Free Databricks Associate-Developer-Apache-Spark Exam Dumps Questions & Answers

Which of the following code blocks immediately removes the previously cached DataFrame transactionsDf from memory and disk?

• A.  transactionsDf.persist()
• B.  array_remove(transactionsDf, "*")
• C.  transactionsDf.unpersist()
  (Correct)
• D.  del transactionsDf
• E.  transactionsDf.clearCache()

Which of the following is the deepest level in Spark's execution hierarchy?

• A.  Job
• B.  Executor
• C.  Stage
• D.  Task
• E.  Slot

Which of the following code blocks concatenates rows of DataFrames transactionsDf and transactionsNewDf, omitting any duplicates?

• A.  transactionsDf.concat(transactionsNewDf).unique()
• B.  transactionsDf.join(transactionsNewDf, how="union").distinct()
• C.  spark.union(transactionsDf, transactionsNewDf).distinct()
• D.  transactionsDf.union(transactionsNewDf).distinct()
• E.  transactionsDf.union(transactionsNewDf).unique()

Which of the following describes tasks?

• A.  Tasks transform jobs into DAGs.
• B.  A task is a collection of slots.
• C.  Tasks get assigned to the executors by the driver.
• D.  A task is a command sent from the driver to the executors in response to a transformation.
• E.  A task is a collection of rows.

Which of the following code blocks creates a new 6-column DataFrame by appending the rows of the
6-column DataFrame yesterdayTransactionsDf to the rows of the 6-column DataFrame todayTransactionsDf, ignoring that both DataFrames have different column names?

• A.  todayTransactionsDf.concat(yesterdayTransactionsDf)
• B.  todayTransactionsDf.unionByName(yesterdayTransactionsDf, allowMissingColumns=True)
• C.  union(todayTransactionsDf, yesterdayTransactionsDf)
• D.  todayTransactionsDf.union(yesterdayTransactionsDf)
• E.  todayTransactionsDf.unionByName(yesterdayTransactionsDf)