Teradata Teradata MCQ 4 — Questions and Answers
Question 1: Which Teradata feature enables rolling window partitioning by automatically deleting the oldest partition and adding a new one?
- Range_N function with NO RANGE
- Partition elimination
- Rolling partition maintenance via ALTER TABLE MODIFY (Correct answer)
- Teradata Time Series tables
Correct answer: Rolling partition maintenance via ALTER TABLE MODIFY
ALTER TABLE MODIFY allows adding and dropping partitions to implement a rolling window without physically moving data.
Question 2: In Teradata's BYNET, what is its primary function?
- High-speed inter-node communication fabric for redistributing rows (Correct answer)
- Disk I/O controller connecting AMPs to storage
- Authentication gateway for user sessions
- Index maintenance subsystem
Correct answer: High-speed inter-node communication fabric for redistributing rows
BYNET is Teradata's high-bandwidth, fault-tolerant interconnect that moves rows between nodes during join and aggregation operations.
Question 3: What does the Teradata 'CASE' expression return when no WHEN clause matches and no ELSE is specified?
- NULL (Correct answer)
- 0
- An error is raised
- An empty string
Correct answer: NULL
If no WHEN condition matches and no ELSE clause is provided, the CASE expression returns NULL.
Question 4: Which Teradata workload management feature assigns queries to performance groups based on rules like user, time of day, or query band?
- TASM (Teradata Active System Management) (Correct answer)
- Teradata Priority Scheduler
- Teradata Virtual Storage
- Index Wizard
Correct answer: TASM (Teradata Active System Management)
TASM classifies workloads using filters and throttles, then manages resources and priority dynamically based on defined rules.
Question 5: In Teradata, what does 'skew factor' measure?
- How unevenly rows are distributed across AMPs (Correct answer)
- The ratio of full-table scans to index scans
- The percentage of NULL values in a column
- The compression ratio achieved on a table
Correct answer: How unevenly rows are distributed across AMPs
Skew factor quantifies data distribution imbalance across AMPs; high skew causes some AMPs to do disproportionately more work.
Question 6: Which Teradata SQL extension allows you to compute cumulative sums or moving averages without a self-join?
- OLAP/window functions with OVER() clause (Correct answer)
- GROUPING SETS
- SAMPLE clause
- NORMALIZE clause
Correct answer: OLAP/window functions with OVER() clause
OLAP functions such as SUM() OVER (ORDER BY ...) compute running totals and other ordered aggregates using a window specification.
Question 7: What is the purpose of Teradata's 'Query Band' feature?
- Attaching metadata key-value pairs to a session or transaction for workload tracking (Correct answer)
- Defining bandwidth limits for individual queries
- Setting row limits on query result sets
- Encrypting query text in the query log
Correct answer: Attaching metadata key-value pairs to a session or transaction for workload tracking
Query Bands let applications tag sessions or transactions with metadata that TASM and DBAs can use for workload classification and chargeback.
Teradata Teradata MCQ 4
Which Teradata feature enables rolling window partitioning by automatically deleting the oldest partition and adding a new one?