNOSE_INFO
          • V$SESSTAT
          • V$SQL_WORKAREA
          • V$OB_OPT_STAT_GATHER_MONITOR
          • GV$SQL_WORKAREA
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          • GV$OB_SYS_TIME_MODEL
          • GV$SESSION_LONGOPS
          • V$OB_SERVERS
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          • V$OB_SERVER_SCHEMA_INFO
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          • GV$OB_UNITS
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          • V$OB_PLAN_CACHE_PLAN_STAT
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          • DBA_OB_LS_REPLICA_TASKS
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          • DBA_OB_MAJOR_COMPACTION
          • USER_DEPENDENCIES
          • STMT_AUDIT_OPTION_MAP
          • ALL_TAB_COLS
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          • ALL_ALL_TABLES
          • DBA_POLICIES
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          • DBA_OB_ACCESS_POINT
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          • DBA_WR_SYSSTAT
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          • ALL_TRIGGERS
          • DBA_SUBPART_KEY_COLUMNS
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          • DBA_OB_USER_DEFINED_RULES
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          • ALL_MVIEWS
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          • ALL_MVIEW_LOGS
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          • ALL_SOURCE
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          • DBA_MVIEW_LOGS
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          • DBA_WR_SNAPSHOT
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          • USER_JOBS
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          • DBA_ALL_TABLES
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          • USER_USERS
          • ALL_SUBPARTITION_TEMPLATES
          • DICTIONARY
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          • USER_SEGMENTS
          • USER_POLICIES
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          • DBA_OB_BALANCE_JOB_HISTORY
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          • DBA_MVIEWS
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          • USER_IND_EXPRESSIONS
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          • USER_PART_TABLES
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          • DBA_TAB_PARTITIONS
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          • USER_PART_INDEXES
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        • Performance views
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          • V$ENCRYPTED_TABLESPACES
          • V$OPEN_CURSOR
          • GV$OB_THREAD
          • GV$SYSSTAT
          • GV$OB_SSTABLES
          • GV$OB_ACTIVE_SESSION_HISTORY
          • V$OB_PARAMETERS
          • V$SYSTEM_EVENT
          • V$OB_TENANT_MEMORY
          • GV$SESSION_WAIT
          • V$OB_TABLET_COMPACTION_PROGRESS
          • GV$OB_TENANT_MEMORY
          • GV$OB_SESS_TIME_MODEL
          • V$OB_SQL_AUDIT
          • GV$OB_LOCKS
          • GV$OB_TABLET_COMPACTION_PROGRESS
          • V$SQL_PLAN_MONITOR
          • V$OB_ACTIVE_SESSION_HISTORY
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          • V$GLOBAL_TRANSACTION
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          • V$OB_PS_STAT
          • V$EVENT_NAME
          • V$OB_THREAD
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          • V$GLOBALCONTEXT
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          • V$OB_PLAN_CACHE_STAT
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          • GV$OB_SQL_AUDIT
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          • runtime_filter_wait_time_ms
          • runtime_filter_max_in_num
          • runtime_bloom_filter_max_size
          • optimizer_features_enable
          • ob_default_lob_inrow_threshold
          • ob_enable_pl_cache
        • Session-level variables
          • runtime_bloom_filter_max_size
          • nls_language
          • last_insert_id
          • ob_org_cluster_id
          • ob_trace_info
          • is_result_accurate
          • runtime_filter_max_in_num
          • ob_max_read_stale_time
          • timestamp
          • parallel_min_scan_time_threshold
          • optimizer_dynamic_sampling
          • runtime_filter_type
          • ob_enable_show_trace
          • runtime_filter_wait_time_ms
          • ob_proxy_partition_hit
          • parallel_degree_policy
          • tracefile_identifier
          • ob_capability_flag
          • ob_proxy_set_trx_executed
          • parallel_degree_limit
          • ob_last_schema_version
      • Parameters
        • Overview
        • Cluster-level parameters
          • location_cache_priority
          • stack_size
          • tableapi_transport_compress_func
          • devname
          • cluster_id
          • disk_io_thread_count
          • enable_pg
          • minor_merge_concurrency
          • tablet_size
          • default_transport_compress_func
          • row_purge_thread_count
          • ofs_list
          • clog_transport_compress_func
          • location_fetch_concurrency
          • rpc_timeout
          • high_priority_net_thread_count
          • datafile_size
          • datafile_maxsize
          • get_leader_candidate_rpc_timeout
          • ob_esi_memory_limit
          • enable_manual_merge
          • global_index_build_single_replica_timeout
          • schema_history_expire_time
          • lease_time
          • schema_history_recycle_interval
          • weak_read_version_refresh_interval
          • location_cache_refresh_sql_timeout
          • backup_dest_option
          • cluster
          • opt_tab_stat_cache_priority
          • enable_auto_leader_switch
          • data_dir
          • storage_meta_cache_priority
          • balancer_timeout_check_interval
          • minor_deferred_gc_time
          • merger_completion_percentage
          • enable_upgrade_mode
          • backup_recovery_window
          • index_block_cache_priority
          • log_archive_checkpoint_interval
          • sql_login_thread_count
          • ob_esi_io_concurrency
          • clog_expire_days
          • user_block_cache_priority
          • trx_2pc_retry_interval
          • memory_chunk_cache_size
          • tcp_keepintvl
          • log_storage_warning_tolerance_time
          • backup_dest
          • server_balance_disk_tolerance_percent
          • backup_backup_dest
          • cpu_count
          • token_reserved_percentage
          • server_data_copy_out_concurrency
          • cpu_reserved
          • switchover_process_thread_count
          • trx_try_wait_lock_timeout
          • ob_ratelimit_stat_period
          • dtl_buffer_size
          • enable_sys_table_ddl
          • rootservice_list
          • dead_socket_detection_timeout
          • local_ip
          • tenant_groups
          • server_permanent_offline_time
          • memstore_limit_percentage
          • backup_zone
          • tablet_meta_table_check_interval
          • location_cache_refresh_min_interval
          • server_data_copy_in_concurrency
          • standby_fetch_log_bandwidth_limit
          • minor_warm_up_duration_time
          • election_blacklist_interval
          • net_thread_count
          • virtual_table_location_cache_expire_time
          • multiblock_read_gap_size
          • rpc_port
          • autoinc_cache_refresh_interval
          • replica_safe_remove_time
          • leak_mod_to_check
          • observer_id
          • ob_esi_session_timeout
          • enable_record_trace_id
          • sql_protocol_min_tls_version
          • log_archive_batch_buffer_limit
          • large_query_threshold
          • enable_ddl
          • enable_rootservice_standalone
          • tenant_cpu_variation_per_server
          • datafile_next
          • plan_cache_evict_interval
          • memory_limit
          • syslog_io_bandwidth_limit
          • system_cpu_quota
          • restore_concurrency
          • enable_ob_ratelimit
          • wait_leader_batch_count
          • sys_bkgd_io_low_percentage
          • diag_syslog_per_error_limit
          • zone_merge_concurrency
          • sys_bkgd_migration_change_member_list_timeout
          • auto_broadcast_location_cache_rate_limit
          • log_disk_percentage
          • mysql_port
          • enable_one_phase_commit
          • log_disk_size
          • tcp_keepcnt
          • ilog_index_expire_time
          • enable_rpc_authentication_bypass
          • enable_ob_esi_process
          • obconfig_url
          • enable_record_trace_log
          • ignore_replay_checksum_error
          • migrate_concurrency
          • tenant_task_queue_size
          • data_storage_warning_tolerance_time
          • merge_thread_count
          • zone_merge_order
          • global_major_freeze_residual_memory
          • enable_rich_error_msg
          • memory_reserved
          • balancer_log_interval
          • px_task_size
          • recyclebin_object_expire_time
          • enable_cgroup
          • min_observer_version
          • enable_sys_unit_standalone
          • workers_per_cpu_quota
          • resource_soft_limit
          • rootservice_ready_check_interval
          • debug_sync_timeout
          • partition_table_check_interval
          • plan_cache_high_watermark
          • index_clog_cache_priority
          • global_write_halt_residual_memory
          • enable_syslog_wf
          • enable_log_archive
          • clog_sync_time_warn_threshold
          • syslog_level
          • system_memory
          • enable_syslog_recycle<main id="notice" type='explain'>
          • clog_disk_usage_limit_percentage
          • enable_rereplication
          • ob_startup_mode
          • clog_cache_priority
          • migration_disable_time
          • enable_async_syslog
          • config_additional_dir
          • ob_event_history_recycle_interval
          • memory_limit_percentage
          • rpc_client_authentication_method
          • unit_balance_resource_weight
          • enable_global_freeze_trigger
          • backup_concurrency
          • rootservice_async_task_thread_count
          • index_info_block_cache_priority
          • max_px_worker_count
          • bf_cache_priority
          • tablet_meta_table_scan_batch_count
          • merger_warm_up_duration_time
          • sys_bkgd_net_percentage
          • balance_blacklist_failure_threshold
          • enable_sql_operator_dump
          • merge_stat_sampling_ratio
          • user_row_cache_priority
          • bf_cache_miss_count_threshold
          • auto_refresh_location_cache_rate_limit
          • enable_sql_audit
          • all_server_list
          • ls_meta_table_check_interval
          • resource_hard_limit
          • datafile_disk_percentage
          • server_check_interval
          • internal_sql_execute_timeout
          • data_storage_error_tolerance_time
          • auto_leader_switch_interval
          • election_cpu_quota
          • zone_merge_timeout
          • data_copy_concurrency
          • max_syslog_file_count
          • sql_audit_memory_limit
          • default_compress
          • enable_tcp_keepalive
          • use_large_pages
          • micro_block_merge_verify_level
          • cache_wash_threshold
          • tcp_keepidle
          • merger_switch_leader_duration_time
          • sys_bkgd_migration_retry_num
          • ssl_external_kms_info
          • enable_perf_event
          • max_string_print_length
          • flush_log_at_trx_commit
          • enable_merge_by_turn
          • enable_dblink
          • balancer_emergency_percentage
          • large_query_worker_percentage
          • location_cache_expire_time
          • ob_esi_syslog_level
          • ob_esi_rpc_port
          • default_compress_func
          • balance_blacklist_retry_interval
          • location_refresh_thread_count
          • server_balance_cpu_mem_tolerance_percent
          • location_cache_cpu_quota
          • builtin_db_data_verify_cycle
          • px_workers_per_cpu_quota
          • server_balance_critical_disk_waterlevel
          • enable_auto_refresh_location_cache
          • rootservice_memory_limit
          • index_cache_priority
          • plan_cache_low_watermark
          • minor_freeze_times
          • ssl_client_authentication
          • all_cluster_list
          • rpc_server_authentication_method
          • multiblock_read_size
          • ignore_replica_checksum_error
          • strict_check_os_params
          • location_cache_refresh_rpc_timeout
          • zone
          • clog_disk_utilization_threshold
          • enable_major_freeze
          • backup_log_archive_option
          • data_disk_usage_limit_percentage
          • user_iort_up_percentage
          • enable_election_group
          • sys_bkgd_io_high_percentage
          • rdma_io_thread_count
          • backup_backup_dest_option
