DP-300 Monitor, configure, and optimize database resources Practice Test 2 — 15 Questions

Question 1

You are managing an Azure SQL Database that runs a critical line-of-business application. Users report that a specific query is running slower than usual. You identify that the query is performing a clustered index scan on a large table with over 10 million rows. The table has a clustered index on an identity column and a nonclustered index on a frequently filtered column. You need to minimize the query execution time without adding additional indexes. What should you do?

Accepted Answer

Update all statistics on the table.. The query is performing a clustered index scan, which means SQL Server is reading all rows in the table. Outdated statistics can cause the optimizer to choose a scan instead of a more efficient seek. Updating all statistics on the table (option B) provides the optimizer with fresh distribution information, potentially allowing it to choose a better execution plan that avoids the scan, thereby reducing query execution time without adding indexes.

Answer

Increase the service tier of the Azure SQL Database to provide more resources.

Answer

Rebuild the clustered index to reduce fragmentation.

Answer

Update the statistics on the nonclustered index only.

Question 2

You are the database administrator for an Azure SQL Managed Instance hosting a data warehouse workload. You notice that the storage space consumed by the database is significantly larger than expected. The database has multiple large tables with clustered columnstore indexes. You suspect that the columnstore indexes have become fragmented and that deleted rows are consuming space. You need to reclaim storage space with minimal impact on query performance during business hours. What should you do?

Accepted Answer

Perform an ALTER INDEX REORGANIZE with the COMPRESS_ALL_ROW_GROUPS option on the affected columnstore indexes.. Option B is correct because REORGANIZE with COMPRESS_ALL_ROW_GROUPS compresses all row groups, including those in the delta store, and removes deleted rows from columnstore indexes. This operation is online and can be performed during business hours with minimal impact on query performance, unlike a rebuild which is offline and resource-intensive. It directly addresses the fragmentation and deleted row space consumption in columnstore indexes.

Answer

Perform an ALTER INDEX REBUILD on the affected columnstore indexes after business hours.

Answer

Perform an ALTER INDEX REORGANIZE on the affected columnstore indexes.

Answer

Rebuild the entire database by creating a new database and copying data.

Question 3

A company has an Azure SQL Database that experiences periodic performance degradation. The database uses the General Purpose service tier. You need to identify the most common performance bottlenecks. You enable the Query Store and collect data for a week. Which Query Store view should you query to find queries that have the highest total resource consumption over time?

Accepted Answer

sys.query_store_query_stats. A is correct because sys.query_store_query_stats aggregates runtime statistics per query across all plans and time intervals, making it the ideal view to identify queries with the highest total resource consumption (e.g., CPU, I/O, duration) over the collected week. Query Store captures historical execution data, and this view provides the cumulative metrics needed to pinpoint the most resource-intensive queries for performance bottleneck analysis.

Answer

sys.query_store_plan

Answer

sys.dm_exec_query_stats

Answer

sys.dm_db_resource_stats

Question 4

You are monitoring an Azure SQL Database using the Automatic Tuning feature. The database has a workload that is read-intensive. You enable the CREATE INDEX and DROP INDEX options. After a week, you observe that the database has created several new indexes automatically. However, you notice that one of the new indexes is causing increased write latency for an application that performs frequent updates. What should you do to resolve the issue without losing the benefits of automatic tuning for other indexes?

Accepted Answer

Manually drop the problematic index using a DROP INDEX command.. Option D is correct because manually dropping the problematic index allows you to resolve the specific performance issue caused by increased write latency while retaining the benefits of automatic tuning for other indexes. The Automatic Tuning feature in Azure SQL Database can create indexes to improve read performance, but these indexes may introduce overhead on write operations. By issuing a DROP INDEX command, you surgically remove only the offending index without disabling the overall tuning mechanism.

Answer

Use the Azure portal to revert all automatic tuning recommendations for the past week.

Answer

Manually create the missing indexes that were dropped by automatic tuning.

Answer

Disable automatic tuning for the entire database.

Question 5

You are responsible for performance tuning of an Azure SQL Database that hosts a customer relationship management (CRM) application. The database has several tables with millions of rows. Users report that a report query that joins four tables is slow. You examine the query execution plan and notice that the database engine is using an Index Spool (Lazy Spool) operator. Which TWO actions should you take to improve query performance? (Choose two.)

Accepted Answer

Create appropriate indexes on the columns used in joins and filters.. An Index Spool (Lazy Spool) operator in an execution plan indicates that the query engine is creating a temporary index on the fly to support join or filter operations, which is a sign of missing or inadequate permanent indexes. Creating appropriate indexes on the columns used in joins and filters (Option C) eliminates the need for the spool, reducing I/O and improving performance. Updating statistics (Option E) ensures the query optimizer has accurate distribution information to generate efficient plans, which can also help avoid spool operations.

Answer

Disable parallelism for the query using the MAXDOP 1 hint.

Answer

Increase the DTU or vCore count of the database.

Answer

Rewrite the query using table hints to force a specific join order.

Question 6

You are the database administrator for an Azure SQL Database used by a financial trading application. The database is in the Business Critical service tier with 16 vCores. The application executes thousands of small, high-frequency transactions per second. Recently, the application's response time has increased, and you observe high PAGELATCH_EX waits in sys.dm_os_waiting_tasks. The database is 500 GB with a single data file (tempdb.mdf) and a single log file (tempdb_log.ldf). TempDB is configured with the default settings. You need to reduce PAGELATCH_EX contention in TempDB. What should you do?

