Datastage Job Sequences

Job Sequences:

• Contain control information, for ex:, specify different courses of action to take depending on where a job in sequence succeeds or fails. 
• Specify a sequence of server or parallel jobs to run. 
• Can be scheduled and run using DataStage Director. 
• Appears in DataStage Repository and in DataStage Director Client as a job.
• This tool is provided in addition to batch job facilities of DataStage Director and job control routine facilities of DataStage Designer.

Job Sequences: 

Can have one or more Activities (vs. ETL Job has stages). The Activities have Triggers (vs Jobs have links) that define control flow.

There are also Control Entities, defined in a similar way to activities, and allow more control over sequence execution. 

Each activity has properties that can be tested in trigger expressions and passed to or activities further on in sequence. Activities can also have parameters, are used to supply job parameters and routine arguments.

job sequence itself has properties, and can have parameters, which can be passed to activities it is sequencing.




Job sequences are optionally restartable. If you run a restartable sequence and one of jobs fails to finish correctly, you can fix problem, n there-run sequence from point at which it left off. Sequence records checkpoint information to enable it to do this. Checkpoint information enables DataStage to restart sequence in a sensible way. You can enable or disable check-pointing at a project-wide level, or for individual job sequences. If you have check-pointing enabled for a job, you can specify that individual components within a sequence are not check-pointed, forcing m to be there-executed whenever sequence is restarted regardless of wher they were executed successfully before.




Also can be specified that sequence automatically handles any errors it encounters when executing jobs. This means you do not have to specify an error handling trigger for every job in sequence. This can also be enabled on a project-wide basis, or for individual job sequences.