Prepare with Databricks : Associate-Developer-Apache-Spark exam braindumps as your best preparation materials

Which of the following describes the role of the cluster manager?

• A. The cluster manager allocates resources to the DataFrame manager.
• B. The cluster manager schedules tasks on the cluster in local mode.
• C. The cluster manager allocates resources to Spark applications and maintains the executor processes in remote mode.
• D. The cluster manager schedules tasks on the cluster in client mode.
• E. The cluster manager allocates resources to Spark applications and maintains the executor processes in client mode.

Which of the following code blocks returns a copy of DataFrame transactionsDf where the column storeId has been converted to string type?

• A. transactionsDf.withColumn("storeId", col("storeId").cast("string"))
• B. transactionsDf.withColumn("storeId", col("storeId", "string"))
• C. transactionsDf.withColumn("storeId", convert("storeId").as("string"))
• D. transactionsDf.withColumn("storeId", convert("storeId", "string"))
• E. transactionsDf.withColumn("storeId", col("storeId").convert("string"))

Which of the following statements about garbage collection in Spark is incorrect?

• A. Garbage collection information can be accessed in the Spark UI's stage detail view.
• B. Serialized caching is a strategy to increase the performance of garbage collection.
• C. In Spark, using the G1 garbage collector is an alternative to using the default Parallel garbage collector.
• D. Optimizing garbage collection performance in Spark may limit caching ability.
• E. Manually persisting RDDs in Spark prevents them from being garbage collected.

In which order should the code blocks shown below be run in order to assign articlesDf a DataFrame that lists all items in column attributes ordered by the number of times these items occur, from most to least often?
Sample of DataFrame articlesDf:
1.+------+-----------------------------+-------------------+
2.|itemId|attributes |supplier |
3.+------+-----------------------------+-------------------+
4.|1 |[blue, winter, cozy] |Sports Company Inc.|
5.|2 |[red, summer, fresh, cooling]|YetiX |
6.|3 |[green, summer, travel] |Sports Company Inc.|
7.+------+-----------------------------+-------------------+

• A. 2, 5, 3
• B. 5, 2
• C. 1. articlesDf = articlesDf.groupby("col")
  2. articlesDf = articlesDf.select(explode(col("attributes")))
  3. articlesDf = articlesDf.orderBy("count").select("col")
  4. articlesDf = articlesDf.sort("count",ascending=False).select("col")
  5. articlesDf = articlesDf.groupby("col").count()
• D. 2, 5, 4
• E. 2, 3, 4
• F. 4, 5

The code block displayed below contains multiple errors. The code block should return a DataFrame that contains only columns transactionId, predError, value and storeId of DataFrame transactionsDf. Find the errors.
Code block:
transactionsDf.select([col(productId), col(f)])
Sample of transactionsDf:
1.+-------------+---------+-----+-------+---------+----+
2.|transactionId|predError|value|storeId|productId| f|
3.+-------------+---------+-----+-------+---------+----+
4.| 1| 3| 4| 25| 1|null|
5.| 2| 6| 7| 2| 2|null|
6.| 3| 3| null| 25| 3|null|
7.+-------------+---------+-----+-------+---------+----+

• A. The column names should be listed directly as arguments to the operator and not as a list and following the pattern of how column names are expressed in the code block, columns productId and f should be replaced by transactionId, predError, value and storeId.
• B. The select operator should be replaced by a drop operator, the column names should be listed directly as arguments to the operator and not as a list, and all col() operators should be removed.
• C. The select operator should be replaced by a drop operator, the column names should be listed directly as arguments to the operator and not as a list, and all column names should be expressed as strings without being wrapped in a col() operator.
• D. The column names should be listed directly as arguments to the operator and not as a list.
• E. The select operator should be replaced by a drop operator.