Note that for parameters of the Boolean type in the following table, the value 0 indicates False and the value 1 indicates True.
Cluster parameters
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| init_log_level |
The initial log level at startup. |
ALL.*:INFO;SHARE.SCHEMA:INFO |
No |
The initial log level is used to generate more detailed logs. The log level is changed to the specified log_level after startup. |
| log_level |
The log level after startup. |
ALL.*:INFO;SHARE.SCHEMA:WARN |
Yes |
/ |
| max_log_file_count |
The maximum number of log files. |
0 |
No |
The value must be greater than or equal to 0. If the value is 0, the number of logs is not restricted. If you change the value to a smaller one, restart OceanBase Change Data Capture (obcdc) for the configuration to take effect. |
| enable_log_limit |
Specifies whether to enable log throttling. |
1 |
Yes |
The value 1 specifies to enable log throttling. The value 0 specifies to disable log throttling. |
| rootserver_list |
The RootService server specified at startup. |
\| |
Yes |
The information about each server must be in the format of server_ip:server_rpc_port:server_sql_port. |
| cluster_url |
The cluster URL specified at startup. |
\| |
No |
If OceanBase Database has a cluster URL, obcdc uses this URL to obtain the RootServer information. High availability is supported for servers. |
| cluster_user |
The username in the sys tenant. |
Empty (required, to be specified by the user) |
No |
Specify a user in the sys tenant. This user must have the read privilege on internal tables. |
| cluster_password |
The password of the preceding user. |
Empty (required, to be specified by the user) |
No |
/ |
| cluster_db_name |
The name of the database where the internal tables that obcdc queries reside. |
oceanbase |
No |
You do not need to modify the value. By default, internal tables are in the oceanbase database. |
| tenant_endpoint |
The list of servers where the tenant resides. |
\| |
No |
The information about each server must be in the format of host:sql_port. Separate the information about different servers with vertical bars (\|). |
| tenant_user |
The name of a user in the tenant. |
\| |
No |
The format is user_name@tenant_name or user_name@tenant_name#cluster. |
| tenant_password |
The password of the preceding user in the tenant. |
\| |
No |
/ |
| config_fpath |
The dump path of the configuration file. |
etc/liboblog.conf |
No |
All obcdc configuration information will be dumped into this file. |
| timezone |
The time zone of obcdc. |
+8:00 |
No |
This parameter specifies the time zone in which data is formatted and exported, which must be consistent with that of the data source. The default time zone is UTC+8. |
| timezone_info_path |
The directory where the timezone metadata file is located. |
etc/timezone_info.conf |
Yes |
When meta_data_refresh_mode is set to data_dict, the timezone_info.conf file in the RPM package must be placed in this directory. |
| skip_ob_version_compat_check |
Specifies whether to skip the OceanBase version compatibility check. |
0 |
No |
obcdc V3.x supports data synchronization with only OceanBase Database V2.x and V3.x. In addition, the obcdc version must be later than the OceanBase Database version. |
| cluster_version_refresh_interval_sec |
The interval for querying the earliest OBServer node version of the OceanBase cluster. |
600 |
No |
This parameter specifies the interval for refreshing the OceanBase cluster version, in seconds. |
| log_router_background_refresh_interval_sec |
The frequency for refreshing the log stream metadata. |
10 |
Yes |
This parameter specifies the interval, in seconds, for refreshing the corresponding server information at the backend for the log stream. |
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| working_mode |
The working mode. |
storage (commercial edition) |
No |
The transaction size must be controlled in business scenarios. If large transactions exist in business scenarios, use the persistence mode. We recommend that you deploy obcdc on the SSD in persistence mode. |
| store_service_path |
The path for storing data in persistence mode. |
./storage |
No |
This parameter is valid only in persistence mode.
Relative path: The persistent data is stored in a relative path in the path of the process that calls obcdc.
Absolute path: The persistent data is stored in the specified absolute path, such as store_service_path=/data/1. |
Synchronization granularity
obcdc supports data synchronization in multiple dimensions. A single obcdc instance can synchronize the data of one cluster, one or more tenants, several databases, and several tables.
| Synchronization granularity |
Single obcdc instance |
Multiple obcdc instances |
| Cluster |
Supported (A single obcdc instance does not support the data of multiple clusters.) |
Supported |
| Tenant |
Supported |
Supported |
| Database |
Not supported |
Not supported |
| Table |
Not supported |
Not supported (For more information, see the following multi-instance-related parameters.) |
If the traffic in the tenant is heavy, a single obcdc instance may fail to synchronize the data of the entire cluster in real time. In this case, you can use multiple obcdc instances to share the load, with each instance synchronizing the data of a different tenant.
