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OceanBase MySQL Migration Synchronization to StarRocks

NineData data replication supports data synchronization between OceanBase MySQL and StarRocks data sources. It supports structure, full volume, and incremental synchronization.

Prerequisites​

  • The source and target data sources have been added to NineData. For instructions on how to add data sources, see Adding Data Sources.
  • The source database type is OceanBase MySQL.
  • The target data source type is StarRocks.

Usage Limitations​

  • Before performing data synchronization, it is necessary to assess the performance of the source and target data sources, and it is recommended to perform data synchronization during off-peak business hours. Otherwise, the full volume data initialization will occupy a certain amount of read and write resources of the source and target data sources, leading to increased database load.
  • It is necessary to ensure that each table in the synchronization object has a primary key or unique constraint, and the column names are unique; otherwise, the same data may be synchronized repeatedly.

Operation Steps​

  1. Log in to the NineData Console.

  2. Click on Replication in the left navigation bar.

  3. On the Replication page, click on the Create Replication in the top right corner.

  4. On the Source & Target tab, configure according to the table below, and click on Next.

    Parameter
    		Description
    NameEnter the name of the data synchronization task. For easy retrieval and management, use a meaningful name, up to 64 characters.
    SourceThe data source where the sync object is located.
    TargetThe data source that receives the sync object.
    TypeChoose the content to be copied to the target data source.
    • Schema: Only syncs the table structure of the source data source, without syncing data.
    • Full: Syncs all objects and data from the source data source, i.e., full data replication. The switch on the right is for toggling periodic full replication. For more information, please refer to Periodic Full Replication.
    • Incremental: After full sync, perform incremental sync based on the log of the source data source. The setting icon represents incremental operation type configuration (not supported by some replication links). You can deselect certain operation types as needed. Once deselected, these operations will be ignored during incremental synchronization.
    Target Table Preparation
    • If target table already exists (selected when Schema is selected)
      • Pre-Check Error and Stop Task: Stop the task when a table with the same name is detected during precheck.
      • Skip and Continue Task: Send a prompt when a table with the same name is detected during precheck and continue the task. During structure replication, ignore this table with the same name. If you are also performing data replication, data will be appended to this table with the same name without overwriting existing data.
      • Delete Objects and Rewrite: Send a prompt when a table with the same name is detected during precheck and continue the task. During structure replication, delete the table with the same name in the target database and replicate the table structure based on the source database. If you are also performing data replication, data will be written after the table structure replication is completed.
      • Keep Schema and Clear Data, then Rewrite (optional when performing both structure and data replication): Send a prompt when a table with the same name is detected during precheck and continue the task. During structure replication, keep the table structure in the target database and, when data replication starts, clear the data in the table with the same name and then replicate from the original table.
    • Target Table Exists Data (required when Schema is not selected)
      • Pre-Check Error and Stop Task: Stop the task when data exists in the target table during precheck.
      • Ignore the existing data and append : Ignore this part of the data when data is detected in the target table during precheck and append other data.
      • Clear the existing data before write: Delete this part of the data when data is detected in the target table during precheck and rewrite it.

  5. On the Objects tab, configure the following parameters, and then click on Next.

    Parameter
    		Description
    Replication ObjectsChoose what to copy. You can choose All Objects to copy all contents of the source database, or choose Customized Object to select the contents to be copied in the Source Object list and click > to add them to the right Target Object list.

    If you need to create multiple identical replication links, you can create a configuration file and import it when creating a new task. Click Import Config at the top right corner, then click Download Template to download the configuration file template to your local machine. After editing, click Upload to upload the configuration file for batch import.

    Parameter
    		Description
    source_table_nameName of the source table containing the objects to be synchronized.
    destination_table_nameName of the target table receiving the synchronized objects.
    source_schema_nameName of the source schema containing the objects to be synchronized.
    destination_schema_nameName of the target schema receiving the synchronized objects.
    source_database_nameName of the source database containing the objects to be synchronized.
    target_database_nameName of the target database receiving the synchronized objects.
    column_listList of columns to be synchronized.
    extra_configurationAdditional configuration information can be set here:
    • column_rules: Used to define column mapping and value rules. Field descriptions:
      • column_name: Original column name.
      • destination_column_name: Target column name.
      • column_value: Value to assign, which can be an SQL function or a constant.
    • filter_condition: Used to specify row-level filtering conditions; only rows that meet the criteria will be copied.
    tip

    • An example of the extra_configuration content is as follows:

      {
        "extra_config": {
          "column_rules": [
            {
              "column_name": "created_time", // Original column name to map.
              "destination_column_name": "migrated_time", // Target column name mapped to "migrated_time".
              "column_value": "current_timestamp()" // Change the column value to the current timestamp.
            }
          ],
          "filter_condition": "id != 0" // Only rows where ID is not 0 will be synchronized.
        }
      }

    • For a complete example of the configuration file, refer to the downloaded template.