Accepted Answer

Add additional TempDB data files equal to the number of vCores (16).. PAGELATCH_EX contention in TempDB is typically caused by allocation page contention when many concurrent transactions compete for the same system page (e.g., PFS, GAM, SGAM). In Azure SQL Database Business Critical tier, adding multiple TempDB data files equal to the number of vCores (16) reduces contention by distributing allocations across files, each with its own allocation structures. This is a proven best practice for high-concurrency workloads like financial trading applications.

Answer

Move TempDB to Azure Premium Storage for better IO latency.

Answer

Increase the database service tier to 24 vCores.

Answer

Increase the initial size of the TempDB data file to 100 GB.

Question 7

A company runs a critical SQL Server database on Azure Virtual Machines. The database experiences intermittent performance degradation during peak hours. The database administrator notices high I/O latency on the data drive. The current disk configuration uses Standard HDDs. What is the most cost-effective action to reduce I/O latency without changing the virtual machine size?

Accepted Answer

Migrate the data files to Premium SSD managed disks.. Migrating the data files to Premium SSD managed disks is the most cost-effective action to reduce I/O latency without changing the virtual machine size. Premium SSDs provide consistent low-latency performance and higher IOPS/throughput compared to Standard HDDs, directly addressing the high I/O latency during peak hours. This change does not require resizing the VM, keeping compute costs unchanged while improving storage performance.

Answer

Enable instant file initialization in SQL Server.

Answer

Increase the virtual machine size to a series with higher I/O limits.

Answer

Migrate the data files to Standard SSD managed disks.

Question 8

You are monitoring an Azure SQL Database using Query Performance Insight and notice that a specific query has a high average duration and high CPU usage. The query plan shows a clustered index scan on a large table. Which two actions should you take to optimize performance? (Choose two.)

Accepted Answer

Update statistics on the table to ensure the optimizer has current information.. Option B is correct because updating statistics provides the query optimizer with current data distribution information, which can lead to a more efficient query plan, potentially avoiding the clustered index scan. In Azure SQL Database, stale statistics are a common cause of suboptimal plans, and updating them is a low-cost, non-disruptive first step before considering index changes.

Answer

Rebuild the clustered index to reduce fragmentation.

Answer

Force a different query plan using Query Store hints.

Answer

Increase the DTU service tier of the database.

Question 9

Drag and drop the steps to configure an Azure SQL Managed Instance link for disaster recovery in the correct order.

Question 10

Drag and drop the steps to configure transparent data encryption (TDE) for an Azure SQL Database using a customer-managed key in Azure Key Vault in the correct order.

Question 11

Match each Azure SQL Database backup type to its description.

Question 12

Match each Azure SQL Database monitoring metric to its meaning.

Question 13

You have a SQL Managed Instance that hosts a critical OLTP database. You notice that the average query wait time has increased significantly over the past hour. You need to identify the top resource waits. What should you use?

Accepted Answer

sys.dm_os_wait_stats. Option C is correct because sys.dm_os_wait_stats provides cumulative wait statistics across all sessions, which can be used to identify top waits. Option A is wrong because sys.dm_db_index_usage_stats shows index usage, not waits. Option B is wrong because Query Store Wait Stats tracks waits per query, but the question asks for top resource waits overall. Option D is wrong because sys.dm_exec_query_stats shows execution statistics, not waits.

Answer

sys.dm_exec_query_stats

Answer

Query Store Wait Stats in SSMS

Answer

sys.dm_db_index_usage_stats

Question 14

You manage an Azure SQL Database with the Premium service tier. You need to reduce storage costs by automatically deleting old audit logs that are older than 90 days. What should you configure?

Accepted Answer

Configure a lifecycle management policy on the Azure Storage account that stores the audit logs.. Option B is correct because Azure SQL Database audit logs are stored in Azure Storage and a retention policy can be set on the storage account to automatically delete blobs after a specified number of days. Option A is wrong because the audit retention policy in SQL Database is only for the number of days to retain audit records, but it does not automatically delete from storage; deletion is handled by storage lifecycle management. Option C is wrong because Extended Events are not the primary method for audit log cleanup. Option D is wrong because backup retention is unrelated to audit logs.

Answer

Create an Extended Events session that filters and deletes old audit events.

Answer

Reduce the backup retention period to 90 days.

Answer

Set the audit retention policy to 90 days in the server's audit settings.

Question 15

You are reviewing an Azure SQL Database server's vulnerability assessment settings. The exhibit shows the current configuration. A recent security audit requires that vulnerability assessment scans be enabled and that results be retained for at least 90 days. What should you do?

Accepted Answer

Change state to Enabled and set retentionDays to 90.. Option D is correct because the exhibit shows the vulnerability assessment is disabled (state: Disabled) and retentionDays is 30, which is less than 90. You must enable it and set retentionDays to at least 90. Option A is wrong because the disabledAlerts list is about alerts not to send, not the scan itself. Option B is wrong because emailAddresses do not affect scan frequency or retention. Option C is wrong because the state must be enabled, not just retentionDays increased.

Answer

Add additional email addresses to ensure notification.

Answer

Change retentionDays to 90 and keep the state as Disabled.

Answer

Remove the disabledAlerts entries to enable all alerts.