Task Stages |
Incremental Data Synchronization is selected by default. You must also select Schema Synchronization and Full Data Synchronization. After the precheck is complete, DTS synchronizes the historical data of selected
objects from the source instance to the destination cluster. The historical data is
the basis for subsequent incremental synchronization.
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Processing Mode of Conflicting Tables |
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Precheck and Report Errors: checks whether the destination database contains tables that have the same names
as tables in the source database. If the source and destination databases do not contain
identical table names, the precheck is passed. Otherwise, an error is returned during
the precheck and the data synchronization task cannot be started.
Note You can use the object name mapping feature to rename the tables that are migrated
to the destination database. You can use this feature if the source and destination
databases contain identical table names and the tables in the destination database
cannot be deleted or renamed. For more information, see Map object names.
- Ignore Errors and Proceed: skips the precheck for identical table names in the source and destination databases.
Warning If you select Ignore Errors and Proceed, data inconsistency may occur and your business may be exposed to potential risks.
- If the source and destination databases have the same schema, and a data record has
the same primary key as an existing data record in the destination database:
- During full data synchronization, DTS does not synchronize the data record to the
destination database. The existing data record in the destination database is retained.
- During incremental data synchronization, DTS synchronizes the data record to the destination
database. The existing data record in the destination database is overwritten.
- If the source and destination databases have different schemas, initial data synchronization
may fail. In this case, only part of the columns are synchronized, or the data synchronization
task fails.
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DDL and DML Operations to Be Synchronized |
The DDL and DML operations that you want to synchronize. For more information, see
SQL operations that can be synchronized.
Note To select the SQL operations performed on a specific database or table, perform the
following steps: In the Selected Objects section, right-click an object. In the dialog box that appears, select the SQL operations
that you want to synchronize.
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SQL Server Incremental Synchronization Mode |
- Incremental Synchronization Based on Logs of Source Database:
- Advantages:
- Provides low latency and good performance.
- Provides no intrusion to the source database.
- Disadvantages:
- Does not support heap tables or tables without primary keys.
- Interrupts DTS tasks due to large amounts of data written to the source database and
frequent log truncation and archiving.
- CDC-based Incremental Synchronization:
- Advantages:
- Supports heap tables and tables without primary keys.
- Does not interrupt DTS tasks for log truncation in the source database.
- Disadvantages:
- Causes DTS to create Change Data Capture (CDC) records in the source databases and
tables.
- Causes higher latency than log-based parsing mode.
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Select Objects |
Select one or more objects from the Source Objects section and click the icon to add the objects to the Selected Objects section.
Note In this scenario, data synchronization is performed between heterogeneous databases.
Therefore, the objects to synchronize are tables, and other objects such as views,
triggers and stored procedures are not synchronized to the destination database.
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Rename Databases and Tables |
- To rename an object in the destination instance, right-click the object in the Selected Objects section. For more information, see Map the name of a single object.
- To rename multiple objects at a time in the destination instance, click Batch Edit in the upper-right corner of the Selected Objects section. For more information, see Map multiple object names at a time.
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Filter data |
You can specify WHERE conditions to filter data. For more information, see Use SQL conditions to filter data.
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Select the SQL operations to be synchronized |
In the Selected Objects section, right-click an object. In the dialog box that appears, select the DML and
DDL operations to synchronize. For more information, see SQL operations that can be synchronized.
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