Visit here for our full Oracle 1z0-083 exam dumps and practice test questions.
Question 181:
What is the purpose of the RESULT_CACHE hint in SQL queries?
A) To cache query results in the buffer cache
B) To cache query results in the result cache for reuse across sessions
C) To cache execution plans
D) To enable query result compression
Answer: B
Explanation:
The RESULT_CACHE hint caches query results in the result cache for reuse across sessions, enabling Oracle to return cached results for identical queries without re-executing them. This capability dramatically improves performance for queries that are executed frequently with the same parameters and return deterministic results.
The result cache is a memory area in the SGA that stores query results and function result values. When a query with the RESULT_CACHE hint executes, Oracle stores its results in this cache along with a signature of the query. Subsequent executions of the same query by any session can retrieve cached results directly, avoiding parse, execution, and data access overhead.
Cache invalidation occurs automatically when underlying data changes. If any tables referenced by a cached query are modified through DML operations, Oracle invalidates cached results that depend on those tables, ensuring result cache entries remain consistent with current data. This automatic management provides transparent caching without application changes.
The syntax includes SELECT /*+ RESULT_CACHE */ columns FROM tables WHERE conditions. The hint can be specified for entire queries or for individual inline views within complex queries. Result caching is most effective for queries on relatively static reference data or frequently repeated queries in application workloads.
Option A is incorrect because the buffer cache stores data blocks, not query results; the result cache is a separate memory structure. Option C is incorrect because execution plans are cached in the library cache, not through the RESULT_CACHE hint. Option D is incorrect because the hint does not enable compression but rather caching of results.
Question 182:
Which view shows information about SQL plan baselines?
A) DBA_SQL_PLAN_BASELINES
B) V$SQL_PLAN_BASELINE
C) DBA_SQL_BASELINES
D) V$SQL_BASELINE
Answer: A
Explanation:
The DBA_SQL_PLAN_BASELINES view shows information about SQL plan baselines including baseline name, SQL handle, plan name, enabled status, accepted status, and other baseline attributes. This view is essential for managing SQL Plan Management by providing visibility into which statements have baselines, which plans are accepted, and how baselines affect query execution.
Each row represents one plan within a SQL plan baseline, with multiple plans possible for each SQL statement. Columns include SQL_HANDLE uniquely identifying the SQL statement, PLAN_NAME identifying the specific plan, ENABLED indicating whether the baseline can be used, ACCEPTED showing whether the plan is accepted for use, FIXED indicating whether the plan is fixed, and ORIGIN showing how the baseline was created.
SQL Plan Management workflow involves querying DBA_SQL_PLAN_BASELINES to identify statements with baselines, examining plan attributes to understand baseline configuration, evolving new plans that Oracle discovers but has not yet accepted, and managing baselines by fixing, enabling, or disabling specific plans based on performance testing results.
Understanding baseline status is important for troubleshooting. If a query is not using an expected plan, checking DBA_SQL_PLAN_BASELINES reveals whether the plan is in the baseline, whether it is enabled and accepted, and whether other plans might be taking precedence. This information guides decisions about plan evolution and baseline management.
Option B is incorrect because VSQLPLANBASELINEisnotastandardOracledynamicperformanceview.OptionCisincorrectbecauseDBASQLBASELINESisnotthecorrectviewname;OracleusesDBASQLPLANBASELINES.OptionDisincorrectbecauseVSQL_PLAN_BASELINE is not a standard Oracle dynamic performance view. Option C is incorrect because DBA_SQL_BASELINES is not the correct view name; Oracle uses DBA_SQL_PLAN_BASELINES. Option D is incorrect because V SQLPLANBASELINEisnotastandardOracledynamicperformanceview.OptionCisincorrectbecauseDBASQLBASELINESisnotthecorrectviewname;OracleusesDBASQLPLANBASELINES.OptionDisincorrectbecauseVSQL_BASELINE is not a valid view name.
Question 183:
What is the purpose of Database Replay in Oracle Database?
A) To replay archived redo logs
B) To capture and replay actual database workload for testing system changes
C) To replay SQL statements from AWR
D) To backup and restore databases
Answer: B
Explanation:
Database Replay captures and replays actual database workload for testing system changes including database upgrades, hardware migrations, parameter changes, and schema modifications in a test environment. This feature enables realistic testing by reproducing production workload characteristics including concurrency, timing, transaction dependencies, and errors, providing high confidence that changes will work correctly in production.
The replay process has two phases: capture and replay. During capture, Oracle records all database activity including SQL statements, bind variables, transaction patterns, timing information, and session characteristics in capture files. These files represent the complete workload and can be transferred to a test system for replay.
