Instances in TPT

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Instances in TPT

Does anyone know the relationship between Instances and loaderslots with reference to TPT. What exactly are Instances for example a session is a thread running on the amp... what are instances. And when we instantiate multiple instances of an operator why do they all use only a single loader slot.

Thanks
3 REPLIES
Junior Contributor

Re: Instances in TPT

Check the manual:
Teradata Parallel Transporter Reference
Chapter 4: Teradata PT Job Scripts
Defining Sessions and Instances

1 job -> 1 or many instances
1 instance -> 1 or many sessions

If there's a bottleneck, because an instance can't process the data fast enough you simply add another instance to remove that bottleneck.

Dieter

Re: Instances in TPT

Yes... but what i was asking was what exactly are instances.... a session is a thread/process running on an amp so what is a instance. If per say Instances were replications of the complete process then why dont they use multiple loader slots.

For example I declare a Load operator with 20 Sessions and 4 Instances, so each instance gets 5 sessions. But still only one loader slot is used. So how actually are the instances implemented.

Hope this clarifies the question

Thanks
Junior Contributor

Re: Instances in TPT

"If per say Instances were replications of the complete process then why dont they use multiple loader slots."

Because they communicate through sessions to the Teradata system, it's like a multi-threaded application.
All those sessions belong to the same load job, but are used by different instances.

Dieter