Databricks Data Engineer Interview: Explain Lazy Evaluation

Why knowing just “transformations don’t execute immediately” won’t cut it - and how Catalyst’s logical plans and pushdown optimizations make all the difference

Interview for a $150k Databricks Data Engineer role: “Explain lazy evaluation and why it matters.” 80% say “transformations don’t execute immediately” and fail.

This separates engineers who memorize definitions from those who understand the architecture. The junior answer is correct but misses the “why.”

Here’s what wins offers:

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⚠️ 𝗧𝗵𝗲 𝗝𝘂𝗻𝗶𝗼𝗿 (…