053试题 5 / 140 - Database Health Monitor

5.Examine the section of the Health Check report given below:
DBMS_HM.GET_RUN_REPORT('HM_RUN_1061')
Run Name : HM_RUN_1061 Run Id : 1061 Check Name : Data Block Integrity Check Mode :
REACTIVE Status : COMPLETED Start Time : 2007-05-12 22:11:02.032292 -07:00 End Time :
2007-05-12 22:11:20.835135 -07:00 Error Encountered : 0
Source Incident Id : 7418
Number of Incidents Created :0
Which two statements are true regarding the Health Check report? (Choose two.)
A. Health Check was performed manually.
B. Health Check was performed to check the disk image block corruptions.
C. Health Check was performed to check interblock and intersegment corruption.
D. Health Check was performed to verify the integrity of database files and report failures.
E. Health Check was performed by the Health Monitor automatically in response to a critical error.

参考答案 AB  
解析
题目意思问，一个health check 报告，问关于这个报告，那个说法是正确的。
从题目意思上看这个报告是手工运行的，不是自动运行的，因为DBMS_HM.GET_RUN_REPORT('HM_RUN_1061')。所以A正确。
根据Check Name : Data Block Integrity Check Mode。说明这个检查是Data Block Integrity Check。主要是检查image block corruptions。所以B正确。

 

参考文档：

https://docs.oracle.com/cd/E11882_01/server.112/e25494/diag.htm#ADMIN11273

Running Health Checks Manually

Health Monitor provides two ways to run health checks manually:

• By using the DBMS_HM PL/SQL package

• By using the Enterprise Manager interface, found on the Checkers subpage of the Advisor Central page

https://docs.oracle.com/cd/E11882_01/server.112/e25494/diag.htm#ADMIN11270

About Health Monitor

Beginning with Release 11g, Oracle Database includes a framework called Health Monitor for running diagnostic checks on the database.

About Health Monitor Checks

Health Monitor checks (also known as checkers, health checks, or checks) examine various layers and components of the database. Health checks detect file corruptions, physical and logical block corruptions, undo and redo corruptions, data dictionary corruptions, and more. The health checks generate reports of their findings and, in many cases, recommendations for resolving problems. Health checks can be run in two ways:

• Reactive—The fault diagnosability infrastructure can run health checks automatically in response to a critical error.

• Manual—As a DBA, you can manually run health checks using either the DBMS_HM PL/SQL package or the Enterprise Manager interface. You can run checkers on a regular basis if desired, or Oracle Support may ask you to run a checker while working with you on a service request.

Health Monitor checks store findings, recommendations, and other information in the Automatic Diagnostic Repository (ADR).

Health checks can run in two modes:

• DB-online mode means the check can be run while the database is open (that is, in OPEN mode or MOUNT mode).

• DB-offline mode means the check can be run when the instance is available but the database itself is closed (that is, in NOMOUNT mode).

All the health checks can be run in DB-online mode. Only the Redo Integrity Check and the DB Structure Integrity Check can be used in DB-offline mode.

See Also:

"Automatic Diagnostic Repository (ADR)"

Types of Health Checks

Health monitor runs the following checks:

• DB Structure Integrity Check—This check verifies the integrity of database files and reports failures if these files are inaccessible, corrupt or inconsistent. If the database is in mount or open mode, this check examines the log files and data files listed in the control file. If the database is in NOMOUNT mode, only the control file is checked.

• Data Block Integrity Check—This check detects disk image block corruptions such as checksum failures, head/tail mismatch, and logical inconsistencies within the block. Most corruptions can be repaired using Block Media Recovery. Corrupted block information is also captured in the V$DATABASE_BLOCK_CORRUPTION view. This check does not detect inter-block or inter-segment corruption.

• Redo Integrity Check—This check scans the contents of the redo log for accessibility and corruption, as well as the archive logs, if available. The Redo Integrity Check reports failures such as archive log or redo corruption.

• Undo Segment Integrity Check—This check finds logical undo corruptions. After locating an undo corruption, this check uses PMON and SMON to try to recover the corrupted transaction. If this recovery fails, then Health Monitor stores information about the corruption in V$CORRUPT_XID_LIST. Most undo corruptions can be resolved by forcing a commit.

• Transaction Integrity Check—This check is identical to the Undo Segment Integrity Check except that it checks only one specific transaction.

• Dictionary Integrity Check—This check examines the integrity of core dictionary objects, such as tab$ and col$. It performs the following operations:

  • Verifies the contents of dictionary entries for each dictionary object.

  • Performs a cross-row level check, which verifies that logical constraints on rows in the dictionary are enforced.

