Monitor and Optimize Query Performance DP-300 Practice Questions (Page 9)

Questions 41–42

1. 41expert · hard

   You manage an Azure SQL Database that is part of a mission-critical application. You receive an Intelligent Insights alert that a query's duration has increased significantly. The alert suggests that the query is now doing a scan instead of a seek. You need to confirm the root cause and take action. What should you do first?

   • AImmediately force the old plan using Query Store.
   • BRebuild the index that the query uses.
   • CReview the Query Store report for the query to see the plan change history.
   • DIncrease the database's performance tier to reduce duration.
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2. 42application · medium

   You are analyzing a query that performs a large number of key lookups. The execution plan shows a nonclustered index seek followed by a key lookup for each row. The query returns about 5% of the rows in the table. What is the most appropriate index change?

   • AUse a columnstore index on the table.
   • BCreate a new clustered index on the nonclustered index key columns.
   • CDrop the nonclustered index and rely on the clustered index scan.
   • DAdd the columns referenced in the SELECT and WHERE clauses to the nonclustered index's INCLUDE list.
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