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V4.2.2

What is ODP?
Installation and deployment
- Overview
- Use OBD to deploy ODP
- Deploy ODP by using OCP
- Deploy ODP by using the CLI
- Deployment modes
Basic operations
Configuration parameter
- View and modify parameters
- Parameter summary
- Parameters that take effect dynamically
  - binlog_service_ip
  - cache_cleaner_clean_interval
  - check_tenant_locality_change
  - client_max_connections
  - client_max_memory_size
  - client_sock_option_flag_out
  - client_tcp_keepcnt
  - client_tcp_keepidle
  - client_tcp_keepintvl
  - client_tcp_user_timeout
  - cluster_count_high_water_mark
  - cluster_expire_time
  - config_server_refresh_interval
  - congestion_fail_window
  - congestion_failure_threshold
  - congestion_retry_interval
  - connection_diagnosis_option
  - connect_observer_max_retries
  - current_local_config_version
  - default_buffer_water_mark
  - default_inactivity_timeout
  - delay_exit_time
  - delay_update_entry_interval
  - detect_server_timeout
  - digest_sql_length
  - enable_abort_conn_info
  - enable_async_log
  - enable_async_pull_location_cache
  - enable_bad_route_reject
  - enable_binlog_service
  - enable_cached_server
  - enable_causal_order_read
  - enable_client_connection_lru_disconnect
  - enable_client_ip_checkout
  - enable_client_ssl
  - enable_cloud_full_username
  - enable_cluster_checkout
  - enable_compression_protocol
  - enable_congestion
  - enable_connection_diagnosis
  - enable_extra_prometheus_metric
  - enable_flow_control
  - enable_full_username
  - enable_get_rslist_remote
  - enable_index_route
  - enable_monitor_stat
  - enable_ob_protocol_v2
  - enable_ob_protocol_v2_with_client
  - enable_partition_table_route
  - enable_performance_mode
  - enable_pl_route
  - enable_primary_zone
  - enable_prometheus
  - enable_proxy_scramble
  - enable_qa_mode
  - enable_qos
  - enable_read_write_split
  - enable_report_session_stats
  - enable_reroute
  - enable_sequence_prefetch
  - enable_server_ssl
  - enable_sharding
  - enable_standby
  - enable_stat
  - enable_strict_stat_time
  - enable_sync_all_stats
  - enable_syslog_file_compress
  - enable_trace
  - enable_trace_stats
  - enable_trans_detail_stats
  - enable_transaction_internal_routing
  - enable_transaction_split
  - enable_weak_reroute
  - enable_xa_route
  - fetch_proxy_bin_random_time
  - fetch_proxy_bin_timeout
  - flow_consumer_reenable_threshold
  - flow_event_queue_threshold
  - flow_high_water_mark
  - flow_low_water_mark
  - hot_upgrade_exit_timeout
  - hot_upgrade_failure_retries
  - hot_upgrade_rollback_timeout
  - idc_list_refresh_interval
  - ignore_local_config
  - internal_cmd_mem_limited
  - ldg_info_refresh_interval
  - log_cleanup_interval
  - log_dir_size_threshold
  - log_file_percentage
  - long_async_task_timeout
  - max_log_file_size
  - max_syslog_file_count
  - max_syslog_file_time
  - metadb_server_state_refresh_interval
  - min_congested_connect_timeout
  - min_keep_congestion_interval
  - monitor_cost_ms_unit
  - monitor_item_limit
  - monitor_item_max_idle_period
  - monitor_log_level
  - monitor_stat_dump_interval
  - monitor_stat_high_threshold
  - monitor_stat_low_threshold
  - monitor_stat_middle_threshold
  - mysql_version
  - need_convert_vip_to_tname
  - net_config_poll_timeout
  - normal_pl_update_threshold
  - ob_max_read_stale_time
  - obproxy_force_parallel_query_dop
  - obproxy_read_consistency
  - obproxy_read_only
  - obproxy_sys_password
  - observer_query_timeout_delta
  - observer_sys_password
  - observer_sys_password1
  - partition_location_expire_relative_time
  - prometheus_sync_interval
  - proxy_hot_upgrade_check_interval
  - proxy_idc_name
  - proxy_info_check_interval
  - proxy_local_cmd
  - proxy_mem_limited
  - proxy_primary_zone_name
  - proxy_route_policy
  - proxy_tenant_name
  - qa_mode_mock_public_cloud_slb_addr
  - qos_stat_clean_interval
  - qos_stat_item_limit
  - query_digest_time_threshold
  - read_stale_retry_interval
  - refresh_idc_list
  - refresh_json_config
