A Delta table is partitioned by 'year' and 'month'. A query filters on 'year = 2024' and 'month = 5'. The query profile shows that the scan reads 100 files out of 1,000. Which of the following is the most likely reason for reading 100 files?

The query is using a broadcast join, causing the scan to read more files

The partition pruning is working correctly, and the 100 files are the files for May 2024

The table is not optimized, so partition pruning is not working

The filter is not pushed down, so the scan reads all files

A query joins two large tables, each with 100 billion rows, on a column that is not bucketed. The query profile shows a SortMergeJoin with a shuffle read of 5 TB. The join key is not skewed. Which of the following would most likely reduce the shuffle and improve performance?

Increase the number of shuffle partitions

Pre-bucket both tables on the join key and use a bucket join

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Domain 6Objective 5

Use the Query Profile to Analyze the Query and Identify Bottlenecks, Such as Bad Data Skipping, Inefficient Types of Joins, and Data Shuffling. DATA-ENGINEER-PROFESSIONAL Practice Questions (Page 4)

Part of the Cost & Performance Optimization domain, which accounts for 13% of the DATA-ENGINEER-PROFESSIONAL exam. Databricks does not publish an official question count, but from its 120-minute exam (~50–80 total, ~7–10 in this domain), expect 1–2 from this objective — we provide 17 practice questions to prepare you well beyond it. (estimate)

17questions here

4free pages

5concepts

13%of the exam

Questions 16–17

16application · medium
A Delta table is partitioned by 'year' and 'month'. A query filters on 'year = 2024' and 'month = 5'. The query profile shows that the scan reads 100 files out of 1,000. Which of the following is the most likely reason for reading 100 files?
Select an answer first
17application · medium
A query joins two large tables, each with 100 billion rows, on a column that is not bucketed. The query profile shows a SortMergeJoin with a shuffle read of 5 TB. The join key is not skewed. Which of the following would most likely reduce the shuffle and improve performance?
Select an answer first

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Use the Query Profile to Analyze the Query and Identify Bottlenecks, Such as Bad Data Skipping, Inefficient Types of Joins, and Data Shuffling. DATA-ENGINEER-PROFESSIONAL Practice Questions (Page 4)

Questions 16–17

A Delta table is partitioned by 'year' and 'month'. A query filters on 'year = 2024' and 'month = 5'. The query profile shows that the scan reads 100 files out of 1,000. Which of the following is the most likely reason for reading 100 files?

A query joins two large tables, each with 100 billion rows, on a column that is not bucketed. The query profile shows a SortMergeJoin with a shuffle read of 5 TB. The join key is not skewed. Which of the following would most likely reduce the shuffle and improve performance?

Keep studying — Cost & Performance Optimization