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Start on Cloud

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

DEPLOY YOUR WAY

OceanBase Cloud

The best way to deploy and scale OceanBase

OceanBase Enterprise

Run and manage OceanBase on your infra

TRY OPEN SOURCE

OceanBase Community Edition

The free, open-source distributed database

OceanBase seekdb

Open source AI native search database

Customer Stories

Real-world success stories from enterprises across diverse industries.

View All
BY USE CASES

Mission-Critical Transactions

Global & Multicloud Application

Elastic Scaling for Peak Traffic

Real-time Analytics

Active Geo-redundancy

Database Consolidation

Comprehensive knowledge hub for OceanBase.

Blog

Live Demos

Training & Certification

Documentation

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

View All
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QUICK START
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OceanBase Database

SQL - V3.2.4Enterprise Edition

  • Documentation Revision History
  • Document Overview
  • Get Started
    • What is OceanBase Database
      • Overview
      • Concepts
      • Compatibility with Oracle
        • Overview
        • SQL data types
        • Built-in functions
        • System views
      • Compatibility with MySQL
      • Management tools
      • Version rules
      • Limitations
    • Deploy OceanBase Database
      • Deployment introduction
      • Deployment process
      • Preparations
        • Prepare servers
        • Server configurations
        • Prepare installation packages
      • HA solution for OceanBase clusters
      • Deploy through the GUI
        • Configure the deployment environment
          • Deploy OAT
          • Verify deployment
          • Configure the clock source
          • Upload installation packages
          • Add a server
          • Initialize a server
        • Deploy OCP
          • Overview
          • Add an OCP configuration file
          • Deploy OCP
          • Verify deployment
        • Deploy the OceanBase cluster
          • (Optional) Configure DNS
          • Add an OBServer to the OCP resource pool
          • Create an OceanBase cluster
        • Deploy ODP
          • Overview
          • Deploy ODP
        • Create an OceanBase tenant
          • View resources available for a business tenant
          • Create a tenant
          • Verify deployment
        • Deploy OMS
          • Overview
          • Add an OMS configuration file
          • Deploy OMS
          • Verify deployment
        • Deploy ODC
          • Overview
          • Add an ODC configuration file
          • Deploy ODC
          • Verify deployment
      • Deploy through the CLI
        • Configure the deployment environment
          • Install oat-cli
          • Use oat-cli to configure the deployment environment
          • Configure the clock source
          • Upload installation packages
          • Configure host information
          • Check the environment before deployment
        • Deploy OCP
          • Overview
          • Generate a configuration file
          • Start deployment
          • Verify deployment
        • Deploy the OceanBase cluster
          • Deploy a single-replica OceanBase cluster
          • Deploy a three-replica OceanBase cluster
        • Deploy ODP
          • Deploy ODP by using the CLI
        • Create an OceanBase tenant
          • View resources available for a business tenant
          • Create a tenant
          • Verify deployment
        • Deploy OMS
          • Overview
          • Modify the configuration file
          • Start deployment
          • Verify deployment
        • Deploy ODC
          • Overview
          • Modify the configuration file
          • Start deployment
          • Verify deployment
    • Data migration
      • Overview
      • Migrate data by using OMS
        • Migrate data by using OMS
        • Migrate data from a MySQL database to a MySQL tenant of OceanBase Database by using OMS
        • Migrate data from a MySQL tenant of OceanBase Database to a MySQL database by using OMS
        • Migrate data from an Oracle database to a MySQL tenant of OceanBase Database by using OMS
        • Migrate data from an Oracle database to an Oracle tenant of OceanBase Database by using OMS
        • Migrate data from an Oracle tenant of OceanBase Database to an Oracle database by using OMS
        • Migrate data from a DB2 LUW database to a MySQL tenant of OceanBase Database by using OMS
        • Migrate data from a DB2 LUW database to an Oracle tenant of OceanBase Database by using OMS
        • Migrate data from a MySQL tenant of OceanBase Database to a DB2 LUW database by using OMS
        • Migrate data from an Oracle tenant of OceanBase Database to a DB2 LUW database by using OMS
        • Migrate data from a TiDB database to a MySQL tenant of OceanBase Database by using OMS
        • Migrate data between MySQL tenants of OceanBase Database by using OMS
        • Use OMS to migrate data between Oracle tenants of OceanBase Database
      • Migrate data by using OBLOADER & OBDUMPER
        • Import data by using OBLOADER
        • Export data by using OBDUMPER
      • Migrate data by using SQL scripts
      • Migrate data by using mysqldump
      • Migrate data by using DataX
      • Migrate data by using the OUTFILE statement
    • Database connections and routing
      • Overview
      • Manage ODP
        • ODP management overview
        • Manage ODP clusters
          • Create an ODP cluster
          • Manage ODP cluster parameters
          • Delete an ODP cluster
          • Upgrade all ODPs in an ODP cluster
          • Restart all ODPs in an ODP cluster
          • Manage OceanBase clusters connected to an ODP cluster
          • Monitor ODP cluster performance
        • Manage ODP
          • Add an ODP
          • Start an ODP
          • Refresh ODP configurations
          • Stop an ODP
          • Restart an ODP
          • Delete an ODP
          • Upgrade an ODP
        • ODP startup parameters
      • Database connections
        • Connect to OceanBase Database from OBClient
        • Connect to OceanBase Database from a MySQL client
        • Connect to OceanBase Database through ODC
      • Physical connections
      • Logical connections
        • Query all sessions
        • Query the details of a session
        • Query the metrics of a session
        • Query session variables
        • Terminate a session
      • Driver management
        • Overview
        • OB-ODBC
        • OBCI
        • OceanBase Connector/C
        • OceanBase Connector/J
      • Routing management
        • Table-based routing of ODP
        • SQL parser
        • LDC-based routing
        • ODP routing strategies
          • Read/Write splitting
          • Follower-first read
          • Blocklist mechanism
    • Cluster and multi-tenant management
      • Manage clusters
        • Create a cluster
        • Manage clusters
        • Manage cluster parameters
          • Overview
          • Query cluster-level parameters
          • Modify cluster-level parameters
        • Manage zones in a cluster
          • Overview of zone management
          • Add or delete a zone
          • Add or delete an encrypted zone
          • Start or stop a zone
          • Modify the configurations of a zone
          • Restart a zone
          • Isolate a failed zone
        • Manage OBServer nodes
          • Add an OBServer node
          • View OBServer node status
          • Stop or start an OBServer node
          • Restart an OBServer node
          • Isolate a failed OBServer node
          • Delete an OBServer node
          • Replace an OBServer node
        • View cluster information
        • Overview of cluster tenant management
        • Monitor cluster performance
        • Cluster performance report
        • View resource information of a cluster
      • Configuration management
        • Overview of configuration management
        • Set parameters
        • Set variables
        • Configure general parameters
        • Examples of parameter configuration in a production environment
        • Recommended minimum resource configuration
      • Resource management
        • Overview
        • Create a resource unit
        • Manage resource units
          • View configurations of a resource unit
          • Modify configurations of a resource unit
          • Drop a resource unit
        • Create a resource pool
        • Manage resource pools
          • Allocate a resource pool to a tenant
          • Modify a resource pool
          • Merge resource pools
          • Split a resource pool
          • Remove a resource pool from a tenant
          • Delete a resource pool
        • Query resource allocation
      • Tenant management
        • Overview of tenant management
        • Create a tenant
        • Copy a tenant
        • Manage tenants
          • Query tenant information
          • Modify a tenant
          • Rename a tenant
          • Drop a tenant
        • Manage users and privileges
          • Users and privileges
            • Overview
            • sys tenant
            • Oracle tenants
            • MySQL tenants
          • Oracle mode
            • Create a user
            • Set password complexity
            • Logon failure handling policies
            • View user privileges
            • Modify user privileges
            • Change the password of a user
            • Lock or unlock a user
            • Drop a user
            • Manage roles
              • Overview
              • Create a role
              • Assign a role to another role
              • Assign a role to a user
              • Specify valid or invalid roles for a user
              • View roles
              • Modify a role
              • Revoke a role
              • Drop a role
          • MySQL mode
            • Create a user
            • Set password complexity
            • Handle logon failures
            • View user privileges
            • Modify user privileges
            • Change the password of a user
            • Lock and unlock a user
            • Drop a user
        • Set and view the tenant allowlist
        • View the topology of a tenant
        • View the resource configurations of a tenant
        • Modify the resource configurations of a tenant
        • View the performance metrics of a tenant
        • View tenant sessions
        • Terminate a tenant session
        • Manage tenant parameters
          • Overview
          • Query tenant-level parameters
          • Modify tenant-level parameters
        • Manage tenant variables
      • Manage data storage
        • Minor compaction management
          • Overview
          • Automatically trigger a minor compaction
          • Manually initiate a minor compaction
          • View minor compaction information
          • Modify minor compaction settings
        • Major compaction management
          • Overview
          • Automatically trigger a major compaction
          • Configure scheduled major compactions
          • Manually initiate a major compaction
          • Manually control a major compaction
          • View major compaction information
            • View the major compaction process
            • View disk usage during a major compaction
          • Major compaction timeouts and errors
          • Modify major compaction settings
        • Data compression
          • Overview
          • Data encoding and compression
      • Manage memory
        • Overview
        • Memory structure
        • Set the maximum memory for an OceanBase database
        • Manage internal system memory
        • Manage internal tenant memory
        • Manage the memory of the plan cache
        • Query memory usage information
        • FAQ
      • Manage processes
        • Overview
        • Multi-tenant threads of OceanBase Database
        • FAQ about multi-tenant threads
        • Background threads of OceanBase Database
      • Manage logs
        • Log overview
        • Log generation levels
          • Log generation levels
          • Set a log generation level
        • Log file size and quantity management
          • Use the log file splitting feature
          • Control the number of log files
        • Query logs
          • Query the log of an SQL request
          • Query the log of a previous SQL request by using the SQL Trace feature
    • Database object management
      • Oracle mode
        • Manage tables
          • Overview
          • Create a table
          • Define column constraints
          • Query table definition
          • Modify a table
          • Empty a table
          • Drop a table
        • Manage table groups
          • Overview
          • Statements for table group management
        • Manage indexes
          • Overview
          • Create indexes
          • Query indexes
          • Drop an index
        • Manage views
        • Manage sequences
        • Manage synonyms
        • Manage triggers
          • Overview
          • Create a DML trigger
          • Create an INSTEAD OF trigger
          • Modify and drop a trigger
          • Disable or enable a trigger
          • Query trigger information
        • Manage directory objects
        • Manage DBLinks
      • MySQL mode
        • Manage databases
          • Create a database
          • View databases
          • Modify a database
          • Drop a database
        • Manage tables
          • Overview
          • Create a table
          • Define an auto-increment column
          • Define column constraints
          • Query table definition
          • Modify a table
          • Empty a table
          • Drop a table
        • Manage table groups
          • Overview
          • Statements for table group management
        • Manage indexes
          • Overview
          • Create indexes
          • Query indexes
          • Drop an index
        • Manage views
        • Manage sequences
        • Manage triggers
          • Overview
          • Create a DML trigger
          • Query trigger information
          • Drop a trigger
    • Distributed storage management
      • Overview of data distribution
      • Manage partitions
        • Oracle mode
          • Overview of partitions
          • Create a partitioned table
          • Manage a partitioned table
          • Create a subpartitioned table
          • Manage a subpartitioned table
          • Partition pruning
          • Query data in specified partitions
          • Create an index for a partitioned table
            • Overview of indexes
            • Local indexes
            • Global indexes
          • Create a partitioned table group
          • Add a partitioned table to a table group
          • Manage a partitioned table group
          • Create a subpartitioned table group
          • Add a subpartitioned table to a table group
          • Manage a subpartitioned table group
        • MySQL mode
          • Overview of partitions
          • Create a partitioned table
          • Manage a partitioned table
          • Create a subpartitioned table
          • Manage a subpartitioned table
          • Partition pruning
          • Query data in specified partitions
          • Create an index for a partitioned table
            • Overview of indexes
            • Local indexes
            • Global indexes
          • Create a partitioned table group
          • Add a partitioned table to a table group
          • Manage a partitioned table group
          • Create a subpartitioned table group
          • Add a subpartitioned table to a table group
          • Manage a subpartitioned table group
      • Manage replicas
        • Overview
        • Create a replica
        • Edit a tenant replica in a zone
        • Delete a tenant replica from a zone
      • Manage locality
        • Overview
        • Modify table locality
        • Modify tenant locality
      • Load balancing
        • Overview of load balancing
        • Manage automatic load balancing
        • Manually manage load balancing
          • Manually migrate and switch partition replicas
          • Set load balancing by using table groups
          • Set load balancing by primary zone
    • Performance tuning
      • Overview
      • Performance tools
        • System tools
          • General tool Top
          • CPU tools
          • Memory tools
          • Disk I/O tools
          • Network tools
        • Internal tables
          • gv$sysstat
          • gv$sql_audit
          • __all_virtual_trans_stat
        • Logs
          • slow trans
          • tenant dump
          • Slow queries
        • OCP
          • Monitoring and alerts
          • SQL diagnostics
          • Performance report
          • ASH report
          • Transaction diagnostics
          • Deadlock detection
      • System tuning
        • OS parameter tuning
        • Database parameter tuning
          • CPU parameters
          • I/O parameters
          • Memory-related parameters
          • Network transmission parameters
        • ODP parameter tuning
          • CPU parameters
          • Network transmission parameters
          • Route parameters on nodes
      • Business model tuning
        • Load balancing
        • SQL diagnostics
        • Distributed transactions
      • SQL tuning guide
        • Execution process of SQL queries
        • SQL execution plan
          • Introduction to SQL execution plans
          • Execution plan operators
            • TABLE SCAN
            • TABLE LOOKUP
            • JOIN
            • COUNT
            • GROUP BY
            • WINDOW FUNCTION
            • SUBPLAN FILTER
            • DISTINCT
            • SEQUENCE
            • MATERIAL
            • SORT
            • LIMIT
            • FOR UPDATE
            • SELECT INTO
            • SUBPLAN SCAN
            • UNION
            • INTERSECT
            • EXCEPT/MINUS
            • INSERT
            • DELETE
            • UPDATE
            • MERGE
            • EXCHANGE
            • GI
          • Plan cache
          • Fast parameterization
          • Real-time execution plan display
        • Distributed execution plan
