Pass the Oracle Database 23ai 1z0-182 Questions and answers with ExamsMirror

A.False. STOP_JOB=IMMEDIATE halts the job, not backgrounds it.

B.False. You can monitor before stopping or after restarting.

C.True. Before stopping, you can reattach with expdp attach=exp_db_full.

D.True. STOP_JOB=IMMEDIATE terminates the job instantly.

A.False. Connect Time Failover doesn’t need TAF; TAF is for runtime failover.

B.False. Source Routing doesn’t mandate encryption.

C.True. Needs multiple addresses (e.g., (ADDRESS_LIST=...)) for failover.

D.False. Load balancing works with tnsnames.ora, no name server required.

E.True. Balances connections across shared server dispatchers.

Background processes manage core database operations. Let’s break it down:

A. Creating dedicated server connections.

Explanation:False. Dedicated server connections are created by the listener, not background processes. The listener hands off the connection to a server process (e.g., ora_s000), which isn’t a background process.

B. Registering services with Oracle Net listeners.

Explanation:True. The LREG process (Listener Registration, formerly PMON’s role) registers services with listeners, using parameters like LOCAL_LISTENER.

Mechanics:LREG sends service details (e.g., orcl) to the listener every 60 seconds or on startup.

C. Writing redo to log files.

Explanation:True. The LGWR (Log Writer) process writes redo entries from the redo log buffer to online redo log files, ensuring transaction durability.

Mechanics:Triggered by commits, log buffer fills, or checkpoints.

D. Writing dirty database block images from the buffer cache.

Explanation:True. The DBWn (Database Writer) processes write modified (dirty) blocks from the buffer cache to data files, maintaining consistency.

Mechanics:Occurs at checkpoints or when free buffers are needed.

E. Reading database blocks into the buffer cache.

Explanation:False. Server processes (foreground) read blocks into the buffer cache during user queries, not background processes.

This command moves/renames a data file online. Let’s evaluate:

A. DML may be performed on tables with one or more extents in this data file during the execution of this command.

Explanation:True. Introduced in 12c and refined in 23ai, MOVE DATAFILE is an online operation, allowing DML (e.g., INSERT, UPDATE) on tables within the file. Oracle ensures consistency via redo and undo.

Mechanics:The file is copied to the new location/name while tracking changes, then switched atomically.

Practical Use:Minimizes downtime in production systems.

B. If Oracle Managed Files (OMF) is used, then the file is renamed but moved to DB_CREATE_FILE_DEST.

Explanation:False. With OMF, omitting the TO clause would place the file in DB_CREATE_FILE_DEST, but here, TO '\u01/sales01.dbf' explicitly specifies the target, overriding OMF defaults.

Mechanics:OMF only applies if the destination is unspecified (e.g., MOVE DATAFILE ... without TO).

Why Incorrect:Explicit path trumps OMF behavior.

C. The tablespace containing SALES1.DBF must be altered READ ONLY before executing the command.

Explanation:False. READ ONLY isn’t required; the operation is online and supports active use.

Why Incorrect:Conflicts with Oracle’s online move feature.

D. The file is renamed and stored in the same location.

Explanation:True. The command renames /u01/sales1.dbf to /u01/sales01.dbf (correcting \u01 to /u01 as a Windows/Unix typo), keeping it in /u01/. REUSE allows overwriting if sales01.dbf exists.

Mechanics:File is copied and renamed in-place within the same filesystem directory.

E. The tablespace containing SALES1.DBF must be altered OFFLINE before executing the command.

Explanation:False. Offline mode isn’t needed; the online move handles activetablespaces.

A.True. CREATE SPFILE FROM PFILE works when idle.

B.False. Includes dynamic parameters too.

C.True. CREATE PFILE FROM SPFILE generates a PFILE.

D.False. A PFILE can start the instance if no SPFILE exists.

E.True. Dynamic parameters (e.g., DB_CACHE_SIZE) are modifiable.

A.False. “Logging out to the abc database” is nonsensical; abc is a script, not a database.

B.False. SQL*Plus finds abc.sql in the current directory by default; a full path isn’t required unless it’s elsewhere.

C.False. The first @ specifies the TNS alias (orcl), the second runs the script (@abc); this is valid syntax.

D & E.True (identical options). The command connects to orcl via TNSNAMES.ORA, authenticates HR, and executes abc.sql.

Mechanics:sqlplus hr/hr@orcl resolves orcl to a listener address, connects, and@abc runs the script post-login.

Optimizer Statistics drive the cost-based optimizer’s query plans. Let’s dissect each option:

A. Optimizer Statistics are collected automatically by an automatic maintenance job that runs during predefined maintenance windows.

Explanation:True. Oracle 23ai uses the AutoTask framework to gather stats automatically during maintenance windows (e.g., nightly 10 PM–2 AM). The GATHER_STATS_PROG job, managed by DBMS_AUTO_TASK_ADMIN, collects stats for stale or missing objects.

