Qlik Replicate Task Configuration Options

[Sonja_Bauernfeind]

The core object of Qlik Replicate is a Task, which is the instance of a table synchronization activity reading data from the Source endpoint and writing it to the target endpoint.

Depending on the use case, Qlik Replicate has multiple task types available. In this article, we provide you with an overview of the Task Types, the Options available in your tasks, and how to Migrate/Import tasks between environments. 

Content:

• Task Types
• Unidirectional
• Bidirectional
• Log Stream
• Task options
• Full load
• Apply Changes
• Store Changes
• Additional Information on Different Types of Tasks
• Task Setup
• Full Load vs CDC
• Log Stream tasks
• Bidirectional tasks
• Task Migration
• Backing up, Restoring, and moving Qlik Replicate
• Exporting, migrating, and importing tasks
• Step-by-Step Migration

Task Types

Unidirectional

The most commonly used type. It replicates data from Database A to Database B.

Bidirectional

Used when Database A also needs to be updated whenever there is any change in Database B. Consists of two separately created tasks.

Log Stream

Qlik Replicate will save the Data Changes from the Source database locally, and these changes can later be down streamed to multiple Targets in parallel, instead of having multiple tasks reading from the same source and writing to different targets.

Task options

Full load

Essentially a full copy of the Source database, Qlik Replicate will read all columns/rows from the Source DB and create the exact same copy on the Target DB (if there are no filters or transformations setup).

Apply Changes

The CDC part of Qlik Replicate. Having this enabled will make so that Qlik Replicate will read the transaction log from the Source and apply any changes (INSERT, UPDATE, DELETE) to the Target DB.

Store Changes

By default disabled, enabling this will make so that a Change or Audit table is created on the Target side and all changes are Inserted into that Table Before and After images.

A task needs at least one option enabled but it can have all 3 enabled (being a task that will Full Load, Capture Data Changes and Store Changes)

Additional Information on Different Types of Tasks

Task Setup

Before you get started with designing the features that you need for a task, you must first define the task's default behavior.

For general information on setting up tasks in Qlik Replicate, see Adding tasks | Qlik Replicate Help.

Full Load vs CDC

Qlik Replicate tasks can be configured to move data from a source DB to a Target DB. These tasks can be configured in a variety of ways to move data from the source to the target database.

For an in-depth comparison and introduction on the two, see An Introduction to Qlik Replicate Tasks: Full Load vs CDC | Official Qlik Support Article.

Log Stream tasks

Log Stream enables a dedicated Qlik Replicate task to save data changes from the transaction log of a single source database and apply them to multiple targets, thereby eliminating the overhead of reading the logs for each target separately.

For an in-depth explanation on how to use Log Stream, see Using the Log Stream | Qlik Replicate Help.

Bidirectional tasks

For information on how to set up bidirectional tasks, see Setting up Bidirectional replication | Qlik Replicate Help.

Task Migration

Backing up, Restoring, and moving Qlik Replicate

• Qlik Replicate Backup and Restore
• How to Move the Data Directory to a Different Replicate Server

Exporting, migrating, and importing tasks

• Migrating Task | Qlik Replicate Help 
• Backing up or Exporting Tasks from Qlik Replicate 

Step-by-Step Migration

1. Before you begin a migration, stop all tasks.
   
   Before stopping the Qlik Replicate services to perform a migration, it’s best to stop all running tasks. If there are Log Stream tasks running, the best practice would be to stop first all child tasks reading from the Log Stream staging folder and then stop the Parent Log Stream task.
   
   
2. Back up the ~/data folder.
   
   See Qlik Replicate Backup and Restore
   
   
3. Export the Qlik Replicate Repository (task/endpoints/server settings).
   
   See Backing up or Exporting Tasks from Qlik Replicate.
   
   
4. Import the Qlik Replicate repository to a test or UAT environment.
   
   See Importing tasks.
   
   
5. Verify all functionality in your test or UAT environment.
   
   
6. Import the Qlik Replicate repository to your Production environment. 
   
   See Importing tasks.
   
   
7. Resume/start tasks to verify all functionality.
   
   We recommend monitoring the tasks on the new server and comparing to old task logs to confirm all tasks were resumed where they should have resumed from.
   
   

Environment

Qlik Replicate