During replay, Oracle reproduces the captured workload on the test system with the proposed changes applied, maintaining the same concurrency patterns, transaction dependencies, and timing characteristics as the original capture. This realistic testing reveals how changes affect the workload, identifying performance regressions, functionality issues, or unexpected behavior before production deployment.
Workload analysis compares replay results against the original capture, highlighting differences in execution times, plans, errors, and resource usage. Reports show which SQL statements performed better or worse, which encountered new errors, and overall system performance differences. This analysis guides decisions about whether to proceed with changes or perform additional tuning.
Option A is incorrect because replaying archived redo logs is part of recovery operations, not Database Replay for workload testing. Option C is incorrect because replaying SQL from AWR involves SQL Performance Analyzer, not Database Replay which captures complete workload including concurrency. Option D is incorrect because backup and restore operations are separate from workload replay functionality.
Question 184:
Which parameter controls whether the database automatically manages the size of the shared pool?
A) SHARED_POOL_SIZE
B) SGA_TARGET
C) AUTO_SHARED_POOL
D) MEMORY_TARGET
Answer: B
Explanation:
The SGA_TARGET parameter enables automatic shared memory management including automatic sizing of the shared pool along with other automatically sized SGA components. When SGA_TARGET is set to a non-zero value, Oracle dynamically distributes memory among the buffer cache, shared pool, large pool, and Java pool based on workload demands, adjusting the shared pool size automatically.
Automatic shared memory management simplifies administration by eliminating the need to manually size individual SGA components. Oracle monitors memory usage patterns and access frequencies, growing components that need more memory and shrinking underutilized components. The shared pool grows when parse activity increases or shrinks when parsing demand decreases, with freed memory reallocated to other components.
Setting SHARED_POOL_SIZE when using automatic management establishes a minimum size for the shared pool, preventing it from shrinking below this threshold even if automatic tuning would suggest a smaller size. This capability allows administrators to guarantee minimum memory for critical components while still benefiting from automatic tuning for the remainder.
The relationship between SGA_TARGET and MEMORY_TARGET extends automatic management. MEMORY_TARGET enables automatic memory management across both SGA and PGA, providing even more flexible memory distribution. With MEMORY_TARGET set, Oracle manages total instance memory, distributing it between SGA and PGA as workload characteristics dictate.
Option A is incorrect because SHARED_POOL_SIZE when set manually controls a fixed shared pool size but does not enable automatic management; SGA_TARGET enables automatic sizing. Option C is incorrect because AUTO_SHARED_POOL is not a valid Oracle parameter. Option D is partially correct as MEMORY_TARGET enables broader automatic memory management including the shared pool, but SGA_TARGET is the more direct answer for SGA component management.
Question 185:
What is the purpose of the CURSOR_SHARING parameter?
A) To share cursors between users
B) To control whether Oracle can replace literals with bind variables for cursor sharing
C) To manage cursor cache size
D) To enable parallel cursor execution
Answer: B
Explanation:
The CURSOR_SHARING parameter controls whether Oracle can replace literals with bind variables for cursor sharing, enabling reuse of execution plans for SQL statements that differ only in literal values. This feature helps applications that use literals instead of bind variables by reducing parse overhead through cursor sharing, though using bind variables in application code is the preferred approach.
Parameter values include EXACT meaning cursors are shared only when SQL text matches exactly including literals, SIMILAR allowing Oracle to replace literals with bind variables for cursor sharing but using different plans when literal values would affect optimal plans, and FORCE which aggressively replaces literals with bind variables to maximize cursor sharing even if this sometimes results in suboptimal plans.
EXACT is the recommended and default value for well-written applications that use bind variables properly. Applications requiring SIMILAR or FORCE indicate potential design issues where SQL is generated with embedded literals. These settings provide relief from parse overhead but the better solution is modifying applications to use bind variables.
The impact of CURSOR_SHARING affects parse performance and execution plan selection. FORCE maximizes cursor sharing and minimizes hard parsing but may cause suboptimal plans when literal values should influence optimization. SIMILAR attempts to balance cursor sharing with plan quality but adds complexity. EXACT avoids these trade-offs but requires application-level bind variable usage.
Option A is incorrect because cursor sharing refers to reusing parsed cursors for similar SQL statements, not sharing cursors between users in a security context. Option C is incorrect because cursor cache size is controlled by shared pool sizing, not CURSOR_SHARING. Option D is incorrect because parallel execution is controlled by different parameters and hints, not CURSOR_SHARING.
Question 186:
Which view provides information about online redo log groups and their members?
