Developing SQL Databases — Question 144

You have several real-time applications that constantly update data in a database. The applications run more than 400 transactions per second that insert and update new metrics from sensors.
A new web dashboard is released to present the data from the sensors. Engineers report that the applications take longer than expected to commit updates.
You need to change the dashboard queries to improve concurrency and to support reading uncommitted data.
What should you do?

Answer options

• A. Use the NOLOCK option.
• B. Execute the DBCC UPDATEUSAGE statement.
• C. Use the max worker threads option.
• D. Use a table-valued parameter.
• E. Set SET ALLOW_SNAPSHOT_ISOLATION to ON.
• F. Set SET XACT_ABORT to ON.
• G. Execute the ALTER TABLE T1 SET (LOCK_ESCALATION = AUTO); statement.
• H. Use the OUTPUT parameters.

Correct answer: A

Explanation

The correct answer is A, as using the NOLOCK option allows the dashboard queries to read data without waiting for locks, thus improving concurrency and enabling the reading of uncommitted data. The other options do not directly address the need to read uncommitted data or improve the performance of the dashboard queries in this context.