LFC Architecture 3

Question 1

Which open table format feature allows querying a Delta table as it existed at a previous point in time?

Accepted Answer

Time travel (versioned snapshots)

Answer

Delta Lake's time travel feature uses the transaction log to reconstruct any historical version of a table using VERSION AS OF or TIMESTAMP AS OF syntax.

Question 2

What type of workload does a Databricks SQL Warehouse primarily optimize for?

Accepted Answer

Interactive BI and SQL analytics queries requiring low latency

Answer

Databricks SQL Warehouses use Photon-powered vectorized execution and result caching to deliver fast, cost-efficient interactive SQL for BI workloads.

Question 3

How does Delta Lake achieve atomicity for write operations on object storage?

Accepted Answer

By writing new data files and committing a new transaction log entry atomically

Answer

Delta Lake writes data files optimistically then commits a single JSON log entry; readers only see committed entries, ensuring atomic all-or-nothing visibility.

Question 4

In Unity Catalog's three-level namespace, what is the correct hierarchy from outermost to innermost?

Accepted Answer

Catalog → Schema → Table

Answer

Unity Catalog uses catalog.schema.table notation, where catalogs group schemas (databases) which in turn group tables and views.

Question 5

What is the role of the Delta Lake transaction log (_delta_log directory)?

Accepted Answer

It records every change to the table as ordered JSON commit files for ACID compliance

Answer

The _delta_log directory contains sequential JSON files that record file additions, removals, and metadata changes, forming the source of truth for table state.

(LFC) Lakehouse Fundamentals Certification Practice Test

(LFC) Lakehouse Fundamentals Certification Practice Test

LFC Architecture 3