Creating an Entire Database Migration Job

Scenario

CDM supports entire DB migration between homogeneous and heterogeneous data sources. The migration principles are the same as those in Table/File Migration Jobs. Each type of Elasticsearch, each key prefix of Redis, or each collection of MongoDB can be executed concurrently as a subtask.

Each time an entire DB migration job is executed, its subtasks are recreated based on the configuration of the migration job. You cannot modify the subtasks and then run the migration job again.

Supported Data Sources lists the data sources supporting entire database migration.

Constraints

Field names of the source and destination parameters cannot contain ampersands (&) or number signs (%).

Prerequisites

• A link has been created. For details, see Creating a Link.

• The CDM cluster can communicate with the data source.

Procedure

1. Log in to the management console and choose Service List > Cloud Data Migration. In the left navigation pane, choose Cluster Management. Locate the target cluster and click Job Management.
2. Choose Entire DB Migration > Create Job. The page for configuring the job is displayed.
   Figure 1 Creating an entire DB migration job
   

3. Configure the related parameters of the source database according to Table 1.

   Table 1 Parameter description

   Source Database	Parameter	Description	Example Value
   DWS MySQL PostgreSQL SQL Server Oracle SAP HANA	Schema/Tablespace	Name of the schema or tablespace from which data will be extracted. This parameter is displayed when Use SQL Statement is set to No. Click the icon next to the text box to go to the page for selecting a schema or directly enter a schema or tablespace. If the desired schema or tablespace is not displayed, check whether the login account has the permissions required to query metadata.	schema
   	WHERE Clause	WHERE clause used to specify the tables to be extracted. This parameter applies to all subtables in the entire DB migration. If this parameter is not set, the entire table is extracted. If the table to be migrated does not contain the fields specified by the WHERE clause, the migration will fail. You can set a date macro variable to extract data generated on a specific date. For details, see Incremental Migration of Relational Databases.	age > 18 and age <= 60
   	Null in Partition Column	Whether a partition field can be null	Yes
   Hive	Database Name	Name of the database to be migrated. The user configured in the source link must have the permission to read the database.	hivedb
   HBase CloudTable	Start Time	Start time (included). The format is yyyy-MM-dd hh:mm:ss. The dateformat time macro variable function is supported. Examples: 2017-12-31 20:00:00, ${dateformat(yyyy-MM-dd, -1, DAY)} 02:00:00, and ${dateformat(yyyy-MM-dd HH:mm:ss, -1, DAY)}	-
   	End Time	End time (excluded) The format is yyyy-MM-dd hh:mm:ss. The dateformat time macro variable function is supported. Examples: 2018-01-01 20:00:00, ${dateformat(yyyy-MM-dd, -1, DAY)} 02:00:00, and ${dateformat(yyyy-MM-dd HH:mm:ss, -1, DAY)}	-
   Redis	Key Filter Character	Filter character used to determine the keys to be migrated For example, if the value of this parameter is a*, all asterisks (*) will be migrated.	-
   DDS	Database Name	Name of the database from which data is to be migrated. The user configured in the source link must have the permission to read the database.	ddsdb
   	Query Filter	Filter used to match documents. Example: {HTTPStatusCode:{$gt:"400",$lt:"500"},HTTPMethod:"GET"}	-

4. Configure the related parameters, from Table 2, for the destination cloud service.

   Table 2 Destination job parameters

   Destination Database	Parameter	Description	Example Value
   RDS for MySQL RDS for PostgreSQL RDS for SQL Server	-	For details about the destination job parameters required for entire DB migration to an RDS database, see To MySQL/SQL Server/PostgreSQL.	schema
   DWS	-	For details about the destination job parameters required for entire DB migration to DWS, see To DWS.	-
   MRS Hive	-	For details about the destination job parameters required for entire DB migration to MRS HIVE, see To Hive.	hivedb
   MRS HBase CloudTable	-	For details about the destination job parameters required for entire DB migration to MRS HBase or CloudTable, see To HBase/CloudTable.	Yes
   Redis	Clear Database	Clears the database data before data import.	Yes
   DDS	Database Name	Name of the database from which data is to be migrated. The user configured in the source link must have the permission to read the database.	mongodb
   	Migration Behavior	Select Add or Replace.	-

5. If a relational database is migrated, after job parameters are configured, click Next to access the page for selecting tables. You can select the tables to be migrated to the migration destination based on your requirements.
6. Click Next and set job parameters.
   Figure 2 Task parameters
   
   Table 3 describes related parameters.

   Table 3 Task configuration parameters

   Parameter	Description	Example Value
   Concurrent Tables	Number of tables to be concurrently executed	3
   Concurrent Extractors	Number of extractors to be concurrently executed. Generally, retain the default value.	1
   Write Dirty Data	Whether to record dirty data. By default, this parameter is set to No.	Yes
   Write Dirty Data Link	This parameter is only displayed when Write Dirty Data is set to Yes. Only links to OBS support dirty data writes.	obs_link
   OBS Bucket	This parameter is only displayed when Write Dirty Data Link is a link to OBS. Name of the OBS bucket to which the dirty data will be written.	dirtydata
   Dirty Data Directory	This parameter is only displayed when Write Dirty Data is set to Yes. Directory for storing dirty data on OBS. Dirty data is saved only when this parameter is configured. You can go to this directory to query data that fails to be processed or is filtered out during job execution, and check the source data that does not meet conversion or cleaning rules.	/user/dirtydir
   Max. Error Records in a Single Shard	This parameter is only displayed when Write Dirty Data is set to Yes. When the number of error records of a single map exceeds the upper limit, the job will automatically terminate and the imported data cannot be rolled back. You are advised to use a temporary table as the destination table. After the data is imported, rename the table or combine it into the final data table.	0

7. Click Save or Save and Run.

   When the job starts running, a sub-job will be generated for each table. You can click the job name to view the sub-job list.

During the migration of an entire Oracle database to Hudi, if you select a view or a table that has no primary key at the source, automatic table creation is not supported.