          • user_tab_col_stat_cache_priority
          • ob_esi_max_syslog_file_count
          • server_cpu_quota_min
          • system_trace_level
          • trx_force_kill_threshold
          • backup_net_limit
          • fuse_row_cache_priority
          • max_kept_major_version_number
          • trace_log_slow_query_watermark
          • enable_separate_sys_clog
          • sys_cpu_limit_trigger
          • enable_smooth_leader_switch
          • balancer_tolerance_percentage
          • balancer_task_timeout
          • row_compaction_update_limit
          • rootservice_async_task_queue_size
          • enable_asan_for_memory_context
          • fast_recovery_concurrency
          • backup_region
          • sql_net_thread_count
          • gc_wait_archive
          • rebuild_replica_data_lag_threshold
          • server_cpu_quota_max
          • trace_log_sampling_interval
          • tablet_ls_cache_priority
          • default_row_format
        • Tenant-level parameters
          • audit_sys_operations
          • audit_trail
          • clog_max_unconfirmed_log_count
          • clog_persistence_compress_func
          • connection_control_failed_connections_threshold
          • connection_control_min_connection_delay
          • connection_control_max_connection_delay
          • enable_clog_persistence_compress
          • enable_early_lock_release
          • enable_monotonic_weak_read
          • external_kms_info
          • enable_sql_extension
          • default_progressive_merge_num
          • backup_data_file_size
          • io_category_config
          • log_disk_utilization_limit_threshold
          • log_disk_utilization_threshold
          • major_compact_trigger
          • ddl_thread_score
          • compaction_low_thread_score
          • max_stale_time_for_weak_consistency
          • compaction_high_thread_score
          • minor_compact_trigger
          • compaction_mid_thread_score
          • ob_enable_batched_multi_statement
          • ob_proxy_readonly_transaction_routing_policy
          • ob_ssl_invited_common_names
          • open_cursors
          • plsql_code_type
          • plsql_debug
          • plsql_optimize_level
          • plsql_warnings
          • sql_work_area
          • tde_method
          • writing_throttling_maximum_duration
          • writing_throttling_trigger_percentage
          • workarea_size_policy
          • plsql_v2_compatibility
          • job_queue_processes
          • ha_high_thread_score
          • ha_mid_thread_score
          • ha_low_thread_score
          • ob_compaction_schedule_interval
          • default_auto_increment_mode
          • ob_query_switch_leader_retry_timeout
          • default_enable_extended_rowid
          • major_freeze_duty_time
          • undo_retention
          • query_response_time_stats
          • query_response_time_flush
          • query_response_time_range_base
          • merger_check_interval
          • freeze_trigger_percentage
          • cpu_quota_concurrency
          • arbitration_timeout
          • compatible
          • log_transport_compress_all
          • log_transport_compress_func
          • rpc_memory_limit_percentage
          • tenant_sql_login_thread_count
          • tenant_sql_net_thread_count
          • dump_data_dictionary_to_log_interval
          • enable_user_defined_rewrite_rules
          • partition_balance_schedule_interval
          • log_disk_throttling_percentage
          • enable_rebalance
          • balancer_idle_time
          • log_disk_throttling_maximum_duration
          • ls_gc_delay_time
          • standby_db_preferred_upstream_log_region
          • archive_lag_target
          • range_optimizer_max_mem_size
          • log_restore_concurrency
          • log_archive_concurrency
          • standby_db_fetch_log_rpc_timeout
          • enable_transfer
          • kv_ttl_duty_duration
          • kv_ttl_history_recycle_interval
          • enable_kv_ttl
          • ttl_thread_score
          • compaction_dag_cnt_limit
          • compaction_schedule_tablet_batch_cnt
          • kv_transport_compress_func
          • kv_transport_compress_threshold
          • optimizer_index_cost_adj
          • default_table_store_format
    • Database object management
      • Overview
      • Oracle mode
        • Create and manage tables
          • Overview
          • Create a table
          • Column skip index attribute
          • Define column constraints
          • Query the definition of a table
          • Modify a table
          • Empty a table
          • Drop a table
          • Lock a table
          • Create and manage external tables
            • Create an external table
            • Overview
            • Manage external files
        • Create and manage partitions
          • Overview
          • Drop a partition
          • Create a partitioned table
          • Rename a partition
          • Partition pruning
          • Truncate a partition
          • Add a partition
          • Query data in specified partitions
          • Modify partitioning rules
          • Create indexes on partitioned tables
            • Global indexes
            • Local indexes
            • Overview
        • Create and manage table groups
          • Drop a table group
          • Query information about a table group
          • Manage tables in a table group
          • Add tables to a table group
          • Modify the SHARDING attribute of a table group
          • Overview
          • Create a table group
        • Create and manage indexes
          • Overview
          • Monitor indexes
          • Create an index
          • Query indexes
          • System functions not supported for function-based indexes
          • System functions supported for function-based indexes
          • Drop an index
        • Manage views
          • Manage standard views
          • Manage materialized views
            • Materialized views
              • Drop a materialized view
              • Refresh a materialized view
              • Query a materialized view
              • Overview
              • Create a materialized view
            • Materialized view logs
              • Overview
              • Create a materialized view log
              • Drop a materialized view log
        • Manage sequences
        • Manage synonyms
        • Create and manage triggers
          • Create an INSTEAD OF trigger
          • Modify and drop a trigger
          • Create a DML trigger
          • Query trigger information
          • Disable or enable a trigger
          • Create a composite trigger
          • Overview
        • Manage directory objects
        • Create and manage DBLinks
          • Drop a DBLink
          • Use a DBLink to access data in a remote database
          • Query existing DBLinks
          • Use a DBLink to modify data in a remote database
          • Install and configure OCI
          • Create a DBLink
      • MySQL mode
        • Create and manage databases
          • Create a database
          • View databases
          • Modify a database
          • Drop a database
        • Create and manage tables
          • Empty a table
          • Create a table
          • Define column constraints
          • Lock a table
          • Modify a table
          • Query the table definition
          • Drop a table
          • Define an auto-increment column
          • Overview
          • Column skip index attribute
          • Create and manage external tables
            • Overview
            • Manage external files
            • Create an external table
        • Create and manage partitions
          • Overview
          • Create a partitioned table
          • Modify partitioning rules
          • Add a partition
          • Drop a partition
          • Truncate a partition
          • Partition pruning
          • Query data in specified partitions
          • Create indexes on partitioned tables
            • Overview
            • Local indexes
            • Global indexes
        • Create and manage table groups
          • Manage tables in a table group
          • Overview
          • Drop a table group
          • Add tables to a table group
          • Create a table group
          • Modify the SHARDING attribute of a table group
          • Query information about a table group
        • Create and manage indexes
          • System functions supported for function-based indexes
          • Query indexes
          • Drop an index
          • Monitor indexes
          • System functions not supported for function-based indexes
          • Create an index
          • Overview
        • Manage views
          • Manage standard views
          • Manage materialized views
            • Materialized views
              • Query a materialized view
              • Overview
              • Create a materialized view
              • Refresh a materialized view
              • Drop a materialized view
            • Materialized view logs
              • Overview
              • Create a materialized view log
              • Drop a materialized view log
        • Create and manage sequences
          • Modify a sequence
          • Query sequences
          • Create a sequence
          • Drop a sequence
          • Reference a sequence
        • Create and manage triggers
          • Overview
          • Create a DML trigger
          • Query trigger information
          • Drop a trigger
        • Create and manage DBLinks
          • Use a DBLink to access data in a remote database
          • Query a DBLink
          • Drop a DBLink
          • Create a DBLink
    • System principles
      • Development of OceanBase Database
      • Overall architecture of OceanBase Database
      • Database objects
        • Oracle mode
          • Partitions
            • Overview
            • Partitioning keys
            • Partitioning types
            • Partitioned indexes
          • Tables
            • Overview
            • Data type
              • ROWID data types
              • Numeric data types
              • Datetime data types
              • LOB data types
              • Character data types
              • Multi-model data types
              • Overview
              • Format model
                • Number format models
                • Overview
                • Datetime format models
            • Integrity constraints
            • Table storage
            • Table compression
            • Partitioned table
            • Tables with and without a primary key
            • Temporary tables
          • Views
            • Views in a database
            • Materialized views
              • Materialized view logs
              • Materialized views
              • Creation and update strategies for materialized views
            • Standard views
              • Standard views
              • Overview
              • Oracle-compatible views
              • View operations and data access
              • OceanBase-specific views
          • Introduction
            • Overview
            • Database object types
            • Database object storage
            • Dependencies between database objects
          • Other objects
            • Sequences
            • Synonyms
          • Data integrity
            • Overview
            • Use of integrity constraints
            • Integrity constraint type
              • UNIQUE KEY constraints
              • Overview
              • FOREIGN KEY constraints
              • PRIMARY KEY constraints
              • NOT NULL constraints
              • CHECK constraints
          • System views
            • Dictionary views
            • Performance views
          • Indexes
            • Local and global indexes
            • Unique and non-unique indexes
            • Index storage
            • Use indexes
            • Overview
        • MySQL mode
          • Data integrity
            • Overview
            • Integrity constraint type
              • PRIMARY KEY constraints
              • Overview
              • NOT NULL constraints
              • UNIQUE KEY constraints
              • FOREIGN KEY constraints
            • Use of integrity constraints
          • Views
            • Views in a database
            • Standard views
              • Overview
              • Overview
              • OceanBase-specific views
              • MySQL-compatible views
              • Oracle-compatible views in MySQL tenants
              • Oracle-compatible views in the sys tenant
              • View operations and data access
            • Materialized views
              • Materialized views
              • Materialized view logs
              • Creation and update strategies for materialized views
          • Introduction
            • Overview
            • Database object types
            • Database object storage
            • Dependencies between database objects
          • Indexes
            • About indexes
            • Index storage
            • Use indexes
