PowerCenter architecture is based on client-server model. It consists of PowerCenter server and PowerCenter client tools. Below is a list of all of the components that are part of the PowerCenter architecture.
Informatica PowerCenter Domain
In its simple terms, Domain can be defined as an environment. You will have a PowerCenter domain for each environment. For example, if you have Development, Test and Production environments, you essentially create 3 different domains — one for each environment. Domain information is stored in a set of tables, which are created and configured as part of PowerCenter server installation. These domain tables store metadata related to services within the PowerCenter, users, groups, etc…
A node is a machine participating in the Informatica Domain. Typically, a node consists of CPU, Memory and Disk. A node can be active or passive depending on the services it is hosting. Informatica domain can consist of more than one node. These nodes can host a wide variety of operating systems such Windows, Lin., HP-UX, etc. Informatics server software is installed on each node participating in a domain.
A domain consists of several services, such as license service, PowerCenter Repository Service and PowerCenter Integration Service. Each of this service provides a unique functionality to clients.
PowerCenter Repository Service (PCRS)
A PowerCenter Repository is a net of tables created when your Informatica Administrator creates a PowerCenter Repository Service during post installation process. The entire code that a developer builds is stored inside the repository. Repository contains hundreds of tables, whereas PowerCenter stores the developer’s code within these tables very intelligently. It is hard to manually look at these tables and comprehend and hence, they should be left alone unless there is a dire need to look at them. Along with developer’s code, repository also contains metadata like definitions of the tables used by the mappings, source and target connections, etc…
When the developer runs a Workflow (a job in PowerCenter), its information is fetched from the repository. Thereafter, the runtime statistics are stored back in the repository again. Hence the repository is a key and live element in PowerCenter architecture
PowerCenter Integration Service (PCIS)
An integration service is the engine that actually runs PowerCenter workflows (jobs). Integration services continuously interact with PowerCenter Repository to fetch the information of the job it is about to start and keeps the repository up-to-date regarding the status of the job, including the processed row counts. Each workflow is assigned to an integration service. Each integration service can run one or more workflows at the same time. Workflows can also be scheduled to run on Integration Service at specific date/time. We will have detailed discussion on this feature in Informatica Online Training.
A grid is a collection of nodes. A PowerCenter Integration Service can not upon an individual node or on a grid. When an Integration Service runs on a grid, it automatically load balances the workflows that it is executing, such that the resources (nodes) are optimally utilized. When a node in the domain fails, integration service can be configured to failover the workflows running on that node to another node(s) to provide a seamless failover of the jobs.
Putting it all together
Now that we have a basic understanding of each component, let’s take a look at it all together. See the picture below.
The above picture represents a single Informatica domain, containing 3 nodes. Out of these, two nodes (node 1 and node 2) are participating together to form a grid. An integration service is running atop of this grid. Node 3 is hosting a PowerCenter repository service, whose repository tables lie in the schema 1 of the database server. The schema 2 of the same database server hosts the domain metadata tables. Informatica server software is installed on all the 3 nodes.
While there are many possible configurations for the given nodes, the one above is an example for understanding how the components fit together in the Informatica PowerCenter architecture.