          • Perform distributed execution and parallel queries
          • Generate a distributed plan
          • Schedule distributed execution plans
          • Manage distributed execution plans
          • Execute parallel queries
          • Perform parameter tuning for a parallel query
          • Parallel DML
        • SQL tuning
          • Overview
          • General procedure of SQL tuning
          • Monitor the SQL execution performance
            • gv$sql_audit
            • SQL Trace
            • Plan cache views
            • Examples of SQL performance analysis
              • Use SQL Audit to analyze wait events in a query
              • Analyze SQL queries that cause an abrupt RT jitter
              • View and analyze the shape of an execution plan
              • Analyze slow SQL queries
              • Query SQL traffic distribution and QPS
              • Check whether SQL queries are balanced across servers in a cluster
              • Find the TOP N SQL queries
              • Analyze whether an unusually large number of remote execution requests exist in the system or the execution of an SQL statement
              • Find full table scan SQL statements in a tenant
              • Find the TOP N queries with the longest execution time within a specified period
              • Analyze queries related to distributed plans
              • Check whether the RPC execution count of a distributed subplan is balanced across servers in a cluster
          • Optimizer statistics
            • Overview of statistics
            • Statistics collection methods
              • Overview
              • Histograms
              • Manual statistics collection
              • Automatic statistics collection
            • Statistics management
              • Overview
              • Deletion
              • Setting
              • Import and export
              • Locking and unlocking
              • History management
              • Statistics preference management
            • Examples
          • Query rewrite
            • Overview
            • Rule-based query rewrite
            • Cost-based query rewrite
          • Query optimization
            • Access path
              • Overview
              • Rule-based path selection
              • Cost-based path selection
            • Join algorithms
              • Overview
              • Join algorithms
              • Join order
          • Manage execution plans
            • Optimizer hints
            • Plan binding
            • SQL plan management
        • Glossary
        • General issues in SQL tuning
      • Performance diagnostics
        • Monitor and diagnose the cluster performance
        • Tenant performance diagnostics
        • Monitor ODP performance
        • Monitor host performance
      • Case analysis
      • Performance test (MySQL mode)
        • Sysbench OLTP
        • BenchMarkSQL
        • TPC-H
      • Performance test (Oracle mode)
        • BenchMarkSQL
        • TPC-H
    • Data high availability
      • Flashback
        • Objects supported by the recycle bin
        • Recycle bin for databases, tables, and indexes
        • Recycle bin for tenants
        • Flash back objects from the recycle bin
        • Restore point
        • Use a flashback query to query data of multiple versions
      • Manage physical backup and restore
        • Introduction to physical backup and restore
        • Deploy NFS
        • Data backup for a cluster
          • Perform a backup by using commands
            • Preparations for backup
            • Initiate a log backup
            • Initiate a data backup
          • Perform a backup for a cluster in OCP
          • Backup of a specified path for a tenant
          • Enable backup for clusters based on log splitting
          • Check the backup progress
          • Stop a backup
          • Automatically clear backup data for clusters
          • Manually clear backup data for clusters
          • Stop backup data clearing for clusters
        • Back up data backups
          • Overview
          • Perform a secondary backup for a cluster by using commands
            • Preparations for secondary backup
            • Initiate a secondary log backup
            • Initiate a secondary data backup
          • Perform a secondary backup for clusters in OCP
          • Perform a secondary backup for tenants
          • View the progress of secondary data backup tasks
          • Stop a secondary backup
          • Automatically clear secondary backup data for clusters
          • Manually clear secondary backup data
          • Stop clearing secondary backup data
        • Update access_id and access_key for OSS in the backup destination during backup
        • Verify data
          • Overview
          • Verify backup data in a cluster
          • Verify backup data in a specified path in a cluster
          • Verify backup data in a specified path across clusters
          • View data verification results
        • Restore data
          • Preparations for restore
          • Perform full restore
          • Restore a specified table
          • Restore secondary backup data
          • View the restore progress and results
          • Cancel restore
        • Routine maintenance
          • Query backup parameters
          • Force stop all backup-related tasks
          • Set backup_zone
      • Primary/Standby cluster management
        • Overview
        • Considerations and limitations
        • Deploy the primary and standby clusters
          • Configuration requirements
          • Deploy a primary cluster
          • Check the configurations of the primary cluster
          • Deploy standby clusters in OCP
        • Tenant management
        • Log transfer service
          • Overview
          • Set the log transfer parameter for a standby cluster
          • Configure log compression
        • Protection mode
          • Overview
          • Protection modes and protection levels
          • Switch to another protection mode
        • Role switching
          • Preparations for a switchover
          • Perform a switchover in a command-line tool
          • Perform a switchover in OCP
          • Perform a failover in a command-line tool
            • Preparations for a failover
            • Perform a lossless failover
            • Connect the original primary cluster after a lossless failover
            • Connect other standby clusters after a lossless failover
            • Perform a lossy failover
            • Restore other clusters after a lossy failover
            • Correct the data after a failover
          • Perform a failover in OCP
        • Standby cluster read service
        • Delete a standby cluster
        • Standby cluster disconnection
          • Preparations for disconnection
          • Disconnect a standby cluster
        • Troubleshooting
          • Failover errors
          • Switchover errors
          • Protection mode switching errors
          • Tenant creation for a standby cluster got stuck
          • Data synchronization enablement errors
          • Standby cluster disconnection errors
    • Database security
      • Data storage encryption
        • Overview
        • MySQL mode
          • Enable storage encryption for a new table
          • Enable storage encryption for an existing table
          • Decrypt a table
        • Oracle mode
          • Enable storage encryption for a new table
          • Enable storage encryption for an existing table
          • Decrypt a table
      • Data transmission encryption
        • Overview
        • Transmission encryption of OBServer nodes
        • Transmission encryption of ODPs
      • RPC connection authentication
      • Set row-level access control
      • Audit databases
        • Overview
        • Enable audit
        • Audit user logon operations
        • Audit user operations
        • Audit specified database objects
    • O&M management
      • O&M overview
        • Overview
        • Monitoring
          • View status monitoring information
          • View performance monitoring information
          • Perform SQL diagnostics
        • Alerts
          • Alert configuration
          • Manage alert subscriptions
          • Perform alert management
          • Manage alert items
      • Database upgrade
        • Overview
        • Perform an upgrade
        • Perform a major compaction
        • Check upgrade results
      • Scale-in and scale-out
        • Overview
        • Cluster-level scale-in and scale-out
          • Scale-out
            • Add zones to a cluster
            • Add OBServer nodes to zones
          • Scale-in
            • Delete zones from a cluster
            • Delete OBServer nodes from zones
        • Scale-in and scale-out of tenant resources
          • Modify unit_config
          • Modify UNIT_NUM
      • Resource isolation
        • cgroup-based resource isolation
          • Enable cgroups-based CPU isolation between tenant worker threads
          • Clear cgroup configurations
      • Routine inspections
        • Overview
        • Check the cluster status
        • Check cluster parameters
        • Check the host status
        • Check tenant resource usage
        • Check cluster resource usage
        • Check the OBServer node status
        • Check the NTP offset
        • Check data backup
        • Check the ODP connection status
      • Troubleshooting
        • Overview
        • Issue analysis
          • View alerts
          • View logs
          • View error codes
          • Query views
        • Troubleshoot OBServer node restart failures
        • Troubleshoot unexpected exit of an observer process
        • Troubleshoot bootstrap failures
        • Troubleshoot database connection issues
        • Troubleshoot clock synchronization issues
        • Troubleshoot the absence of a leader
        • Troubleshoot replica migration issues
        • Troubleshoot exhausted tenant MemStore memory
        • Tenant memory overrun
        • Troubleshoot major compaction exceptions
        • Overloaded OBServer nodes
        • Troubleshoot row lock contention
        • Troubleshoot transaction errors
      • Emergency response
        • Overview
        • Analysis, diagnosis, and decision-making process
        • Common emergency response
          • Exceptions caused by hardware
            • Node failures
            • Network jitter
            • ODP faults
            • Other exceptions related to hardware and network
          • Exceptions caused by capacity changes
            • Exceptions of SQL queries
            • High disk I/O on an OBServer node
            • Overloaded NIC on an OBServer node
            • Full occupation of tenant memory
            • Full usage of ODP threads
            • Full usage of OBServer clog disk
            • Full usage of the OBServer data disk
            • Accumulated request queue of a tenant
          • Other cluster exceptions
            • Blocked tenant minor compaction
            • Blocked cluster major compaction
            • sys tenant or RootService exceptions
            • Insufficiency or leakage of system memory
            • Slow query of the queuing table
    • System references
      • System parameters
        • Overview
        • Summary of system parameters
        • Cluster-level parameters
          • all_cluster_list
          • auto_broadcast_location_cache_rate_limit
          • auto_delete_expired_backup
          • auto_leader_switch_interval
          • auto_refresh_location_cache_rate_limit
          • autoinc_cache_refresh_interval
          • backup_backup_archive_log_batch_count
          • backup_backup_archivelog_retry_interval
          • backup_backup_dest
          • backup_backupset_batch_count
          • backup_backup_dest_option
          • backup_backupset_retry_interval
          • backup_concurrency
          • backup_dest
          • backup_dest_option
          • backup_log_archive_option
          • backup_net_limit
          • backup_recovery_window
          • backup_region
          • backup_zone
          • balance_blacklist_failure_threshold
          • balance_blacklist_retry_interval
          • balancer_emergency_percentage
          • balancer_idle_time
          • balancer_log_interval
          • balancer_task_timeout
          • balancer_timeout_check_interval
          • balancer_tolerance_percentage
          • bf_cache_miss_count_threshold
          • bf_cache_priority
          • builtin_db_data_verify_cycle
          • cache_wash_threshold
          • clog_cache_priority
          • clog_disk_usage_limit_percentage
          • clog_disk_utilization_threshold
          • clog_expire_days
          • clog_sync_time_warn_threshold
          • clog_transport_compress_all
          • clog_transport_compress_func
          • cluster
          • cluster_id
          • config_additional_dir
          • cpu_count
          • cpu_quota_concurrency
          • cpu_reserved
          • data_copy_concurrency
          • data_dir
          • data_disk_usage_limit_percentage
          • data_storage_error_tolerance_time
          • data_storage_warning_tolerance_time
          • datafile_disk_percentage
          • datafile_size
          • dead_socket_detection_timeout
          • debug_sync_timeout
          • default_compress
          • default_compress_func
          • default_row_format
          • default_transport_compress_func
          • devname
          • disk_io_thread_count
          • dtl_buffer_size
          • election_blacklist_interval
          • election_cpu_quota
          • enable_async_syslog
          • enable_auto_leader_switch
          • enable_auto_refresh_location_cache
          • enable_ddl
          • enable_election_group
          • enable_global_freeze_trigger
          • enable_log_archive
          • enable_major_freeze
          • enable_manual_merge
          • enable_merge_by_turn
          • enable_ob_ratelimit
          • enable_one_phase_commit
          • enable_perf_event
          • enable_pg
          • enable_rebalance
          • enable_record_trace_id
          • enable_record_trace_log
          • enable_rereplication
          • enable_rich_error_msg
          • enable_rootservice_standalone
          • enable_separate_sys_clog
          • enable_smooth_leader_switch
          • enable_sql_audit
          • enable_sql_operator_dump
          • enable_sys_unit_standalone
          • enable_syslog_recycle
          • enable_syslog_wf
          • enable_tcp_keepalive
          • enable_unit_balance_resource_weight
          • enable_upgrade_mode
          • fast_recovery_concurrency
          • flush_log_at_trx_commit
          • force_refresh_location_cache_interval
          • force_refresh_location_cache_threshold
          • freeze_trigger_percentage
          • fuse_row_cache_priority
          • gc_wait_archive
          • get_leader_candidate_rpc_timeout
          • global_index_build_single_replica_timeout
          • global_major_freeze_residual_memory
          • global_write_halt_residual_memory
          • high_priority_net_thread_count
          • ignore_replay_checksum_error
          • ignore_replica_checksum_error
          • ilog_index_expire_time
          • index_cache_priority
          • index_clog_cache_priority
          • index_info_block_cache_priority
          • internal_sql_execute_timeout
          • large_query_threshold
          • large_query_worker_percentage
          • leak_mod_to_check
          • lease_time
          • location_cache_cpu_quota
          • location_cache_expire_time
          • location_cache_priority
          • location_cache_refresh_min_interval
          • location_cache_refresh_rpc_timeout
          • location_cache_refresh_sql_timeout
          • location_fetch_concurrency
          • location_refresh_thread_count
          • log_archive_batch_buffer_limit
          • log_archive_checkpoint_interval
          • log_archive_concurrency
          • log_restore_concurrency
          • major_compact_trigger
          • major_freeze_duty_time
          • max_kept_major_version_number
          • max_px_worker_count
          • max_string_print_length
          • max_syslog_file_count
          • memory_chunk_cache_size
          • memory_limit
          • memory_limit_percentage
          • memory_reserved
          • memstore_limit_percentage
          • merge_stat_sampling_ratio
          • merge_thread_count
          • merger_check_interval
          • merger_completion_percentage
          • merger_switch_leader_duration_time
          • merger_warm_up_duration_time
          • micro_block_merge_verify_level
          • migrate_concurrency
          • migration_disable_time
          • min_observer_version
          • minor_compact_trigger
          • minor_deferred_gc_time
          • minor_freeze_times
          • minor_merge_concurrency
          • minor_warm_up_duration_time
          • multiblock_read_gap_size
          • multiblock_read_size
          • mysql_port
          • net_thread_count
          • ob_event_history_recycle_interval
          • ob_ratelimit_stat_period
          • obconfig_url
          • ofs_list
          • partition_table_check_interval
          • partition_table_scan_batch_count
          • plan_cache_evict_interval
          • plan_cache_high_watermark
          • plan_cache_low_watermark
          • px_task_size
          • px_workers_per_cpu_quota
          • rebuild_replica_data_lag_threshold
          • recyclebin_object_expire_time
          • replica_safe_remove_time
          • resource_hard_limit
          • resource_soft_limit
          • restore_concurrency
          • rootservice_async_task_queue_size
          • rootservice_async_task_thread_count
          • rootservice_list
          • rootservice_memory_limit
          • rootservice_ready_check_interval
          • row_compaction_update_limit
          • row_purge_thread_count
          • rpc_port
          • rpc_timeout
          • schema_history_expire_time
          • schema_history_recycle_interval
          • server_balance_cpu_mem_tolerance_percent
          • server_balance_critical_disk_waterlevel
          • server_balance_disk_tolerance_percent