            • Unique and non-unique indexes
            • Spatial indexes
            • Local and global indexes
          • Partitions
            • Partitioned indexes
            • Overview
            • Partitioning types
            • Partitioning keys
          • Tables
            • Table storage
            • Tables with and without a primary key
            • Partitioned table
            • Table compression
            • Integrity constraints
            • Overview
            • Data type
              • Numeric data types
              • LOB data types
              • Datetime data types
              • Overview
              • Multi-model data types
              • JSON data types
              • Spatial data types
              • Character data types
          • System views
            • Dictionary views
            • Performance views
      • OBServer node architecture
        • Structure of the OBServer node installation directory
        • Configuration files
        • Logs
        • Memory management
          • Memory-related views
          • Memory-related parameters
          • Diagnose memory errors
          • Memory usage logs
          • Overview
        • observer thread model
          • Threads
          • Worker threads
          • Background threads
      • Storage architecture
        • Overview
        • Data storage
          • Overview
          • MemTables
          • SSTables
          • Columnar storage
          • Compression and encoding
        • Compaction
          • Overview
          • Major compaction
          • Minor compaction
        • Multi-level caches
        • Query processing
        • Data integrity
          • Detect silent data corruption
      • User interface and query language
        • Client programming languages
        • SQL
          • Query SQL execution plans
          • Execution process of SQL queries
          • Introduction
            • SQL data access
            • SQL standards
            • Overview
          • Distributed execution plan
            • Perform distributed execution and parallel queries
            • Manage distributed execution plans
            • Run and disable a parallel query
            • Generate distributed execution plans
            • Perform parameter tuning for a parallel query
          • SQL statements
            • Overview
            • DDL statements
            • DCL statements
            • DML statements
        • PL
          • PL concepts
            • MySQL mode
              • Functions
              • Stored procedures
              • Subprograms
              • Triggers
            • Oracle mode
              • Subprograms
              • Triggers
              • Functions
              • Stored procedures
              • Packages
          • PL subprogram execution mechanism
      • Data link
        • Overview
        • Database proxy
          • Overview
          • SQL routing
          • Connection management
          • ODP configuration management
          • Logs and monitoring
        • Database connector
          • Overview
          • OBCI
          • OceanBase Connector/J
          • OceanBase Connector/C
      • Distributed database objects
        • Overview
        • Cluster architecture
        • Data partitions and replicas
          • Overview
          • Log streams
          • Partition replica type
            • Overview
            • Full-featured replica
            • Read-only replicas
          • Multi-replica consensus protocols
          • Data balancing
            • Intra-tenant balancing
            • Views and parameters related to data balancing
        • Dynamic scaling
          • Cluster scaling
          • Tenant resource scaling
            • Horizontal scaling of tenant resources
            • Overview
            • Cross-zone management of tenant resources
            • Vertical scaling of tenant resources
      • Multi-tenant architecture
        • Tenants
        • Overview
        • Compatibility modes
        • Tenants and resource management
          • Resource unit balancing
          • Multi-tenant resource isolation
          • Tenant resource management
      • Transaction management
        • Transaction concurrency and consistency
          • Overview
          • Multi-version read consistency
          • Concurrency control
            • Overview
            • Lock mechanism
          • Transaction isolation level
            • Transaction isolation levels in MySQL mode
            • Overview
            • Transaction isolation levels in Oracle mode
          • Weak consistency read
        • Transaction
          • Overview
          • Statement-level atomicity
          • Redo logs
          • Transaction structure
          • XA transactions
          • Local transactions
          • GTS
          • Transaction control
            • Active transactions
            • Overview
            • Savepoint
            • Transaction control statements
              • MySQL transaction control
              • Oracle transaction control
          • Distributed transaction
            • Overview
            • Two-phase commit
      • Data reliability and high availability
        • Deployment solutions for disaster recovery
        • Arbitration-based high availability solution
        • Physical Standby Database solution
        • Data protection
          • Recycle bin
          • Flashback queries
          • Overview
        • High availability architecture
          • Overview
          • ODP high availability
          • Leader election in distributed systems
          • Multi-replica log synchronization
          • Paxos protocol
          • Automatic handling of node failures
        • Backup and restore
          • Overview
          • Backup directory structures
          • Restore architecture
          • Backup architecture
      • Database security
        • Security audit
        • Monitoring and alerting
        • Access control
        • Authentication
        • Data transmission encryption
        • Data storage encryption
        • Overview
    • Database design specifications and practices
      • Character set specifications
      • Comments
      • ORM conventions
      • Database connection specifications
      • Exception handling
      • Object structure design specifications
        • Field design
        • Table structure design
        • Partitioned table design
        • Index design
        • Other structural designs
      • Object naming conventions
        • Tenant naming conventions
        • Overview
        • Other naming conventions
        • User naming conventions
        • Field naming conventions
        • Table naming conventions
    • Performance tuning
      • Overview
      • SQL tuning
        • Execution process of SQL queries
        • SQL execution plans
          • Fast parameterization
          • Plan cache
          • Display real-time execution plans
          • Introduction to SQL execution plans
          • SQL tuning practice with EXPLAIN
          • Execution plan operators
            • SUBPLAN FILTER
            • COUNT
            • INTERSECT
            • SUBPLAN SCAN
            • JOIN
            • DELETE
            • SEQUENCE
            • EXCHANGE
            • GROUP BY
            • FOR UPDATE
            • TABLE SCAN
            • UNION
            • MERGE
            • EXCEPT/MINUS
            • UPDATE
            • WINDOW FUNCTION
            • SELECT INTO
            • GI
            • LIMIT
            • DISTINCT
            • MATERIAL
            • INSERT
            • SORT
        • Distributed execution plans
          • Schedule distributed execution plans
          • Parallel DML
          • Enable parallel execution and set the degree of parallelism
          • Perform parameter tuning for a parallel query
          • Manage distributed execution plans
          • Perform distributed execution and parallel queries
          • Auto DOP
          • Execute parallel queries
          • Generate a distributed plan
        • Parallel execution plans
          • Quick start
          • Classification and optimization of parallel execution
          • Introduction
          • Parallel execution tuning tips
          • Parallel execution diagnostics
          • Set concurrent execution
            • Concurrency control and queuing
            • Set a DOP for parallel execution
            • Set parallel execution parameters
        • SQL tuning
          • General procedure
          • Overview
          • 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
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What's New Overview Differences between the Enterprise Edition and the Community Edition System architecture Compatibility with Oracle SQL data types Built-in functions System views Compatibility with MySQL Limitations Video tutorials Try out OceanBase Database Community Edition Try out operational OLAP Try out parallel import and data compression Try out the multi-tenant feature Build a Java application Build a C application Basic SQL operations (Oracle mode) Basic SQL operations (MySQL mode) Before you begin Build a Python application Build a Java application Build a C application Build a Go application Delete old clusters Overview High availability deployment solutions for OceanBase clusters Overview Deploy OceanBase Database in a Kubernetes cluster Deployment process Import data from SQL files to OceanBase Database Overview Use OMS to migrate data from a DB2 LUW database to a MySQL tenant of OceanBase Database Use OMS to migrate data from a DB2 LUW database to an Oracle tenant of OceanBase Database Use DBCAT to migrate table schemas from a DB2 LUW database to OceanBase Database Use OMS to migrate data from an Oracle database to a MySQL tenant of OceanBase Database Use OMS to migrate data from an Oracle database to an Oracle tenant of 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 Use OMS to migrate data from a MySQL tenant of OceanBase Database to a MySQL database Use OMS to migrate incremental data from an Oracle tenant of OceanBase Database to a MySQL database 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 Use Flink CDC to migrate data from OceanBase Database to a MySQL database Migrate data from a MySQL database in OceanBase Database to a MySQL database using ChunJun Use OBLOADER & OBDUMPER to migrate data from a MySQL tenant to an Oracle tenant in OceanBase Database Use OMS to migrate data from an OceanBase tenant to another of the same type Use OMS to migrate data from an OceanBase tenant to another of the same type in active-active disaster recovery scenarios Use OBLOADER & OBDUMPER to migrate data between Oracle tenants in OceanBase Database Use OBLOADER & OBDUMPER to migrate data between MySQL tenants in OceanBase Database Use OBLOADER & OBDUMPER to migrate data from an Oracle tenant to a MySQL tenant in OceanBase Database Import data in bypass mode by using the INSERT INTO SELECT statement Import data in bypass mode by using the LOAD DATA statement Overview Use Flink CDC to synchronize data from a MySQL database to OceanBase Database Use OMS to migrate data from a MySQL database to a MySQL tenant of OceanBase Database Use mydumper and myloader to migrate data from a MySQL database to OceanBase Database Use ChunJun to migrate data from a MySQL database to OceanBase Database Migrate data from a MySQL database to OceanBase Database using CloudCanal Use DataX to migrate table data from a MySQL database to OceanBase Database Use DBCAT to migrate schemas from a MySQL database to OceanBase Database Use Canal to synchronize data from a MySQL database to OceanBase Database Import data by using the LOAD DATA statement Use DataX to migrate CSV files to OceanBase Database 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 Use OMS to migrate data from an Oracle tenant of OceanBase Database to an Oracle database Use OMS to migrate data from a PostgreSQL database to a MySQL tenant of OceanBase Database Export data by using OUTFILE statements Migrate resource units Migrate data between tables Use OMS to migrate data from a MySQL tenant of OceanBase Database to a DB2 LUW database Use OMS to migrate data from an Oracle tenant of OceanBase Database to a DB2 LUW database Use OMS to migrate data from a TiDB database to a MySQL tenant of OceanBase Database Log on to an OceanBase tenant Overview Traffic distribution Data distribution Overview Identify bottlenecks on the data link Deadlock detection Overview Check tenant resource usage Check cluster parameters Check cluster resource usage Check the host status Check the NTP offset Check the OBServer node status Overview Cluster parameters Overview Introduction to physical backup and restore Experience physical backup and restore with simplified deployment Deploy NFS Optimize backup and restore performance Emergency response overview Analysis, diagnosis, and decision-making procedure Flashback queries
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OceanBase Database Enterprise Edition V4.2.0