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| enable_white_black_list |
Specifies whether to enable the allowlist and blocklist feature in obcdc. |
1 |
No |
By default, the allowlist and blocklist feature is enabled, with the allowlist and blocklist parameters being effective. If you disable the allowlist and blocklist feature, all data of the tenants included in the allowlist is synchronized. |
| tb_white_list |
The allowlist of the tables to be synchronized. |
*.*.* |
No |
The information about each table must be in the format of tenant name.database name.table name, for example, mytenant1.db1.tb1\|mytenant2.db2.\*. |
| tb_black_list |
The blocklist of tables not to be synchronized. |
\| |
No |
The format is the same as above. |
| tablegroup_white_list |
The allowlist of table groups to be synchronized. |
*.* |
No |
The information about each table group must be in the format of tenant name.table group name, for example, mytenant1.\*\|or_tenant\*.tg\*. |
| tablegroup_black_list |
The blocklist of table groups not to be synchronized |
\| |
No |
The format is the same as above. |
| enable_filter_sys_tenant |
Specifies whether to filter synchronization data of the sys tenant. |
0 |
No |
Enable this option when the sys tenant is abnormal but the user tenants are normal. |
Note
obcdc provides data filtering capabilities based on table and table group allowlists and blocklists.
- Only the tables and table groups in the allowlist but not in the blocklist will be synchronized. By default, all tables and table groups in all tenants are in the allowlist, and the blocklist is empty. We recommend that you configure an allowlist for the production environment to synchronize data of specified tenants. Do not use the default values, which may pull redundant data.
- The fnmatch function is used to match tables and table groups based on regular expressions. By default, case sensitivity is disabled for matching tables and table groups. You can set `enable_oracle_mode_match_case_sensitive` to `1` to enable case sensitivity for tenants in Oracle mode.
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| instance_num |
The total number of obcdc instances. |
1 |
No |
/ |
| instance_index |
The index of the current obcdc instance to the total number of obcdc instances (which can be understood as the hash bucket ID). |
0 |
No |
The value range is [0, instance_num). Each obcdc instance processes only the data of the log streams that match the following formula: hash(tenant_id, ls_id) % instance_num = instance_index. |
| enable_global_unique_index_belong_to_multi_instance |
Specifies whether to synchronize tables with globally unique indexes in multi-instance scenarios. |
0 |
Yes |
The value 0 specifies not to synchronize tables with globally unique indexes in multi-instance scenarios. |
Throttling
To prevent out-of-memory (OOM) issues caused by data heaping in the memory in the case of exceptions, obcdc provides throttling capabilities. Throttling is triggered based on the internal status of obcdc. Data pulling stops during throttling and resumes when obcdc becomes normal. The following table describes the throttling control parameters. You can modify them to adjust the throttling level as needed.
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| memory_limit |
The memory limit for triggering throttling. |
20G |
Yes |
It is one of the throttling metrics. obcdc tries to keep the memory usage within the specified value of memory_limit. However, it does not restrict obcdc from using memory higher than memory_limit. The minimum value is 2G. |
| memory_usage_warn_threshold |
The ratio of the memory usage to the value of the memory_limit parameter for triggering log pull throttling. |
85 |
Yes |
/ |
| system_memory_avail_percentage_lower_bound |
The lower limit of available system memory, in percentage. |
10 |
Yes |
The value range is [10, 80]. |
| part_trans_task_active_count_upper_bound |
The maximum number of active partition transactions. |
200000 |
Yes |
This parameter specifies the number of active partition transaction structs in memory (allocated and not recycled). |
| storager_task_count_upper_bound |
The throttling threshold of the number of tasks for storager to persist. |
1000 |
Yes |
The minimum value is 1. |
| storager_mem_percentage |
The percentage of memory used by the persistence module in the throttling memory. |
1 |
Yes |
The value 0 specifies automatic adjustment. |
| part_trans_task_reusable_count_upper_bound |
The maximum number of partition transactions to reuse. |
10240 |
Yes |
This parameter specifies the sum of tasks to be generated to the user queue, tasks to be generated by users, tasks to be returned by users, and tasks pending for garbage collection (GC). |
| ready_to_seq_task_upper_bound |
The maximum number of tasks to be sequenced. |
2000 |
Yes |
This parameter specifies the maximum number of tasks to be sequenced, including tasks pending for parsing, tasks pending for formatting, and tasks pending for persistence. |
| pause_fetcher |
Specifies whether to forcibly stop pulling logs. |
0 |
Yes |
The value 0 specifies to forcibly stop pulling logs regardless of the logical computing result of the throttling conditions. |
| direct_load_inc_thread_num |
The number of threads for reading and parsing incremental direct load logs. |
0 |
Yes |
This is a parameter used to limit memory usage. Its value can be automatically adapted based on the memory_limit parameter of obcdc or be manually modified for dynamic adjustment.
