Databricks Certified Data Engineer - Associate

Explanation

Correct Answer: D - They can use clusters that are from a cluster pool

Why this is correct:

1. Cluster pools are pre-provisioned clusters that are kept in a warm state, ready to be assigned to jobs.
2. When a job starts, if it uses a cluster from a pool, the cluster is already running and only needs to be attached to the job, significantly reducing startup time.
3. This is specifically designed to address the problem described: clusters taking a long time to start for nightly jobs.

Why other options are incorrect:

A. They can use endpoints available in Databricks SQL - SQL endpoints are for running SQL queries, not for general data engineering jobs with multiple tasks. This doesn't address cluster startup time.

B. They can use jobs clusters instead of all-purpose clusters - While jobs clusters are optimized for job execution, they still need to start from scratch each time unless they're from a pool. This doesn't inherently solve the startup time issue.

C. They can configure the clusters to autoscale for larger data sizes - Autoscaling helps with handling varying workloads but doesn't reduce cluster startup time. In fact, autoscaling might add overhead as nodes need to be added dynamically.

Key Concept: Cluster pools maintain clusters in a warm state, allowing jobs to start quickly by reusing existing infrastructure rather than provisioning new clusters from scratch each time.