Last Updated:2026-04-15 08:30:02  Updated
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V4.2.0 BP1
Version information
Bug fixes
V4.2.0 Beta
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V4.2.0 BP1

Version information

  • Release date: September 14, 2023
  • Version: V4.2.0 BP1
  • RPM version: oceanbase-4.2.0.0-101000042023091319

Bug fixes

  • Fixed the issue where, in the Oracle mode, when the RS tenant and the regular tenant are not on the same server, Error 4013 may occur during SQL execution if memory allocation using the tenant ID is attempted on the RS server.

  • Fixed the correctness issue caused by the execution of the index skip scan plan when the full index suffix condition is not specified for parallel execution. For example, the index key is c1, c2, c3, but only c2 is specified and c3 is not specified.

  • Fixed the issue where explicit setting of _optimizer_better_inlist_costing=true for a specific tenant may cause core dump or other abnormal behavior after a restart.

  • Fixed the issue where after upgrading from V4.1.x to V4.2.x, incorrect maintenance of max_ls_id leads to prolonged execution times for business operations.

V4.2.0 Beta

Version information

  • Release date: August 2, 2023
  • Version: V4.2.0 Beta
  • Description: The Beta version resolved most of the issues and is becoming more and more stable. However, there may still be some minor issues or errors that need to be addressed in the final stable release, so we recommend that you use this version in a testing environment.

Overview

OceanBase Database V4.2.0 further enhanced the core features based on V4.1.0 and included all major functionalities of the V3.x series. It further improved product scalability, resource utilization, performance, compatibility, and ease of use. V4.2.x will serve as a long-term support (LTS) version.

Core features of V4.2.0 include:

  • MySQL compatibility

    • Function index: OceanBase Database already supports function-based indexes in earlier versions in Oracle mode. The MySQL mode of V4.2.0 now supports MySQL 8.0-compatible function-based indexes, further enhancing feature stability.
    • OBCDC: The new version now supports the output of row data according to the column definition sequence, meeting the compatibility requirements of MySQL Binlog Service. OBCDC no longer depends on the system tenant, but supports data synchronization with user tenants. This means that user tenants can use OBCDC on their own, without relying on the system tenant. V4.2.0 also supports data synchronization for tables without primary keys.
  • Oracle compatibility

    • LOCK TABLE: OceanBase Database provides LOCK TABLE syntaxes for Oracle tenants in V4.1.0 and earlier versions. However, many limitations on using the syntaxes exist. OceanBase Database V4.2.0 provides higher compatibility with LOCK TABLE syntaxes and enhances the features that are unavailable in earlier versions. Specifically, you can lock multiple tables, partitions, and subpartitions, and make the WAIT N and NOWAIT keywords take effect.
  • Multi-model support

    • Oracle XML: The XMLType data type is supported in Oracle mode. Nine XML expressions and basic XML creation, query, and modification capabilities are provided.
  • Performance improvements

    • Enhancement of optimizer/executor/procedural language (PL) capabilities: Enhanced the query rewriting and optimization capabilities, with a focus on improving the performance of executor operators. Optimized the plan cache and parallel execution logic for PL and supported SQL statements that return complex data types.
    • Statistics functionality enhancement: Enhanced the stability and availability of the statistics functionality, added the monitoring and diagnostic functionality for statistics collection, and optimized the performance and memory overhead of statistics collection.
    • Dynamic sampling: Supports dynamic sampling, allowing optimizers to collect statistical information during SQL execution and generate optimal execution plans. This helps to improve query performance.
    • Query plan evolution: Supports query plan evolution to avoid performance regression of execution plans.
    • Runtime Filter: Provided full support for Runtime Filter, improving the analytical processing (AP) performance.
    • Performance optimization under 4 CPU cores (4C): Optimized the performance in various OLTP scenarios by over 20% in 4C environments with default parameter settings.
    • Performance optimization of reading transaction data: Optimized the performance of querying transaction tables during the minor compaction of uncommitted data.
    • Parallel minor compaction of transaction data tables: OceanBase Database V4.1.0 already supports parallel MINOR_MERGE (combining multiple mini SSTables into a minor SSTable). V4.2.0 additionally supports parallel MINI_MERGE for transaction data tables (freezing the MemTable and converting it into a mini SSTable through minor compaction).
    • Fast generation of random data: Introduced the built-in function GENERATOR(N). This function can be used with random functions such as RANDOM([N]), RANDSTR(N, gen) and distribution control functions like NORMAL(<mean>, <stddev>, <gen>), UNIFORM(<min>, <max>, <gen>), and ZIPF(<s>, <N>, <gen>) to generate random data quickly. Compared with Oracle Connect By and MySQL Recursive CTE, OceanBase Table Generator has significant performance advantages.
  • OLAP capabilities

    • Read-only external tables: Supports the creation and reading of read-only external tables when performing online analytical processing (OLAP) operations, thereby reducing costs of loading or inserting data into databases.
  • Scalability enhancement

    • Transfer and load balancing: Uses the transfer technology to split and merge log streams, supporting data migration across nodes on a per-partition basis. This provides flexible scaling and dynamic data balancing capabilities.
    • Replicated tables: Reconstructed replicated tables based on the single-node log stream architecture. The new version introduced partition-based readable version number verification and log stream-based lease-granting mechanism to ensure the correctness of strong consistency reads. Additionally, this version improved the ability to switch leaders without killing transactions. This means that uncommitted replicated table transactions can continue to execute after a leader switch initiated by users or load balancing. Compared with V3.x, V4.2.0 has better write transaction performance, stronger disaster recovery capability for replicated tables, and lower impact on read operations in case of replica failure.
  • High availability enhancement

    • Physical standby database: OceanBase Database V4.1.0 introduced an archive-based primary/standby solution, offering flexible configuration without requiring network connection between primary and standby tenants. However, many scenarios still require a primary/standby solution based on direct network connection to reduce storage and network costs, and to simplify backup and restore operations. V4.2.0 extended support in these scenarios.
    • Log write throttling: When the speed of committing logs to the disk is greater than the minor compaction speed, the log disk will become full. In V4.2.0, when the log disk usage reaches a specified threshold, the speed of committing logs to the disk is limited, to minimize the occurrences that the log disk becomes full because of the high write pressure in the cluster. For more information, see the log_disk_throttling_percentage and log_disk_throttling_maximum_duration parameters.
  • Resource utilization optimization

    • Idle CPU optimization: Made optimizations for high-frequency, time-consuming SQL statements and background threads to reduce the CPU overhead of internal SQL execution and periodic execution of background threads. According to a test conducted on a single tenant in an idle environment (30 tables and a million rows of data per table), the default CPU overhead is around 0.2C.
    • On-demand expansion of disk data files: Supports progressive disk expansion, where an appropriate disk size is first pre-allocated and then automatically expanded based on actual usage.
    • Shared memory identification mechanism: Added a defense mechanism in the technical means to mark the code that is expected to use the shared memory and to optimize the situation where the shared resources increase with the code merge.
  • Usability enhancement

    • Auto degree of parallelism (DOP): Support for auto DOP to automatically calculate query parallelism, reducing the threshold for parallel execution.
    • End-to-end diagnostics enhancement: OceanBase Database V4.1.0 introduced end-to-end diagnostic capabilities, and V4.2.0 added some trace logging information based on the end-to-end diagnostic framework. This version also provides interactive Show Trace capabilities based on transactions and SQL queries.
    • Logical plan management: Made several improvements to make logical plans more user-friendly. These improvements include the ability to save EXPLAIN plan information, feedback on the execution of logical plans, and real-time plans for running SQL queries. Additionally, rich interfaces for the DBMS_XPLAN package were also provided to display plans for specific queries, baseline plans, and real-time session plans in a formatted manner.
    • Background thread statistics: Versions earlier than V4.2.0 tended to record front-end thread diagnosis information from a client perspective. However, for OceanBase Database, background threads constitute the vast majority. Therefore, it is necessary to learn about the state of background threads, both for troubleshooting issues and diagnosing performance. V4.2.0 adds the [G]V$OB_THREAD view to record the status information of all threads.
  • Security enhancement

    • Backup and restore for encryption-enabled tenants: OceanBase Database V4.1.0 does not support backup and restore for tenants that have enabled encryption. OceanBase Database V4.2.0 adapts the transparent data encryption (TDE) capability to the new backup and restore mechanism. You can separately back up the primary keys during the backup and specify the primary key backup information during the restore. Features such as backup and restore and the primary/standby databases are also supported for encrypted tenants.
  • National standards

    • GB18030-2022 character set: Provided support for GB18030-2022 character set since OceanBase Database V4.2.0. GB18030-2022 character set was released on July 19, 2022, and formally implemented on August 1, 2023. It supports more rare Chinese characters and minority languages, making it a mandatory standard for information systems.
  • Product forms

    • Standalone architecture-based primary/standby solution: OceanBase Database V4.1.0 introduced the standalone architecture, and V4.2.0 further expanded this architecture to include a primary/standby solution.
    • Read-only replicas (R replicas): OceanBase Database V4.2.0 introduced read-only replicas to provide read-only capabilities, which are different from full-featured replicas.

Description of core features

MySQL compatibility

Function index: MySQL 8.0 introduced the function-based index feature to optimize query performance. Typically, if a function or expression is used for a query column, a regular index cannot be used for optimization, and a function-based index is needed to improve query performance. Function index can use the return value of a function as part of the index, thereby speeding up query execution. Starting from V4.2.0, OceanBase Database supports MySQL 8.0-compatible function-based index under the MySQL tenant, and it can be created using statements such as CREATE TABLE, CREATE INDEX, and ALTER TABLE. In addition, V4.2.0 also enhances the index extraction capability and can effectively use indexes in most scenarios where there is implicit conversion outside the index expression, or the reference column on a prefix index has a LIKE predicate. For more information, see Create an index.

Oracle compatibility

LOCK TABLE: OceanBase Database provides LOCK TABLE syntaxes for Oracle tenants in V4.1.0 and earlier versions. You can lock a single table and make the WAIT N and NOWAIT keywords take effect. However, many limitations on using the syntaxes exist. For example, the LOCK TABLE statement can lock only a single table, but it cannot lock multiple tables or partitions. The WAIT N and NOWAIT keywords do not actually take effect. After you specify the WAIT N or NOWAIT keyword in a statement, the execution behavior remains unchanged. The statement waits for a lock until the statement or transaction times out. OceanBase Database V4.2.0 and later provide higher compatibility with LOCK TABLE syntaxes and enhances the features that are unavailable in earlier versions. Specifically, you can lock multiple tables, partitions, and subpartitions, and make the WAIT N and NOWAIT keywords take effect. For more information, see LOCK TABLE.

Multi-model support

Support for Oracle XML: XML is a standard self-explanatory text-based data exchange format. XML is widely needed in configuration description and data exchange scenarios. OceanBase Database V4.2.0 supports the following features of XML:

  • XMLType: You can define data of the XML type and manipulate XML data by using PL or SQL statements.
  • Basic functions: OceanBase Database V4.2.0 supports constructor functions such as XMLParse, XMLElement, XMLAttribute, XMLContent, and XMLAgg, and XPath-based query functions such as Extract and ExtractXML. You can call the XMLUpdate function to make incremental modifications on XML documents, such as modifying the data of an XML node. You can call the XMLSERIALIZE function to convert the XML data stored in a database into standard XML text.
  • Storage: OceanBase Database V4.2.0 supports the native XML binary storage format, which is a query-friendly storage format. Compared with text-based storage, this format can avoid parsing XML documents and accelerate XML queries.
  • Indexes: OceanBase Database V4.2.0 supports the creation of indexes in XML documents based on virtual generated columns.

For more information, see XMLType overview.

