What happens when using LIMIT/OFFSET in Spark without an explicit ORDER BY clause?

Goal: determine if Spark applies a global sort when LIMIT/OFFSET used without ORDER BY and what performance implications arise.

Constraints: Spark does not guarantee partition order; without ORDER BY, LIMIT/OFFSET may trigger a shuffle to sort the entire dataset before returning subset, leading to nondeterministic results and potential memory pressure on skewed data.

Does Spark implicitly sort the whole dataset when LIMIT/OFFSET lacks ORDER BY? What shuffle volume and stage duration can be observed in the Spark UI? How does data skew affect the cost of this implicit sort?