Teradata Random 4 — Questions and Answers
Question 1: What is the role of the BYNET in a Teradata MPP system?
- Provides disk storage for AMPs
- Provides high-speed interconnect for communication between nodes (Correct answer)
- Manages user session authentication
- Handles SQL parsing
Correct answer: Provides high-speed interconnect for communication between nodes
The BYNET is Teradata's proprietary high-speed interconnect network that enables AMPs and PEs on different nodes to communicate and exchange data.
Question 2: In Teradata, what distinguishes a SET table from a MULTISET table?
- SET tables allow NULL primary index values; MULTISET tables do not
- SET tables reject exact duplicate rows; MULTISET tables allow them (Correct answer)
- SET tables support fallback; MULTISET tables do not
- SET tables use UPI; MULTISET tables use NUPI
Correct answer: SET tables reject exact duplicate rows; MULTISET tables allow them
A SET table automatically eliminates exact duplicate rows on insert, while a MULTISET table allows complete duplicate rows.
Question 3: Which Teradata utility supports concurrent DML operations (INSERT, UPDATE, DELETE) on populated tables with minimal locking?
- FastLoad
- FastExport
- TPump (Correct answer)
- BTEQ
Correct answer: TPump
TPump (Teradata Parallel Data Pump) is designed for continuous low-volume DML on active tables with fine-grained row-hash locking to minimize contention.
Question 4: What is a Teradata Volatile Table and when is it dropped?
- A permanent table that auto-purges after 30 days
- A temporary table that exists only for the duration of the user session (Correct answer)
- A table with no primary index
- A table replicated across all AMPs
Correct answer: A temporary table that exists only for the duration of the user session
A Volatile Table is a session-scoped temporary table automatically dropped when the user session ends.
Question 5: Which Teradata access right allows a user to SELECT from a table but not modify it?
- EXECUTE
- SELECT (Correct answer)
- UPDATE
- REFERENCES
Correct answer: SELECT
The SELECT privilege grants read-only access, allowing a user to query rows from a table without any ability to modify data.
Question 6: In Teradata, what does ZEROIFNULL function do?
- Returns NULL if a column is zero
- Replaces NULL with zero for numeric expressions (Correct answer)
- Converts zero values to empty strings
- Rounds null values to zero decimal places
Correct answer: Replaces NULL with zero for numeric expressions
ZEROIFNULL returns 0 when its argument is NULL, preventing null propagation in arithmetic calculations.
Question 7: What is the purpose of Teradata's Permanent Journal?
- To log all DDL changes for auditing
- To record before and after images of data for recovery after system failure (Correct answer)
- To store EXPLAIN plan outputs permanently
- To cache frequently accessed rows
Correct answer: To record before and after images of data for recovery after system failure
The Permanent Journal stores before and/or after images of modified rows to support recovery of committed transactions after a crash.
Teradata Random 4
What is the role of the BYNET in a Teradata MPP system?