How teradata process select columns

Database
Enthusiast

How teradata process select columns

Hi,

I want to understand how teradata process select part of a query.Suppose I have table with 20 columns and column 1 is PI.Now if i execute below query

sel column1,column2,column3 from tabe where column1='abc'

It will use tableid+rowid to fetch the rec but will it give all 20 columns values or just required 3 columns.

2 REPLIES
Enthusiast

Re: How teradata process select columns

It seems the complete row has to be moved from the disk to the AMP’s FSG cache and thats why columnar?

Junior Contributor

Re: How teradata process select columns

Correct, all row-based DBMSes need to read the full row from disk.

In spool it's just the needed columns...