Data Replication

What Is Data Replication?

Data replication refers to the process of first updating data in a source system and then synchronizing the data with a target system. The data replication mechanism makes it possible to develop and maintain content in the background without disturbances to the live system.

Data replication affects both database data (such as catalog, product, or user data) and file system data (such as images or product attachments).

Concurrent mass data operations and individually triggered "single-object" operations may produce inconsistent data. Intershop Commerce Management features a specific object-locking mechanism to prevent concurrent modifications of the same data. In case a user intends to edit an object that is already locked by another process, Intershop Commerce Management shows a warning and, depending on the operation, provides options to either:

  • Steal the lock, where the "calling" process takes priority and can run,

  • Wait a specified time and then fail, where the "calling" process waits the defined time for the previous lock to be released in order to run afterwards, or fails if the timeout is reached.

  • Fail, where the "calling" process is terminated immediately.

Data replication involves two main stages: Defining data replication tasks and executing these tasks as data replication processes. Both stages are described in more detail below.

Data Replication Tasks

Data replication tasks determine the content to be replicated. They are defined by the responsible data replication managers individually for each channel in Intershop Commerce Management. For example, the data replication manager for the channel "inTRONICS" can define data replication tasks for this particular channel.

For each data replication tasks, the data replication manager defines:

  • Start Date

    The start date sets the earliest time at which a replication task can be executed.

  • Replication Groups

    To each replication task, one or more data replication groups are assigned. Data replication groups identify the content to be replicated. Each replication group refers to a certain content domain. For example, the data replication group "Organization" includes the organization profile, the departments, the users and roles, and all preferences defined for an organization.

Figure 1. Data replication tasks
Data replication tasks

For details about data replication tasks, see Data Replication Task Management.

Data Replication Processes

Once defined, data replication tasks are submitted to the Intershop Commerce Management system administrator for execution. To execute data replication tasks, the system administrator defines data replication processes in Intershop Organization Management.

For each data replication process, the system administrator defines:

  • Target System

    A source system can be connected to multiple target systems. However, each replication process can address a single target system (or a single target cluster) only.

  • Replication Tasks

    Each replication process executes one or more replication tasks as submitted by the responsible data replication managers. Only replication tasks whose start date has been reached can be included with a replication process.

  • Activation Rules

    Data replication processes can be started manually, or as scheduled jobs at predefined times.

  • Data Replication Type

    The data replication type determines whether a replication process involves only content transfer, content publication, or both. Additional replication types are available for special tasks or to undo a replication process involving content publication.