Oracle Database 19c: Performance Management and Tuning Practice Exam 2025: Latest Questions

A DBA notices that the database is experiencing performance degradation. When examining AWR reports, which wait event would indicate that users are waiting for database blocks to be read from disk into memory?

Which Oracle performance tuning methodology recommends starting with the most significant bottleneck first and addressing issues in a top-down manner?

A SQL statement is performing poorly. Upon investigation, you find that the optimizer is choosing a full table scan instead of using an available index. The statistics are current. What SQL Plan Management feature can you use to force the optimizer to use a better execution plan without modifying the SQL code?

Your database has 32GB of physical memory and you want to optimize the System Global Area (SGA). Which initialization parameter enables Oracle to automatically manage the sizing of SGA components like the buffer cache, shared pool, and large pool?

A developer reports that a query retrieving customer orders is running slowly. You examine the execution plan and see a NESTED LOOPS join between CUSTOMERS (1,000 rows) and ORDERS (1,000,000 rows) tables. The ORDERS table is being accessed first. What is the most likely problem?

Which dynamic performance view provides real-time information about currently active sessions and their wait events, making it essential for diagnosing ongoing performance issues?

You are tuning a data warehouse query that joins multiple large dimension tables to a fact table. The query is using HASH joins, but you notice excessive direct path reads and writes to temporary tablespace. What is the most effective solution to improve performance?

An application experiences periodic performance degradation every day at noon. When you check the AWR report for that time period, you see high values for 'latch: cache buffers chains' wait event. What is the most likely cause and appropriate solution?

You need to capture detailed execution statistics for a specific SQL statement to diagnose why it's performing poorly in production but runs fine in test. Which method allows you to gather comprehensive statistics including actual row counts, memory usage, and timing information for each step of the execution plan?

Your OLTP database has multiple tablespaces on different storage tiers. You notice that certain datafiles show significantly higher I/O wait times than others in AWR reports. The application cannot be modified. Which Oracle feature can help redistribute I/O across multiple storage devices to balance the load?

A database administrator notices that the shared pool is experiencing high fragmentation and frequent reloads of SQL statements. Which initialization parameter should be adjusted to reserve a portion of the shared pool for large contiguous memory allocations?

During a performance analysis, you observe that many sessions are waiting on 'log file sync' events. The average wait time is consistently high. Which of the following actions is MOST likely to reduce these wait times?

An application executes a SQL query that performs poorly. The execution plan shows a HASH JOIN operation with a cardinality estimate of 100 rows, but the actual number of rows is 500,000. What is the MOST appropriate immediate action to resolve this issue?

You are analyzing I/O performance and notice that the average read time for a particular datafile is significantly higher than others. The datafile contains a heavily accessed table. Which query would BEST help identify the specific segments causing the I/O bottleneck?

A development team reports that a batch process using MERGE statements is running slowly. Upon investigation, you find that the target table has 15 indexes. What is the BEST recommendation to improve performance?

You need to monitor real-time SQL execution statistics for active sessions without waiting for the SQL to complete. Which view provides the most current execution statistics for currently executing SQL statements?

An OLTP database is experiencing performance degradation. Analysis shows high wait times for 'db file sequential read' events concentrated during business hours. The tablespace is using Automatic Segment Space Management (ASSM) with an 8KB block size. What is the MOST likely cause and solution?

You are configuring memory management for a database server with 64GB RAM dedicated to Oracle. The workload is mixed OLTP and batch processing. Which memory management approach provides the best balance of automation and control?

A SQL statement is using bind variables, but the execution plan varies significantly between executions with different bind values, leading to suboptimal performance. The query filters on a column with highly skewed data distribution. What feature should be enabled to address this issue?

You are troubleshooting a performance issue where the database is experiencing periodic slowdowns. AWR reports show that during these periods, the 'log file parallel write' wait event spikes significantly while 'log file sync' remains relatively stable. What is the MOST likely root cause?

A DBA notices that a session is frequently executing a SQL statement that performs full table scans on a large table. The statement includes a WHERE clause on a column that has low cardinality. What is the MOST appropriate action to improve performance?

During peak hours, you observe high wait events for 'log file sync' in your OLTP database. Which TWO configuration changes would MOST effectively reduce these wait events?

You need to gather performance statistics for a specific SQL statement that is currently running in production. Which view should you query to see real-time execution statistics including physical reads, logical reads, and elapsed time for an active SQL statement?

A database is experiencing performance degradation due to library cache contention. You observe high values for 'library cache: mutex X' wait events. After analyzing V$LIBRARYCACHE, you find that the RELOADS column shows high values for the SQL AREA namespace. What is the MOST likely cause and appropriate solution?

You are troubleshooting a poorly performing query. After reviewing the execution plan, you notice that the optimizer chose a HASH JOIN instead of a NESTED LOOPS join, which you believe would be more efficient for this particular query with selective predicates. What is the BEST approach to influence the optimizer's decision?