Performance improvements

Statistics functionality enhancement

Starting from OceanBase Database V4.0.0, statistics collection is fully initiated and maintained by the SQL layer, and statistics are no longer collected during major compaction. However, due to the incomplete functionality of statistics collection, there are some issues with performance and memory consumption during collection, which further affects the generation of the SQL plan. Additionally, the lack of effective monitoring methods for statistics collection makes it difficult for users to determine the status and expiration of statistics collection on various data tables, resulting in operational difficulties.

V4.2.0 enhanced the stability and usability of statistics collection. Online statistics collection optimizes the data structure and collection performance, improving performance by around 10% for the INSERT INTO SELECT and LOAD DATA methods. Offline statistics collection optimizes the plan generation path and memory usage, improving performance by 10%-20% in the scenario where 64 concurrent offline statistics collection tasks are being performed on the partitioned table tpcds_100g.

In addition, V4.2.0 now supports statistics collection monitoring and diagnostics, with the addition of the dynamic performance view [G]V$OB_OPT_STAT_GATHER_MONITOR for querying the real-time status of statistics collection tasks, the dictionary view DBA_OB_TASK_OPT_STAT_GATHER_HISTORY for querying the execution status of history statistics collection tasks, and the dictionary view DBA_OB_TABLE_OPT_STAT_GATHER_HISTORY for querying the execution status of history collection tasks on tables.

Dynamic sampling

When executing SQL queries, the optimizer in OceanBase Database needs to collect statistical information on tables and indexes in order to choose the optimal execution plan. If the statistical information is inaccurate or incomplete, the chosen execution plan may not be optimal, leading to a decrease in query performance. Basic statistical information is usually obtained through automatic or manual collection. However, if the data distribution changes, statistical information is not collected, or complex SQL queries are encountered, existing statistical information may no longer be accurate.

OceanBase Database V4.2.0 introduced the dynamic sampling feature, which samples database objects in advance during the plan generation phase, estimates the number of rows through sampling, and generates better execution plans for the cost model. Currently, you can control the dynamic sampling feature through system variables, query hints, and system parameters and the sampling set size is limited by the degree of parallelism. For more information, see Perform dynamic sampling by using optimizer.

Runtime Filter

Since V3.1.0, OceanBase Database has supported Join Bloom Filter to quickly filter data during data scanning in Join operations. In V4.0.0, Partition Bloom Filter was introduced to dynamically filter partitions for scenarios where Join keys are partition columns or partition column prefixes. Furthermore, in V4.1.0, multiple Bloom Filters can be generated within adjacent data flow operators (DFOs) and within a single DFO. Filters that dynamically filter data during execution, such as In, Range, and Bloom Filter, are collectively referred to as Runtime Filter (RF). V4.2.0 provides full support for Runtime Filter, improving the AP processing performance. You can manually enable Runtime Filter by using px_join_filter or px_part_join_filter, and disable it by using no_px_join_filter or no_px_part_join_filter. Additionally, four system variables are provided to adjust the execution strategy of Runtime Filter if necessary. For more information, see Runtime Filter.

Performance optimization under 4C

OceanBase Database V4.2.0 improved Sysbench performance under 4C16G (4 CPU cores and 16 GB of memory) scenarios by over 20% with a series of optimizations. These optimizations include auto-increment ID optimization, New Sort adaptive optimization, Callback Allocator optimization in PDML scenarios, time function call optimization, optimization of obtaining snapshots of single log stream statements, optimization of obtaining snapshots at tenant level, and optimization of enable_trace_log and enable_sql_audit.

Fast generation of random data

Table functions can return a data table as a result. Based on this, V4.2.0 introduced the Table Generator feature, which includes the built-in function generator(N). This function can be called in a Table function as table(generator(N)). In addition, new random functions such as RANDOM([N]) and RANDSTR(N, gen) and distribution control functions such as NORMAL(<mean> , <stddev> , <gen>), UNIFORM(<min> , <max> , <gen>), andZIPF(<s> , <N> , <gen>) are added and can be used with Table Generator to generate data. Compared with Oracle Connect By and MySQL Recursive CTE, OceanBase Table Generator has significant performance advantages. For more information, see GENERATOR.

OLAP capabilities

Read-only external tables

Tables in a database are stored in the database's storage space, while data of external tables is stored in an external storage service. External tables can be queried like regular tables, but are limited to read operations and do not support data manipulation language (DML) operations. Typically, when processing external data, data must be loaded or inserted into the database by using ETL tools. During this process, the database consumes resources such as storage space, disk I/O, and CPU. In contrast, external tables can directly read external data sources for query analysis without loading or inserting them into the database. For more information about the usage method and limitations, see Create external tables.

Scalability enhancement

Transfer and load balancing

OceanBase Database V4.0.0 underwent an architecture upgrade by introducing the concept of adaptive log streams to achieve an integrated architecture for standalone and distributed modes. This architecture provides more flexible scalability and supports dynamic transformation between standalone and distributed modes. However, the scalability was not fully improved in the released version V4.1.0, as the partitions and log streams were statically bound and therefore partition distribution could not be dynamically adjusted. This restricted the capabilities of automatic load balancing and deployment flexibility.

OceanBase Database V4.2.0 is the first version to fully implement the integrated architecture for standalone and distributed modes. It uses the transfer technology to split and merge log streams, supporting data migration across nodes on a per-partition basis. This truly achieved dynamic transformation between standalone and distributed modes, further improving the scalability.

The load balancing feature at the tenant level is mainly reflected in the following two aspects:

  • Tenant-level horizontal scaling: Users can extend their read-write service capabilities within and across zones by dynamically adjusting the Unit Number (the number of units that provide services in each zone) and Primary Zone (the list of zones that provide read-write services). The load balancing module will adaptively adjust the distribution of log streams and partitions based on the configured service capabilities.
  • Partition balancing: Partition distribution can be dynamically adjusted to achieve balance in the number of partitions and storage space on service nodes, even in the case of dynamic changes in tables and partitions.

For more information, see Load balancing.

Replicated tables

Replicated tables are a special type of table in OceanBase Database that can read the latest modifications from any "healthy" replica. For users with low write frequency and those that are more concerned about read operation latency and load balancing, replicated tables are a good choice. Replicated tables can sacrifice a small part of transaction commit performance while reading the latest data on any "healthy" follower. Here, "healthy" means that the follower has a smooth network connection and minimal replay progress gap with the leader.

In OceanBase Database V3.2.0, the replicated table feature was already supported, allowing a backup replica to be created on every server specified for a given tenant, and the main replica and all backup data are kept in strong synchronization using a fully synchronous policy. V4.2.0 further improved the replicated table feature, enhancing the ability to switch leaders without killing transactions. That is, when a user or load balancing initiates a leader switch, the execution can continue after the switch without killing transactions. Additionally, the new version of replicated tables has better write transaction performance, stronger disaster recovery capability for replicated tables, and lower impact on read operations when a replica fails. For more information, see Create a table.

High availability enhancement

Physical standby database

OceanBase Database V4.1.0 introduced a primary/standby solution based on third-party media archiving. This solution meets the basic requirements of primary and standby databases and is flexible in configuration, for example, not requiring network connectivity between primary and standby tenants. However, compared with the direct connectivity method, this approach has some disadvantages, such as increased storage and network costs, decreased performance and stability, increased maintenance difficulty, and usage limitations such as requiring the archiving to enabled for the standby database before a switchover.

Considering these factors, V4.2.0 enhanced physical standby databases with direct network connectivity, which shortened the log synchronization link between primary and standby databases and is more suitable for standalone and small to medium-sized users. Additionally, considering limitations in available bandwidth and potential instabilities in communication between standby databases, V4.2.0 also supports bandwidth throttling for standby databases. This helps avoid situations where excessive traffic from some standby databases affects the performance of other nodes when network bandwidth is limited. For more information about how to use the physical standby database, see Overview of physical standby database.

Resource utilization optimization

On-demand disk file expansion

OceanBase Database uses a strategy of pre-allocating disk space, which ensures that the database occupies a continuous block of disk space, avoiding resource shortages caused by other applications preempting the disk. Additionally, OceanBase Database allows customization of the file system based on this strategy to improve data access efficiency. However, in the case of a small amount of user data, there may be wasted disk space. V4.2.0 provides a new user configuration option for progressive disk expansion, which pre-allocates a reasonable disk size and automatically expands it based on the actual usage of the disk. For more information, see Configure dynamic expansion of disk data files.

Usability enhancement

Auto DOP

Parallel execution is a key capability for optimizing large data queries, and the optimizer generally uses DOP to describe the amount of parallel resources available. In previous versions, users had to determine whether to enable parallelism and adjust the DOP size with the consideration of execution conditions, response time requirements, and system resources. If needed, they had to modify the system variables and HINT based on their experience. V4.2.0 introduced the auto DOP feature while retaining the ability to manually adjust the DOP. This feature evaluates the time required to execute the query when generating a query plan, automatically determines whether to enable parallel execution, and determines the optimal DOP for the current query. The DOP selection policy can be controlled through the system variable parallel_degree_policy. For more information, see Auto DOP.

End-to-end diagnostics enhancement

OceanBase Database V4.2.0 significantly improved its diagnostic capabilities, including the first implementation of visual end-to-end tracing for SQL requests. This feature helps users quickly locate and trace specific problems during a particular execution phase, and identify the server and module in which the issue occurred with the aid of detailed execution information. It also provides Show Trace capabilities based on transactions and SQL queries. For business departments, they are often more concerned about the overall time consumption of a business service. For example, in an OLTP system, a business service is typically composed of one or more transactions. Therefore, tracing at the transaction level aligns better with the user's actual business scenario.

Each transaction forms a trace, recording the relevant execution information of each SQL request in the entire internal process of OBClient > ODP > OBServer. Users can quickly identify which statements were executed in a transaction and view their execution details from the client's perspective. Show Trace also provides convenient business system association capabilities for users. Users can set the app trace id corresponding to the calling request on the business database connection through the JDBC interface or SQL interface. This app trace id will be recorded in the end-to-end tracing information and displayed in Show Trace. When users find errors in a request or service database call associated with a certain app trace id, they can use this app trace id to quickly search for the corresponding database trace associated with the app trace id in the end-to-end diagnostic system, and then directly view the time consumption and error points of the request in each phase of the database link to quickly determine the component that triggered the issue. For more information, see Show a trace.

Logical plan management

V4.2.0 enhanced logical plan management with the following features:

  • After a user obtains the plan information of a query through the EXPLAIN syntax, the user can query the history through DBMS_XPLAN.display before the current session is disconnected. Alternatively, the user can specify to save the information to a target table using the EXPLAIN INTO syntax.
  • Automatically saves the plans of all executed queries, including physical and logical plans, for subsequent troubleshooting. The database clears the saved query plans when the cluster is restarted.
  • Displays the baseline plan of SQL plan management (SPM) using DBMS_XPLAN.DISPLAY_SQL_PLAN_BASELINE.
  • Displays the plan information of executing queries using DBMS_XPLAN.DISPLAY_ACTIVE_SESSION_PLAN and SESSION_ID.