  6. On the Mapping tab, select different actions based on the selected replication type. If updates occur in the source and target data sources during the configuration mapping phase, you can click the Refresh Metadata button in the upper right corner of the page to refresh the information of the source and target data sources.

    • Includes Schema: Configure the table name after the target table is synchronized to the target data source, and click Save and Pre-Check.

    • Excludes Schema: The system automatically selects the same name database in the target data source by default. If it does not exist, you need to manually select the target database. The table names and column names in the target database need to be consistent with the sync objects. If they are not consistent, you can manually map the table names and column names.

    You can also perform the following operations:

    • Click on the on the right side of the page to customize the column names after they are synchronized to the target data source.

    • On the page, click on , and configure the filtering conditions through comparison expressions. Only data that meets the filtering conditions will be synchronized to the target data source. For example, if you set the filtering condition to emp_no>=10005, then data in the emp_no column that is less than 10005 will not be synchronized to the target data source.

    • Click on the replace_tablename icon next to to search for table names and replace them with target names.

    • Enter the table name in the text box at the top right to quickly locate the target table.

    • Click in the upper right corner to define general rules in bulk (such as converting table and column name case, adding prefixes or suffixes, replacements, etc.), enabling unified mapping configuration for a large number of tables and columns.

  7. On the Pre-check tab, wait for the system to complete the precheck. After the precheck passes, click on Launch.

    tip
    • You can check Enable data consistency comparison. After the sync task is completed, automatically initiate data consistency comparison based on the source data source to ensure data consistency on both ends. Depending on your choice of Type, the timing of starting Enable data consistency comparison is as follows:
      • Schema: Initiated after structure replication is completed.
      • Schema + Full, Full: Initiated after full replication is completed.
      • Schema + Full + Incremental, Incremental: Initiated when the incremental data is first consistent with the source data source and Delay is 0 seconds. You can click on View Details to view the synchronization delay on the Details page. sync_delay
    • If the precheck fails, click on Details on the right side of the target check item to investigate the cause of the failure, manually fix it, and then click Check Again to re-execute the precheck until it passes.
    • Items in Result with Warning can be repaired or ignored depending on the specific situation.

  8. On the Launch page, when prompted with Launch Successfully, the sync task begins to run. At this point, you can perform the following operations:

    • Click on View Details to view the execution status of each stage of the sync task.
    • Click on Back to list to return to the Replication task list page.