A) V$LOGFILE
B) V$LOG
C) DBA_LOG_GROUPS
D) Both A and B provide complementary information
Answer: D
Explanation:
Both VLOGFILEandVLOGFILE and V LOGFILEandVLOG provide complementary information about online redo log groups and their members. VLOGshowsinformationaboutredologgroupsincludinggroupnumber,sequencenumber,status,andsize,whileVLOG shows information about redo log groups including group number, sequence number, status, and size, while V LOGshowsinformationaboutredologgroupsincludinggroupnumber,sequencenumber,status,andsize,whileVLOGFILE shows individual log file members within each group including file names, locations, and status. Together, these views provide complete visibility into online redo log configuration and operational status.
V$LOG contains one row per redo log group with information including group number, thread number for RAC configurations, sequence number indicating which log is currently active, bytes showing log size, members indicating how many files are in the group, status showing whether the log is CURRENT, ACTIVE, or INACTIVE, and archived indicating whether the log has been archived. This group-level view helps understand log switching patterns and archiving status.
V$LOGFILE contains one row per log file member showing the group number the member belongs to, member file name with full path, type indicating whether it is online or standby redo log, and status showing whether the member is valid or has errors. This file-level view helps identify individual file issues and verify that all log groups are properly multiplexed.
Joining these views provides comprehensive redo log information. A typical query joins VLOGwithVLOG with V LOGwithVLOGFILE on group number to show which files belong to which groups, their locations, current status, and whether multiplexing is properly configured. This combined view supports redo log management, troubleshooting, and capacity planning.
Option A is partially correct as VLOGFILEshowsmemberinformationbutdoesnotshowgroup−leveldetailslikesequencenumbersandstatus.OptionBispartiallycorrectasVLOGFILE shows member information but does not show group-level details like sequence numbers and status. Option B is partially correct as V LOGFILEshowsmemberinformationbutdoesnotshowgroup−leveldetailslikesequencenumbersandstatus.OptionBispartiallycorrectasVLOG shows group information but not individual member details. Option C is incorrect because DBA_LOG_GROUPS is not a standard Oracle view. Option D correctly recognizes that both views together provide complete redo log information.
Question 187:
What is the purpose of In-Memory Column Store in Oracle Database?
A) To store all database columns in memory
B) To provide a columnar in-memory format for analytical query performance
C) To cache frequently accessed columns
D) To compress column data automatically
Answer: B
Explanation:
In-Memory Column Store provides a columnar in-memory format for analytical query performance by maintaining a separate columnar representation of selected tables alongside the traditional row-based storage. This dual-format architecture enables fast analytical queries through columnar scanning while preserving row-based access for transactional operations.
The columnar format stores each column’s data contiguously in memory, enabling efficient scanning of specific columns without reading unneeded data. When analytical queries need to scan millions of rows but access only a few columns, columnar format dramatically reduces memory bandwidth requirements and enables SIMD vector processing for faster computation. This architecture particularly benefits data warehouse and analytical workloads.
Tables are populated into the In-Memory Column Store by specifying INMEMORY attribute during table creation or through ALTER TABLE statements. Oracle manages populating and maintaining the in-memory representation automatically, keeping it synchronized with disk-based data as DML operations occur. Queries transparently benefit from in-memory access when appropriate.
Compression options for in-memory data include various levels optimized for different balance points between compression ratio and query performance. MEMCOMPRESS FOR QUERY LOW provides minimal compression with fastest query performance, while MEMCOMPRESS FOR CAPACITY HIGH provides maximum compression with slightly reduced query speed. These options allow tuning memory usage against performance requirements.
Option A is incorrect because not all columns are stored in memory automatically; specific tables or columns must be designated for in-memory storage. Option C is incorrect because this is not a simple cache but a columnar storage format with specific analytical optimization. Option D is incorrect because while compression is available, automatic compression of columns is not the primary purpose.
Question 188:
Which parameter controls the size of the In-Memory Column Store?
A) INMEMORY_SIZE
B) MEMORY_INMEMORY_SIZE
C) INMEMORY_AREA_SIZE
D) SGA_INMEMORY_SIZE
Answer: A
Explanation:
The INMEMORY_SIZE parameter controls the size of the In-Memory Column Store, specifying how much memory is allocated within the SGA for storing columnar representations of in-memory enabled tables. Setting this parameter to a non-zero value enables the In-Memory Column Store feature and determines how much table data can be cached in columnar format.
The parameter specifies memory size in bytes or using size units like M for megabytes or G for gigabytes. For example, INMEMORY_SIZE=2G allocates 2 gigabytes for the In-Memory Column Store. This memory is separate from the buffer cache and other SGA components, dedicated specifically to maintaining columnar representations of in-memory enabled objects.