For more information, see DISPLAY_ACTIVE_SESSION_PLAN.

National standards

GB18030-2022 character set

GB18030-2022 character set was released on July 19, 2022, and formally implemented on August 1, 2023, becoming a mandatory standard for full-text execution in information systems. Compared with the GB18030-2005 standard, the new standard supports more rare Chinese characters and minority languages. OceanBase Database V4.2.0 supports the new GB18030_2022 character set, along with the corresponding sorting methods. The character set name is GB18030_2022 in MySQL mode and ZHS32GB18030_2022 in Oracle mode. For more information, see Character sets.

Product forms

Standalone architecture-based primary/standby solution

OceanBase Database V4.1.0 introduced the standalone architecture, allowing users to deploy OceanBase Database on a single server. In V4.2.0, this architecture is further expanded to include a primary/standby solution. This allows users to deploy OceanBase Database on two servers, with one acting as the primary database and the other as the standby database. For more information, see the Physical standby database section of this topic.

Read-only replicas (R replicas)

Read-only replicas do not participate in the consensus protocol voting and cannot become leaders. They only replay logs generated by the leader and generate corresponding data locally. In other words, read-only replicas can only provide read services but not write services.

OceanBase Database V4.2.0 introduced read-only replicas, which can be used by replicated tables. That is, with broadcast log streams, read-only replicas can be deployed on OBServer nodes that do not need to participate in the voting, while full-featured replicas are deployed on OBServer nodes that need to participate in the voting. The purpose of doing so is to ensure that, ideally, replicated tables can provide strong consistency reads on any OBServer node.

Here is a comparison between read-only replicas and full-featured replicas:

Replica type Participates in election voting? Participates in log voting? SSTable Has clog Has MemTable
Full-featured replica Yes Yes Yes Yes Yes
Read-only replica No No Yes Yes Yes

Performance test report

The tests aim at comparing the performance of OceanBase Database V4.2 and V4.1 in different scenarios.

Test environment specifications

Type Specification
CPU architecture x86_64
ECS type ecs.g7.8xlarge
Compute 32 cores
Memory 128 GB
Disk 300 GB system disk, 2*400 GB cloud disks
Operating system CentOS Linux release 7.9.2009 (Core)

Version for test

Product Version information
OBServer (V4.2) OBServer (OceanBase_CE 4.2.0.0)
REVISION: 1-b274f1768fb31f46c38e691b2883324b01605b4b
BUILD_TIME: Jul 19 2023 08:31:51
ODP (V4.2) ODP (OceanBase 4.2.0.0 3883.el7)
REVISION: 3883-local-b6e947efa65fec48be04f5fb78d70019651503cf
BUILD_TIME: Jul 20 2023 09:36:15
OBServer (V4.1) OBServer (OceanBase_CE 4.1.0.0)
REVISION: 100000172023031416-6d4641c7bcd0462f0bf3faed011803c087ea1705
BUILD_TIME: Mar 14 2023 16:53:58
ODP (V4.1) ODP (OceanBase 4.1.0.0 1)
REVISION: 5617-local-e6798c479feaab9f9a60b89f87e4df5e284250b6
BUILD_TIME: Mar 11 2023 21:42:11

Note

To improve user experience and usability, the following tests are based on a small number of basic commonly used parameter settings for tuning, without performing extensive large-scale tuning or point-to-point optimization.

OLTP test with Sysbench

Test plan

  1. Deploy an OceanBase cluster by using OBD. Deploy ODP and Sysbench on two separate servers, which will act as stress servers to avoid resource contention. Note that ODP is deployed on a separate server with 64 CPU cores and 128 GB of memory (server type: ecs.c7.16xlarge).
  2. Configure the OceanBase cluster. Make sure that the cluster is in the 1-1-1 architecture, with three zones and each zone having one OBServer node. After the cluster is deployed successfully, create the tenant and user required for running the Sysbench test (The sys tenant is a built-in system tenant used for managing the cluster, therefore, do not use the sys tenant to run the test). In two separate tests, set the primary zone for the tenant to RANDOM and Zone1, respectively. RANDOM indicates that the leader of the newly created table partition is randomly assigned to one of the three servers, while Zone1 indicates that the leader for the newly created table partition is concentrated on one server in Zone1.
  3. Launch the Sysbench client and run the point_select, read_write, read_only, and write_only tests.
  4. Set --time to 60s for each round of test. The number of threads can be 32, 64, 128, 256, 512, or 1,024.
  5. Prepare the test data: 30 non-partitioned tables with 1 million rows of data (--tables=30, -table_size set to 1000000).

Tenant specifications

  • MAX_CPU = 26
  • MEMORY_SIZE = 70g

Parameter tuning

ALTER system SET enable_sql_audit=false;
ALTER system SET enable_perf_event=false;
ALTER system SET syslog_level='PERF';
ALTER system SET enable_record_trace_log=false;

Test results

  • Point select performance

    Threads V4.1 QPS [RANDOM] V4.1 95% Latency (ms) [RANDOM] V4.2 QPS [RANDOM] V4.2 95% Latency (ms) [RANDOM] V4.2 QPS [Zone1] V4.2 95% Latency (ms) [Zone1]
    32 135146.05 0.27 138746.60 0.26 137423.12 0.27
    64 252277.60 0.30 252231.37 0.29 246275.56 0.31
    128 431564.13 0.36 447755.19 0.34 377949.26 0.50
    256 686271.21 0.55 730315.66 0.48 461791.47 0.94
    512 937428.74 0.95 1009966.93 0.90 535462.87 1.67
    1024 985232.01 2.35 1012734.80 2.66 537828.40 3.89
  • Read-only performance

    Threads V4.1 QPS [RANDOM] V4.1 95% Latency (ms) [RANDOM] V4.2 QPS [RANDOM] V4.2 95% Latency (ms) [RANDOM] V4.2 QPS [Zone1] V4.2 95% Latency (ms) [Zone1]
    32 115232.45 4.74 121733.00 4.65 119054.75 4.74
    64 214733.98 5.18 221563.16 5.09 208659.70 5.37
    128 366616.03 6.09 392138.56 5.67 282377.72 8.43
    256 553922.27 8.74 577951.13 8.58 316931.91 23.10
    512 662368.79 15.83 763726.51 17.01 317668.32 42.61
    1024 653733.97 54.83 740835.95 38.94 315535.24 80.03
  • Write-only performance

    Threads V4.1 QPS [RANDOM] V4.1 95% Latency (ms) [RANDOM] V4.2 QPS [RANDOM] V4.2 95% Latency (ms) [RANDOM] V4.2 QPS [Zone1] V4.2 95% Latency (ms) [Zone1]
    32 36840.88 5.37 43984.28 7.17 60851.38 4.10
    64 62582.56 8.13 82554.92 6.55 110359.75 4.49
    128 107054.05 9.56 114874.89 10.09 167415.76 5.99
    256 155494.00 13.70 181982.10 12.52 209163.02 10.27
    512 242458.53 17.32 253635.91 19.29 238568.50 18.28
    1024 291343.40 31.94 292482.33 36.89 249176.87 37.56
  • Read/Write performance

    Threads V4.1 QPS [RANDOM] V4.1 95% Latency (ms) [RANDOM] V4.2 QPS [RANDOM] V4.2 95% Latency (ms) [RANDOM] V4.2 QPS [Zone1] V4.2 95% Latency (ms) [Zone1]
    32 66669.18 11.45 72554.47 11.87 92995.95 7.84
    64 124559.80 12.52 139369.33 11.65 162191.70 9.22
    128 209150.84 15.27 247061.25 12.30 219285.86 13.70
    256 309329.85 20.00 313660.08 23.95 246672.33 25.74
    512 395940.95 33.12 497734.89 25.74 270444.49 57.87
    1024 454400.54 64.47 547816.87 54.83 256076.76 121.08

TPC-C benchmark test with BenchmarkSQL

Test plan

  1. Deploy an OceanBase cluster by using OBD. Deploy ODP and TPC-C on one server to avoid insufficient stress on the client.
  2. Configure the OceanBase cluster. Make sure that the cluster is in the 1-1-1 architecture, with three zones and each zone having one OBServer node. After the cluster is deployed successfully, create the tenant and user required for running the TPC-C benchmark test (The sys tenant is a built-in system tenant used for managing the cluster, therefore, do not use the sys tenant to run the test). In two separate tests, set the primary zone for the tenant to RANDOM and Zone1, respectively. RANDOM indicates that the leader of the newly created table partition is randomly assigned to one of the three servers, while Zone1 indicates that the leader for the newly created table partition is concentrated on one server in Zone1.

Tenant specifications

  • MAX_CPU = 26
  • MEMORY_SIZE = 70g

Parameter tuning

#obproxy
ALTER proxyconfig SET proxy_mem_limited='4G';
ALTER proxyconfig set enable_compression_protocol=false;

#sys
ALTER system SET enable_sql_audit=false;
ALTER system SET enable_perf_event=false;
ALTER system SET syslog_level='PERF';
ALTER system SET enable_record_trace_log=false;

Software versions

  • mysql-connector-java-5.1.47
  • BenchmarkSQL V5.0

Test configuration

  • warehouse = 1000
  • loadWorder = 40
  • terminals = 800
  • runMins = 5
  • newOrderWeight = 45
  • paymentWeight = 43
  • orderStatusWeight = 4
  • deliveryWeight = 4
  • stockLevelWeight = 4

Test results

Test type V4.1 RANDOM V4.2 RANDOM V4.2 Zone1
tpmC (NewOrders) 293350.85 289711.96 139886.99
tpmTOTAL 652025.02 644025.66 310953.51
Transaction Count 3260125 3221995 1555658

TPC-H benchmark test

Test plan

  1. Deploy an OceanBase cluster by using OBD. Deploy TPC-H on a separate server as the stress machine. You do not need to deploy ODP, as you can directly connect to any server for testing.
  2. Configure the OceanBase cluster. Make sure that the cluster is in the 1-1-1 architecture, with three zones and each zone having one OBServer node. After the cluster is deployed successfully, create the tenant and user required for running the TPC-H test (The sys tenant is a built-in system tenant used for managing the cluster, therefore, do not use the sys tenant to run the test). Set the primary zone of the tenant to RANDOM. Perform data loading first, then execute the 22 SQL queries multiple times and calculate the average.
  3. Prepare 100 GB of test data.