          • server_check_interval
          • server_cpu_quota_max
          • server_cpu_quota_min
          • server_data_copy_in_concurrency
          • server_data_copy_out_concurrency
          • server_permanent_offline_time
          • server_temporary_offline_time
          • sql_audit_memory_limit
          • sql_audit_queue_size
          • ssl_client_authentication
          • ssl_external_kms_info
          • stack_size
          • switchover_process_thread_count
          • sys_bkgd_io_high_percentage
          • sys_bkgd_io_low_percentage
          • sys_bkgd_migration_change_member_list_timeout
          • sys_bkgd_migration_retry_num
          • sys_bkgd_net_percentage
          • sys_cpu_limit_trigger
          • syslog_io_bandwidth_limit
          • syslog_level
          • system_cpu_quota
          • system_memory
          • system_trace_level
          • tableapi_transport_compress_func
          • tablet_size
          • tcp_keepcnt
          • tcp_keepidle
          • tcp_keepintvl
          • tenant_cpu_variation_per_server
          • tenant_groups
          • tenant_task_queue_size
          • token_reserved_percentage
          • trace_log_sampling_interval
          • trace_log_slow_query_watermark
          • trx_2pc_retry_interval
          • trx_force_kill_threshold
          • trx_try_wait_lock_timeout
          • unit_balance_resource_weight
          • use_large_pages
          • user_block_cache_priority
          • user_iort_up_percentage
          • user_row_cache_priority
          • user_tab_col_stat_cache_priority
          • virtual_table_location_cache_expire_time
          • wait_leader_batch_count
          • weak_read_version_refresh_interval
          • workers_per_cpu_quota
          • zone
          • zone_merge_concurrency
          • zone_merge_order
          • zone_merge_timeout
          • ob_esi_rpc_port
          • enable_ob_esi_process
          • ob_esi_session_timeout
          • ob_esi_io_concurrency
          • ob_esi_memory_limit
          • ob_esi_syslog_level
          • ob_esi_max_syslog_file_count
          • sql_login_thread_count
          • diag_syslog_per_error_limit
          • enable_cgroup
          • rpc_client_authentication_method
          • rpc_server_authentication_method
          • max_trx_part_size
        • 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
          • default_progressive_merge_num
          • enable_clog_persistence_compress
          • enable_early_lock_release
          • enable_monotonic_weak_read
          • external_kms_info
          • enable_sql_extension
          • job_queue_processes
          • max_stale_time_for_weak_consistency
          • ob_enable_batched_multi_statement
          • ob_proxy_readonly_transaction_routing_policy
          • ob_ssl_invited_common_names
          • open_cursors
          • plsql_ccflags
          • plsql_code_type
          • plsql_debug
          • plsql_optimize_level
          • plsql_v2_compatibility
          • plsql_warnings
          • sql_work_area
          • tde_method
          • writing_throttling_maximum_duration
          • writing_throttling_trigger_percentage
          • workarea_size_policy
          • ob_query_switch_leader_retry_timeout
      • System variables (MySQL mode)
        • Overview
        • System variable summary
        • auto_increment_cache_size
        • auto_increment_increment
        • auto_increment_offset
        • autocommit
        • binlog_row_image
        • block_encryption_mode
        • character_set_client
        • character_set_connection
        • character_set_database
        • character_set_filesystem
        • character_set_results
        • character_set_server
        • character_set_system
        • collation_connection
        • collation_database
        • collation_server
        • connect_timeout
        • datadir
        • debug_sync
        • default_password_lifetime
        • div_precision_increment
        • error_on_overlap_time
        • explicit_defaults_for_timestamp
        • foreign_key_checks
        • group_concat_max_len
        • identity
        • init_connect
        • interactive_timeout
        • is_result_accurate
        • last_insert_id
        • license
        • lower_case_table_names
        • max_allowed_packet
        • max_sp_recursion_depth
        • max_user_connections
        • net_buffer_length
        • net_read_timeout
        • net_write_timeout
        • nls_calendar
        • nls_characterset
        • nls_comp
        • nls_currency
        • nls_date_format
        • nls_date_language
        • nls_dual_currency
        • nls_iso_currency
        • nls_language
        • nls_length_semantics
        • nls_nchar_characterset
        • nls_nchar_conv_excp
        • nls_numeric_characters
        • nls_sort
        • nls_territory
        • nls_timestamp_format
        • nls_timestamp_tz_format
        • ob_bnl_join_cache_size
        • ob_capability_flag
        • ob_compatibility_mode
        • ob_create_table_strict_mode
        • ob_default_replica_num
        • ob_early_lock_release
        • ob_enable_aggregation_pushdown
        • ob_enable_blk_nestedloop_join
        • ob_enable_hash_group_by
        • ob_enable_index_direct_select
        • ob_enable_jit
        • ob_enable_plan_cache
        • ob_enable_sql_audit
        • ob_enable_trace_log
        • ob_enable_transformation
        • ob_enable_transmission_checksum
        • ob_enable_truncate_flashback
        • ob_global_debug_sync
        • ob_last_schema_version
        • ob_log_level
        • ob_max_parallel_degree
        • ob_org_cluster_id
        • ob_pl_block_timeout
        • ob_plan_cache_evict_high_percentage
        • ob_plan_cache_evict_low_percentage
        • ob_plan_cache_percentage
        • ob_proxy_global_variables_version
        • ob_proxy_partition_hit
        • ob_proxy_set_trx_executed
        • ob_query_timeout
        • ob_read_consistency
        • ob_reserved_meta_memory_percentage
        • ob_route_policy
        • ob_safe_weak_read_snapshot
        • ob_sql_audit_percentage
        • ob_sql_work_area_percentage
        • ob_stmt_parallel_degree
        • ob_tcp_invited_nodes
        • ob_temp_tablespace_size_percentage
        • ob_timestamp_service
        • ob_trace_info
        • ob_trx_idle_timeout
        • ob_trx_lock_timeout
        • ob_trx_timeout
        • optimizer_capture_sql_plan_baselines
        • optimizer_use_sql_plan_baselines
        • parallel_max_servers
        • parallel_servers_target
        • performance_schema
        • plugin_dir
        • query_cache_size
        • query_cache_type
        • read_only
        • recyclebin
        • resource_manager_plan
        • secure_file_priv
        • sql_auto_is_null
        • sql_mode
        • sql_quote_show_create
        • sql_safe_updates
        • sql_select_limit
        • sql_throttle_current_priority
        • sql_throttle_network
        • sql_throttle_priority
        • sql_throttle_rt
        • sql_warnings
        • system_time_zone
        • time_zone
        • timestamp
        • tracefile_identifier
        • transaction_isolation
        • transaction_read_only
        • tx_isolation
        • tx_read_only
        • undo_retention
        • version
        • version_comment
        • wait_timeout
        • validate_password_check_user_name
        • validate_password_length
        • validate_password_mixed_case_count
        • validate_password_number_count
        • validate_password_policy
        • validate_password_special_char_count
        • server_uuid
        • binlog_format
        • binlog_checksum
        • binlog_rows_query_log_events
        • log_bin
        • server_id
        • default_storage_engine
        • max_connections
        • event_scheduler
        • cte_max_recursion_depth
        • regexp_stack_limit
        • regexp_time_limit
      • System variables (Oracle mode)
        • Overview
        • System variable summary
        • auto_increment_cache_size
        • auto_increment_increment
        • auto_increment_offset
        • autocommit
        • binlog_row_image
        • block_encryption_mode
        • character_set_client
        • character_set_connection
        • character_set_database
        • character_set_filesystem
        • character_set_results
        • character_set_server
        • character_set_system
        • collation_connection
        • collation_database
        • collation_server
        • connect_timeout
        • datadir
        • debug_sync
        • default_password_lifetime
        • div_precision_increment
        • error_on_overlap_time
        • explicit_defaults_for_timestamp
        • foreign_key_checks
        • group_concat_max_len
        • identity
        • init_connect
        • interactive_timeout
        • is_result_accurate
        • last_insert_id
        • license
        • lower_case_table_names
        • max_allowed_packet
        • max_sp_recursion_depth
        • max_user_connections
        • net_buffer_length
        • net_read_timeout
        • net_write_timeout
        • nls_calendar
        • nls_characterset
        • nls_comp
        • nls_currency
        • nls_date_format
        • nls_date_language
        • nls_dual_currency
        • nls_iso_currency
        • nls_language
        • nls_length_semantics
        • nls_nchar_characterset
        • nls_nchar_conv_excp
        • nls_numeric_characters
        • nls_sort
        • nls_territory
        • nls_timestamp_format
        • nls_timestamp_tz_format
        • ob_bnl_join_cache_size
        • ob_capability_flag
        • ob_compatibility_mode
        • ob_create_table_strict_mode
        • ob_default_replica_num
        • ob_early_lock_release
        • ob_enable_aggregation_pushdown
        • ob_enable_blk_nestedloop_join
        • ob_enable_hash_group_by
        • ob_enable_index_direct_select
        • ob_enable_jit
        • ob_enable_plan_cache
        • ob_enable_sql_audit
        • ob_enable_trace_log
        • ob_enable_transformation
        • ob_enable_transmission_checksum
        • ob_enable_truncate_flashback
        • ob_global_debug_sync
        • ob_last_schema_version
        • ob_log_level
        • ob_max_parallel_degree
        • ob_org_cluster_id
        • ob_pl_block_timeout
        • ob_plan_cache_evict_high_percentage
        • ob_plan_cache_evict_low_percentage
        • ob_plan_cache_percentage
        • ob_proxy_global_variables_version
        • ob_proxy_partition_hit
        • ob_proxy_set_trx_executed
        • ob_query_timeout
        • ob_read_consistency
        • ob_reserved_meta_memory_percentage
        • ob_route_policy
        • ob_safe_weak_read_snapshot
        • ob_sql_audit_percentage
        • ob_sql_work_area_percentage
        • ob_stmt_parallel_degree
        • ob_tcp_invited_nodes
        • ob_temp_tablespace_size_percentage
        • ob_timestamp_service
        • ob_trace_info
        • ob_trx_idle_timeout
        • ob_trx_lock_timeout
        • ob_trx_timeout
        • optimizer_capture_sql_plan_baselines
        • optimizer_use_sql_plan_baselines
        • parallel_max_servers
        • parallel_servers_target
        • performance_schema
        • plugin_dir
        • query_cache_size
        • query_cache_type
        • read_only
        • recyclebin
        • resource_manager_plan
        • secure_file_priv
        • sql_auto_is_null
        • sql_quote_show_create
        • sql_select_limit
        • sql_throttle_current_priority
        • sql_throttle_network
        • sql_throttle_priority
        • sql_throttle_rt
        • sql_warnings
        • system_time_zone
        • sql_safe_updates
        • time_zone
        • timestamp
        • tracefile_identifier
        • transaction_isolation
        • transaction_read_only
        • tx_isolation
        • tx_read_only
        • undo_retention
        • version
        • version_comment
        • wait_timeout
        • validate_password_check_user_name
        • validate_password_length
        • validate_password_mixed_case_count
        • validate_password_number_count
        • validate_password_policy
        • validate_password_special_char_count
        • event_scheduler
      • System views (MySQL mode)
        • Overview
        • Dictionary views
          • Overview
          • mysql.help_topic
          • mysql.help_category
          • mysql.help_keyword
          • mysql.help_relation
          • mysql.db
          • mysql.proc
          • mysql.time_zone
          • mysql.time_zone_name
          • mysql.time_zone_transition
          • mysql.time_zone_transition_type
          • mysql.user
          • information_schema.CHARACTER_SETS
          • information_schema.CHECK_CONSTRAINTS
          • information_schema.COLLATIONS
          • information_schema.COLLATION_CHARACTER_SET_APPLICABILITY
          • information_schema.COLUMNS
          • information_schema.DBA_OUTLINES
          • information_schema.ENGINES
          • information_schema.GLOBAL_STATUS
          • information_schema.GLOBAL_VARIABLES
          • information_schema.KEY_COLUMN_USAGE
          • information_schema.PARAMETERS
          • information_schema.PARTITIONS
          • information_schema.PROCESSLIST
          • information_schema.REFERENTIAL_CONSTRAINTS
          • information_schema.ROUTINES
          • information_schema.SCHEMATA
          • information_schema.SCHEMA_PRIVILEGES
          • information_schema.SESSION_STATUS
          • information_schema.SESSION_VARIABLES
          • information_schema.STATISTICS
          • information_schema.TABLES
          • information_schema.TABLE_CONSTRAINTS
          • information_schema.TABLE_PRIVILEGES
          • information_schema.USER_PRIVILEGES
          • information_schema.USER_RECYCLEBIN
          • information_schema.VIEWS
          • information_schema.CONNECTION_CONTROL_FAILED_LOGIN_ATTEMPTS
          • oceanbase.CDB_OB_BACKUP_ARCHIVELOG_SUMMARY
          • oceanbase.CDB_OB_BACKUP_JOB_DETAILS
          • oceanbase.CDB_OB_BACKUP_SET_DETAILS
          • oceanbase.CDB_OB_BACKUP_PROGRESS
          • oceanbase.CDB_OB_BACKUP_SET_EXPIRED
          • oceanbase.CDB_OB_BACKUP_ARCHIVELOG_PROGRESS
          • oceanbase.CDB_OB_BACKUP_CLEAN_HISTORY
          • oceanbase.CDB_OB_BACKUP_TASK_CLEAN_HISTORY
          • oceanbase.CDB_OB_RESTORE_PROGRESS
          • oceanbase.CDB_OB_RESTORE_HISTORY
          • oceanbase.CDB_CKPT_HISTORY
          • oceanbase.CDB_OB_BACKUP_VALIDATION_JOB
          • oceanbase.CDB_OB_BACKUP_VALIDATION_JOB_HISTORY
          • oceanbase.CDB_OB_TENANT_BACKUP_VALIDATION_TASK
          • oceanbase.CDB_OB_BACKUP_VALIDATION_TASK_HISTORY
          • oceanbase.CDB_OB_BACKUP_BACKUP_ARCHIVELOG_SUMMARY
          • oceanbase.CDB_OB_BACKUP_BACKUPSET_TASK_HISTORY
          • oceanbase.CDB_OB_BACKUP_BACKUPSET_TASK
          • oceanbase.CDB_OB_BACKUP_BACKUPSET_JOB_HISTORY
          • oceanbase.CDB_OB_BACKUP_BACKUPSET_JOB
          • oceanbase.CDB_OB_BACKUP_SET_OBSOLETE
          • oceanbase.CDB_OB_BACKUP_ARCHIVELOG
          • oceanbase.CDB_OB_BACKUP_BACKUP_ARCHIVELOG
          • oceanbase.CDB_OB_BACKUP_BACKUPPIECE_JOB
          • oceanbase.CDB_OB_BACKUP_BACKUPPIECE_JOB_HISTORY
          • oceanbase.CDB_OB_BACKUP_BACKUPPIECE_TASK
          • oceanbase.CDB_OB_BACKUP_BACKUPPIECE_TASK_HISTORY
          • oceanbase.CDB_OB_BACKUP_PIECE_FILES
          • oceanbase.CDB_OB_BACKUP_SET_FILES
          • information_schema.ST_GEOMETRY_COLUMNS
          • information_schema.ST_SPATIAL_REFERENCE_SYSTEMS
          • oceanbase.DBA_RSRC_PLANS
          • oceanbase.DBA_RSRC_PLAN_DIRECTIVES
          • oceanbase.DBA_RSRC_GROUP_MAPPINGS
          • oceanbase.DBA_RSRC_CONSUMER_GROUPS
        • Performance views
          • Overview
          • gv$plan_cache_stat
          • gv$plan_cache_plan_stat
          • gv$session_event
          • gv$session_wait
          • gv$session_wait_history
          • gv$system_event
          • gv$sesstat
          • gv$sysstat
          • gv$sql_audit
          • gv$latch
          • gv$memory
          • gv$memstore
          • gv$memstore_info
          • gv$plan_cache_plan_explain
          • gv$obrpc_outgoing
          • gv$obrpc_incoming
          • gv$sql
          • gv$sql_plan_monitor
          • gv$outline
          • gv$concurrent_limit_sql
          • gv$sql_plan_statistics
          • gv$server_memstore
          • gv$unit_load_balance_event_history
          • gv$tenant
          • gv$database
          • gv$table
          • gv$unit
          • gv$partition
          • gv$lock_wait_stat
          • gv$session_longops
          • gv$tenant_memstore_allocator_info
          • gv$minor_merge_info
          • gv$tenant_px_worker_stat
          • gv$partition_audit
          • gv$ps_stat
          • gv$ps_item_info
          • gv$sql_workarea
          • gv$sql_workarea_histogram
          • gv$ob_sql_workarea_memory_info
          • gv$server_schema_info
          • gv$merge_info
          • gv$lock
          • gv$sstable
          • gv$ob_trans_table_status
          • gv$tenant_memory_info
          • v$statname
          • v$event_name
          • v$session_event
          • v$session_wait
          • v$session_wait_history
          • v$sesstat
          • v$sysstat
          • v$system_event
          • v$memory
          • v$memstore
          • v$memstore_info
          • v$plan_cache_stat
          • v$plan_cache_plan_stat
          • v$plan_cache_plan_explain
          • v$sql_audit
          • v$obrpc_outgoing
          • v$obrpc_incoming
          • v$sql
          • v$sql_plan_monitor
          • v$sql_plan_statistics
          • v$unit
          • v$partition
          • v$lock_wait_stat
          • v$session_longops
          • v$latch
          • v$tenant_memstore_allocator_info
          • v$tenant_px_worker_stat
          • v$partition_audit
          • v$ob_cluster
          • v$ob_standby_status
          • v$ob_cluster_stats
          • v$ob_cluster_event_history
          • v$ps_stat
          • v$ps_item_info
          • v$sql_workarea
          • v$sql_workarea_active
          • v$sql_workarea_histogram
          • v$ob_sql_workarea_memory_info
          • v$ob_timestamp_service
          • v$server_schema_info
          • v$merge_info
          • v$lock
