Certified Data Engineer Professional Exam

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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?

The total count of rows is calculated by scanning all data files

The total count of rows will be returned from cached results unless REFRESH is run

The total count of records is calculated from the Delta transaction logs

The total count of records is calculated from the parquet file metadata

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

MDWPartnersOption: C

I would've said C

vexor3Option: C

C is correct

hpkrOption: C

C is correct

BrianNguyen95Option: C

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

FreyrOption: C

Correct Answer: C