Sizing considerations include the size of tables and columns designated as in-memory, compression ratios which affect how much data fits in allocated memory, and analytical workload requirements determining how much data should be available in columnar format. Unlike the buffer cache where data enters automatically based on access patterns, the In-Memory Column Store is populated explicitly based on INMEMORY object attributes.
The relationship with other memory parameters means INMEMORY_SIZE allocates memory from the overall SGA. When using automatic memory management through SGA_TARGET or MEMORY_TARGET, the in-memory area is allocated from the managed memory pool. Total SGA size must accommodate buffer cache, shared pool, and in-memory area together.
Option B is incorrect because MEMORY_INMEMORY_SIZE is not a valid Oracle parameter name. Option C is incorrect because INMEMORY_AREA_SIZE is not the correct parameter name. Option D is incorrect because SGA_INMEMORY_SIZE is not a valid parameter; Oracle uses INMEMORY_SIZE.
Question 189: What is the purpose of the DBMS_WORKLOAD_REPOSITORY package?
A) To capture database workload
B) To create and manage AWR snapshots and reports
C) To tune workload performance
D) To schedule workload operations
Answer: B
Explanation:
The DBMS_WORKLOAD_REPOSITORY package creates and manages AWR snapshots and reports, providing programmatic control over Automatic Workload Repository functionality. This package enables administrators to manually create snapshots outside the automatic schedule, generate AWR reports for specific time periods, modify snapshot retention settings, and manage AWR baseline creation and maintenance.
Key procedures include CREATE_SNAPSHOT to manually capture an AWR snapshot at the current point in time, useful for capturing performance data before and after specific operations, AWR_REPORT_TEXT and AWR_REPORT_HTML to generate AWR reports in text or HTML format for specified snapshot intervals, DROP_SNAPSHOT_RANGE to remove old snapshots outside retention policies, and MODIFY_SNAPSHOT_SETTINGS to adjust snapshot interval and retention period.
Manual snapshot creation supports before-and-after performance analysis. Taking snapshots immediately before and after a maintenance operation, application deployment, or configuration change enables precise comparison of performance metrics during those specific periods. This focused analysis complements regular automatic snapshots taken hourly.
AWR report generation through DBMS_WORKLOAD_REPOSITORY provides programmatic access to performance analysis, enabling automated report generation in scripts, scheduled report production for regular performance reviews, and custom report creation for specific time periods of interest. Reports can be generated for any snapshot interval available in the AWR repository.
Option A is incorrect because capturing workload is done by AWR automatically or through Database Replay features, not primarily by this package which manages AWR snapshots. Option C is incorrect because tuning workload performance involves advisors and tuning tools, while this package manages performance data collection. Option D is incorrect because scheduling is handled by DBMS_SCHEDULER, while this package manages AWR data.
Question 190:
Which view shows information about current waits for active sessions?
A) V$SESSION_WAIT
B) V$ACTIVE_SESSION_HISTORY
C) V$SESSION_WAIT_HISTORY
D) All of the above provide wait information
Answer: D
Explanation:
All of the mentioned views provide wait information with different perspectives and purposes. VSESSIONWAITshowscurrentwaiteventsforsessions,VSESSION_WAIT shows current wait events for sessions, V SESSIONWAITshowscurrentwaiteventsforsessions,VACTIVE_SESSION_HISTORY provides sampled historical wait information, and V$SESSION_WAIT_HISTORY maintains recent wait history for each session. Together, these views enable comprehensive wait event analysis from real-time to historical perspectives.
V$SESSION_WAIT displays what each session is currently waiting for, showing the wait event name, wait time, and event-specific parameters. This view provides immediate visibility into what is blocking sessions at the present moment, essential for diagnosing current performance issues. When a session is active on CPU rather than waiting, the wait event shows as “SQL*Net message from client” or similar idle events.
V$ACTIVE_SESSION_HISTORY samples session activity including wait events every second, storing samples in memory and periodically flushing to disk for persistent storage in DBA_HIST_ACTIVE_SESS_HISTORY. This sampling provides a historical record of what sessions were doing, enabling analysis of past performance issues and identification of patterns that might not be visible in current real-time views.
V$SESSION_WAIT_HISTORY keeps the last 10 wait events for each session, providing recent wait context that helps understand what a session was doing immediately before its current state. This history is valuable when investigating intermittent issues or understanding session behavior patterns that span multiple wait events.
Option A is correct for current real-time wait information. Option B is correct for historical sampled wait data. Option C is correct for recent wait history per session. Option D correctly identifies that all three views provide complementary wait information at different granularities and time horizons.