          • v$sql_monitor_statname
          • v$restore_point
          • v$ob_cluster_failover_info
          • v$encrypted_tables
          • v$encrypted_tablespaces
          • v$sstable
          • v$ob_trans_table_status
          • v$ob_all_clusters
          • v$tenant_memory_info
          • GV$OB_DTL_INTERM_RESULT_MONITOR
          • V$OB_DTL_INTERM_RESULT_MONITOR
          • V$RSRC_PLAN
      • System views (Oracle mode)
        • Overview
        • Dictionary views
          • Overview
          • ALL_ALL_TABLES
          • ALL_ARGUMENTS
          • ALL_COL_COMMENTS
          • ALL_COLL_TYPES
          • ALL_COL_PRIVS
          • ALL_CONSTRAINTS
          • ALL_CONS_COLUMNS
          • ALL_DEF_AUDIT_OPTS
          • ALL_DEPENDENCIES
          • ALL_DIRECTORIES
          • ALL_ERRORS
          • ALL_INDEXES
          • ALL_IND_COLUMNS
          • ALL_IND_EXPRESSIONS
          • ALL_IND_PARTITIONS
          • ALL_IND_SUBPARTITIONS
          • ALL_METHOD_PARAMS
          • ALL_OBJECTS
          • ALL_PART_COL_STATISTICS
          • ALL_PART_HISTOGRAMS
          • ALL_PART_INDEXES
          • ALL_PART_KEY_COLUMNS
          • ALL_PART_TABLES
          • ALL_PROCEDURES
          • ALL_PROFILES
          • ALL_SCHEDULER_JOB_ARGS
          • ALL_SCHEDULER_PROGRAM_ARGS
          • ALL_SEQUENCES
          • ALL_SOURCE
          • ALL_SUBPART_COL_STATISTICS
          • ALL_SUBPART_HISTOGRAMS
          • ALL_SUBPARTITION_TEMPLATES
          • ALL_SUBPART_KEY_COLUMNS
          • ALL_SYNONYMS
          • ALL_TABLES
          • ALL_TAB_COL_STATISTICS
          • ALL_TAB_COLS
          • ALL_TAB_COLUMNS
          • ALL_TAB_COMMENTS
          • ALL_TAB_HISTOGRAMS
          • ALL_TAB_PARTITIONS
          • ALL_TAB_PRIVS
          • ALL_TAB_STATISTICS
          • ALL_TAB_STATS_HISTORY
          • ALL_TAB_SUBPARTITIONS
          • ALL_TRIGGERS
          • ALL_TYPES
          • ALL_TYPE_ATTRS
          • ALL_TYPE_METHODS
          • ALL_USERS
          • ALL_VIEWS
          • AUDIT_ACTIONS
          • DBA_ALL_TABLES
          • DBA_ARGUMENTS
          • DBA_AUDIT_EXISTS
          • DBA_AUDIT_OBJECT
          • DBA_AUDIT_SESSION
          • DBA_AUDIT_STATEMENT
          • DBA_AUDIT_TRAIL
          • DBA_COLL_TYPES
          • DBA_COL_COMMENTS
          • DBA_COL_PRIVS
          • DBA_CONSTRAINTS
          • DBA_CONS_COLUMNS
          • DBA_ERRORS
          • DBA_INDEXES
          • DBA_IND_COLUMNS
          • DBA_IND_EXPRESSIONS
          • DBA_IND_PARTITIONS
          • DBA_IND_SUBPARTITIONS
          • DBA_METHOD_PARAMS
          • DBA_OBJECTS
          • DBA_OBJ_AUDIT_OPTS
          • DBA_PART_INDEXES
          • DBA_PART_KEY_COLUMNS
          • DBA_PART_TABLES
          • DBA_PROCEDURES
          • DBA_PROFILES
          • DBA_ROLES
          • DBA_ROLE_PRIVS
          • DBA_SCHEDULER_JOB_ARGS
          • DBA_SCHEDULER_JOBS
          • DBA_SCHEDULER_PROGRAM
          • DBA_SCHEDULER_PROGRAM_ARGS
          • DBA_SEGMENTS
          • DBA_SEQUENCES
          • DBA_SOURCE
          • DBA_STMT_AUDIT_OPTS
          • DBA_SUBPARTITION_TEMPLATES
          • DBA_SUBPART_KEY_COLUMNS
          • DBA_SYNONYMS
          • DBA_SYS_PRIVS
          • DBA_TABLES
          • DBA_TABLESPACES
          • DBA_TAB_COLS
          • DBA_TAB_COLUMNS
          • DBA_TAB_COMMENTS
          • DBA_TAB_PARTITIONS
          • DBA_TAB_PRIVS
          • DBA_TAB_STATS_HISTORY
          • DBA_TAB_SUBPARTITIONS
          • DBA_TRIGGERS
          • DBA_TYPES
          • DBA_TYPE_ATTRS
          • DBA_TYPE_METHODS
          • DBA_USERS
          • DBA_VIEWS
          • DBA_JOBS_RUNNING
          • DBA_JOBS
          • DBA_RECYCLEBIN
          • DBA_DEPENDENCIES
          • DBA_RSRC_CONSUMER_GROUPS
          • DBA_RSRC_GROUP_MAPPINGS
          • DBA_RSRC_PLANS
          • DBA_RSRC_PLAN_DIRECTIVES
          • DBA_DIRECTORIES
          • DBA_PART_COL_STATISTICS
          • DBA_PART_HISTOGRAMS
          • DBA_SUBPART_COL_STATISTICS
          • DBA_SUBPART_HISTOGRAMS
          • DBA_TAB_COL_STATISTICS
          • DBA_TAB_HISTOGRAMS
          • DBA_TAB_STATISTICS
          • DICT
          • DICTIONARY
          • NLS_DATABASE_PARAMETERS
          • NLS_INSTANCE_PARAMETERS
          • NLS_SESSION_PARAMETERS
          • ROLE_ROLE_PRIVS
          • ROLE_SYS_PRIVS
          • ROLE_TAB_PRIVS
          • STMT_AUDIT_OPTION_MAP
          • TENANT_VIRTUAL_GLOBAL_VARIABLE
          • TENANT_VIRTUAL_SESSION_VARIABLE
          • USER_ALL_TABLES
          • USER_ARGUMENTS
          • USER_AUDIT_OBJECT
          • USER_AUDIT_SESSION
          • USER_AUDIT_STATEMENT
          • USER_AUDIT_TRAIL
          • USER_COLL_TYPES
          • USER_COL_COMMENTS
          • USER_COL_PRIVS
          • USER_CONSTRAINTS
          • USER_CONS_COLUMNS
          • USER_ERRORS
          • USER_INDEXES
          • USER_IND_COLUMNS
          • USER_IND_EXPRESSIONS
          • USER_IND_PARTITIONS
          • USER_IND_SUBPARTITIONS
          • USER_OBJECTS
          • USER_PART_INDEXES
          • USER_PART_KEY_COLUMNS
          • USER_PART_TABLES
          • USER_PROCEDURES
          • USER_PROFILES
          • USER_ROLE_PRIVS
          • USER_SEGMENTS
          • USER_SEQUENCES
          • USER_SOURCE
          • USER_SUBPARTITION_TEMPLATES
          • USER_SUBPART_KEY_COLUMNS
          • USER_SYNONYMS
          • USER_SYS_PRIVS
          • USER_TAB_STATS_HISTORY
          • USER_TAB_SUBPARTITIONS
          • USER_TRIGGERS
          • USER_TABLES
          • USER_TABLESPACES
          • USER_TAB_COLS
          • USER_TAB_COLUMNS
          • USER_TAB_COMMENTS
          • USER_TAB_PARTITIONS
          • USER_TAB_PRIVS
          • USER_TYPES
          • USER_TYPE_ATTRS
          • USER_TYPE_METHODS
          • USER_JOBS
          • USER_VIEWS
          • USER_RECYCLEBIN
          • USER_DEPENDENCIES
          • USER_PART_COL_STATISTICS
          • USER_PART_HISTOGRAMS
          • USER_SUBPART_COL_STATISTICS
          • USER_SUBPART_HISTOGRAMS
          • USER_TAB_COL_STATISTICS
          • USER_TAB_HISTOGRAMS
          • USER_TAB_STATISTICS
          • DBA_CONTEXT
        • Performance views
          • Overview
          • GV$CONCURRENT_LIMIT_SQL
          • GV$DBLINK
          • GV$GLOBAL_TRANSACTION
          • GV$INSTANCE
          • GV$LOCK
          • GV$MEMORY
          • GV$MEMSTORE
          • GV$MEMSTORE_INFO
          • GV$OB_SQL_WORKAREA_MEMORY_INFO
          • GV$OPEN_CURSOR
          • GV$OUTLINE
          • GV$PLAN_CACHE_PLAN_EXPLAIN
          • GV$PLAN_CACHE_PLAN_STAT
          • GV$PLAN_CACHE_STAT
          • GV$PS_ITEM_INFO
          • GV$PS_STAT
          • GV$SERVER_MEMSTORE
          • GV$SESSION_WAIT
          • GV$SESSION_WAIT_HISTORY
          • GV$SESSTAT
          • GV$SQL_AUDIT
          • GV$SQL_WORKAREA
          • GV$SQL_WORKAREA_ACTIVE
          • GV$SQL_WORKAREA_HISTOGRAM
          • GV$SYSSTAT
          • GV$SYSTEM_EVENT
          • GV$SSTABLE
          • GV$TENANT_MEMORY_INFO
          • V$DBLINK
          • V$ENCRYPTED_TABLES
          • V$ENCRYPTED_TABLESPACES
          • V$GLOBAL_TRANSACTION
          • V$INSTANCE
          • V$LOCK
          • V$MEMORY
          • V$MEMSTORE
          • V$MEMSTORE_INFO
          • V$NLS_PARAMETERS
          • V$OB_SQL_WORKAREA_MEMORY_INFO
          • V$OPEN_CURSOR
          • V$PLAN_CACHE_PLAN_EXPLAIN
          • V$PLAN_CACHE_PLAN_STAT
          • V$PLAN_CACHE_STAT
          • V$PS_ITEM_INFO
          • V$PS_STAT
          • V$RESTORE_POINT
          • V$RSRC_PLAN
          • V$SESSION_WAIT
          • V$SESSION_WAIT_HISTORY
          • V$SESSTAT
          • V$SQL_AUDIT
          • V$SQL_MONITOR_STATNAME
          • V$SQL_WORKAREA
          • V$SQL_WORKAREA_ACTIVE
          • V$SQL_WORKAREA_HISTOGRAM
          • V$SSTABLE
          • V$SYSSTAT
          • V$SYSTEM_EVENT
          • V$TIMEZONE_NAMES
          • V$TENANT_MEMORY_INFO
          • V$VERSION
          • GV$OB_DTL_INTERM_RESULT_MONITOR
          • V$OB_DTL_INTERM_RESULT_MONITOR
          • V$GLOBALCONTEXT
      • Error codes (MySQL mode)
        • Overview
        • 0001 to 3999
        • 4000 to 4499
        • 4500 to 4999
        • 5000 to 5999
        • 6000 to 6999
        • 7000 to 7999
        • 8000 to 8999
        • 9000 to 9499
        • 9500 to 9999
        • 22998, 30926, 38104, and 38105
      • Error codes (Oracle mode)
        • Overview
        • ORA-00000 to ORA-00999
        • ORA-01000 to ORA-01499
        • ORA-01500 to ORA-01999
        • ORA-02000 to ORA-04999
        • ORA-05000 to ORA-10000
        • ORA-10000 to ORA-19999
        • ORA-20000 to ORA-29999
        • ORA-30000 to ORA-49999
        • ORA-50000 to ORA-99999
        • PLS-00000 to PLS-00999
      • Reserved keywords (MySQL mode)
      • Reserved keywords (Oracle mode)
  • Develop
    • Developer guide (MySQL mode)
      • Connect to OceanBase Database
        • Overview
        • Connect to an OceanBase Database tenant by using a MySQL client
        • Connect to an OceanBase Database tenant by using OBClient
        • Connect to OceanBase Database by using ODC
      • Application development
        • Java
          • Java APIs
          • Connect Java applications to OceanBase Database
        • Python applications
        • Connect C applications to OceanBase Database
      • Create and manage database objects
        • About DDL statements
        • View the currently connected database
        • Change the password of a user
        • Data type
          • Common data types
          • Unsupported data types
        • Create database objects by using ODC
          • Create a table in ODC
          • Create a view in ODC
          • Create a function in ODC
          • Create a stored procedure in ODC
        • Create and manage tables
          • About tables
          • Create a table
          • About auto-increment columns
          • About types of column constraints
          • About table structure modification
          • About table clearing
          • About table dropping
          • Flash back a dropped table
          • About table privileges
        • Create and manage partition tables
          • About partitioned tables
          • Create a partitioned table
          • Manage a partitioned table
          • Create a subpartitioned table
          • Manage a subpartitioned table
          • Partition routing
          • Indexes on partitioned tables
          • Suggestions on using partitioned tables
        • Create and manage indexes
          • Overview
          • Create an index
          • Drop an index
        • Create and manage table groups
          • Overview
          • Create table groups
            • Create a non-partitioned table group
            • Create a subpartitioned table group
          • Specify a table group when creating a table
          • View information about a table group
          • Add a table to a table group
          • Drop a table group
        • Create and manage views
          • About views
          • Create a view
          • Modify a view
          • Drop a view
        • Create and manage sequences
          • About sequences
          • Create a sequence
          • Modify a sequence
          • Drop a sequence
        • Create and manage triggers
          • About triggers
          • Create a trigger
          • Drop a trigger
      • Query
        • Overview of queries
        • Run queries in ODC
        • Single-table queries
        • WHERE queries
        • ORDER BY queries
        • GROUP BY queries
        • Use the LIMIT clause in queries
        • Multi-table join queries
          • Multi-table join queries
          • INNER JOIN queries
          • OUTER JOIN queries
          • Subqueries
        • Use operators and functions in a query
          • Use arithmetic operators in queries
          • Use numerical functions in queries
          • Use string concatenation functions in queries
          • Use string functions in queries
          • Use date and time functions in queries
          • Use type conversion functions in queries
          • Use aggregate functions in queries
          • Use NULL-related functions in queries
          • Use the CASE conditional operator in queries
          • Use the SELECT FOR UPDATE statement to lock query results
        • Execution plan
          • View an execution plan
          • Understand an execution plan
        • Use SQL hints in queries
        • Variables of query timeout
      • DML statements and transactions
        • DML statements
          • About DML statements
          • About the INSERT statement
          • UPDATE statements
          • About the DELETE statement
          • About the REPLACE INTO statement
        • Transactions
          • About transaction control statements
          • Start a transaction
          • Transaction savepoints
          • Commit a transaction
          • Roll back a transaction
          • About transaction timeout
    • Developer guide (Oracle mode)
      • Connect to OceanBase Database
        • Overview
        • Connect to an OceanBase Database tenant by using OBClient
        • Connect to OceanBase Database by using ODC
      • Application development
        • Java
          • OceanBase Connector/J
          • Java APIs
          • Connect Java applications to OceanBase Database
        • Python
          • OceanBase Connector/J in Python
          • Python APIs
          • Connect Python applications to OceanBase Database
        • C
          • OBCI
          • OBCI APIs
          • Connect C applications to OceanBase Database
      • Create and manage database objects
        • DDL statements
        • View the currently connected database
        • Change the password of a user
        • Create database objects by Using ODC
          • Create tables, views, functions, and stored procedures in ODC
          • Create a trigger in ODC
          • Create a sequence in ODC
          • Create a program package in ODC
          • Create a synonym in ODC
          • Create a type in ODC
        • Data type
          • Data types
          • Unsupported data types
        • Create and manage tables
          • Overview
          • Create a table
          • Define an auto-increment column by using the SEQUENCE keyword
          • Types of column constraints
          • Modify the structure of a table
          • Clear a table
          • Drop a table
          • Flash back a dropped table
          • Table privileges
        • Create and manage partition tables
          • Overview
          • Create a partitioned table
          • Manage a partitioned table
          • Create a subpartitioned table
          • Manage a subpartitioned table
          • Partition routing
          • Indexing on partitioned tables
          • Recommendations for using partitioned tables
        • Create and manage indexes
          • Drop an index
          • Overview
          • Create an index
        • Create and manage table groups
          • Overview
          • Create table groups
            • Create a non-partitioned table group
            • Create a subpartitioned table group
          • Specify a table group when creating a table
          • View information about a table group
          • Add a table to a table group
          • Drop a table group
        • Create and manage views
          • About views
          • Create a view
          • Modify a view
          • Drop a view
        • Create and manage sequences
          • Overview
          • Create a sequence
          • Modify a sequence
          • Drop a sequence
        • Create and manage synonyms
          • Overview
          • Create a synonym
          • Drop a synonym
        • Create and manage triggers
          • Overview
          • Create a trigger
          • Modify a trigger
          • Drop a trigger
          • Enable or disable a trigger
      • Query
        • About queries
        • Run queries in ODC
        • Single-table queries
        • Conditional queries
        • ORDER BY queries
        • GROUP BY queries
        • Use Row_Limiting_Clause in queries
        • Multi-table join queries
          • Multi-table join queries
          • INNER JOIN queries
          • OUTER JOIN queries
          • Subqueries
        • Use operators and functions in a query
          • Use arithmetic operators in queries
          • Use numerical functions in queries
          • Use string connectors in queries
          • Use string functions in queries
          • Use datetime functions in queries
          • Use type conversion functions in queries
          • Use aggregate functions in queries
          • Use NULL-related functions in queries
          • Use CASE functions in queries
          • Use the SELECT FOR UPDATE statement to lock query results
        • Execution plan
          • View execution plans of queries
          • Understand execution plans
        • Use SQL hints in queries
        • About query timeout variables
      • DML statements and transactions
        • DML statements
          • About DML statements
          • About the INSERT statement
          • About the UPDATE statement
          • About the MERGE statement
          • About the DELETE statement
        • Transactions
          • About transaction control statements
          • Start a transaction
          • Transaction savepoints
          • Commit a transaction
          • Roll back a transaction
          • About transaction timeout
    • Data migration
      • About data migration and synchronization
      • Migrate data by using OMS
      • Export and import data by using ODC
        • Overview
        • Export and import file formats
        • Batch export and import
        • Single table export and import
      • Migrate data by using SQL scripts
        • Common SQL scripts for data migration
        • Export data by using OUTFILE statements
        • Export data by using the LOAD DATA statement
      • Migrate data by using mysqldump
      • Migrate data by using OBLOADER & OBDUMPER
        • Import data by using OBLOADER
        • Export data by using OBDUMPER
      • Migrate data by using DataX
        • DataX
        • Examples of using DataX in OceanBase Database
    • Design conventions and constraints
      • Object naming conventions
        • Overview
        • Tenant naming conventions
