Google Professional Data Engineer Question 213
Select 3Google Cloud PlatformYou are a data engineer at a retail company, and your team is analyzing customer purchasing trends using Google BigQuery. You need to ensure that your queries are optimized for performance and cost-efficiency while exploring and analyzing the data. Which of the following practices should you follow?
- A
Use SELECT * to retrieve all columns from the dataset during the exploration phase.
- B
Use partitioned tables to limit the amount of data scanned by queries.
- C
Preview the dataset using the BigQuery console before running large queries.
- D
Leverage query execution plans to identify and optimize expensive operations.
- E
Store all intermediate query results in a new table, regardless of their size.
Show answer and explanation
Correct answers: B, C, D
Explanation
To explore and analyze data efficiently in Google BigQuery, it is important to minimize unnecessary data scans and costs. Using partitioned tables ensures that only relevant data is queried. Previewing datasets provides insights without running costly queries. Additionally, analyzing query execution plans allows you to identify and optimize expensive operations. Avoiding practices like SELECT * and indiscriminate storage of intermediate results can help maintain cost-efficiency and performance.
- A. Incorrect.
Using SELECT * retrieves all columns, which can unnecessarily scan large amounts of data, increasing costs. This is not an optimal practice during exploration.
- B. Correct.
Partitioned tables help reduce the volume of data scanned by limiting the range of data queried, making this a best practice.
- C. Correct.
Previewing the dataset allows you to understand its structure and content without incurring query costs, making it a cost-efficient method during exploration.
- D. Correct.
Query execution plans help identify inefficiencies in your queries, enabling optimization. This is a crucial step when exploring and analyzing data.
- E. Incorrect.
Storing all intermediate results without assessing their necessity can lead to increased storage costs and inefficiencies. This is not an advised practice.