Notice
If you enable the incremental direct load feature and use obcdc for data synchronization, proceed with caution when adjusting this parameter. Otherwise, the memory usage limit may be exceeded.
|
| direct_load_inc_queue_backlog_lowest_tolerance |
The task backlog threshold for triggering throttling. |
0 |
Yes |
This is a parameter used to limit memory usage. Its value can be automatically adapted based on the memory_limit parameter of obcdc or be manually modified for dynamic adjustment.
Notice
If you enable the incremental direct load feature and use obcdc for data synchronization, proceed with caution when adjusting this parameter. Otherwise, the memory usage limit may be exceeded.
|
The reference throttling conditions are as follows:
- Condition 1: The number of active partitions exceeds the threshold specified by
part_trans_task_active_count_upper_bound. || The memory held by obcdc exceeds the threshold specified by memory_limit. || The available memory of the system is lower than the threshold specified by system_memory_avail_percentage_lower_bound.
- Condition 2: The number of partition transaction structures to be reused exceeds the threshold specified by
part_trans_task_reusable_count_upper_bound. || The number of tasks to be sequenced exceeds the threshold specified by ready_to_seq_task_upper_bound.
- Condition 3 (since OceanBase Database V3.x): The number of tasks to be persisted exceeds the threshold specified by
storager_task_count_upper_bound. && The memory held by obcdc exceeds the throttling triggering threshold (memory_limit) multiplied by the percentage of memory used by the persistence module in the throttling memory (storager_mem_percentage).
Throttling triggering condition: ((Condition 1 && Condition 2) || Condition 3) || (pause_fetcher != 0).
The following table shows the automatic adjustment strategy for the direct_load_inc_thread_num and direct_load_inc_queue_backlog_lowest_tolerance parameters.
| memory_limit |
2G |
4G |
8G |
16G |
32G |
128G |
| direct_load_inc_thread_num |
1 |
1 |
1 |
2 |
3 |
5 |
| direct_load_inc_queue_backlog_lowest_tolerance |
4096 |
8192 |
16384 |
32768 |
65536 |
131072 |
When the available memory is sufficient, increase direct_load_inc_thread_num to speed up the reading and parsing of incremental direct load logs, and increase direct_load_inc_queue_backlog_lowest_tolerance. When the available memory is insufficient, decrease direct_load_inc_thread_num and direct_load_inc_queue_backlog_lowest_tolerance or keep their default values.
