Teradata Interview Questions

1. What is Master Index and Cylinder Index?

Teradata uses logical address system, unlike other DBMS which are physical address system. This allows Teradata to locate the data easily if the data gets reallocated or de-fragmented. Master Index and Cylinder Index are two structure of this logical system which helps Teradata to locate the data on the data block.

While reading the data row, Master Index is used to identify the Cylinder Index in which data is stored. Cylinder Index is used to provide the correct data block for that row.


2. What is Clique in Teradata?

Combination of Teradata nodes that share a common sets of disk arrays are called Clique. Clique provides the protection from the Node failure i.e. if any of the node goes down from a clique, AMP vprocs will be migrated to the other nodes within clique.


3. What is Cluster in Teradata?

A set of AMP called Cluster in Teradata.

This is a logical group which provides fallback capability. If an AMP goes down, the data can be accessed via the fallback amp within the same cluster. The default cluster size is 2.