50 Oracle Database 19c: Performance Management and Tuning Practice Questions: Question Bank 2025

A DBA notices that many SQL statements are experiencing hard parses. Which view should be queried to identify the number of hard parses versus soft parses in the system?

An application is experiencing poor performance due to excessive logical reads. Which SQL tuning technique would be MOST effective in reducing logical I/O for queries scanning large tables?

Which component of the System Global Area (SGA) is primarily responsible for caching execution plans?

A developer reports that a query performs well when executed with literal values but poorly when using bind variables. What is the MOST likely cause of this performance difference?

When using Automatic Workload Repository (AWR), what is the default snapshot interval and retention period?

A query is performing a full table scan despite having an appropriate index. After checking statistics, you find they are current. What should you verify NEXT to diagnose the issue?

Which wait event indicates that sessions are waiting for free space in the shared pool to load new SQL or PL/SQL objects?

What is the primary purpose of the Program Global Area (PGA) in Oracle Database architecture?

An AWR report shows high 'db file scattered read' wait events. What type of operations are MOST likely causing these waits?

A complex query with multiple table joins is executing slowly. SQL Tuning Advisor recommends creating a SQL Profile. What does a SQL Profile contain?

A DBA notices that the database buffer cache hit ratio is 92%, but queries are still performing poorly. Which additional metric should be examined to identify the real performance issue?

Which initialization parameter controls the maximum amount of memory that can be automatically allocated to SQL work areas for all sessions?

An application experiences performance degradation during batch processing. The AWR report shows high 'enq: TX - row lock contention' wait events. What is the most effective tuning approach?

What is the primary purpose of the V$SQL_MONITOR view in performance tuning?

A query uses a bind variable for a column with highly skewed data distribution. The execution plan is suboptimal for certain bind values. Which feature should be used to address this issue?

Which background process is responsible for writing dirty buffers from the database buffer cache to disk to ensure that sufficient free buffers are available?

During peak hours, the AWR report shows that 'library cache: mutex X' is the top wait event. What is the most likely cause and recommended solution?

A DBA wants to capture execution statistics for a specific SQL statement over multiple executions to understand its performance behavior. Which method provides the most detailed operational-level statistics?

In a data warehouse environment, which storage option would provide the best I/O performance for large sequential scans while reducing storage costs?

A SQL statement with multiple table joins is executing slowly. The execution plan shows a Cartesian join between two large tables. What is the most likely root cause?

A database administrator notices that a query is performing poorly due to excessive logical reads. Upon examination, the query joins multiple tables without proper indexes. What is the FIRST step the DBA should take to identify which columns need indexing?

Your production database is experiencing slow response times during peak hours. You query V$SYSMETRIC and notice that the 'Database CPU Time Ratio' is consistently at 45%. What does this metric indicate?

An application experiences performance degradation after a significant data volume increase. The DBA runs SQL Tuning Advisor, which recommends creating a SQL profile. What is the PRIMARY purpose of a SQL profile?

A DBA is tuning the PGA memory allocation for a data warehouse that runs many concurrent sort-heavy queries. The current setting is PGA_AGGREGATE_TARGET = 4GB and WORKAREA_SIZE_POLICY = AUTO. Users report that queries frequently spill to disk. Which approach is MOST appropriate?

During performance troubleshooting, you observe high wait times for 'log file sync' events. Which of the following is the MOST likely cause of this issue?

A SQL statement performs well in the development environment but poorly in production despite identical data volumes. The DBA discovers that the optimizer is choosing different execution plans. What is the BEST tool to ensure the production database uses the better execution plan from development?

You need to analyze the performance of a specific SQL statement that completed execution 2 hours ago. The statement is no longer in the shared pool. Which view would provide historical execution statistics for this SQL?

A database supports a mixed workload with both OLTP and batch reporting. During batch windows, reports run slowly despite adequate system resources. Analysis shows high 'read by other session' wait events. What is the MOST likely cause and solution?

You want to implement Real-Time SQL Monitoring for a long-running batch process. The SQL statement includes the /*+ MONITOR */ hint, but monitoring data is not being captured. What is the MOST likely reason?

An organization's database experiences performance issues during month-end processing. The DBA wants to compare current performance metrics with the same period last month. Which Oracle feature provides the BEST capability for this type of historical comparison?

A DBA notices that the buffer cache hit ratio is 98%, but query performance is still poor. What is the MOST likely explanation for this scenario?

Which background process is primarily responsible for writing dirty buffers from the database buffer cache to datafiles to ensure that there are enough free buffers available?

An application is experiencing performance degradation due to library cache contention. Which of the following would MOST effectively address this issue?

What is the purpose of the OPTIMIZER_ADAPTIVE_FEATURES parameter in Oracle Database 19c?

A developer reports that a query with multiple table joins is performing poorly. Upon investigation, you discover that the optimizer is choosing a NESTED LOOPS join when a HASH JOIN would be more appropriate. Statistics are current. What is the BEST approach to resolve this issue?

Which view provides information about the current wait events for active sessions in the database?

A database is experiencing high wait times for 'log file sync' events. Which of the following actions would MOST likely improve this situation?

What is the primary benefit of using Real-Time SQL Monitoring for performance analysis?

An OLTP database is experiencing performance issues during peak hours. Analysis shows high wait times for 'latch: cache buffers chains'. What does this indicate and what is the recommended approach?

When using Automatic Workload Repository (AWR), what is the purpose of creating a baseline?

A DBA notices that the library cache is experiencing high invalidation rates after routine application deployments. Which action would BEST minimize the performance impact of library cache invalidations?

During performance analysis, you observe that wait event 'latch: cache buffers chains' is consuming significant database time. What is the PRIMARY cause of this wait event?

An application developer wants to ensure that a specific SQL statement always uses a particular execution plan regardless of statistics changes. Which method provides the MOST flexible and maintainable solution?

You are configuring Automatic Memory Management (AMM) for a new Oracle 19c database. Which initialization parameter must be set to enable AMM?

A batch processing job is experiencing poor performance due to excessive context switching between PL/SQL and SQL engines. Which optimization technique would MOST effectively reduce this overhead?

Which view would you query to identify SQL statements that have been automatically tuned by the SQL Tuning Advisor during its automatic execution?

A production database is experiencing performance degradation with high wait times for 'log file sync'. After investigation, you discover that the LGWR process is writing to slow storage. Which action would provide the MOST immediate performance improvement?

When analyzing a Real-Time SQL Monitoring report, you notice that one step in the execution plan consumed 95% of the total elapsed time and shows 'FIRST ROWS' as the optimizer mode. What does this indicate about the query execution?

You need to capture performance metrics for a specific application module. Which Oracle feature allows you to tag and track database operations by application module and action for detailed performance analysis?

A complex query with multiple joins is experiencing inconsistent performance. After reviewing V$SQL, you notice multiple child cursors for the same SQL_ID with different execution plans. Adaptive cursor sharing is enabled, but the performance remains unpredictable. What is the BEST approach to stabilize query performance?