Teradata Teradata Architecture 2

Question 1

What is a Primary Index in Teradata and why is it important?

Accepted Answer

It determines data distribution across AMPs and is critical for query performance

Answer

The Primary Index determines how rows are distributed across AMPs; a well-chosen PI ensures even distribution and efficient row retrieval.

Question 2

What is the difference between a Unique Primary Index (UPI) and a Non-Unique Primary Index (NUPI)?

Accepted Answer

UPI guarantees one row per AMP bucket; NUPI allows multiple rows to hash to the same AMP

Answer

A UPI ensures no two rows share the same hash value, guaranteeing a single row per hash bucket, while NUPI allows duplicates on the same AMP.

Question 3

In Teradata, what is a Secondary Index used for?

Accepted Answer

Provides an alternate access path to data without redistributing rows

Answer

A Secondary Index creates an alternate access path so queries not using the PI can still access rows efficiently without a full-table scan.

Question 4

What is the purpose of Fallback in Teradata?

Accepted Answer

Stores a second copy of each row on a different AMP for fault tolerance

Answer

Fallback protection keeps a duplicate copy of every row on a different AMP, ensuring data availability if one AMP fails.

Question 5

What is a node in Teradata's hardware architecture?

Accepted Answer

A physical server containing CPUs, memory, and disk that hosts multiple Vprocs

Answer

A node is a physical server with its own CPUs, memory, and I/O that hosts multiple Parsing Engines and AMPs (Vprocs).

Teradata Practice Test