View Synchronization Results​

  1. Log in to the NineData Console.

  2. Click on Replication > Data Replication in the left navigation bar.

  3. On the Replication page, click on the Task ID of the target synchronization task, the page details are as follows.

    result

    Number
    		Function
    		Description
    1Sync DelayThe data synchronization delay between the source data source and the target data source. 0 seconds means there is no delay between the two ends, at which point you can choose to switch the business to the target data source for smooth migration.
    2Configure AlertsAfter configuring alerts, the system will notify you in the way you choose when the task fails. For more information, please refer to Operations Monitoring Introduction.
    3More
    • Pause: Pause the task, only tasks with Running status are selectable.
    • Duplicate: Create a new replication task with the same configuration as the current task.
    • Terminate: End tasks that are unfinished or listening (i.e., in incremental synchronization). Once the task is terminated, it cannot be restarted, so please proceed with caution. If the synchronization objects contain triggers, a trigger replication option will pop up, please select as needed.
    • Delete: Delete the task. Once the task is deleted, it cannot be recovered, so please proceed with caution.
    4Structure Replication (displayed in scenarios involving structure replication)Displays the progress and detailed information of structure replication.
    • Click on Log on the right side of the page: View the execution logs of structure replication.
    • Click on refresh on the right side of the page: View the latest information.
    • Click on View DDL in the Actions column on the right side of the target object in the list: View SQL playback.
    5Full Replication (displayed in scenarios involving full replication)Displays the progress and detailed information of full replication.
    • Click on Monitor on the right side of the page: View various monitoring indicators during full replication. During full replication, you can also click on Flow Control Settings on the right side of the monitoring indicator page to limit the rate of writing to the target data source per second. The unit is rows/second.
    • Click on Log on the right side of the page: View the execution logs of full replication.
    • Click on refresh on the right side of the page: View the latest information.
    6Incremental Replication (displayed in scenarios involving incremental replication)Displays various monitoring indicators of incremental replication.
    • Click on View Threads on the right side of the page: View the operations currently being executed by the current replication task, including:
      • Thread ID: Replication tasks are executed in multiple threads, displaying the current thread number in progress.
      • Execute SQL: Details of the SQL statement currently being executed by the current thread.
      • Response Time: The response time of the current thread. If this value increases, it indicates that the current thread may be stuck for some reason.
      • Event Time: The timestamp when the current thread was started.
      • Status: The status of the current thread.
    • Click on Flow Control Settings on the right side of the page: Limit the rate of writing to the target data source per second. The unit is rows/second.
    • Click on Log on the right side of the page: View the execution logs of incremental replication.
    • Click on refresh on the right side of the page: View the latest information.
    7Modify ObjectDisplays the modification records of synchronization objects.
    • Click on Modify Objects on the right side of the page to configure the synchronization objects.
    • Click on refresh on the right side of the page: View the latest information.
    8Data ComparisonDisplays the comparison results between the source data source and the target data source. If you have not enabled data comparison, please click on Enable Comparison on the page.
    • Click on Re-compare on the right side of the page: Re-initiate the comparison between the current source and target data sources.
    • Click on Stop on the right side of the page: After the comparison task starts, you can click this button to stop the comparison task immediately.
    • Click on Log on the right side of the page: View the execution logs of consistency comparison.
    • Click on Monitor (displayed only in data comparison): View the trend chart of RPS (records per second) comparison. Click on Details to view earlier records.
    • Click on details in the Actions column on the right side of the comparison list (displayed under the Data tab only in the case of inconsistency): View details of the comparison between the source and target sides.
    • Click on sql in the Actions column on the right side of the comparison list (displayed only in the case of inconsistency): Generate change SQL. You can directly copy this SQL to the target data source to execute and modify the inconsistent content.
    9ExpandDisplay detailed information of the current replication task. Common Options:
    • Export table configuration: Export the current task's database and table configuration, allowing for quick import when creating a new replication task. This helps rapidly establish multiple replication links with the same replication objects.
    • Alert Rules: Configure the alarm strategy for the current task.

Appendix 1: Pre-Check Item List​

Check ItemCheck Content
Source Data Source Connection CheckCheck the gateway status of the source data source, whether the instance is reachable, and the accuracy of the username and password
Target Data Source Connection CheckCheck the gateway status of the target data source, whether the instance is reachable, and the accuracy of the username and password
Source Library Permission CheckCheck whether the account permissions of the source database meet the requirements

Appendix 2: Data Type Mapping Table​

CategoryOceanBase MySQL Data TypeStarRocks Data Type
NumericTINYINT TINYINT
TINYINT UNSIGNED SMALLINT
SMALLINT SMALLINT
SMALLINT UNSIGNEDINTEGER
MEDIUMINT INTEGER
MEDIUMINT UNSIGNED BIGINT
INT INTEGER
INT UNSIGNED BIGINT
BIGINT BIGINT
BIGINT UNSIGNEDLARGEINT
BIT(M) LARGEINT
DECIMAL() DECIMAL
NUMERIC DECIMAL
FLOATFLOAT
DOUBLEDOUBLE
BOOL，BOOLEANTINYINT
DATE AND TIMEDATEDATE
DATETIME[(fsp)] DATETIME
TIMESTAMP[(fsp)] DATETIME
TIME[(fsp)] STRING
STRINGYEAR[(4)] SMALLINT
CHAR
  • CHAR length*3 ≤ 255：CHAR(3*size)
  • CHAR length*3 > 255：VARCHAR(3*size)
VARCHAR VARCHAR(3*size)
BINARY/VARBINARY STRING
TINYTEXT/TEXT/MEDIUMTEXT/LONGTEXTVARCHAR[(maxSize)]
maxSize is the maximum length of the VARCHAR type, which varies by version as follows:
  • StarRocks version < 2.1.0：65533
  • StarRocks version ≥ 2.1.0：1048576
TINYBLOB/BLOB/MEDIUMBOLB/LONGBLOBSTRING
ENUM STRING
SETSTRING
JSONJSON JSON
SPATIALGEOMETRYSTRING
GEOMCOLLECTION/GEOMTRYCOLLECTIONSTRING
POINTSTRING
LINESTRINGSTRING
POLYGONSTRING
MULTIPOINTSTRING
MULTIPOLYGONSTRING
MULTILINESTRINGSTRING

Data Replication Introduction