Mechanics:Controlled by STATISTICS_LEVEL=TYPICAL (default) and the DEFAULT_MAINTENANCE_PLAN. It prioritizes objects with >10% changes (stale stats) or no stats.

Practical Use:Ensures stats are current without manual intervention, critical for dynamic workloads.

Edge Case:Disabled if STATISTICS_LEVEL=BASIC or the job is manually disabled via DBMS_AUTO_TASK_ADMIN.DISABLE.

B. Optimizer Statistics are collected in real-time as data is inserted, deleted, or updated.

Explanation:False. Stats aren’t updated in real-time; this would be too resource-intensive. Instead, Oracle tracks changes (e.g., via DBA_TAB_MODIFICATIONS) and updates stats periodically via AutoTask or manually. Real-time stats exist in 23ai for specific cases (e.g., GATHER_TABLE_STATS with REAL_TIME_STATS), but it’s not the default.

Why Incorrect:Real-time collection would degrade performance for OLTP systems, contradicting Oracle’s batch approach.

C. Optimizer Statistics can be manually collected at multiple levels using DBMS_STATS.GATHER_*_STATS PL/SQL procedures.

Explanation:True. The DBMS_STATS package offers granular control: GATHER_TABLE_STATS, GATHER_SCHEMA_STATS, GATHER_DATABASE_STATS, etc., allowing stats collection for tables, schemas, or the entire database.

Mechanics:Example: BEGIN DBMS_STATS.GATHER_TABLE_STATS('HR', 'EMPLOYEES'); END;. Options like ESTIMATE_PERCENT and DEGREE fine-tune the process.

Practical Use:Used for immediate stats updates post-DML or for custom schedules outside maintenance windows.

Edge Case:Overuse can lock stats (e.g., FORCE=TRUE), requiring careful management.

D. Optimizer Statistics are collected by the Statistics Advisor.

Explanation:False. The Statistics Advisor (new in 23ai) analyzes and recommends stats improvements but doesn’t collect them. Collection is still via DBMS_STATS or AutoTask.

Why Incorrect:It’s a diagnostic tool, not an executor.

E. Optimizer Statistics are collected automatically by Automatic Workload Repository (AWR) Snapshot.

Explanation:False. AWR snapshots capture performance metrics (e.g., wait times), not optimizer stats. Stats collection is a separate process via AutoTask or manual commands.

Why Incorrect:AWR and stats collection serve distinct purposes—monitoring vs. optimization.

A.True. Multiple sessions with different users are possible.

B.False. Buffer cache and redo log buffer are in SGA, not large pool.

C.True. Session tracks login state.

D.True. Each process has its own PGA.

E.False. Connection is the network link; session is the state.

F.True. Same user can have multiple sessions (e.g., via different terminals).

A.True. Integrates with MOS for patches and support.

B.True. Manages Exadata, etc.

C.True. Covers WebLogic and other middleware.

D.False. Web-based, but not built into the DB.

E.False. Can manage stopped instances via agents.

Dictionary-managed tablespaces (DMTs) use the data dictionary for extent management, whilelocally managed tablespaces (LMTs) use bitmaps. Let’s evaluate compatibility:

A. Capacity planning growth reports based on historical data in the Automatic Workload Repository (AWR).

Explanation:True. AWR tracks space usage (e.g., DBA_HIST_TBSPC_SPACE_USAGE) regardless of tablespace type, enabling growth reports for both DMTs and LMTs.

Mechanics:MMON collects metrics like segment growth, stored in SYSAUX, accessible via EM or scripts.

Practical Use:Helps predict when to add data files, universal across management types.

B. Online table segment shrink.

Explanation:False. ALTER TABLE ... SHRINK SPACE requires LMTs with Automatic Segment Space Management (ASSM), unavailable in DMTs, which lack bitmap-based free space tracking.

Why Incorrect:DMTs use freelists, incompatible with shrink operations.

C. Online index segment shrink.

Explanation:False. Like tables, ALTER INDEX ... SHRINK SPACE requires LMTs with ASSM, not supported in DMTs.

Why Incorrect:Same limitation as B; DMTs can’t compact online.

D. Oracle Managed Files (OMF).

Explanation:True. OMF automates file naming and placement (via DB_CREATE_FILE_DEST) for both DMTs and LMTs, agnostic to extent management.

Mechanics:Example: CREATE TABLESPACE ts1; creates an OMF file in either type.

Edge Case:DMTs are rare in 23ai, but OMF still applies.

E. Automatic data file extension (AUTOEXTEND).

Explanation:True. AUTOEXTEND ON allows data files to grow as needed, supported in both DMTs and LMTs since early versions.

Mechanics:ALTER DATABASE DATAFILE ... AUTOEXTEND ON NEXT 100M; works universally.