Teradata Random 2 — Questions and Answers
Question 1: Which Teradata feature allows a table to be automatically replicated across multiple AMPs for small lookup tables?
- Fallback Protection (Correct answer)
- NoPI Table
- Replicated Table (NOPI with replication)
- Hash Index
Correct answer: Fallback Protection
Fallback Protection replicates each row on a second AMP, ensuring availability if one AMP fails.
Question 2: What does the Teradata EXPLAIN command return?
- The actual row counts of a query result
- The execution plan the optimizer intends to use (Correct answer)
- The DDL definition of a table
- The current session statistics
Correct answer: The execution plan the optimizer intends to use
EXPLAIN returns the optimizer's step-by-step plan for executing a query, without actually running it.
Question 3: In Teradata, what is the purpose of the COLLECT STATISTICS statement?
- To archive old table data
- To gather demographic data about columns for the optimizer (Correct answer)
- To compress table extents
- To enable row-level locking
Correct answer: To gather demographic data about columns for the optimizer
COLLECT STATISTICS gathers column and index demographics stored in the data dictionary to help the optimizer build efficient query plans.
Question 4: Which locking level in Teradata is the most granular?
- Database
- Table
- Row Hash (Correct answer)
- AMP
Correct answer: Row Hash
Row Hash locking is the most granular level, locking only rows with the same hash value rather than the entire table.
Question 5: What happens when Teradata encounters a skewed PI column during data loading?
- Rows are evenly redistributed automatically
- Some AMPs receive disproportionately more rows, causing performance issues (Correct answer)
- The load aborts immediately
- Teradata reassigns a new PI automatically
Correct answer: Some AMPs receive disproportionately more rows, causing performance issues
A skewed PI results in uneven AMP workload distribution, where some AMPs have far more data than others, degrading query performance.
Question 6: Which Teradata utility is designed for high-speed bulk loading into empty tables?
- BTEQ
- FastLoad (Correct answer)
- MultiLoad
- TPump
Correct answer: FastLoad
FastLoad is optimized for loading large volumes of data into empty tables at very high speeds by bypassing the transient journal.
Question 7: What is the function of the Teradata Parsing Engine (PE)?
- Stores data in AMPs
- Parses SQL, optimizes queries, and dispatches execution steps to AMPs (Correct answer)
- Manages disk I/O scheduling
- Handles network communication between nodes
Correct answer: Parses SQL, optimizes queries, and dispatches execution steps to AMPs
The Parsing Engine receives SQL, checks syntax and semantics, optimizes the query plan, then coordinates execution across AMPs.
Teradata Random 2
Which Teradata feature allows a table to be automatically replicated across multiple AMPs for small lookup tables?