Tenant specifications

  • MAX_CPU = 26
  • MEMORY_SIZE = 70g

Parameter tuning

#sys
ALTER system flush plan cache GLOBAL;
ALTER system SET enable_sql_audit=false;
ALTER system SET enable_perf_event=false;
ALTER system SET syslog_level='PERF';
ALTER system SET enable_record_trace_log=false;

# Test tenant
SET GLOBAL ob_sql_work_area_percentage = 80;
SET GLOBAL ob_query_timeout = 36000000000;
SET GLOBAL ob_trx_timeout = 36000000000;
SET GLOBAL max_allowed_packet = 67108864;
SET GLOBAL parallel_servers_target = 624;

Test results

Query V4.1 (s) V4.2 (s)
Q1 2.18 2.24
Q2 0.23 0.48
Q3 1.48 1.49
Q4 0.53 0.66
Q5 0.98 0.95
Q6 0.13 0.14
Q7 1.46 1.35
Q8 0.92 1.09
Q9 2.82 4.46
Q10 1.10 0.95
Q11 0.17 0.19
Q12 1.36 1.34
Q13 1.89 1.86
Q14 0.29 0.41
Q15 0.88 0.88
Q16 0.66 0.67
Q17 1.62 1.57
Q18 0.82 0.91
Q19 0.61 0.64
Q20 1.07 1.12
Q21 2.54 2.52
Q22 1.08 1.11
Total 24.82 27.03

Note

In OceanBase Database V4.2.0, an optimization path for Runtime Filter was introduced. However, the optimizer has not fully adjusted its filtering estimation for Runtime Filter. As a result, there may be estimation deviations in certain scenarios, which can lead to the selection of suboptimal execution plans and longer execution times. Improvements are expected to be implemented in V4.2.2.

TPC-DS benchmark test

Test plan

  1. Deploy an OceanBase cluster by using OBD. Deploy TPC-DS on a separate server as the stress machine. You do not need to deploy ODP, as you can directly connect to any server for testing.
  2. Configure the OceanBase cluster. Make sure that the cluster is in the 1-1-1 architecture, with three zones and each zone having one OBServer node. After the cluster is deployed successfully, create the tenant and user required for running the TPC-DS test (The sys tenant is a built-in system tenant used for managing the cluster, therefore, do not use the sys tenant to run the test). Set the primary zone of the tenant to RANDOM. Perform data loading first, then execute the 99 SQL queries multiple times and calculate the average.
  3. Prepare 100 GB of test data.

Tenant specifications

  • MAX_CPU = 26
  • MEMORY_SIZE = 70g

Parameter tuning

#sys
ALTER system flush plan cache GLOBAL;
ALTER system SET enable_sql_audit=false;
ALTER system SET enable_perf_event=false;
ALTER system SET syslog_level='PERF';
ALTER system SET enable_record_trace_log=false;

# Test tenant
SET GLOBAL ob_sql_work_area_percentage = 80;
SET GLOBAL ob_query_timeout = 36000000000;
SET GLOBAL ob_trx_timeout = 36000000000;
SET GLOBAL max_allowed_packet = 67108864;
SET GLOBAL parallel_servers_target = 624;

Test results

Query V4.1 (s) V4.2 (s)
Q1 0.63 0.64
Q2 3.46 1.17
Q3 0.16 0.17
Q4 9.43 9.76
Q5 1.63 1.71
Q6 0.37 0.42
Q7 0.28 0.31
Q8 0.39 0.26
Q9 1.89 1.90
Q10 0.50 0.51
Q11 5.79 6.02
Q12 0.28 0.23
Q13 2.04 0.57
Q14 11.38 11.22
Q15 0.23 0.23
Q16 0.92 0.95
Q17 0.52 0.46
Q18 0.32 0.37
Q19 0.17 0.28
Q20 0.19 0.19
Q21 0.29 0.31
Q22 1.11 1.23
Q23 14.20 14.55
Q24 1.56 1.41
Q25 0.62 0.49
Q26 0.21 0.22
Q27 0.35 0.42
Q28 7.44 6.58
Q29 0.64 0.53
Q30 0.27 0.31
Q31 0.62 0.67
Q32 0.11 0.11
Q33 0.77 0.55
Q34 0.37 0.56
Q35 0.87 0.90
Q36 0.31 0.32
Q37 0.42 0.46
Q38 1.49 1.60
Q39 2.31 0.85
Q40 0.16 0.17
Q41 0.18 0.08
Q42 0.11 0.13
Q43 0.64 0.65
Q44 0.45 0.49
Q45 0.39 0.32
Q46 0.81 0.65
Q47 1.16 1.21
Q48 0.61 0.66
Q49 0.86 0.92
Q50 0.81 0.68
Q51 2.82 2.83
Q52 0.11 0.12
Q53 0.24 0.25
Q54 1.05 1.04
Q55 0.11 0.11
Q56 1.01 0.56
Q57 0.79 0.80
Q58 0.60 0.65
Q59 13.64 3.11
Q60 1.13 0.69
Q61 0.30 0.33
Q62 0.40 0.42
Q63 0.23 0.24
Q64 1.84 1.89
Q65 2.70 2.77
Q66 0.46 0.49
Q67 16.12 9.59
Q68 0.67 0.48
Q69 0.44 0.46
Q70 1.18 1.36
Q71 0.54 0.54
Q72 1.47 1.34
Q73 0.31 0.41
Q74 6.36 4.36
Q75 2.26 2.55
Q76 0.49 0.50
Q77 0.71 0.74
Q78 3.64 3.46
Q79 0.65 0.70
Q80 1.78 3.45
Q81 0.30 0.26
Q82 0.67 0.79
Q83 0.69 0.76
Q84 0.19 0.20
Q85 0.84 0.92
Q86 0.36 0.33
Q87 1.59 1.70
Q88 0.65 0.85
Q89 0.30 0.32
Q90 0.19 0.47
Q91 0.13 0.16
Q92 0.10 0.10
Q93 0.75 0.76
Q94 0.62 0.65
Q95 6.37 6.36
Q96 0.38 0.44
Q97 0.93 0.94
Q98 0.30 0.30
Q99 0.70 0.80
Total time 160.83 138.75

Compatibility changes

Product behavioral changes

Feature Version Description
Table group 4.2
  • Partitioning attributes on table groups are no longer supported. The partitioning method for tables within a table group is no longer restricted by partition attributes, and partition management operations related to table groups are also no longer supported.
  • The semantics of aggregation and dispersion of partitions within a table group are no longer the same. The SHARDING attribute is introduced for table groups in V4.2.0 to control the aggregation and dispersion of table data within table groups. The TableGroup SHARDING attribute has three values: NONE, PARTITION, and ADAPTIVE.
Cap parameters 4.2 The default unit for Cap parameters is MB, but it is often wrongly assumed by users to be bytes, leading to settings that are far beyond the limit. To avoid unexpected results caused by updates to parameters without specifying the unit, the value unit must now be specified when updating Cap parameters. Updates without specifying the unit will fail.

View changes

View Version Change type Description
CDB/DBA_OB_TABLEGROUPS 4.2 Modified The partition attribute field will no longer have any meaning and will be displayed as NULL.
CDB/DBA_OB_TABLEGROUP_PARTITIONS 4.2 Deprecated The view will be deprecated and will no longer display data.
CDB/DBA_OB_TABLEGROUP_SUBPARTITIONS 4.2 Deprecated The view will be deprecated and will no longer display data.
CDB/DBA_OB_BALANCE_JOBS 4.2 New Displays the load balancing jobs being executed under a tenant. Only one load balancing job (JOB) can run under a tenant at a time, and each job can generate multiple load balancing tasks (TASK).
CDB displays data of all the tenants, but only the system tenant can access it.
CDB/DBA_OB_BALANCE_JOB_HISTORY 4.2 New Displays the history of load balancing jobs in the tenant.
CDB displays data of all the tenants, but only the system tenant can access it.
CDB/DBA_OB_BALANCE_TASKS 4.2 New Displays the load balancing jobs being executed in the tenant. Multiple load balancing tasks can run at the same time, and these tasks (TASK) belong to the same load balancing job (JOB).
CDB displays data of all the tenants, but only the system tenant can access it.
CDB/DBA_OB_BALANCE_TASK_HISTORY 4.2 New Displays the history of load balancing tasks in the tenant.
CDB displays data of all the tenants, but only the system tenant can access it.
CDB/DBA_OB_TRANSFER_TASKS 4.2 New Displays the transfer tasks being executed in the tenant.
CDB displays data of all the tenants, but only the system tenant can access it.
CDB/DBA_OB_TRANSFER_TASK_HISTORY 4.2 New Displays the history of transfer tasks in the tenant.
CDB displays data of all the tenants, but only the system tenant can access it.
CDB/DBA_OB_TABLE_LOCATIONS 4.2 Modified Added columns DUPLICATE_SCOPE, OBJECT_ID, TABLEGROUP_NAME, TABLEGROUP_ID, and SHARDING. This allows you to better observe the load balancing status of the cluster or tenant.
DBA_OB_TENANTS 4.2 Modified Added columns UNIT_NUM and COMPATIBLE to display the number of units in the cluster or tenant.
[G]V$OB_THREAD 4.2 New Displays the status information of all threads, with each row representing a thread.
[G]V$OB_LOCKS 4.2 New Implements the proprietary lock view [G]V$OB_LOCKS of OceanBase Database based on the V$LOCK view of Oracle. OceanBase Database adds locks of the TR type to the Oracle V$LOCK view to describe "row locks" before a minor compaction occurs.
[G]V$OB_ARBITRATION_SERVICE_STATUS 4.2 New Displays the connection status between the OceanBase cluster and the arbitration service.
[G]V$OB_ARBITRATION_MEMBER_INFO 4.2 New Displays information about the arbitration members of the cluster.
[G]V$OB_OPT_STAT_GATHER_MONITOR 4.2 New Displays the real-time status of statistics collection tasks.
DBA_OB_TASK_OPT_STAT_GATHER_HISTORY 4.2 New Displays the execution status of historical collection tasks.
DBA_OB_TABLE_OPT_STAT_GATHER_HISTORY 4.2 New Displays the execution status of historical collection tasks for tables.
[G]V$OB_UNITS 4.2 Modified Added the ZONE_TYPE and REGION columns.
CDB/DBA_OB_DATA_DICTIONARY_IN_LOG 4.2 Modified Displays the range of the data dictionary in the system log streams for easy consumption by CDC.
[G]V$OB_LOCKS 4.2 New Displays the current user's status for holding or requesting locks on various tables.
CDB/DBA_OB_LOG_RESTORE_SOURCE 4.2 New Displays the log restore source of the physically restored tenant and standby tenant.
V$OB_LS_LOG_RESTORE_STATUS 4.2 New Displays the log restore status at the log stream level.
V$OB_TIMESTAMP_SERVICE 4.2 New Displays the GTS and STS values of the tenant's clock service, the information about the node where the clock service is located, and the clock source type.
[G]V$OB_PX_P2P_DATAHUB 4.2 New Displays information about parallel data transmission operations.
[G]V$SQL_JOIN_FILTER 4.2 New Displays execution information of join filters.
DBA_OB_TABLE_STAT_STALE_INFO 4.2 New Displays the number of DDL operations performed on each table since the last statistics collection operation, and whether the current statistics have expired.
CDB/DBA/ALL_OB_EXTERNAL_TABLE_FILES 4.2 New Displays the file list corresponding to all created external tables in the current tenant.
CDB/DBA_OB_ACCESS_POINT 4.2 New Displays the list of servers that the tenants can access.
DBA_DB_LINKS 4.2 New Displays all DBLinks created in the current tenant. This view is new for MySQL tenants.
[G]V$OB_SQL_PLAN 4.2 New Displays the plan information collected by running the EXPLAIN PLAN command.
[G]V$OB_LOG_STAT 4.2 Modified Added the ARBITRATION_MEMBER, DEGRADED_LIST, and LEARNER_LIST columns.

