Teradata MCQ Flashcards

Which Teradata feature enables rolling window partitioning by automatically deleting the oldest partition and adding a new one?

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.

In Teradata's BYNET, what is its primary function?

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.

What does the Teradata 'CASE' expression return when no WHEN clause matches and no ELSE is specified?

Answer: NULL

If no WHEN condition matches and no ELSE clause is provided, the CASE expression returns NULL.

Which Teradata workload management feature assigns queries to performance groups based on rules like user, time of day, or query band?

Answer: TASM (Teradata Active System Management)

TASM classifies workloads using filters and throttles, then manages resources and priority dynamically based on defined rules.

In Teradata, what does 'skew factor' measure?

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.

Which Teradata SQL extension allows you to compute cumulative sums or moving averages without a self-join?

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.

What is the purpose of Teradata's 'Query Band' feature?

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.