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Certified Data Engineer Professional Exam - Question 119


A Databricks SQL dashboard has been configured to monitor the total number of records present in a collection of Delta Lake tables using the following query pattern:

SELECT COUNT (*) FROM table -

Which of the following describes how results are generated each time the dashboard is updated?

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Correct Answer: C

The total count of records is calculated from the Delta transaction logs. Delta Lake optimizes COUNT(*) queries by storing the row counts in the transaction logs, thereby avoiding the need for a full table scan and significantly improving query performance.

Discussion

5 comments
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MDWPartnersOption: C
May 30, 2024

I would've said C

FreyrOption: C
Jun 1, 2024

Correct Answer: C

BrianNguyen95Option: C
Jun 5, 2024

Delta Lake optimizes COUNT(*) queries by reading the row counts stored in the Delta transaction log. This eliminates the need for a full table scan, resulting in significantly faster query performance. pen_spark

hpkrOption: C
Jun 13, 2024

C is correct

vexor3Option: C
Jul 20, 2024

C is correct