Question 191:
What is the purpose of the DBMS_SQL package?
A) To optimize SQL statements
B) To execute dynamic SQL with more control than native dynamic SQL
C) To parse SQL syntax
D) To format SQL output
Answer: B
Explanation:
The DBMS_SQL package executes dynamic SQL with more control than native dynamic SQL, providing a procedural interface for parsing, binding, executing, and fetching results from SQL statements constructed at runtime. While native dynamic SQL using EXECUTE IMMEDIATE is simpler and preferred for most cases, DBMS_SQL offers capabilities not available through native dynamic SQL including the ability to parse once and execute many times with different bind values, support for method 4 dynamic SQL with unknown number of select list items or bind variables, and detailed control over cursor management and execution phases.
The DBMS_SQL workflow involves multiple steps with explicit control at each phase. OPEN_CURSOR allocates a cursor for use, PARSE compiles the SQL statement, BIND_VARIABLE associates values with bind variables in the statement, EXECUTE runs the statement, FETCH_ROWS retrieves result rows for queries, and CLOSE_CURSOR releases the cursor. This multi-step approach provides flexibility for complex dynamic SQL scenarios.
Use cases include applications that need to parse statements once and execute many times with different bind values, improving performance by avoiding repeated parsing, SQL with unknown structure at design time where the number or types of columns or bind variables is determined at runtime, and situations requiring fine-grained control over cursor execution phases for performance optimization or special processing requirements.
Native dynamic SQL through EXECUTE IMMEDIATE is simpler and sufficient for most dynamic SQL needs. Use DBMS_SQL only when specific capabilities it provides are necessary. For straightforward dynamic execution, native dynamic SQL has lower overhead and cleaner syntax.
Option A is incorrect because optimizing SQL involves SQL Tuning Advisor and optimization features, not DBMS_SQL which executes dynamic SQL. Option C is incorrect because while DBMS_SQL includes a parse phase, its purpose is execution, not just parsing. Option D is incorrect because formatting SQL output uses SQL*Plus formatting commands or presentation layer logic, not DBMS_SQL.
Question 192:
Which parameter controls whether Oracle uses asynchronous I/O for datafile operations?
A) DISK_ASYNCH_IO
B) ASYNC_IO
C) FILESYSTEMIO_OPTIONS
D) USE_ASYNC_IO
Answer: A
Explanation:
The DISK_ASYNCH_IO parameter controls whether Oracle uses asynchronous I/O for datafile operations, enabling concurrent I/O operations that improve performance by allowing the database to initiate multiple I/O requests without waiting for each to complete sequentially. Asynchronous I/O is particularly beneficial for systems with multiple CPUs and I/O subsystems capable of handling concurrent requests.
When DISK_ASYNCH_IO is set to TRUE, Oracle can submit I/O requests to the operating system and continue processing without blocking until the I/O completes. The operating system handles multiple concurrent I/O operations, and Oracle checks for completion asynchronously. This approach significantly improves throughput compared to synchronous I/O where each I/O operation blocks until completed.
The parameter works in conjunction with operating system support for asynchronous I/O. Not all operating systems and file systems support asynchronous I/O, so Oracle automatically detects capabilities and adjusts behavior accordingly. On systems without proper async I/O support, setting the parameter to TRUE has no effect as Oracle falls back to synchronous operations.
The FILESYSTEMIO_OPTIONS parameter provides additional control over file I/O behavior including directio, asynch, setall, and none values that affect both asynchronous I/O and direct I/O usage. These parameters work together to optimize I/O operations based on operating system capabilities and workload characteristics.
Option B is incorrect because ASYNC_IO is not a valid Oracle parameter name for this purpose. Option C is partially related as FILESYSTEMIO_OPTIONS affects I/O behavior but is more comprehensive than just asynchronous I/O control. Option D is incorrect because USE_ASYNC_IO is not an Oracle parameter name.
Question 193:
What is the purpose of the UTL_FILE package?
A) To manage database files
B) To read from and write to operating system files from PL/SQL
C) To transfer files between databases
D) To backup files automatically
Answer: B
Explanation:
The UTL_FILE package reads from and writes to operating system files from PL/SQL, providing file I/O capabilities within stored procedures, functions, and anonymous PL/SQL blocks. This package enables PL/SQL programs to interact with the file system for tasks like generating reports, reading configuration files, logging application events, and exchanging data with external systems.
Key procedures and functions include FOPEN to open files for reading or writing, IS_OPEN to check whether a file handle represents an open file, GET_LINE to read a line from a file, PUT_LINE to write a line to a file, NEW_LINE to write line terminators, FFLUSH to physically write buffered data, and FCLOSE to close files. These operations provide comprehensive file manipulation capabilities from PL/SQL.
