Each instance of a table synchronization activity comprises a task in Qlik Replicate. You define a task using the browser-based Qlik Replicate Console. When defining a task, you specify the following:
- The source and target endpoints
- The source and target tables to be kept in sync
- The relevant source table columns
- The filtering conditions (if any) for each source table as Boolean predicates (in SQLite syntax) on the values of one or more source columns
- The target table columns (optionally), including their data types and values (as expressions or functions over the values of one or more source or target columns, using SQL syntax). If not specified, Replicate uses the same column names and values as the source tables, with default mapping of the source DBMS data types onto the target DBMS data types. Replicate automatically takes care of the required filtering, transformations, and computations during the Load or CDC execution.
When a task is defined, you can activate it immediately. Replicate automatically creates and loads the target tables with the necessary metadata definitions and activates the CDC. Using the Qlik Replicate Console, you can then monitor, stop, or restart the replication process.
Using multiple tasks
You can define and activate several replication tasks at once. This is best if the tasks:
- Have different source tables
- Share some source tables but have different filtering conditions on the source rows
- Update different target tables
Updating the same target table and row by two different replication tasks would not be good practice and may cause unpredictable results.
The different replication tasks work independently and run concurrently. Each has its own Initial Load, CDC, and Log Reader processes.