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| enable_dump_pending_trans_info |
Specifies whether to regularly collect and print statistics on the status of distributed transactions in obcdc. |
0 |
Yes |
The value 0 specifies not to regularly collect and print statistics on the status of distributed transactions in obcdc. If the value is set to 1, the statistics are printed once every 10 seconds. |
| print_fetcher_slowest_ls_num |
The number of partitions with the lowest log-pulling speed. |
10 |
Yes |
/ |
| print_rpc_handle_info |
Specifies whether to print information related to remote procedure calls (RPCs). |
0 |
Yes |
The value 0 specifies not to print RPC-related information. |
| print_stream_dispatch_info |
Specifies whether to print the log stream information. |
0 |
Yes |
The value 0 specifies not to print the log stream information. |
| print_ls_heartbeat_info |
Specifies whether to print partition heartbeat information. |
0 |
Yes |
The value 0 specifies not to print partition heartbeat information. |
| print_ls_serve_info |
Specifies whether to print the partition service information, such as the partition status and the number of transactions of the partition. |
0 |
Yes |
The value 0 specifies not to print the partition service information, such as the partition status and the number of transactions of the partition. |
| print_participant_not_serve_info |
Specifies whether to print the information about all transactions that are not in service (no data is generated) for the distributed transaction. |
0 |
Yes |
The value 0 specifies not to print the information about all transactions that are not in service (no data is generated) for the distributed transaction. |
| print_ls_server_list_update_info |
Specifies whether to print the details of the servers when the list of partition servers is updated. |
0 |
Yes |
The value 0 specifies not to print the details of the servers when the list of partition servers is updated. |
| enable_formatter_print_log |
Specifies whether to enable formatter to generate logs whose formatting data is omitted. |
0 |
Yes |
The value 0 specifies not to enable formatter to generate logs whose formatting data is omitted. |
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| enable_direct_load_inc |
Specifies whether to synchronize data imported in incremental direct load mode. |
0 |
No |
In V4.3.1, data imported in incremental direct load mode is not synchronized by default. |
| enable_output_virtual_generated_column |
Specifies whether to output virtual generated columns. |
0 |
No |
This parameter must be used in conjunction with enable_output_by_table_def.
Note
For OceanBase Database V4.3.x, this parameter was introduced in V4.3.5 BP5. That is, when OceanBase Database is of V4.3.5 BP5 or later V4.3.x series, CDC supports outputting virtual generated columns.
|
obcdc V4.1 can obtain metadata such as information about schemas and log streams from data dictionaries, without the need to pull logs from OBServer nodes by using RPCs.
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| meta_data_refresh_mode |
The mode for obtaining metadata such as information about schemas and log streams. |
online |
No |
- online mode: obcdc queries OBServer nodes for schema information by using SchemaService. In this mode, obcdc must be able to access OBServer nodes.
- data_dict mode: obcdc parses schema information based on the data dictionaries in logs.
|
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| skip_rename_tenant_ddl |
Specifies whether to ignore DDL statements that rename a tenant. |
0 |
Yes |
The renamed tenant is not affected if it is not included in the obcdc synchronization allowlist. Otherwise, an error message is displayed and the process is terminated. This is because the rename operation overruns the allowlist restriction. In this case, we recommend that you modify the allowlist to support the tenants before and after the rename operation. When the value is set to true, the system will skip the DDL statements of the renamed tenant and continue the data synchronization. |
| enable_oracle_mode_match_case_sensitive |
The case sensitivity of tenants against the blocklist or allowlist in the Oracle mode of OceanBase Database. |
0 |
No |
/ |
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| ls_count_upper_limit |
The number of partition progress values. |
2000000 |
No |
A maximum of 200 million partitions are supported. |
| check_switch_server_interval_min |
The interval, in minutes, of periodic partition check for the necessity of switching log-pulling servers. |
30 |
Yes |
/ |
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| access_systable_helper_thread_num |
The maximum number of connections in the connection pool for SQL execution. |
64 |
No |
The value range is [48, 1024]. |
| rs_sql_connect_timeout_sec |
The timeout period for SQL connections of the RootService. |
40 |
Yes |
/ |
| rs_sql_query_timeout_sec |
The timeout period for SQL requests of the RootService. |
30 |
Yes |
/ |
| tenant_sql_connect_timeout_sec |
The timeout period for SQL connections of a tenant. |
40 |
Yes |
/ |
| tenant_sql_query_timeout_sec |
The timeout period for SQL requests of a tenant. |
30 |
Yes |
/ |
| sql_server_change_interval_sec |
The time interval, in seconds, for changing the SQL execution server. |
60 |
Yes |
/ |
Filter data based on cluster_id
obcdc allows you to filter data based on the cluster_id blocklist. Although OceanBase Database specifies a valid cluster_id range, you can specify the cluster_id values to filter out the following unwanted data in a synchronization task. For more information about how to configure cluster_id values, see ob_org_cluster_id.
- The data that is not included in the valid
cluster_id range specified by OceanBase Database and OceanBase Migration Service (OMS). The value range is [1, 4294901759] U [4294901760, 4294967295].
- The data whose
cluster_id is specified in the cluster_id_black_list field.