Security considerations are important with UTL_FILE. The UTL_FILE_DIR initialization parameter or Oracle directory objects control which operating system directories PL/SQL programs can access. This restriction prevents PL/SQL code from reading or writing arbitrary files on the database server. Directory objects provide better security and management than UTL_FILE_DIR.
Common use cases include generating flat file reports from database data, reading configuration or parameter files during application initialization, logging application events and errors to external log files, exchanging data with external systems through file interfaces, and implementing file-based batch processes that integrate with non-database systems.
Option A is incorrect because managing database files like datafiles and control files involves different mechanisms, not UTL_FILE which operates on operating system files external to the database. Option C is incorrect because transferring files between databases typically uses database links or replication features, not UTL_FILE. Option D is incorrect because backups use RMAN and backup utilities, not UTL_FILE.
Question 194:
Which view provides information about current SQL execution details including actual execution statistics?
A) V$SQL
B) V$SQL_MONITOR
C) V$SQLSTATS
D) V$SQL_PLAN_MONITOR
Answer: B
Explanation:
The V$SQL_MONITOR view provides information about current SQL execution details including actual execution statistics, real-time monitoring data, and execution progress for long-running queries. This view is part of Oracle’s Real-Time SQL Monitoring feature which automatically monitors SQL statements that run for more than 5 seconds or use parallel execution, providing unprecedented visibility into query execution.
SQL monitoring captures detailed execution information including actual rows processed at each step, memory and temporary space usage, I/O statistics, elapsed time and CPU time per operation, parallel execution details, and progress indicators for long operations. This data enables precise diagnosis of performance issues by showing exactly where time and resources are consumed during execution.
The view contains columns for SQL_ID identifying the statement, SQL_EXEC_START and SQL_EXEC_ID identifying specific executions, STATUS showing whether execution is in progress or completed, elapsed time and CPU time consumed, and various statistics about rows processed, I/O operations, and resource usage. This comprehensive information supports both real-time monitoring and post-execution analysis.
Real-Time SQL Monitoring is particularly valuable for troubleshooting because it shows actual execution behavior rather than estimated behavior from execution plans. Comparing actual rows processed versus estimated rows quickly identifies cardinality estimation problems. Seeing which plan operations consume most time directs tuning efforts to the actual bottlenecks rather than assumed problem areas.
Option A is incorrect because VSQLshowscumulativestatisticsforSQLinthecursorcachebutnotdetailedper−executionmonitoringinformation.OptionCisincorrectbecauseVSQL shows cumulative statistics for SQL in the cursor cache but not detailed per-execution monitoring information. Option C is incorrect because V SQLshowscumulativestatisticsforSQLinthecursorcachebutnotdetailedper−executionmonitoringinformation.OptionCisincorrectbecauseVSQLSTATS shows aggregated SQL statistics but not execution details. Option D is partially related as it shows plan-level monitoring details but V$SQL_MONITOR is the primary view for SQL execution monitoring.
Question 195:
What is the purpose of the DISABLE VALIDATE constraint state?
A) To disable and remove constraint validation
B) To disable DML on the table while maintaining constraint definition
C) To validate existing data without enforcing the constraint
D) To temporarily disable constraint checking
Answer: B
Explanation:
The DISABLE VALIDATE constraint state disables DML on the table while maintaining constraint definition, effectively making the table read-only while keeping the constraint metadata active. This unusual state is useful in specific scenarios like data warehouse loading where you want to prevent modifications while ensuring the constraint definition remains in place for optimizer benefit and documentation purposes.
When a constraint is in DISABLE VALIDATE state, Oracle does not enforce the constraint for DML operations because DML is blocked entirely. However, the constraint definition remains active in the data dictionary, and the optimizer can use constraint information for query optimization decisions like join elimination or partition pruning. This provides query optimization benefits without the overhead of constraint enforcement during bulk loading.
The syntax ALTER TABLE table_name MODIFY CONSTRAINT constraint_name DISABLE VALIDATE puts the constraint into this state. The table becomes read-only for data modifications, preventing INSERT, UPDATE, and DELETE operations. Queries continue to work normally, and the constraint definition remains visible in data dictionary views.
Use cases include data warehouse maintenance windows where historical tables should not change but must remain queryable, bulk loading scenarios where you want to prevent concurrent modifications without disabling constraints completely, and situations requiring guaranteed data stability while maintaining constraint metadata for optimizer use and schema documentation.
Option A is incorrect because validation is maintained, not removed; the state keeps constraint metadata active. Option C is incorrect because validation in this context means the constraint is active in metadata, not that data is being validated. Option D is incorrect because while checking is disabled, the primary purpose is making the table read-only while maintaining constraint definition.