        • User naming conventions
        • Table naming conventions
        • Field naming conventions
        • Other naming conventions
      • Object structure conventions
        • Field design
        • Table structure design
        • Partitioned table design
        • Index design
        • Other structural designs
      • Character set specifications
      • Database connection specifications
      • Best practices for database design
        • Configuration example (database connection pool)
          • Overview of database connection pool configuration
          • Example of configuring a Tomcat connection pool
          • Example of configuring a C3P0 connection pool
          • Example of configuring a Proxool connection pool
          • Example of configuring a HiKariCP connection pool
          • Example of configuring a DBCP connection pool
          • CommonPool configuration example
          • Example of configuring a JDBC connection pool
        • Development framework connection example
          • SpringBoot connection example
          • SpringBatch connection example
          • SpringJDBC connection example
          • SpringJPA connection example
          • Hibernate connection example
          • MyBatis connection example
        • Use of table comments
        • ORM conventions
        • Exception handling
    • SQL syntax
      • System tenant
        • Overview
        • ALTER SYSTEM
          • BACKUP
          • BALANCE TASK
          • BOOTSTRAP
          • CANCEL MIGRATE UNIT
          • CHANGE TENANT
          • CLUSTER
          • CONVERT
          • DELETE BACKUPSET
          • DELETE OBSOLETE BACKUP
          • FAILOVER
          • FLUSH PLAN CACHE
          • JOB
          • MERGE
          • MIGRATE UNIT
          • PARAMETER
          • REFRESH
          • REPLICA
          • RESTORE
          • ROOTSERVICE
          • SERVER
          • SET STANDBY CLUSTER
          • SWITCHOVER
          • THROTTLE
          • UPGRADE
          • VALIDATE
          • ZONE
        • ALTER RESOURCE POOL
        • ALTER RESOURCE UNIT
        • ALTER TENANT
        • CREATE RESOURCE POOL
        • CREATE RESOURCE UNIT
        • CREATE TENANT
        • DROP RESOURCE POOL
        • DROP RESOURCE UNIT
        • DROP TENANT
        • SET DECRYPTION
        • SET ENCRYPTION
      • User tenants (MySQL mode)
        • Elements
          • Data type
            • Overview
            • Numeric data types
              • Overview
              • Integer data types
              • Fixed-point data types
              • Floating-point data types
              • Bit value data type
            • Date and time data types
              • Overview
              • DATE, DATETIME, and TIMESTAMP types
              • TIME type
              • YEAR type
            • Character data types
              • Overview
              • CHAR and VARCHAR
              • BINARY and VARBINARY
            • BLOB and TEXT data types
              • Overview
              • BLOB types
              • TEXT types
            • ENUM data type
            • SET data type
            • JSON data types
              • Overview
              • Create a JSON value
              • Query and modify JSON values
              • Convert a JSON data type
            • Spatial data types
              • Overview
              • SRS
              • Create a spatial column
              • Create a spatial index
              • Spatial data formats
          • Expressions
            • Overview
            • Expression syntax
            • Convert data types in expression evaluation
          • Character sets and collations
            • 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
            • Numbers
            • Datetime values
            • Bit values
            • Boolean values
            • NULLs
          • Schema object names
          • User-defined variables
          • Comments
        • Operators
          • Overview
          • Operator precedence
          • Arithmetic operators
          • Bitwise operators
          • Comparison operators
          • Logical operators
          • Assignment operators
          • Date and time operators
          • Concatenation operators
          • BINARY operator
          • CASE conditional operator
        • Sequence pseudocolumns
        • Functions
          • Overview
          • Single-row functions
            • Date and time functions
              • ADDDATE
              • CONVERT_TZ
              • CURDATE
              • CURRENT_DATE
              • CURRENT_TIME
              • CURRENT_TIMESTAMP
              • CURTIME
              • DATE
              • DATE_ADD
              • DATE_FORMAT
              • DATE_SUB
              • DATEDIFF
              • DAYOFMONTH
              • DAYOFWEEK
              • DAYOFYEAR
              • EXTRACT
              • FROM_DAYS
              • FROM_UNIXTIME
              • GET_FORMAT
              • HOUR
              • LAST_DAY
              • LOCALTIME
              • LOCALTIMESTAMP
              • MAKEDATE
              • MAKETIME
              • MICROSECOND
              • MINUTE
              • MONTH
              • MONTHNAME
              • NOW
              • PERIOD_ADD
              • PERIOD_DIFF
              • QUARTER
              • SEC_TO_TIME
              • SECOND
              • STR_TO_DATE
              • SUBDATE
              • SUBTIME
              • SYSDATE
              • TIME
              • TIME_FORMAT
              • TIME_TO_SEC
              • TIME_TO_USEC
              • TIMEDIFF
              • TIMESTAMP
              • TIMESTAMPADD
              • TIMESTAMPDIFF
              • TO_DAYS
              • TO_SECONDS
              • UNIX_TIMESTAMP
              • USEC_TO_TIME
              • UTC_DATE
              • UTC_TIME
              • UTC_TIMESTAMP
              • WEEK
              • WEEKDAY
              • WEEKOFYEAR
              • YEARWEEK
              • YEAR
              • DAY
            • String functions
              • ASCII
              • BIN
              • BIT_LENGTH
              • CHAR
              • CHAR_LENGTH
              • CONCAT
              • CONCAT_WS
              • EXPORT_SET
              • ELT
              • FIELD
              • FIND_IN_SET
              • FORMAT
              • HEX
              • INSERT
              • INSTR
              • INT2IP
              • IP2INT
              • LCASE
              • LEFT
              • LENGTH
              • LOCATE
              • LOWER
              • LPAD
              • LTRIM
              • MAKE_SET
              • MID
              • OCT
              • ORD
              • POSITION
              • QUOTE
              • REGEXP
              • REGEXP_INSTR
              • REGEXP_LIKE
              • REGEXP_REPLACE
              • REGEXP_SUBSTR
              • REPEAT
              • REPLACE
              • REVERSE
              • RIGHT
              • RLIKE
              • RPAD
              • RTRIM
              • SPACE
              • STRCMP
              • SUBSTR
              • SUBSTRING
              • SUBSTRING_INDEX
              • TRIM
              • UCASE
              • UNHEX
              • UPPER
              • WEIGHT_STRING
              • TO_BASE64
              • FROM_BASE64
            • Conversion functions
              • CAST
              • CONVERT
            • Mathematical functions
              • ABS
              • ACOS
              • ASIN
              • ATAN
              • ATAN2
              • BIT_COUNT
              • CEIL
              • CEILING
              • CONV
              • COS
              • COT
              • CRC32
              • DEGREES
              • EXP
              • FLOOR
              • LN
              • LOG
              • LOG10
              • LOG2
              • MOD
              • NEG
              • PI
              • POW
              • POWER
              • RADIANS
              • RAND
              • ROUND
              • SIGN
              • SIN
              • SQRT
              • TAN
              • TRUNCATE
            • Comparison functions
              • GREATEST
              • INTERVAL
              • ISNULL
              • LEAST
            • Process control functions
              • IF
              • IFNULL
              • NULLIF
              • ORA_DECODE
          • Aggregate functions
            • APPROX_COUNT_DISTINCT
            • AVG
            • BIT_AND
            • BIT_OR
            • BIT_XOR
            • COUNT
            • GROUP_CONCAT
            • GROUPING
            • MAX
            • MIN
            • STD
            • STDDEV
            • STDDEV_POP
            • STDDEV_SAMP
            • SUM
            • VAR_POP
            • VAR_SAMP
            • VARIANCE
          • Analytic functions
            • APPROX_COUNT_DISTINCT
            • AVG
            • COUNT
            • CUME_DIST
            • DENSE_RANK
            • FIRST_VALUE
            • LAG
            • LAST_VALUE
            • LEAD
            • MAX
            • MIN
            • NTH_VALUE
            • NTILE
            • PERCENT_RANK
            • RANK
            • ROW_NUMBER
            • STD
            • STDDEV
            • STDDEV_POP
            • STDDEV_SAMP
            • SUM
            • VAR_POP
            • VAR_SAMP
            • VARIANCE
          • Encryption functions
            • AES_DECRYPT
            • AES_ENCRYPT
            • MD5
          • Information functions
            • BENCHMARK
            • CHARSET
            • COERCIBILITY
            • COLLATION
            • CONNECTION_ID
            • CURRENT_USER
            • DATABASE
            • FOUND_ROWS
            • LAST_INSERT_ID
            • SCHEMA
            • ROW_COUNT
            • SESSION_USER
            • SYSTEM_USER
            • USER
            • VERSION
            • OB_VERSION
          • JSON functions
            • Functions that create JSON values
              • JSON_ARRAY
              • JSON_OBJECT
              • JSON_QUOTE
            • Functions that search JSON values
              • JSON_CONTAINS
              • JSON_CONTAINS_PATH
              • JSON_EXTRACT
              • JSON_KEYS
              • JSON_OVERLAPS
              • JSON_SEARCH
              • JSON_VALUE
              • MEMBER OF
            • Functions that modify JSON values
              • JSON_ARRAY_APPEND
              • JSON_ARRAY_INSERT
              • JSON_INSERT
              • JSON_MERGE
              • JSON_MERGE_PATCH
              • JSON_MERGE_PRESERVE
              • JSON_REMOVE
              • JSON_REPLACE
              • JSON_SET
              • JSON_UNQUOTE
            • Functions that return JSON text attributes
              • JSON_DEPTH
              • JSON_LENGTH
              • JSON_TYPE
              • JSON_VALID
            • JSON utility functions
              • JSON_PRETTY
              • JSON_STORAGE_SIZE
            • JSON aggregate functions
              • JSON_ARRAYAGG
              • JSON_OBJECTAGG
          • Other functions
            • ANY_VALUE
            • COALESCE
            • DEFAULT
            • INET_ATON
            • INET_NTOA
            • INET6_ATON
            • INET6_NTOA
            • IS_IPV4
            • IS_IPV4_COMPAT
            • IS_IPV4_MAPPED
            • IS_IPV6
            • NVL
            • SLEEP
            • UUID
            • UUID_SHORT
            • VALUES
          • Spatial functions
            • Create a geometric function
            • Spatial operation functions
            • Spatial relation functions
            • Geometry property functions
            • Geometric format conversion functions
        • Queries and subqueries
          • Overview
          • Subqueries
          • JOIN
        • SQL statements
          • General syntax
          • CTE
          • ALTER DATABASE
          • ALTER OUTLINE
          • ALTER SEQUENCE
          • ALTER TABLE
          • ALTER TABLEGROUP
          • ALTER USER
          • ALTER VIEW
          • ANALYZE
          • CREATE DATABASE
          • CREATE INDEX
          • CREATE OUTLINE
          • CREATE RESTORE POINT
          • CREATE SEQUENCE
          • CREATE TABLE
          • CREATE TABLEGROUP
          • CREATE USER
          • CREATE VIEW
          • DEALLOCATE PREPARE
          • DELETE
          • DESCRIBE
          • DROP DATABASE
          • DROP INDEX
          • DROP OUTLINE
          • DROP RESTORE POINT
          • DROP TABLE
          • DROP TABLEGROUP
          • DROP SEQUENCE
          • DROP USER
          • DROP VIEW
          • EXECUTE
          • EXPLAIN
          • FLASHBACK
          • GRANT
          • HELP
          • INSERT
          • KILL
          • LOAD DATA
          • OPTIMIZE
          • PREPARE
          • PURGE
          • PURGE RECYCLEBIN
          • RENAME TABLE
          • RENAME USER
          • REPLACE
          • REVOKE
          • SAVEPOINT
          • SCHEMA
          • SELECT
            • SELECT
            • JOIN clause
            • OVER clause
            • UNION clause
          • SELECT INTO
          • SET
          • SET CHARSET
          • SET NAMES
          • SET PASSWORD
          • SET TRANSACTION
          • SHOW
          • TRANSACTION
          • TRUNCATE TABLE
          • UPDATE
          • USE
      • User tenants (Oracles mode)
        • SQL overview
        • Pseudocolumns
          • Overview
          • Hierarchical query pseudocolumns
          • Sequence pseudocolumns
          • ORA_ROWSCN pseudocolumn
          • ROWNUM pseudocolumn
          • ROWID pseudocolumn
        • Elements
          • Built-in data types
            • Overview of built-in data types
            • Character data types
              • Overview of character data types
              • CHAR data type
              • NCHAR data type
              • NVARCHAR2 data type
              • VARCHAR2 data type
              • VARCHAR data type
            • Numeric data types
              • Overview
              • NUMBER data type
              • FLOAT data type
              • Floating-point numbers
              • Precedence of numeric data types
            • Date, time, and interval data types
              • Overview of datetime and interval data types
              • DATE data type
              • TIMESTAMP data type
              • TIMESTAMP WITH TIME ZONE date type
              • TIMESTAMP WITH LOCAL TIME ZONE data type
              • INTERVAL YEAR TO MONTH data type
              • INTERVAL DAY TO SECOND data type
              • Calculation of dates, timestamps, and intervals
            • RAW data type
            • Large object data types
              • Overview
              • BLOB data type
              • CLOB data type
            • Rowid data types
            • User-defined data types
          • Comparison rules of data types
            • Overview
            • Numeric value comparison rules
            • Date value comparison rules
            • Character value comparison rules
            • Data type precedence
            • Data type conversion rules
            • Security considerations for data conversion
          • Literals
            • Overview
            • Text literals
            • Numeric literals
            • Datetime literals
              • Date literals
              • Timestamp literals
            • Interval literals
          • Format models
            • Overview
            • Number format models
            • Datetime format models
            • RR datetime format element
            • String-to-date conversion rules
          • Null values
            • Overview of nulls
            • Nulls in SQL functions
            • Nulls in comparison conditions
            • Nulls in conditional expressions
          • Comments
            • Overview
            • Comments within SQL statements
            • Comments on schema and nonschema objects
            • Hint
              • Overview of hints
              • Lists of hints
                • Hints related to access path
                • Hints related to join orders
                • Hints related to joins
                • Hints related to parallel execution
                • Hints related to query strategy
                • Hints related to query conversion
                • Other hints
          • Database objects
            • Schema objects
            • Non-schema objects
          • Database naming conventions
            • Overview
            • Database object names and qualifiers
            • Suggestions on schema object names
          • Methods of referencing database objects
            • Overview
            • Reference schema objects
            • Reference objects in a remote database
              • Create database links
              • Reference database links
            • Reference partition tables and indexes
            • Reference an attribute or method of an object type
        • Operators
          • Overview of operators
          • Operator precedence
          • Arithmetic operators
          • Concatenation operator
          • Hierarchical query operators
          • Set operators
          • COLLATE operator
        • Functions
          • Function overview
          • Single-row functions
            • Numeric functions
              • ABS
              • ACOS
              • ASIN
              • ATAN
              • ATAN2
              • BITAND
              • CEIL
              • COS
              • COSH
              • EXP
              • FLOOR
              • LN
              • LOG
              • MOD
              • NANVL
              • POWER
              • REMAINDER
              • ROUND
              • SIGN
              • SIN
              • SINH
              • SQRT
              • TAN
              • TANH
              • TRUNC
              • WIDTH_BUCKET
            • String functions that return strings
              • CHR
              • CONCAT
              • INITCAP
              • LOWER
              • LPAD
              • LTRIM
              • NLS_LOWER
              • NLS_UPPER
              • REGEXP_REPLACE
              • REGEXP_SUBSTR
              • REPLACE
              • RPAD
              • RTRIM
              • SUBSTR
              • TRANSLATE
              • TRANSLATE ... USING
              • TRIM