System variable changes

Variale Version Change type Description
runtime_filter_type 4.2 New A global and session-level system variable used to set the tenant-level Runtime Filter type, which includes BLOOM_FILTER, RANGE, and IN types. If the value is set to an empty string, the Runtime Filter feature is turned off.
runtime_filter_wait_time_ms 4.2 New A global and session-level system variable used to set the maximum wait time for Runtime Filter. Default value: 10 ms.
runtime_filter_max_in_num 4.2 New A global and session-level system variable used to set the maximum number of distinct values (NDV) in the Runtime IN Filter. Default value: 1024.
runtime_bloom_filter_max_size 4.2 New A global and session-level system variable used to set the maximum memory usage for Runtime Bloom Filter, in bytes. Default value: 2 1024 1024 * 1024 (2 GB).
optimizer_dynamic_sampling 4.2 New A global and session-level system variable that specifies the level of dynamic sampling. Valid values: 0 and 1. The value 0 indicates to disable dynamic sampling and 1 indicates to enable it. Default value: 1.
parallel_degree_policy 4.2 New A global and session-level system variable that specifies the strategy for SQL parallel execution. Default value: MANUAL, which specifies to use auto DOP.
parallel_degree_limit 4.2 New A global and session-level system variable used to limit the maximum DOP chosen by the optimizer when the auto DOP policy is used. Default value: 0, which specifies not to limit the DOP chosen by the optimizer.
parallel_min_scan_time_threshold 4.2 New A global and session-level system variable used to increase the DOP when the estimated execution time for a base table scan exceeds the value of parallel_min_scan_time_threshold, thereby initiating more parallel queries. Default value: 1000 ms.
secure_file_priv 4.2 Modified A global system variable that can now only be modified by SQL statements executed by clients connected to the database via a local Unix Socket. This change was made for security reasons.

Parameter changes

Parameter Version Change type Description
enable_rebalance 4.2 Modified Adjusted to be a tenant-level parameter. Controls inter-tenant balancing for the system tenant and intra-tenant balancing for regular tenants.
balancer_idle_time 4.2 Modified Adjusted to be a tenant-level parameter. Represents the interval between the disaster recovery thread and balancing thread for the system tenant, and the interval for the log stream balancing thread for regular tenants.
partition_balance_schedule_interval 4.2 New A tenant-level parameter that sets the partition balance scheduling interval.
log_disk_throttling_percentage 4.2 New A tenant-level parameter that represents the percentage of non-recoverable log disk space that triggers log write throttling. When the non-recoverable log disk space reaches log_disk_throttling_percentage/100, log write throttling is triggered. Log write throttling stops when the non-recoverable log disk space falls below log_disk_throttling_percentage/100. Setting this parameter to 100 disables log write throttling. Default value: 60.
log_disk_throttling_maximum_duration 4.2 New A tenant-level parameter that represents the maximum expected available time for log disk space after log write throttling is triggered. The remaining available log disk space is expected to be consumed after log_disk_throttling_maximum_duration. A larger value extends the duration of log throttling and increases its intensity. Default value: 2 h.
_optimizer_ads_time_limit 4.2 New A hidden tenant-level parameter that controls the maximum sampling time (in seconds) for optimizer dynamic sampling. Default value: 10.
datafile_maxsize 4.2 New A cluster-level parameter that controls the upper limit for automatic disk data file expansion. Default value: 0.
datafile_next 4.2 New A cluster-level parameter that controls the step size for automatic disk data file expansion. Default value: 0.
_datafile_usage_upper_bound_percentage 4.2 New A cluster-level parameter that triggers automatic disk file expansion when the data file usage exceeds this value. Default value: 90.
standby_db_fetch_log_rpc_timeout 4.2 New A tenant-level parameter that sets the RPC timeout for fetching logs in the standby database, to control the detection of an unavailable server in the main database and switch to another server. Default value: 15s.
location_refresh_thread_count 4.2 Modified Changed the default value from 4 to 2.
enable_record_trace_id 4.2 Modified Changed the default value from True to False.
plan_cache_evict_interval 4.2 Modified Changed the default value from 1s to 5s.
devname 4.2 Modified Changed the effective mode of this parameter from dynamically taking effective to read-only.
local_ip 4.2 New A cluster-level parameter that represents the IP address of the installed OBServer node. This parameter is read-only.
observer_id 4.2 New A cluster-level parameter that is used by the RootService to assign a unique identifier to OBServer nodes in the cluster. This parameter is read-only.
standby_fetch_log_bandwidth_limit 4.2 New A cluster-level parameter that is used to set the maximum bandwidth occupied by all servers in the standby database when synchronizing logs from the primary database. The default value is 0, which specifies not to limit the bandwidth.
ls_gc_delay_time 4.2 New A tenant-level parameter that specifies the delay time for deleting log streams in the primary tenant in a physical standby scenario.
archive_lag_target 4.2 New A tenant-level parameter that specifies the delay time for log archiving in the tenant.
standby_db_preferred_upstream_log_region 4.2 New A tenant-level parameter that specifies the preferred region for synchronizing upstream logs in a physical standby scenario.
storage_meta_cache_priority 4.2 New A cluster-level parameter that specifies the priority of storing Meta Cache in kvcache.
range_optimizer_max_mem_size 4.2 New A tenant-level parameter that specifies the maximum memory usage of the Query Range module.
rootservice_memory_limit 4.2 Deprecated A cluster-level parameter that specifies the maximum memory capacity for Root Service.
trace_log_sampling_interval 4.2 Deprecated A cluster-level parameter that specifies the interval for periodically printing trace log information.
tenant_cpu_variation_per_server 4.2 Deprecated A cluster-level parameter that specifies the maximum allowed deviation in CPU quota between multiple units of a tenant.
token_reserved_percentage 4.2 Deprecated A cluster-level parameter that specifies a percentage of idle tokens reserved for the tenant.
global_write_halt_residual_memory 4.2 Deprecated A cluster-level parameter that specifies the threshold of remaining global memory that triggers the pause of write operations for regular tenants. The sys tenant is not affected.
plan_cache_high_watermark 4.2 Deprecated A cluster-level parameter that specifies the threshold of memory usage for the execution plan cache. When the memory usage exceeds the threshold, automatic eviction is triggered.
plan_cache_low_watermark 4.2 Deprecated A cluster-level parameter that specifies the threshold of memory usage for the execution plan cache. When the memory usage is less than the threshold, eviction is stopped.
max_px_worker_count 4.2 Deprecated A cluster-level parameter that specifies the maximum number of threads used by the SQL parallel query engine.
io_category_config 4.2 Deprecated A tenant-level parameter that specifies the percentage of I/O requests for each category.

Function/PL package changes

Function/PL package Version Change type Description
DBMS_SQL.LAST_ERROR_POSITION 4.2 New Returns the position where the syntax error occurs during the last call to DBMS_SQL.PARSE. This package applies to the Oracle mode.
DBMS_SESSION.RESET_PACKAGE 4.2 New Clears the status of all package variables in the current session. This package applies to the Oracle mode.
RANDOM([N]) 4.2 New Generates a random 64-digit integer. This function applies to both modes.
RANDSTR(N, gen) 4.2 New Generates a random string of N characters in length. gen indicates the random method. This function applies to both modes.
NORMAL(<mean> , <stddev> , <gen>) 4.2 New Returns a floating-point number that follows a normal distribution (also known as Gaussian distribution). This function applies to both modes.
UNIFORM(<min> , <max> , <gen>) 4.2 New Returns an integer or floating-point number that follows a uniform distribution. This function applies to both modes.
ZIPF(<s> , <N> , <gen>) 4.2 New Returns an integer that follows a Zipf distribution. This function applies to both modes.

Recommended versions of tools

The recommended platform tool versions for OceanBase Database V4.2.0 Beta are described in the following table:

Tool Version Remarks
ODP ODP V4.2.1 -
OCP OCP V4.1 OCP V4.1 is recommended for now. OCP V4.2.0 is expected be released in the middle of August 2023.
ODC ODC V4.1.3 BP3 ODC V4.1.3 BP3 is recommended for now. ODC V4.2.1 is expected be released at the end of August 2023.
OBCDC OBCDC V4.2.0 -
OMS OMS V4.1.0 OMS V4.1.0 is recommended for now. OMS V4.2.0 is expected be released in the middle of August 2023.
OceanBase C++ Call Interface (OCCI) OCCI V1.0.3 -
OceanBase Call Interface (OBCI) OBCI V2.0.7 -
OceanBase Embedded SQL in C (ECOB) ECOB V1.1.8 -
OBClient OBClient V2.2.3 -
LibOBClient LibOBClient V2.2.3 -
OBJDBC JDBC V2.4.4 -
ODBC ODBC V2.0.8 -

Upgrade notes

  • Online upgrade from OceanBase Database V4.1.0 to OceanBase Database V4.2.0_Beta is supported.
  • Online upgrade from OceanBase Database V3.x to OceanBase Database V4.2.0 is not supported.
  • OceanBase Database V3.x data can be migrated and upgraded to OceanBase Database V4.2.0 by using the logical migration feature of OMS.

Considerations

  • Enabling RPC SSL is not recommended in this version. Related issues will be optimized in future versions.
  • Upgrading from GB18030 to GB18030-2022 character set requires a logical upgrade.

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What is on this page
V4.2.0 BP1
Version information
Bug fixes
V4.2.0 Beta
Version information
Overview
Description of core features
Performance test report
Compatibility changes
Recommended versions of tools
Upgrade notes
Considerations