What is the difference between a Job and a Transformation?

Question

When creating new objects in spoon there's two possibilities: Job and Transfromation. They've got a different set of possible components (although with some level of overlap) and the XML that is generated looks very similar. What's the difference between these two?

Savannahsavant

Answer 1

This is what I had most problems to understand when starting with Pentaho as well.

• A job has one start place, and executes one step at a time, with one flow through the steps.

• A transformation has many possible start places and all steps execute in parallel. If a step has a step before it, it will take the data in there, and use it.

In my use I usually schedule jobs, to run transformations in process to get and transform data.

This is a normal question so it's in the FAQ.

Jessi

The OP is right the lines are blurred these days. especially now that a transformation can itself execute a job :o) But fundamentally the job is just workflow/prep tasks, and the trans is where you do your real work! – Unbecoming

@Codek: If I can always get the tasks done by ordered transformations, do I still need to use the jobs? If yes, what should be the use case that I have to use the jobs? – Orban

of course not. there's nothing wrong with just having transformations if that's what you need! Also ; Transformations can call jobs as well! – Unbecoming

Answer 2

Turns out the answer is in the FAQ. From the Pentaho FAQ:

Q: In Spoon I can make jobs and transformations, what's the difference between the two?

A: Transformations are about moving and transforming rows from source to target. Jobs are more about high level flow control: executing transformations, sending mails on failure, transferring files via FTP, ...

Another key difference is that all the steps in a transformation execute in parallel, but the steps in a job execute in order.

Savannahsavant