              • UPPER
            • String functions that return numbers
              • ASCII
              • INSTR
              • LENGTH
              • 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
            • General comparison functions
              • GREATEST
              • LEAST
            • Conversion functions
              • ASCIISTR
              • CAST
              • CHARTOROWID
              • CONVERT
              • HEXTORAW
              • NUMTODSINTERVAL
              • NUMTOYMINTERVAL
              • RAWTOHEX
              • ROWIDTOCHAR
              • ROWIDTONCHAR
              • TO_BINARY_DOUBLE
              • TO_BINARY_FLOAT
              • TO_BLOB
              • TO_CHAR (character)
              • TO_CHAR (datetime)
              • TO_CHAR (number)
              • TO_CLOB
              • TO_DATE
              • TO_DSINTERVAL
              • TO_MULTI_BYTE
              • TO_NUMBER
              • TO_NCHAR (character)
              • TO_NCHAR (datetime)
              • TO_NCHAR (number)
              • TO_SINGLE_BYTE
              • TO_TIMESTAMP
              • TO_TIMESTAMP_TZ
              • TO_YMINTERVAL
              • UNISTR
            • Encoding and decoding functions
              • DECODE
              • DUMP
              • ORA_HASH
              • VSIZE
            • Null value-related functions
              • COALESCE
              • LNNVL
              • NANVL
              • NULLIF
              • NVL
              • NVL2
            • Environment and identifier functions
              • SYS_CONTEXT
              • SYS_GUID
              • UID
              • USER
              • USERENV
              • OB_VERSION
            • Hierarchical functions
              • SYS_CONNECT_BY_PATH
            • XML functions
              • XMLAGG
              • XMLATTRIBUTES
              • XMLELEMENT
              • XMLPARSE
          • Aggregate functions
            • APPROX_COUNT_DISTINCT
            • AVG
            • CORR
            • COUNT
            • COVAR_POP
            • COVAR_SAMP
            • CUME_DIST
            • DENSE_RANK
            • GROUPING
            • KEEP
            • LISTAGG
            • MAX
            • MEDIAN
            • MIN
            • PERCENT_RANK
            • PERCENTILE_CONT
            • PERCENTILE_DISC
            • RANK
            • REGR_ (Linear Regression) Functions
            • ROLLUP
            • STDDEV
            • STDDEV_POP
            • STDDEV_SAMP
            • SUM
            • VAR_POP
            • VAR_SAMP
            • VARIANCE
            • WMSYS.WM_CONCAT/WM_CONCAT
          • Analytic 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) Functions
            • ROW_NUMBER
            • STDDEV
            • STDDEV_POP
            • STDDEV_SAMP
            • SUM
            • VAR_POP
            • VAR_SAMP
            • VARIANCE
            • WMSYS.WM_CONCAT/WM_CONCAT
        • Expressions
          • Overview
          • Simple expressions
          • Compound expressions
          • Case expressions
          • Column expressions
          • CURSOR expressions
          • Datetime expressions
          • Function expressions
          • Interval expressions
          • Scalar subquery expressions
          • Type constructor expressions
          • Expression list
        • Conditions
          • Overview of SQL conditions
          • Condition precedence
          • Comparison conditions
          • Floating-point conditions
          • Logical conditions
          • Pattern-matching conditions
          • Null conditions
          • Compound conditions
          • BETWEEN condition
          • EXISTS condition
          • IN condition
        • Queries and subqueries
          • Overview of queries and subqueries
          • Simple query
          • Hierarchical query
          • Compound queries
          • Join queries
          • Subquery
          • DUAL table query
        • SQL statements
          • DDL
            • ALTER INDEX
            • ALTER KEYSTORE
            • ALTER OUTLINE
            • ALTER PROFILE
            • ALTER ROLE
            • ALTER SEQUENCE
            • ALTER SESSION
            • ALTER SYSTEM FLUSH PLAN CACHE
            • ALTER SYSTEM PARAMETER
            • ALTER TABLE
            • ALTER TABLEGROUP
            • ALTER USER
            • CREATE DIRECTORY
            • CREATE DATABASE LINK
            • CREATE INDEX
            • CREATE KEYSTORE
            • CREATE OUTLINE
            • CREATE PROFILE
            • CREATE RESTORE POINT
            • CREATE ROLE
            • CREATE SEQUENCE
            • CREATE SYNONYM
            • CREATE TABLE
            • CREATE TABLEGROUP
            • CREATE TABLESPACE
            • CREATE USER
            • CREATE VIEW
            • DROP DIRECTORY
            • DROP DATABASE LINK
            • DROP INDEX
            • DROP OUTLINE
            • DROP PROFILE
            • DROP RESTORE POINT
            • DROP ROLE
            • DROP SEQUENCE
            • DROP SYNONYM
            • DROP TABLE
            • DROP TABLEGROUP
            • DROP TABLESPACE
            • DROP USER
            • DROP VIEW
            • RENAME
            • TRUNCATE TABLE
          • DML
            • DELETE
            • INSERT
            • MERGE
            • PURGE
            • SELECT
              • SIMPLE SELECT
              • Set-based SELECT
              • WITH clause
            • UPDATE
          • DCL
            • ANALYZE
            • AUDIT
            • COMMENT
            • COMMIT
            • EXPLAIN
            • FLASHBACK TABLE BEFORE DROP
            • GRANT
            • KILL
            • REVOKE
            • ROLLBACK
            • SAVEPOINT
            • SET NAMES
            • SET PASSWORD
            • SET ROLE
            • SET VARIABLE
            • SHOW
            • SHRINK
            • TRANSACTION
    • PL reference
      • What is PL?
        • Overview
        • Main features of PL
        • PL architecture
      • PL reference (MySQL mode)
        • Syntax of PL stored programs
        • Stored programs
          • Overview
          • Variables in stored programs
          • Stored procedures
          • Stored functions
          • Triggers
          • Access control and account management
          • Limitations on stored programs
        • Cursors
          • Overview
          • Cursor execution process
          • Limitations on server cursors
        • Conditional control statements
          • CASE
          • IF
          • ITERATE
          • LEAVE
          • LOOP
          • REPEAT
          • RETURN
          • WHILE
        • Data manipulation statements
          • CALL
          • DO
        • Data definition statements
          • CREATE FUNCTION
          • CREATE PROCEDURE
          • CREATE TRIGGER
          • DROP FUNCTION
          • DROP PROCEDURE
          • DROP TRIGGER
        • Database management statements
          • SHOW CREATE FUNCTION
          • SHOW CREATE PROCEDURE
          • SHOW CREATE TRIGGER
          • SHOW FUNCTION STATUS
          • SHOW PROCEDURE STATUS
          • SHOW TRIGGERS
        • Dictionary view
          • INFORMATION_SCHEMA PARAMETERS
          • INFORMATION_SCHEMA ROUTINES
          • INFORMATION_SCHEMA TRIGGERS
        • Exception handling
          • Overview
          • DECLARE ... CONDITION
          • DECLARE ... HANDLER
          • GET DIAGNOSTICS
          • RESIGNAL
          • SIGNAL
          • Effective scope of an exception handler
          • Diagnostics area
          • Exception handling and OUT/INOUT parameters
          • Limitations on exception handling
        • PL packages
          • DBMS_RESOURCE_MANAGER
            • Overview
            • CREATE_CONSUMER_GROUP
            • CREATE_PLAN
            • CREATE_PLAN_DIRECTIVE
            • DELETE_CONSUMER_GROUP
            • DELETE_PLAN
            • DELETE_PLAN_DIRECTIVE
            • SET_CONSUMER_GROUP_MAPPING
            • UPDATE_PLAN_DIRECTIVE
          • DBMS_STATS
            • Overview
            • DELETE_COLUMN_STATS
            • DELETE_TABLE_STATS
            • EXPORT_COLUMN_STATS
            • EXPORT_TABLE_STATS
            • FLUSH_DATABASE_MONITORING_INFO
            • GATHER_TABLE_STATS
            • IMPORT_COLUMN_STATS
            • IMPORT_TABLE_STATS
            • LOCK_PARTITION_STATS
            • LOCK_SCHEMA_STATS
            • LOCK_TABLE_STATS
            • SET_COLUMN_STATS
            • SET_TABLE_STATS
            • UNLOCK_PARTITION_STATS
            • UNLOCK_SCHEMA_STATS
            • UNLOCK_TABLE_STATS
        • Reserved and non-reserved PL keywords
      • PL reference (Oracle mode)
        • Language basics
          • Character sets
          • Lexical units
          • Declaration
          • Reference identifiers
          • Scope and visibility of identifiers
          • Assign values
          • Expressions
          • PL blocks
          • Subprograms
          • Error-reporting functions
        • Data types
          • Overview
          • SQL data types
          • LOB data types
          • BOOLEAN type
          • User-defined subtypes
          • PLS_INTEGER and BINARY_INTEGER
          • Arrays
        • Flow control
          • Overview
          • Conditional control
          • Loop control
          • Sequential control
        • Collections and records
          • Overview
          • Collections
          • Associative arrays
          • Varrays
          • Nested tables
          • Collection constructor function
          • Collection methods
            • Overview of collection methods
            • DELETE method
            • TRIM method
            • EXTEND method
            • EXISTS method
            • FIRST and LAST methods
            • COUNT method
            • LIMIT method
            • PRIOR and NEXT methods
          • Records
          • Insert records into a table and update a table by using records
          • Create and call a subprogram with record type parameters
        • Static SQL
          • Overview
          • Cursors
            • Overview
            • Cursor attributes
            • Implicit cursors
            • Explicit cursors
            • Cursor variables
            • Traverse cursor data by using the FOR loop
            • Modify and drop a cursor
          • Transaction processing and control
          • Autonomous transactions
            • Overview
            • Control autonomous transactions
            • Autonomous triggers
        • Dynamic SQL
          • Overview
          • Execute dynamic SQL statements
          • DBMS_SQL system package
        • Stored procedures and functions
          • Overview
          • Create a stored procedure
          • Create a function
          • Manage stored procedures and functions
          • Privilege control
          • User-defined aggregate functions
            • Overview
            • Interface for user-defined aggregate functions
            • Create user-defined aggregate functions
            • Use user-defined aggregate functions
        • Triggers
          • Overview
          • Create a DML trigger
          • Modify and drop a trigger
          • Disable or enable a trigger
          • Query trigger information
          • INSTEAD OF DML trigger
        • Packages
          • Overview
          • Create a program package
          • Overloaded programs in a package
          • Manage program packages
          • Definition of the PL environment by the STANDARD package
        • Exception handling
          • Overview
          • Compile-Time alerts
          • Exception types
          • Exception handling processes
        • DDL operations on stored PL units
          • Overview
          • ALTER FUNCTION
          • ALTER PACKAGE
          • ALTER PROCEDURE
          • ALTER TRIGGER
          • ALTER TYPE
          • CREATE FUNCTION
          • CREATE PACKAGE
          • CREATE PACKAGE BODY
          • CREATE PROCEDURE
          • CREATE TRIGGER
          • CREATE TYPE
          • CREATE TYPE BODY
          • DROP FUNCTION
          • DROP PACKAGE
          • DROP PROCEDURE
          • DROP TRIGGER
          • DROP TYPE
          • DROP TYPE BODY
        • PL packages
          • Overview
          • DBMS_APPLICATION_INFO
            • Overview
            • READ_CLIENT_INFO
            • READ_MODULE
            • SET_ACTION
            • SET_CLIENT_INFO
            • SET_MODULE
          • DBMS_CRYPTO
            • Overview
            • ENCRYPT
            • DECRYPT
            • HASH
          • DBMS_DEBUG
            • Overview
            • ATTACH_SESSION
            • CONTINUE
            • DEBUG_ON
            • DEBUG_OFF
            • DETACH_SESSION
            • DELETE_BREAKPOINT
            • DISABLE_BREAKPOINT
            • ENABLE_BREAKPOINT
            • GET_VALUE
            • GET_VALUES
            • GET_RUNTIME_INFO
            • GET_TIMEOUT_BEHAVIOUR
            • INITIALIZE
            • PROBE_VERSION
            • PRINT_BACKTRACE
            • SET_TIMEOUT
            • SET_TIMEOUT_BEHAVIOUR
            • SET_BREAKPOINT
            • SHOW_BREAKPOINTS
          • DBMS_DESCRIBE
            • Overview
            • DESCRIBE_PROCEDURE
          • DBMS_JOB
            • Overview
            • BROKEN
            • CHANGE
            • ZONE
            • INTERVAL
            • NEXT_DATE
            • REMOVE
            • RUN
            • SUBMIT
            • USER_EXPORT
            • WHAT
          • DBMS_LOB
            • Overview
            • APPEND
            • CLOSE
            • COMPARE
            • COPY
            • CREATETEMPORARY
            • ERASE
            • FREETEMPORARY
            • GETLENGTH
            • ISOPEN
            • INSTR
            • OPEN
            • READ
            • SUBSTR
            • TRIM
            • WRITE
            • WRITEAPPEND
          • DBMS_LOCK
            • Overview
            • SLEEP
          • DBMS_METADATA
            • Overview
            • GET_DDL
          • DBMS_OUTPUT
            • Overview
            • DISABLE
            • ENABLE
            • GET_LINE
            • GET_LINES
            • NEW_LINE
            • PUT
            • PUT_LINE
          • DBMS_PLAN_CACHE
            • Overview
            • PURGE
          • DBMS_RANDOM
            • Overview
            • INITIALIZE
            • NORMAL
            • RANDOM
            • SEED
            • STRING
            • TERMINATE
            • VALUE
          • DBMS_RESOURCE_MANAGER
            • Overview
            • CREATE_CONSUMER_GROUP
            • CREATE_PLAN
            • CREATE_PLAN_DIRECTIVE
            • DELETE_CONSUMER_GROUP
            • DELETE_PLAN
            • DELETE_PLAN_DIRECTIVE
            • SET_CONSUMER_GROUP_MAPPING
            • UPDATE_PLAN_DIRECTIVE
          • DBMS_SCHEDULER
            • Overview
            • CREATE_JOB
            • CREATE_PROGRAM
            • DEFINE_PROGRAM_ARGUMENT
            • DISABLE
            • DROP_JOB
            • DROP_PROGRAM
            • ENABLE
            • GENERATE_JOB_NAME
            • RUN_JOB
            • SET_ATTRIBUTE
            • SET_JOB_ARGUMENT_VALUE
          • DBMS_SESSION
            • Overview
            • CLEAR_ALL_CONTEXT
            • CLEAR_CONTEXT
            • CLEAR_IDENTIFIER
            • SET_CONTEXT
            • SET_IDENTIFIER
          • DBMS_SQL
            • Overview
            • BIND_VARIABLE
            • CLOSE_CURSOR
            • COLUMN_VALUE
            • DEFINE_COLUMN
            • DEFINE_ARRAY
            • DESCRIBE_COLUMNS
            • EXECUTE
            • EXECUTE_AND_FETCH
            • FETCH_ROWS
            • IS_OPEN
            • OPEN_CURSOR
            • PARSE
          • DBMS_STATS
            • Overview
            • DELETE_COLUMN_STATS
            • DELETE_TABLE_STATS
            • EXPORT_COLUMN_STATS
            • EXPORT_TABLE_STATS
            • FLUSH_DATABASE_MONITORING_INFO
            • GATHER_TABLE_STATS
            • IMPORT_COLUMN_STATS
            • IMPORT_TABLE_STATS
            • LOCK_PARTITION_STATS
            • LOCK_SCHEMA_STATS
            • LOCK_TABLE_STATS
            • SET_COLUMN_STATS
            • SET_TABLE_STATS
            • UNLOCK_PARTITION_STATS
            • UNLOCK_SCHEMA_STATS
            • UNLOCK_TABLE_STATS
          • DBMS_UTILITY
            • Overview
            • ACTIVE_INSTANCES
            • COMMA_TO_TABLE
            • CURRENT_INSTANCE
            • DB_VERSION
            • FORMAT_CALL_STACK
            • FORMAT_ERROR_BACKTRACE
            • FORMAT_ERROR_STACK
            • GET_ENDIANNESS
            • GET_HASH_VALUE
            • GET_PARAMETER_VALUE
            • GET_SQL_HASH
            • GET_TIME
            • IS_BIT_SET
            • IS_CLUSTER_DATABASE
            • NAME_RESOLVE
            • NAME_TOKENIZE
            • OLD_CURRENT_SCHEMA
            • OLD_CURRENT_USER
            • PORT_STRING
            • TABLE_TO_COMMA
          • DBMS_XA
            • Overview
            • DBMS_XA constants
            • DBMS_XA_XID object type
            • DIST_TXN_SYNC
            • XA_COMMIT
            • XA_END
            • XA_FORGET
            • XA_GETLASTOER
            • XA_PREPARE
            • XA_RECOVER
            • XA_ROLLBACK
            • XA_SETTIMEOUT
            • XA_START
          • ODCICONST
            • Overview
            • ODCIArgDesc.ArgType
            • ODCIEnv.CallProperty
            • ODCIEnv.Envflags
            • ODCIIndexAlter
            • ODCIIndexAlter parameter alter_option
            • ODCIIndexInfo.IndexInfoFlags
            • ODCIIndexInfo.IndexParaDegree
            • ODCIPredInfo.Flags
            • ODCIQueryInfo.Flags
            • ODCIStatsOptions.Flags
            • ODCIStatsOptions.Options
            • Return Status
            • ScnFlg
          • UTL_FILE
            • Overview
            • FCLOSE
            • FFLUSH
            • FOPEN
            • FGETPOS
            • FREMOVE
            • FRENAME
            • FSEEK
            • NEW_LINE
            • GET_LINE
            • PUT
            • PUT_LINE
          • UTL_ENCODE
            • Overview
            • BASE64_DECODE
            • BASE64_ENCODE
          • UTL_I18N
            • Overview
            • RAW_TO_CHAR
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Summary of system parameters