- Each cluster ID in the
cluster_id_black_list field must range from cluster_id_value_min to cluster_id_value_max.
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| cluster_id_black_list |
The blocklist of cluster IDs. |
\| |
No |
Separate multiple cluster IDs with vertical bars (\|). Each cluster ID ranges from cluster_id_value_min to cluster_id_value_max. |
| cluster_id_black_value_min |
The lower limit of cluster IDs in the synchronization blocklist. |
2147473648 |
No |
/ |
| cluster_id_black_value_min |
The upper limit of cluster IDs in the synchronization blocklist. |
2147483647 |
No |
/ |
obcdc can send SQL and RPC requests to OBServer nodes. OceanBase Database provides parameters that allow you to block all requests sent to specific servers.
In addition, as obcdc pulls logs at the partition level, a built-in blocklist is provided to add servers that have timed out or errors when pulling partition logs to the blocklist. Servers are automatically added to or removed from the blocklist.
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| server_blacklist |
A blocklist of OBServer nodes that are blocked from receiving RPC requests from obcdc. |
\| |
Yes |
The information about each OBServer node must be in the format of svr_ip:rpc_port. Separate the information about multiple OBServer nodes with vertical bars (\|). Logs are not pulled from the OBServer nodes in the blocklist. When an OBServer node cannot provide log services due to reasons such as network partitioning and high latency, you can manually add the node to the blocklist. |
| sql_server_blacklist |
A blocklist of OBServer nodes that are blocked from receiving SQL requests from obcdc. |
\| |
Yes |
The information about each OBServer node must be in the format of svr_ip:rpc_port. Separate the information about multiple OBServer nodes with vertical bars (\|). |
Partition-level blocklist parameters (generally not modified)
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| blacklist_survival_time_sec |
The waiting time, in seconds, of servers in the blocklist. |
30 |
No |
/ |
| blacklist_survival_time_upper_limit_min |
The maximum period, in minutes, of servers in the blocklist. |
4 |
Yes |
/ |
| blacklist_survival_time_penalty_period_min |
The penalty time interval threshold, in minutes. If a server is added to the blocklist again within this time interval, the time for the server to stay in the blocklist is doubled. |
1 |
Yes |
/ |
| blacklist_history_overdue_time_min |
The period, in minutes, after which a server is deleted from the blocklist history. |
30 |
Yes |
The minimum value is 10. |
| blacklist_history_clear_interval_min |
The time interval, in minutes, for clearing the information about servers in the blocklist. |
20 |
Yes |
The minimum value is 10. |
| Parameter |
Description |
Default value |
Real-time modification supported |
| all_server_cache_update_interval_sec |
The time interval, in seconds, for updating the cached list of servers. |
5 |
Yes |
| all_zone_cache_update_interval_sec |
The time interval, in seconds, for updating the cached zone information. |
5 |
Yes |
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| idle_pool_thread_num |
The number of threads that process the pending partition-level log-pulling tasks. |
4 |
No |
The value range is [1, 32]. |
| dead_pool_thread_num |
The number of threads that recycle the partition-level log-pulling tasks. |
1 |
No |
The value range is [1, 32]. |
| stream_worker_thread_num |
The number of threads that dispatch the partition-level log-pulling tasks. |
8 |
No |
The value range is [1, 64]. |
| start_lsn_locator_thread_num |
The number of threads that locate the ID of the starting partition log. |
4 |
No |
The value range is [1, 32]. |
| lob_data_merger_thread_num |
The number of threads that process large object (LOB) data. |
2 |
No |
The value rang is [1, +∞). |
| start_lsn_locator_locate_count |
The number of requests that complete the task of locating the starting partition log. |
1 |
N |
The minimum value is 1. To locate the ID of the starting partition log, the follower partitions of the specified number must return the same starting log ID. |
| skip_start_lsn_locator_result_consistent_check |
Specifies whether to skip checking the consistency of the starting log ID. |
No |
No |
/ |
| svr_stream_cached_count |
The initial size of the object pool of the server log stream. |
16 |
No |
The minimum value is 1. |
| fetch_stream_cached_count |
The initial number of logs in the object pool of the partition log stream. |
16 |
No |
The minimum value is 1. |
| start_lsn_locator_rpc_timeout_sec |
The timeout period, in seconds, of RPC requests for locating the starting partition log ID. |
