String comparison Teradata optimizer process

Database
Teradata Employee

String comparison Teradata optimizer process

Hi ,

 

 

Could anyone help me to understand the below points.

- How to select this time plan basing on what cost information which optimizer examined in advanve of the execution,
- and whether the selected plan is determined as much lower cost by optimizer,
- or whether there were any other plan which will cause the error and not so different as the cost value.

 

Thanks in Advance.

 

Best Regards,

Sunder48

3 REPLIES
Junior Contributor

Re: String comparison Teradata optimizer process

There's a whole manual on this topic: 

SQL Request and Transaction Processing (online)

SQL Requestband Transaction Processing (PDF download)

Teradata Employee

Re: String comparison Teradata optimizer process

Not sure I understand all of your question, especially the part about an error occurring.

 

However:

- the optimizer selects the plan not the user. The choice is based primarily on cost of alternate plans (with a few heuristics for special cases).

- There is not visibility into alternate plans and costs that the optimizer considered.

Teradata Employee

Re: String comparison Teradata optimizer process

Thank you both for the response.