Last Updated:2023-10-27 09:57:43  Updated
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What is on this page
Cluster-level parameters
Bandwidth parameters
Load balancing parameters
Replica parameters
Backup and restore parameters
Primary and standby cluster parameters
Cluster parameters
SQL parameters
External storage API parameters
CPU parameters
Directory parameters
Memory parameters
Debugging parameters
Compression algorithm parameters
Transaction and transaction log parameters
Minor and major compaction parameters
PX parameters
Cache parameters
Location cache parameters
Log parameters
Partition parameters
Read/write and query parameters
RootService parameters
Concurrency parameters
I/O parameters
TCP parameters
RPC security parameters
Other parameters
Unsupported parameters
Tenant-level parameters
User logon parameters
Audit parameters
Transaction and transaction log parameters
Minor and major compaction parameters
Encryption parameters
PL parameters
Compatibility parameters
Read/write and query parameters
Routing parameters
Other parameters
Unsupported parameters

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This topic describes cluster- and tenant-level parameters in OceanBase Database.

Cluster-level parameters

Bandwidth parameters

Parameter Description
enable_ob_ratelimit Specifies whether to enable rate limiting between regions in a remote procedure call (RPC) connection.
ob_ratelimit_stat_period The interval for calculating and updating the maximum bandwidth on OBServer nodes.

Load balancing parameters

Parameter Description
balancer_idle_time The interval for waking up the idle threads of backend tasks such as load balancing.
balancer_log_interval The interval for printing statistical logs generated by the threads of backend tasks such as load balancing.
balancer_timeout_check_interval The interval for checking whether backend tasks such as load balancing time out.
balancer_task_timeout The timeout period of backend tasks such as load balancing.
balancer_tolerance_percentage The tolerance for disk imbalance among multiple units of a tenant, which is set in the load balancing strategy. If the imbalance is within the range that starts at the average value minus the tolerance and ends at the average value plus the tolerance, no balancing action is triggered.
balancer_emergency_percentage The load threshold of each unit. When the load of a unit exceeds the specified threshold, you can enable replica migration to an external system for load balancing even during a major compaction.
enable_rebalance Specifies whether to enable automatic load balancing.
server_balance_critical_disk_waterlevel The disk usage threshold that triggers disk load balancing.
server_balance_disk_tolerance_percent The tolerance for disk load imbalance among nodes, which is set in the load balancing strategy.
tenant_groups The tenant groups used in the load balancing strategy.
resource_hard_limit Specifies how resource units are allocated.
resource_soft_limit Specifies whether to enable unit balancing.
unit_balance_resource_weight The resource weight used in the unit balancing strategy. Generally, you do not need to set this parameter.
enable_sys_unit_standalone Specifies whether the unit of the sys tenant exclusively occupies a node.

Replica parameters

Parameter Description
balance_blacklist_failure_threshold The maximum number of consecutive failures of a backend task such as replica migration.
balance_blacklist_retry_interval The retry interval for a backend task such as replica migration that is added to the blocklist.
enable_rereplication Specifies whether to enable automatic data synchronization to replicas.
global_index_build_single_replica_timeout The timeout period for creating a replica during global index creation.
ignore_replica_checksum_error Specifies whether to ignore the checksum errors of replicas.
replica_safe_remove_time The retention period of a deleted replica before it can be cleared.
sys_bkgd_migration_change_member_list_timeout The timeout period for modifying the Paxos member list during replica migration.
sys_bkgd_migration_retry_num The maximum number of retries after a replica migration task fails.
enable_smooth_leader_switch Specifies whether to enable smooth leader switchover.
election_blacklist_interval The interval during which the dismissed leader cannot be re-elected as the leader.
enable_auto_leader_switch Specifies whether to enable automatic leader switchover.
get_leader_candidate_rpc_timeout The timeout period of an internal request for obtaining the leader candidate in the automatic leader switchover strategy.
rebuild_replica_data_lag_threshold The threshold of the size difference of transaction logs between the leader and a follower. When the difference reaches the threshold, replica reconstruction is triggered.

Backup and restore parameters

Parameter Description
enable_log_archive Specifies whether to enable log archiving.
backup_dest_option The parameters for backup.
backup_backup_dest_option The parameters for second backup.
backup_log_archive_option The options for log archiving during backup.
backup_zone The zone for which backup tasks are run.
log_archive_checkpoint_interval The interval between log archiving checkpoints of cold data.
log_archive_concurrency The concurrency of log archiving.
log_archive_batch_buffer_limit The maximum memory available for log archiving on a single server when physical backup is enabled.
log_restore_concurrency The concurrency of log restoration.
auto_delete_expired_backup Specifies whether to enable automatic deletion of expired backups.
backup_concurrency The concurrency of data writes to the file system during backup.
backup_dest The path for baseline data backup and log archiving.
backup_net_limit The total bandwidth for cluster backup.
backup_recovery_window The time window in which backups can be recovered.
backup_region The region for which backup tasks are run.
restore_concurrency The maximum concurrency of tenant data restore from backups.
backup_backup_dest The destination for second backup.
backup_backup_archive_log_batch_count The number of batches of tasks for secondary log backup.
backup_backup_archivelog_retry_interval The interval for retrying tasks for secondary log backup.
backup_backupset_batch_count The number of batches of tasks for secondary baseline data backup.
backup_backupset_retry_interval The interval for retrying tasks for secondary baseline data backup.

Primary and standby cluster parameters

Parameter Description
switchover_process_thread_count The size of the thread pool for primary/standby cluster switchover.

Cluster parameters

Parameter Description
cluster The name of the current OceanBase cluster.
cluster_id The ID of the current OceanBase cluster.
rpc_timeout The timeout period of an internal request in the cluster.

SQL parameters

Parameter Description
sql_login_thread_count The number of threads for processing SQL logon requests.

External storage API parameters

Parameter Description
ob_esi_rpc_port The communication port between the obesi process and the observer process.
enable_ob_esi_process Specifies whether to enable the obesi process (external storage API).
ob_esi_session_timeout The timeout period of the active session resources for the obesi process.
ob_esi_io_concurrency The I/O concurrency for the obesi process.
ob_esi_memory_limit The maximum memory size for the obesi process.
ob_esi_syslog_level The current log level for the obesi process.
ob_esi_max_syslog_file_count The maximum number of log files that can be retained for the obesi process.

CPU parameters

Parameter Description
cpu_count The total number of CPUs in the system. If the parameter is set to 0, the system will automatically detect the number of CPUs.
cpu_quota_concurrency The maximum concurrency allowed for each CPU quota of a tenant.
cpu_reserved The number of CPUs reserved in the system. The remaining CPUs are exclusively occupied by OceanBase Database.
election_cpu_quota The CPU quota allocated to backend tasks related to replica election.
server_balance_cpu_mem_tolerance_percent The tolerance of CPU and memory resource imbalance in the node load balancing strategy.
server_cpu_quota_max The maximum CPU quota for the system.
server_cpu_quota_min The minimum CPU quota for the system. The system automatically reserves the quota.
system_cpu_quota The CPU quota for the SYS tenant.
sys_cpu_limit_trigger The CPU utilization threshold. When CPU utilization reaches the threshold, backend tasks in the system will be suspended.
token_reserved_percentage The percentage of idle tokens reserved for tenants in the scheduling of CPUs for the tenants.
workers_per_cpu_quota The number of worker threads allocated to each CPU quota.

Directory parameters

Parameter Description
config_additional_dir The local directories for storing multiple copies of configuration files for redundancy.
data_dir The directory for storing SSTables and other data.

Memory parameters

Parameter Description
datafile_disk_percentage The percentage of used space to the total space of the disk where the data_dir directory is located. This disk will be initialized for data storage by the OceanBase Database system.
data_disk_usage_limit_percentage The percentage of data write space to the total space of the disk. When the data write space reaches the threshold, data can no longer be written to the disk.
enable_sql_operator_dump Specifies whether to allow intermediate SQL processing results to be written to the disk to release the memory.
global_write_halt_residual_memory The global available memory threshold that triggers the suspension of write operations of user tenants. (The sys tenant is not affected.)
leak_mod_to_check The internal debugging feature used for memory leakage check.
memory_chunk_cache_size The total cache size of the memory allocator.
memory_limit The total size of available memory.
memory_limit_percentage The percentage of available memory to total memory in the system.
memory_reserved The memory size reserved by the system for the KV cache.
memstore_limit_percentage The percentage of the memory that can be occupied by the MemStore to the total available memory of a tenant.
system_memory The memory size reserved by the system for the SYS500 tenant.
sql_audit_memory_limit The maximum memory available for SQL audit data.
use_large_pages Manages the use of large memory pages by the database.

Debugging parameters

Parameter Description
debug_sync_timeout The timeout period for a Debug Sync operation. When the value is set to 0, Debug Sync is disabled.
enable_rich_error_msg Specifies whether to add debugging information, such as the server address, error time, and trace ID, to the client message.

Compression algorithm parameters

Parameter Description
default_compress_func The default algorithm for compressing table data. You can also specify another compression algorithm when creating a table.
default_compress The default compression strategy used during table creation in Oracle mode.
tableapi_transport_compress_func The algorithm for compressing TableAPI query results for transmission.
default_transport_compress_func The RPC compression algorithm used for the entire cluster.

Transaction and transaction log parameters

Parameter Description
trx_try_wait_lock_timeout The maximum amount of time that a statement waits for a locked row to be unlocked.
trx_force_kill_threshold The maximum amount of time that the system waits before killing a transaction due to a freeze or leader switchover.
clog_cache_priority The caching priority of transaction logs.
clog_sync_time_warn_threshold The warning threshold of time consumed for synchronizing transaction logs. When the consumed time reaches the threshold, a WARN-level log is generated.
clog_disk_usage_limit_percentage The maximum percentage of I/O usage of the transaction log disk.
clog_transport_compress_all Specifies whether to compress transaction logs for transmission.
clog_transport_compress_func The algorithm for compressing transaction logs for internal transmission.
dtl_buffer_size The size of the cache allocated to the SQL data transmission module.
enable_one_phase_commit Specifies whether to enable one-phase commit.
ignore_replay_checksum_error Specifies whether to ignore checksum errors that occur during transaction log playback.
trx_2pc_retry_interval The interval for retrying a failed two-phase commit task.
clog_disk_utilization_threshold The usage of the clog or ilog disk space that triggers log file reuse.
index_clog_cache_priority The priority of the transaction log index in the cache system.
clog_expire_days The retention period of clog files. When the retention period of a clog file expires, it will be deleted.
gc_wait_archive Specifies whether to start garbage collection for a partition until all the logs in the partition have been archived.