60 |
Yes |
The minimum value is 1. |
| start_lsn_locator_batch_count |
The batch number of the RPC requests for locating the starting partition log ID. |
2000 |
Yes |
The minimum value is 1. |
| heartbeat_interval_sec |
The time interval, in seconds, to send RPC requests for partition heartbeats. |
1 |
Yes |
The minimum value is 1. |
| fetch_log_rpc_timeout_sec |
The timeout period, in seconds, of RPC requests for pulling partition logs. |
15 |
Yes |
The minimum value is 1. |
| progress_limit_sec_for_dml |
The maximum number of logs that can be pulled for DML operations. |
300 |
Yes |
The minimum value is 1. Log-pulling in some partitions can be much faster than others. To ensure that the log-pulling progress is roughly at the same pace across partitions, the maximum number of DML logs that can be provided by the server is limited to the sum of the minimum number of pulled logs among all partitions and the value of the progress_limit_sec_for_dml parameter. |
| ls_fetch_progress_update_timeout_sec |
The timeout threshold, in seconds, of RPC requests for pulling partition logs. |
3 |
Yes |
The minimum value is 1. |
| ls_fetch_progress_update_timeout_sec_for_lagged_replica |
The timeout threshold, in seconds, of pulling logs from the lagged replica. |
15 |
Yes |
The minimum value is 1. |
| enable_continue_use_cache_server_list |
Specifies whether to use the server information in the cache. |
0 |
No |
Enable this option when the sys tenant is abnormal but the user tenants are normal. |
| fetching_log_mode |
The log pulling mode. |
integrated |
No |
- integrated mode: This is the default log pulling mode in which obcdc sends RPC requests to an OBServer node to pull logs. In this case, you must configure the address (
cluter_url or rootserver_list) of the OBServer node and the username (cluster_user) and password (cluster_password) in the sys tenant.
- direct mode: In this mode, obcdc directly consumes archived logs without the need to send RPC requests to the OBServer node to pull logs. In this case, you must configure the archive destination in the form of a Network File System (NFS) path or Object Storage Service (OSS) information. For more information about the archive destination, see Overview of log archiving. The server where obcdc is located must be able to directly access the archive destination.
Notice
obcdc cannot pull discontinuous archived logs.
|
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| region |
The region from which obcdc preferentially pulls logs. |
default_region |
Yes |
The region is queried from the internal table of OceanBase Database. obcdc preferentially pulls logs from OBServer nodes in the specified region. |
| Parameter |
Description |
Default value |
Value range |
Real-time modification supported |
| io_thread_num |
The number of I/O threads for RPC requests. |
4 |
[1, +∞) |
No |
| rpc_result_cached_count |
The initial number of pulled logs in the object pool of RPC requests for pulling logs. |
16 |
[1, +∞) |
No |
| rpc_process_handler_time_upper_limit_msec |
The maximum time, for processing an RPC request. |
200 |
[1, +∞) |
Yes |
| rpc_result_count_per_rpc_upper_limit |
The maximum number of unprocessed results of the log-pulling RPC request in a log stream. |
16 |
[1, +∞) |
Yes |
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| ssl_client_authentication |
Specifies whether to enable secure communication. |
0 |
No |
The default value is 0, which specifies to disable secure communication. |
| ssl_external_kms_info |
The secure communication method. |
file |
No |
For external communication, only the file mode is supported. You must create a wallet directory in the boot directory of obcdc, and put the following key file in the wallet directory: ca.pem/client-cert.pem/client-key.pem. |
| Parameter |
Description |
Default value |
Value range |
Real-time modification supported |
| sequencer_thread_num |
The number of threads in the thread pool for sequencing distributed transactions. |
5 |
[1, +∞) |
No |
| sequencer_queue_length |
The number of partition transactions waiting to be sequenced. |
102400 |
[1, +∞) |
No |
| Parameter |
Description |
Default value |
Value range |
Real-time modification supported |
| redo_dispatched_memory_limit_exceed_ratio |
Specifies the size limit of the redo logs to be processed when enable_output_trans_order_by_sql_operation is set to 1. To be specific, the size of the redo logs allowed to be processed in the memory is redo_dispatched_memory_limit_exceed_ratio * redo_dispatcher_memory_limit. |
2 |
[1, +∞) |
Yes |
| redo_dispatcher_memory_limit |
The size limit of the redo logs to be processed. |
