Frequently Asked Questions

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1) what is a server?

The power center server moves data from source to targets based on a workflow and mapping Metadata stored in a repository.


2) what is a work flow?

A workflow is a set of instructions that describe how and when to run tasks related to extracting,transformation and loading data.


3) what is session?

A session is a set of instructions that describes how to move data from source to target using a mapping.


4) What is workflow monitor?

Use the work flow monitor work flows and stop the power center server.


5) Explain a work flow process?

The power center server uses both process memory and system shared memory to perform these tasks.

Load manager process: stores and locks the workflow tasks and start the DTM run the sessions.

Data Transformation Process DTM: Perform session validations,create threads to initialize the session,read,write and transform data, and handle pre and post session operations.


The default memory allocation is 12,000,000 bytes.


6) What are types of threads in DTM?

The main DTM thread is called the master thread.

Mapping thread.

Transformation thread.

Reader thread.

Writer thread.

Pre-and-post session thread.


7) Explain work flow manager tools?

1) Task developer.

2) Work flow designer.

3) Worklet designer.


8) Explain work flow schedule?

You can sehedule a work flow to run continuously, repeat at given time or interval or you manually start a work flow.By default the workflow runs on demand.


9) Explain stopping or aborting a session task?

If the power center is executing a session task when you issue the stop the command the power center stop reading data. If continuous processing and writing data and committing data to targets.

If the power center can’t finish processing and committing data you issue the abort command.

You can also abort a session by using the Abort() function in the mapping logic.


10) What is a worklet?

A worklet is an object that represents a set of taske.It can contain any task available in the work flow manager. You can run worklets inside a workflow. You can also nest a worklet in another worklet.The worklet manager does not provide a parameter file for worklets.

The power center server writes information about worklet execution in the workflow log.


11) what is a commit interval and explain the types?

A commit interval is the interval at which power center server commits data to targets during a session. The commit interval the number of rows you want to use as a basis for the commit point.

Target Based commit: The power center server commits data based on the number of target rows and the key constraints on the target table. The commit point also depends on the buffer block size and the commit interval.

Source-based commit:---------------------------------------------

User-defined commit:----------------------------------------------


12) Explain bulk loading?

You can use bulk loading to improve performance of a session that inserts a large amount of data to a db2,sysbase,oracle or MS SQL server database.

When bulk loading the power center server by passes the database log,which speeds performance.

With out writing to the database log, however the target database can’t perform rollback.As a result you may not be perform recovery.

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