Question 196:
Which package provides procedures for managing SQL profiles?
A) DBMS_SQL_PROFILE
B) DBMS_SQLTUNE
C) DBMS_SQL_MANAGE
D) DBMS_ADVISOR
Answer: B
Explanation:
The DBMS_SQLTUNE package provides procedures for managing SQL profiles along with other SQL tuning capabilities including running SQL Tuning Advisor, managing SQL tuning sets, and implementing tuning recommendations. This comprehensive tuning package is the primary interface for programmatic SQL performance optimization and SQL profile management.
SQL profile management procedures include ACCEPT_SQL_PROFILE to implement a SQL profile recommended by SQL Tuning Advisor, DROP_SQL_PROFILE to remove a SQL profile, ALTER_SQL_PROFILE to modify profile attributes like name or category, and LOAD_SQLSET to create SQL tuning sets containing SQL statements for analysis. These procedures provide complete lifecycle management for SQL profiles.
The package also includes procedures for running SQL Tuning Advisor programmatically. CREATE_TUNING_TASK creates a new tuning task for specified SQL statements, SET_TUNING_TASK_PARAMETER configures task parameters, EXECUTE_TUNING_TASK runs the analysis, and REPORT_TUNING_TASK retrieves recommendations. This workflow enables automated SQL tuning without using Enterprise Manager interfaces.
SQL tuning sets managed through DBMS_SQLTUNE capture SQL statements with their execution contexts for analysis. CREATE_SQLSET creates a new tuning set, LOAD_SQLSET populates it with SQL statements from cursor cache or AWR, and SELECT_SQLSET queries statements in the set. Tuning sets enable batch analysis of multiple SQL statements and support SQL Performance Analyzer for testing.
Option A is incorrect because DBMS_SQL_PROFILE is not a valid Oracle package name. Option C is incorrect because DBMS_SQL_MANAGE is not an Oracle package, though it might seem related to SQL management. Option D is incorrect because while DBMS_ADVISOR runs various advisors, SQL profile management is specifically in DBMS_SQLTUNE.
Question 197:
What is the purpose of the PGA_AGGREGATE_TARGET parameter?
A) To set the target size for each session’s PGA
B) To set the target aggregate PGA memory for all server processes
C) To limit total database memory
D) To control PGA memory for background processes only
Answer: B
Explanation:
The PGA_AGGREGATE_TARGET parameter sets the target aggregate PGA memory for all server processes collectively, enabling automatic PGA memory management that distributes available PGA memory among sessions based on their workload requirements. This parameter simplifies PGA configuration by eliminating the need to set individual work area sizes for different operation types like sorts and hash joins.
When PGA_AGGREGATE_TARGET is set, Oracle automatically manages work area sizes for SQL operations using PGA memory. Sessions performing memory-intensive operations like large sorts or hash joins receive more PGA allocation from the aggregate target, while sessions with lighter memory needs receive less. This dynamic allocation optimizes memory usage across all sessions based on current workload characteristics.
The parameter specifies a target, not a hard limit in most Oracle versions. Sessions can exceed the target temporarily if needed for operation completion, though Oracle attempts to keep total PGA usage near the target. In Oracle 12c and later, PGA_AGGREGATE_LIMIT provides a hard limit on total PGA usage to prevent memory exhaustion.
Automatic PGA memory management controlled by PGA_AGGREGATE_TARGET replaces older manual configuration of individual work area parameters like SORT_AREA_SIZE and HASH_AREA_SIZE. Automatic management provides better memory utilization by allocating memory dynamically based on actual workload needs rather than static per-operation limits.
Option A is incorrect because the parameter sets aggregate memory for all sessions, not per-session limits. Option C is incorrect because limiting total database memory uses MEMORY_TARGET which includes both SGA and PGA. Option D is incorrect because the parameter affects server processes handling user sessions, not background processes which have separate memory management.
Question 198:
Which view shows information about materialized view refresh times and methods?
A) DBA_MVIEWS
B) DBA_MVIEW_REFRESH_TIMES
C) V$MVIEW_REFRESH
D) DBA_REFRESH_CHILDREN
Answer: A
Explanation:
The DBA_MVIEWS view shows information about materialized views including refresh times and methods along with comprehensive materialized view attributes. This view contains columns for refresh method such as COMPLETE, FAST, or FORCE, refresh mode indicating ON DEMAND or ON COMMIT, last refresh date, staleness indicating whether the view is stale, and many other attributes controlling materialized view behavior.