512 MB |
[128 MB, +∞) |
Yes |
| extra_redo_dispatch_memory_size |
The extra redo size allocated to skew participants to avoid deadlocks, which may cause obcdc not to generate data in a data skew scenario. |
4 MB |
[0 MB, 512 MB] |
Yes |
| Parameter |
Description |
Default value |
Value range |
Real-time modification supported |
| msg_sorter_task_count_upper_limit |
The maximum number of tasks for the row data sorting module in a transaction. |
200000 |
[1, +∞) |
No |
| msg_sorter_thread_num |
The total number of threads for the row data sorting module in a transaction. |
1 |
[1, 32] |
No |
Parameters valid only in persistence mode
| Parameter |
Description |
Default value |
Real-time modification supported |
| storager_thread_num |
The number of threads in the thread pool of the storager module. |
10 |
No |
| storager_queue_length |
The number of tasks to be persisted. |
102400 |
No |
| Parameter |
Description |
Default value |
Real-time modification supported |
| reader_thread_num |
The number of threads in the thread pool for reading data from the storager module. |
10 |
No |
| reader_queue_length |
The number of data deserialization tasks waiting to be processed. |
102400 |
No |
| Parameter |
Description |
Default value |
Value range |
Real-time modification supported |
| batch_buf_count |
The number of memory buffers for batch redo log persistence. |
10 |
[5, +∞) |
No |
| batch_buf_size |
The size of a memory buffer for batch redo log persistence. |
20 MB |
[2 MB, +∞) |
No |
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| dml_parser_thread_num |
The number of threads in the thread pool for parsing DML statements. |
5 |
No |
The minimum value is 1. |
| ddl_parser_thread_num |
The number of threads in the thread pool for parsing DDL statements. |
1 |
No |
The minimum value is 1. |
| skip_reversed_schema_version |
Specifies whether to ignore schema version rollback. |
0 |
No |
Generally, the schema version monotonically increases during the processing of DDL statements. The rollback of the schema version indicates an exception. However, you can use this parameter to skip the exception. |
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| formatter_thread_num |
The number of threads in the thread pool for data formatting. |
10 |
No |
The minimum value is 1. |
| skip_dirty_data |
Specifies whether to skip data exceptions. |
0 |
Yes |
Current exceptions:
- Non-full column logging. This means that commit logs (clogs) recorded only columns that have been changed. Parameter:
binlog_row_image.
- Exceptions in DDL statements of the tenant restored from a physical backup.
|
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| enable_output_trans_order_by_sql_operation |
Specifies whether to generate data rows in the transaction in the order that the SQL statements are executed. |
0 |
No |
The execution order refers to the order in which OceanBase Database makes changes to the data. It may not be the same as the order in which the SQL statements are sent from the client. |
| sort_trans_participants |
Specifies whether to sort SQL statements by the distributed transaction participants. |
1 |
No |
The parameter specifies whether to sort statements by the partition key. You can maintain a stable statement output sequence by using this parameter together with the enable_output_trans_order_by_sql_operation parameter. |
| enable_output_hidden_primary_key |
Specifies whether to generate the hidden primary keys of tables without primary keys. |
0 |
No |
You can generate the hidden primary keys of tables without primary keys by setting the parameter value to 1. |
| enable_convert_timestamp_to_unix_timestamp |
Specifies whether to convert a timestamp to an integer in the Unix format. |
0 |
No |
/ |
| enable_output_invisible_column |
Specifies whether to generate the hidden columns. |
0 |
No |
/ |
| enable_output_by_table_def |
Controls whether to output columns in the order specified by the user. |
0 |
No |
/ |
| output_heartbeat_interval_msec |
The time interval, for generating the information about security timestamps. |
1000 |
Yes |
/ |
| Parameter |
Description |
Default value |
Real-time modification supported |
Remarks |
| resource_collector_thread_num |
The number of threads in the thread pool for recycling resources. |
10 |
No |
The minimum value is 1. |
| resource_collector_thread_num_for_br |
The number of threads in the thread pool for recycling binlog records. |
7 |
No |
The value of this parameter must be larger than that of the resource_collector_thread_num parameter. |
Notice
We recommend that you do not modify the parameters that are not listed in this topic.
