Exam DP-600 topic 1 question 112 discussion

Actual exam question from Microsoft's DP-600

Question #: 112
Topic #: 1

HOTSPOT
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You have a Fabric workspace that uses the default Spark starter pool and runtime version 1.2.

You plan to read a CSV file named Sales_raw.csv in a lakehouse, select columns, and save the data as a Delta table to the managed area of the lakehouse. Sales_raw.csv contains 12 columns.

You have the following code.

For each of the following statements, select Yes if the statement is true. Otherwise, select No.

NOTE: Each correct selection is worth one point.

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Suggested Answer:

by Mike5611 at Oct. 8, 2024, 3:34 p.m.

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mghf61

Highly Voted 5 months, 2 weeks ago

No, No, Yes The spark reads all columns first before selection , so spark.read , read all columns

upvoted 29 times

Mhunity

4 months, 3 weeks ago

correct N,N,Y

upvoted 4 times

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Mike5611

Highly Voted 7 months ago

1. YES - The .select() function in the code specifies the exact columns ('SalesOrderNumber', 'OrderDate', 'CustomerName', and 'UnitPrice') to be selected. Therefore, only these columns will be read from the CSV. 2. NO - The withColumn("Year", year("OrderDate")) function adds a new column called "Year" by extracting the year from the "OrderDate" column. However, it does not replace the "OrderDate" column—it only adds the new "Year" column. 3. YES - The inferSchema='true' tells Spark to infer the data types of each column in the CSV, which requires an extra scan of the data to determine these types. This can indeed increase execution time.

upvoted 10 times

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zxc01

Most Recent 5 days, 15 hours ago

No, No, Yes. you need to use paraquet/orc or some similar file formats where they can provide file metadata and searchable organization of data. otherwise, spark will load the complete record in-memory, apply schema and can pick that particular column. CSV file will load whole file in Spark engine memory, then get columns with select.

upvoted 1 times

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nappi1

4 months, 2 weeks ago

Yes, No, Yes is right

upvoted 5 times

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