Allowing multiple instances when it is not necessary

[gsherry1]

Hello Forum

Why aren't all jobs enabled to allow multiple instances by default, and what are the drawbacks of enabling the multi instance capability when it is not required.

Thanks,

Greg

[kduke]

Good point. There is not much down side. It complicates the Director listings and that is about it. I think restartability is a little more complicated but is not an issue.

[chulett]

I don't know... multi-instance jobs typically have to be designed with that capability in mind. Checking that by default allows you to run the job as a multi-instance job when that may not be appropriate.

To me it kind of falls into the same category as including job parameters that nothing in the job uses.

[ray.wurlod]

Ultimately the reason is that multi-instance capability did not exist in version 1.0, and the default has never been changed.

My personal view is that enabling multi-instance unnecessarily introduces an unwanted level of complexity, even if it's only a small level.

[kcbland]

There should be no overhead to the physical job execution. If a job is unnecessarily enabled but never ran as an instance, there is probably no impact whatsoever to performance. There's no extraneous job log messaging, etc.

[jdmiceli]

Hello all!

Just because I have not yet gotten to test the usefulness of this feature, is there anything special I have to do in the design process to take advantage of the benefits of multi-instance mode? I guess I'm looking at it from an unload point of view, where I may be unloading a table that has tens of millions of rows and I want to speed up the process.

As always, your expertice is greatly appreciated.

Bestest!

[ray.wurlod]

Not a great deal of value for parallel jobs (this IS the parallel forum) where it's just as easy to throw a configuration file with more nodes into the mix.