  - refresh_rslist
  - request_buffer_length
  - route_diagnosis_level
  - routing_cache_mem_limited
  - sequence_entry_expire_time
  - sequence_fail_retry_count
  - sequence_prefetch_threshold
  - server_detect_fail_threshold
  - server_detect_mode
  - server_detect_refresh_interval
  - server_routing_mode
  - server_state_refresh_interval
  - server_tcp_init_cwnd
  - server_tcp_keepcnt
  - server_tcp_keepidle
  - server_tcp_keepintvl
  - server_tcp_user_timeout
  - short_async_task_timeout
  - skip_proxy_sys_private_check
  - skip_proxyro_check
  - slow_proxy_process_time_threshold
  - slow_query_time_threshold
  - slow_transaction_time_threshold
  - sock_option_flag_out
  - sock_packet_mark_out
  - sock_packet_tos_out
  - sock_recv_buffer_size_out
  - sock_send_buffer_size_out
  - sql_table_cache_expire_relative_time
  - sql_table_cache_mem_limited
  - sqlaudit_mem_limited
  - ssl_attributes
  - stat_dump_interval
  - stat_table_sync_interval
  - syslog_level
  - target_db_server
  - tenant_location_valid_time
  - tunnel_request_size_threshold
  - username_separator
  - xflush_log_level
- Parameters that take effect after a restart
  - automatic_match_work_thread
  - block_thread_num
  - enable_cpu_isolate
  - enable_cpu_topology
  - enable_global_ps_cache
  - enable_strict_kernel_release
  - grpc_client_num
  - grpc_thread_num
  - ip_listen_mode
  - listen_port
  - local_bound_ip
  - local_bound_ipv6_ip
  - net_accept_threads
  - obproxy_config_server_url
  - prometheus_cost_ms_unit
  - prometheus_listen_port
  - rootservice_cluster_name
  - rootservice_list
  - shard_scan_thread_num
  - stack_size
  - task_thread_num
  - work_thread_num
Connection management
- Principles
- Session status synchronization
- Client session
- Server session
- Connection diagnostics
Data routing
- Factors affecting data routing
- ODP routing
- Intra-tenant routing
  - Overview
  - IP address-based routing
  - Partitioned table-based routing for strong-consistency reads
  - Global index table-based routing for strong-consistency reads
  - Replication table-based routing for strong-consistency reads
  - Primary zone-based routing for strong-consistency reads
  - Strategy-based routing
  - Distributed transaction routing
  - Rerouting
  - Forcible routing
- Read/Write separation
- Follower latency threshold
High availability mechanism
- Overview
- High availability of ODP services
- High availability of OceanBase Database
- High availability testing
Security and protocols
Operation and maintenance
- Troubleshooting
  - Troubleshooting logic
  - Monitoring logs
- Performance analysis
- Show Trace
- Routing diagnostics
  - Overview
  - Obtain diagnostic information
  - Diagnostic point troubleshooting
    - Overview
    - SQL_PARSE
    - ROUTE_INFO
    - LOCATION_CACHE_LOOKUP
    - ROUTINE_ENTRY_LOOKUP_DONE
    - FETCH_TABLE_RELATED_DATA
    - TABLE_ENTRY_LOOKUP_DONE
    - EXPR_PARSE
    - CALC_ROWID
    - RESOLVE_TOKEN
    - RESOLVE_EXPR
    - CALC_PARTITION_ID
    - PARTITION_ID_CALC_DONE
    - PARTITION_ENTRY_LOOKUP_DONE
    - ROUTE_POLICY
    - CONGESTION_CONTROL
    - RETRY
    - HANDLE_RESPONSE
  - Examples
Release Notes
- Versioning rules
- Enterprise Edition
  - V4.2
    - ODP Enterprise Edition V4.2.2
    - ODP Enterprise Edition V4.2.1
  - V4.1
    - ODP Enterprise Edition V4.1.0
  - V4.0
    - ODP Enterprise Edition V4.0.0
  - V3.2
    - ODP V3.2.11
    - ODP Enterprise Edition V3.2.3.5
- Community Edition
  - V4.2
    - ODP Community Edition V4.2.1
    - ODP Community Edition V4.2.0
  - V4.1
    - ODP Community Edition V4.1.0
  - V4.0
    - ODP Community Edition V4.0.0

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sequence_prefetch_threshold

Last Updated：2026-04-14 09:41:35 Updated

sequence_prefetch_threshold specifies the maximum cost for triggering prefetch. A prefetch is triggered when the cost reaches the specified threshold.

Attribute	Description
Parameter type	Integer
Default value	7000
Value range	[0, 10000]

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