Câu 81: Google Cloud Professional Data Engineer

You are using Google BigQuery as your data warehouse. Your users report that the following simple query is running very slowly, no matter when they run the query:SELECT country, state, city FROM [myproject:mydataset.mytable] GROUP BY countryYou check the query plan for the query and see the following output in the Read section of Stage:1: What is the most likely cause of the delay for this query?

1. A. Users are running too many concurrent queries in the system
2. B. The [myproject:mydataset.mytable] table has too many partitions
3. C. Either the state or the city columns in the [myproject:mydataset.mytable] table have too many NULL values
4. D. Most rows in the [myproject:mydataset.mytable] table have the same value in the country column, causing data skew — đáp án hiện tại