Key columns include MVIEW_NAME identifying the view, OWNER showing the schema, REFRESH_METHOD indicating how refresh occurs with C for complete, F for fast, or FORCE to attempt fast and fall back to complete, REFRESH_MODE showing whether refresh is manual or automatic, LAST_REFRESH_DATE showing when the view was last updated, and STALENESS indicating whether the view needs refresh.
The view provides essential information for managing materialized view refresh strategies. Administrators query DBA_MVIEWS to verify refresh configuration, identify stale views needing refresh, confirm that refresh methods are optimal for each view, and plan refresh schedules based on refresh frequency requirements and last refresh times.
Additional views complement DBA_MVIEWS for complete materialized view management. DBA_MVIEW_REFRESH_TIMES shows detailed refresh timing history, DBA_REFRESH and DBA_REFRESH_CHILDREN show refresh group memberships for coordinated refresh of multiple views, and USER_MVIEWS and ALL_MVIEWS provide scoped views for current user or accessible materialized views.
Option B is incorrect because DBA_MVIEW_REFRESH_TIMES is not a standard Oracle view name, though it describes related functionality. Option C is incorrect because V$MVIEW_REFRESH is not a standard dynamic performance view. Option D is incorrect because DBA_REFRESH_CHILDREN shows refresh group membership, not comprehensive materialized view information including refresh methods.
Question 199:
What is the purpose of the NOPARALLEL hint?
A) To prevent parallel execution of a SQL statement
B) To disable parallel processing permanently
C) To reduce the degree of parallelism
D) To force serial execution temporarily
Answer: A
Explanation:
The NOPARALLEL hint prevents parallel execution of a SQL statement, forcing serial execution even when the optimizer might otherwise choose parallel execution based on table attributes, system configuration, or estimated execution cost. This hint is useful when parallel execution overhead would exceed benefits for specific queries or when serial execution is required for specific operational reasons.
Parallel execution can introduce overhead from coordinating multiple parallel execution servers, communication between processes, and resource consumption that may not be justified for smaller operations. The NOPARALLEL hint allows explicitly disabling parallelism for queries where the overhead would hurt rather than help performance, such as small table scans or operations that complete very quickly.
The syntax includes SELECT /*+ NOPARALLEL(table_alias) */ columns FROM table table_alias WHERE conditions. The hint can specify table aliases to disable parallelism for specific table access within complex queries, or be applied at the statement level to prevent any parallel operations.
Use cases include queries known to be fast enough serially that parallel overhead is not beneficial, situations where system resources are constrained and parallel execution would cause contention, development and testing scenarios where consistent serial execution is desired for repeatability, and operational requirements where parallel execution interferes with other concurrent operations.
Option B is incorrect because the hint affects the specific SQL statement, not permanent database-wide settings. Option C is incorrect because reducing parallelism degree uses the PARALLEL hint with a lower degree value, not NOPARALLEL which eliminates parallelism entirely. Option D is partially correct but less precise than option A; the hint prevents rather than just forces serial execution.
Question 200:
Which parameter controls the maximum number of redo log file groups that can be defined in the control file?
A) MAXLOGFILES
B) MAXLOGGROUPS
C) MAX_LOG_FILES
D) LOG_FILE_GROUPS
Answer: A
Explanation:
The MAXLOGFILES parameter controls the maximum number of redo log file groups that can be defined in the control file, setting an upper bound on redo log group creation at database creation time. This parameter is specified in the CREATE DATABASE statement and becomes a fixed attribute of the control file, determining how many log group entries the control file can accommodate.
The parameter establishes a limit on the number of online redo log groups that can exist in the database throughout its lifetime. When the database is created, the control file is structured to accommodate up to MAXLOGFILES groups. This limit cannot be increased without recreating the control file using CREATE CONTROLFILE command, making initial sizing important.
Typical values range from 8 to 255 depending on anticipated needs. Most databases use relatively few log groups, often 3 to 6, but setting MAXLOGFILES higher provides flexibility for future needs without requiring control file recreation. The parameter consumes minimal control file space, so setting it somewhat higher than immediately needed is prudent.
The distinction between MAXLOGFILES and MAXLOGMEMBERS is important. MAXLOGFILES limits the number of groups, while MAXLOGMEMBERS limits how many member files can exist within each group for multiplexing. Together, these parameters establish the complete upper bounds for redo log configuration.
Option B is incorrect because MAXLOGGROUPS is not the parameter name Oracle uses; the parameter is MAXLOGFILES. Option C is incorrect because MAX_LOG_FILES uses incorrect parameter naming with underscores. Option D is incorrect because LOG_FILE_GROUPS is not a valid Oracle parameter name for this purpose.