Minor and major compaction parameters

Parameter Description
enable_global_freeze_trigger Specifies whether to enable automatic triggering of a global freeze.
enable_manual_merge Specifies whether to enable manual major compaction.
enable_merge_by_turn Specifies whether to enable the rotating major compaction strategy.
enable_major_freeze Specifies whether to enable automatic global freezing.
freeze_trigger_percentage The threshold of memory used by tenants for triggering a global freeze.
global_major_freeze_residual_memory The threshold of remaining memory for triggering a global freeze.
major_freeze_duty_time The time to trigger a freeze and a major compaction every day.
max_kept_major_version_number The number of frozen data versions to be retained.
merge_stat_sampling_ratio The sampling rate of data column statistics in a major compaction.
major_compact_trigger The number of minor compactions for triggering a global major compaction.
merge_thread_count The number of worker threads for daily major compactions.
merger_check_interval The interval for scheduling the thread for checking the major compaction status.
merger_completion_percentage The percentage of compacted replicas at which the major compaction task is considered completed.
merger_switch_leader_duration_time The interval for a batch leader switchover in a daily major compaction.
merger_warm_up_duration_time The preload time of new baseline data in a major compaction.
minor_compact_trigger The threshold for triggering the next-level compaction in hierarchical minor compactions.
minor_deferred_gc_time The interval between the time when garbage collection starts for SSTables and the time when the major compaction ends.
minor_freeze_times The number of minor compactions for triggering a global major compaction.
minor_warm_up_duration_time The preload time of the new MemTable generated after a minor compaction.
minor_merge_concurrency The number of concurrent threads in a minor compaction.
micro_block_merge_verify_level The verification level of macroblocks in a major compaction.
row_compaction_update_limit The number of data updates that triggers a major compaction of rows in the memory.
row_purge_thread_count The maximum number of worker threads for a major compaction of rows in the memory.
zone_merge_concurrency The number of zones supported in a major compaction.
zone_merge_order The order of zones in a rotating major compaction.
zone_merge_timeout The timeout period for the major compaction of a zone.

PX parameters

Parameter Description
px_workers_per_cpu_quota The ratio of Parallel eXecution (PX) worker threads.
px_task_size The amount of data processed by the SQL parallel query engine in each task.
max_px_worker_count The maximum number of threads for the SQL parallel query engine.

Cache parameters

Parameter Description
bf_cache_miss_count_threshold The number of macroblock misses that triggers the creation of the Bloom filter cache.
bf_cache_priority The priority of the Bloom filter cache.
cache_wash_threshold The remaining capacity threshold that triggers cache cleanup.
fuse_row_cache_priority The priority of the fuse row cache in the cache system.
multiblock_read_gap_size The size of multiple block caches from which data can be read in one I/O operation.
user_row_cache_priority The priority of the baseline data row cache in the cache system.
user_tab_col_stat_cache_priority The priority of the statistics cache in the cache system.
index_cache_priority The priority of the index cache in the cache system.
index_info_block_cache_priority The priority of the block index in the cache system.
autoinc_cache_refresh_interval The refresh interval for the auto-increment column cache.
plan_cache_evict_interval The eviction interval for the execution plan cache.
enable_auto_refresh_location_cache Specifies whether to enable automatic refresh of the location cache.
auto_refresh_location_cache_rate_limit The maximum number of partitions that can be automatically refreshed on each OBServer node at a time.
auto_broadcast_location_cache_rate_limit The maximum number of partitions whose location changes can be broadcast on each OBServer node per second.
user_block_cache_priority The priority of the data block cache in the cache system.

Location cache parameters

Parameter Description
virtual_table_location_cache_expire_time The validity period of the location cache of the virtual table.
location_cache_refresh_rpc_timeout The timeout period for refreshing the location cache through RPC.
location_cache_refresh_sql_timeout The timeout period for refreshing the location cache through SQL.
force_refresh_location_cache_interval The maximum interval for refreshing the location cache.
force_refresh_location_cache_threshold The maximum number of times that the location cache is refreshed per second. Throttling is performed if this threshold is exceeded.
location_cache_priority The priority of the location cache in the cache system.
location_cache_refresh_min_interval The minimum interval for sending location cache refresh requests, which prevents excessive refresh requests from overloading the system.
location_cache_cpu_quota The CPU quota for the location cache module.
location_fetch_concurrency The maximum number of concurrent requests for refreshing the location cache on a single server.
location_cache_expire_time The validity period of partition location information in the partition location cache. We recommend that you do not modify this parameter.
location_refresh_thread_count The number of threads used by OBServer node to obtain partition location information from RootService.

Log parameters

Parameter Description
enable_record_trace_log Specifies whether to record trace logs.
enable_async_syslog Specifies whether to enable asynchronous writing of system logs.
enable_syslog_recycle Specifies whether to enable recycling for system logs.
enable_syslog_wf Specifies whether to print system logs above the WARN level to a separate log file.
enable_separate_sys_clog Specifies whether to separately store system transaction logs and user transaction logs.
flush_log_at_trx_commit The transaction log write strategy adopted when transactions are committed.
max_string_print_length The maximum length of a single row when system logs are printed.
max_syslog_file_count The maximum number of log files that can be retained.
syslog_level The level of system logs.
trace_log_sampling_interval The interval at which trace logs are printed.
ilog_index_expire_time The validity period of ilog files on OBServer nodes. Expired files can no longer be read.
diag_syslog_per_error_limit The number of DIAG system logs allowed for each error code per second. When this threshold is reached, no more logs will be printed.

Partition parameters

Parameter Description
enable_pg Specifies whether to enable the partition group feature.
partition_table_check_interval The interval at which the OBServer node deletes non-existent replicas from a partitioned table.
partition_table_scan_batch_count The number of records in a partitioned table that can be read in a batch.
tablet_size The size of each shard during intra-partition parallel processing such as parallel compactions and queries.

Read/write and query parameters

Parameter Description
weak_read_version_refresh_interval The version refresh interval for weak consistency reads. This parameter affects the latency of weak consistency reads.
large_query_worker_percentage The percentage of worker threads reserved for large queries.
large_query_threshold The execution time threshold to identify a large query.
trace_log_slow_query_watermark The execution time threshold to identify a slow query. Trace logs of slow queries are written to system logs.

RootService parameters

Parameter Description
auto_leader_switch_interval The working interval of the backend thread for automatic leader switchover.
rootservice_async_task_queue_size The size of the internal asynchronous task queue for RootService.
rootservice_async_task_thread_count The size of the thread pool for internal asynchronous tasks of RootService.
rootservice_list The servers on which RootService and its replicas run.
rootservice_ready_check_interval The wait time after RootService is started, during which the cluster status is checked.
rootservice_memory_limit The maximum memory available to RootService.
wait_leader_batch_count The maximum number of partitions to which RootService can send a command for leader switchover.
enable_rootservice_standalone Specifies whether to allow the SYS tenant and RootService to exclusively occupy an OBServer node.
lease_time The heartbeat lease period.
server_check_interval The interval at which the server checks the table consistency.
server_permanent_offline_time The time threshold for heartbeat missing at which a server is considered permanently offline. Data replicas on a permanently offline server must be automatically supplemented.
ob_event_history_recycle_interval The interval at which historical events are recycled.

Concurrency parameters

Parameter Description
server_data_copy_in_concurrency The maximum concurrency for data migration to a single node.
server_data_copy_out_concurrency The maximum concurrency for data migration from a single node.
fast_recovery_concurrency The maximum concurrency for executing fast restore tasks scheduled by RootService on an OBServer node.
data_copy_concurrency The maximum concurrency for data migration and replication in the system.
migrate_concurrency The maximum concurrency for internal data migration.

I/O parameters

Parameter Description
sys_bkgd_io_high_percentage The highest percentage of disk bandwidth that can be used by backend I/O operations.
sys_bkgd_io_low_percentage The lowest percentage of traffic for backend I/O operations.
syslog_io_bandwidth_limit The maximum I/O bandwidth available for system logs. If this value is reached, the remaining system logs are discarded.
user_iort_up_percentage The I/O latency threshold for the user disk. When the I/O latency of the user disk reaches this threshold, the traffic of backend I/O operations will be throttled.
disk_io_thread_count The number of disk I/O threads. The value must be an even number.
multiblock_read_size The I/O aggregate throughput in data access.
net_thread_count The number of network I/O threads.

TCP parameters

Parameter Description
enable_tcp_keepalive Specifies whether to enable the keepalive mechanism for client connections.
tcp_keepidle The interval in seconds before sending a keepalive probe packet when no data is sent on a client connection.
tcp_keepintvl The interval between two probes in seconds when you enable the keepalive mechanism for client connections.
tcp_keepcnt The maximum number of retries before terminating a non-active connection.

RPC security parameters

Parameter Description
rpc_client_authentication_method The security authentication method for the RPC client.
rpc_server_authentication_method The security authentication method for the RPC server.

Other parameters

Parameter Description
all_cluster_list The list of servers that access the same URL specified for config_url.
builtin_db_data_verify_cycle The cycle of a bad block check in the unit of days. When the value is set to 0, the bad block check is not performed.
data_storage_warning_tolerance_time The tolerance period after which the data disk is set to the WARNING state.
dead_socket_detection_timeout The interval for detecting invalid sockets.
internal_sql_execute_timeout The interval of DML requests in the system.
migration_disable_time The period during which data migration is suspended for a node after data migration to the node fails due to reasons such as full disk usage.
schema_history_expire_time The validity period of history metadata.
ofs_list The list of URLs for connecting to the OceanBase File System (OFS) of all the zones so that RootService can access files across zones in OFS deployment mode. OFS is a distributed storage system independently designed for OceanBase Database.
datafile_size The size of a data file. This parameter is generally left unspecified.
devname The name of the network interface card (NIC) to which the service process is bound.
enable_perf_event Specifies whether to enable the information collection feature for performance events.
enable_record_trace_id Specifies whether to record the trace ID configured by the application.
enable_upgrade_mode Specifies whether to enable the upgrade mode. In upgrade mode, some backend system features are suspended.
enable_ddl Specifies whether to allow the execution of DDL statements.
high_priority_net_thread_count The number of network threads with a high priority. When this parameter is set to 0, this feature is disabled.
mysql_port The port number for the SQL service protocol.
obconfig_url The URL of the OBConfig service.
rpc_port The RPC port.
ssl_client_authentication Specifies whether to enable SSL authentication.
stack_size The size of the function call stack for programs.
tenant_task_queue_size The request queue size of each tenant.
zone The name of the zone where the node is located. This parameter is generally left unspecified.
ssl_external_kms_info The information that the SSL feature of OceanBase Database relies on, which is recorded in JSON strings for different SSL modes. Such a JSON string contains at least the ssl_mode field.
recyclebin_object_expire_time The period during which a schema object can be retained in the recycle bin. After the period elapses, the object will be purged from the recycle bin.
default_row_format The default row format used in table creation in MySQL mode.
enable_election_group Specifies whether to enable the election group strategy.
enable_sql_audit Specifies whether to enable SQL audit.
min_observer_version The earliest OBServer version in the cluster.
sys_bkgd_net_percentage The maximum percentage of network bandwidth for backend system tasks.
schema_history_recycle_interval The interval for recycling schema multi-version history files.

Unsupported parameters

Parameter Description
all_cluster_list The list of servers that access the same URL specified for config_url.
enable_unit_balance_resource_weight Specifies whether to enable manual configuration of resource weights.
plan_cache_high_watermark The memory threshold to trigger plan cache eviction. Automatic eviction is triggered when the memory occupied by the plan cache reaches the specified threshold.
plan_cache_low_watermark The memory threshold to stop plan cache eviction. The eviction is stopped when the memory occupied by the plan cache decreases to the specified threshold.
server_temporary_offline_time The time threshold for heartbeat missing at which a server is considered temporarily offline.
sql_audit_queue_size The maximum number of records of SQL audit data allowed.
tenant_cpu_variation_per_server The variation allowed for CPU quota scheduling among multiple units of a tenant.
system_trace_level The level of system trace logs to be printed.

Tenant-level parameters

User logon parameters

Note

The following table describes the parameters that take effect only in MySQL mode.

Parameter Description
connection_control_failed_connections_threshold The threshold of failed logon attempts.
connection_control_min_connection_delay The minimum lock period for an account whose number of failed logon attempts reaches the specified threshold.
connection_control_max_connection_delay The maximum lock period for an account whose number of failed logon attempts reaches the specified threshold.

Audit parameters

Parameter Description
audit_sys_operations Specifies whether to track the operations of the SYS user.
audit_trail Specifies whether to enable database audit.

Transaction and transaction log parameters

Parameter Description
writing_throttling_maximum_duration The time required for allocating the remaining memory of the MemStore after the write speed is limited. This parameter controls the write speed by controlling the memory allocation progress.
writing_throttling_trigger_percentage The upper limit of the write speed.
clog_persistence_compress_func The algorithm for compressing transaction logs for storage.
clog_max_unconfirmed_log_count The maximum number of unconfirmed logs allowed in the transaction module.
enable_clog_persistence_compress Specifies whether to compress transaction logs for storage.

Minor and major compaction parameters

Parameter Description
default_progressive_merge_num The default number of progressive major compactions during table creation.

Encryption parameters

Parameter Description
external_kms_info The key management information.
tde_method The encryption method for a transparent tablespace.

PL parameters

Parameter Description
plsql_ccflags The compilation constants of the PL compiler.
plsql_code_type The compilation mode of PL/SQL code.
plsql_debug Specifies whether to compile code for debugging.
plsql_optimize_level The compilation optimization level.
plsql_v2_compatibility Specifies whether compatibility with Oracle 8 is supported.
This parameter applies only to the Oracle mode and does not take effect now.
plsql_warnings Controls the error reporting behavior of the PL/SQL compiler. You can use this parameter to specify the status of a warning code or a warning code type to enable, disable, or error.

Compatibility parameters

Note

The following table describes the parameters that take effect only in MySQL mode.

Parameter Description
enable_sql_extension Specifies whether to enable SQL extension for tenants.

Read/write and query parameters

Parameter Description
enable_monotonic_weak_read Specifies whether to enable monotonic reads.
max_stale_time_for_weak_consistency The maximum latency allowed in weak consistency reads.

Routing parameters

Parameter Description
ob_proxy_readonly_transaction_routing_policy Specifies whether ODP routes a transaction based on read-only statements.

Other parameters

Parameter Description
enable_early_lock_release Specifies whether to enable the early lock release (ELR) feature.
workarea_size_policy Specifies whether the size of an SQL workarea is manually or automatically adjusted.
open_cursors The maximum number of cursors that can be concurrently opened in a single session.
ob_ssl_invited_common_names The list of identities of applications running under the current tenant. The identity of an application comes from the cn (common name) field of the subject of the client certificate in two-way SSL authentication.
ob_enable_batched_multi_statement Specifies whether to enable group-based execution optimization for the batch processing feature.
job_queue_processes The maximum number of concurrent tasks that can be run under each tenant. You can set this parameter to prevent tenant resources from being excessively occupied by tasks.
Note
This parameter takes effect only in Oracle mode.
ob_query_switch_leader_retry_timeout The maximum retry period for failed queries, in us.

Unsupported parameters

Parameter Description
sql_work_area The workarea memory of a tenant.

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What is on this page
Cluster-level parameters
Bandwidth parameters
Load balancing parameters
Replica parameters
Backup and restore parameters
Primary and standby cluster parameters
Cluster parameters
SQL parameters
External storage API parameters
CPU parameters
Directory parameters
Memory parameters
Debugging parameters
Compression algorithm parameters
Transaction and transaction log parameters
Minor and major compaction parameters
PX parameters
Cache parameters
Location cache parameters
Log parameters
Partition parameters
Read/write and query parameters
RootService parameters
Concurrency parameters
I/O parameters
TCP parameters
RPC security parameters
Other parameters
Unsupported parameters
Tenant-level parameters
User logon parameters
Audit parameters
Transaction and transaction log parameters
Minor and major compaction parameters
Encryption parameters
PL parameters
Compatibility parameters
Read/write and query parameters
Routing parameters
Other parameters
Unsupported parameters