  • Performs an object relationship check, which verifies that parent-child relationships between dictionary objects are enforced.

  The Dictionary Integrity Check operates on the following dictionary objects:

  tab$, clu$, fet$, uet$, seg$, undo$, ts$, file$, obj$, ind$, icol$, col$, user$, con$, cdef$, ccol$, bootstrap$, objauth$, ugroup$, tsq$, syn$, view$, typed_view$, superobj$, seq$, lob$, coltype$, subcoltype$, ntab$, refcon$, opqtype$, dependency$, access$, viewcon$, icoldep$, dual$, sysauth$, objpriv$, defrole$, and ecol$.

END

-- 2019-08-21 add

题目：

140.Which two statements are true regarding Health Monitor checks in Oracle Database 11g? (Choose two.)
A. Health Monitor checks can be used to scan the contents of the redo log and archive logs for accessibility and corruption.
B. Health Monitor checks can be used to verify the integrity of database files and report failures if these files are inaccessible, corrupt or inconsistent.
C. Health Monitor checks can be used to verify the contents of dictionary entries for each dictionary object and fix it automatically.
D. Health Monitor checks are always initiated manually when there is some critical error.
 
参考答案 AB
解析，题目意思问，关于health monitor，哪两个说法是正确的。
扫描重做日志和存档日志的内容，查看可访问性和损坏情况。这个指的是Redo Integrity Check 。A正确。
验证数据库文件的完整性，如果这些文件不可访问、损坏或不一致，则报告失败。这个指的是DB Structure Integrity Check。B正确。
health check会给出建议，但是不会自动修改。所以C错误。
 

参考文档：

https://docs.oracle.com/cd/E11882_01/server.112/e25494/diag.htm#ADMIN11270

About Health Monitor

Beginning with Release 11g, Oracle Database includes a framework called Health Monitor for running diagnostic checks on the database.

About Health Monitor Checks

Health Monitor checks (also known as checkers, health checks, or checks) examine various layers and components of the database. Health checks detect file corruptions, physical and logical block corruptions, undo and redo corruptions, data dictionary corruptions, and more. The health checks generate reports of their findings and, in many cases, recommendations for resolving problems. Health checks can be run in two ways:

• Reactive—The fault diagnosability infrastructure can run health checks automatically in response to a critical error.

• Manual—As a DBA, you can manually run health checks using either the DBMS_HM PL/SQL package or the Enterprise Manager interface. You can run checkers on a regular basis if desired, or Oracle Support may ask you to run a checker while working with you on a service request.

Health Monitor checks store findings, recommendations, and other information in the Automatic Diagnostic Repository (ADR).

Health checks can run in two modes:

• DB-online mode means the check can be run while the database is open (that is, in OPEN mode or MOUNT mode).

• DB-offline mode means the check can be run when the instance is available but the database itself is closed (that is, in NOMOUNT mode).

All the health checks can be run in DB-online mode. Only the Redo Integrity Check and the DB Structure Integrity Check can be used in DB-offline mode.

See Also:

"Automatic Diagnostic Repository (ADR)"

Types of Health Checks

Health monitor runs the following checks:

• DB Structure Integrity Check—This check verifies the integrity of database files and reports failures if these files are inaccessible, corrupt or inconsistent. If the database is in mount or open mode, this check examines the log files and data files listed in the control file. If the database is in NOMOUNT mode, only the control file is checked.

• Data Block Integrity Check—This check detects disk image block corruptions such as checksum failures, head/tail mismatch, and logical inconsistencies within the block. Most corruptions can be repaired using Block Media Recovery. Corrupted block information is also captured in the V$DATABASE_BLOCK_CORRUPTION view. This check does not detect inter-block or inter-segment corruption.

• Redo Integrity Check—This check scans the contents of the redo log for accessibility and corruption, as well as the archive logs, if available. The Redo Integrity Check reports failures such as archive log or redo corruption.

• Undo Segment Integrity Check—This check finds logical undo corruptions. After locating an undo corruption, this check uses PMON and SMON to try to recover the corrupted transaction. If this recovery fails, then Health Monitor stores information about the corruption in V$CORRUPT_XID_LIST. Most undo corruptions can be resolved by forcing a commit.

• Transaction Integrity Check—This check is identical to the Undo Segment Integrity Check except that it checks only one specific transaction.

• Dictionary Integrity Check—This check examines the integrity of core dictionary objects, such as tab$ and col$. It performs the following operations:

  • Verifies the contents of dictionary entries for each dictionary object.

  • Performs a cross-row level check, which verifies that logical constraints on rows in the dictionary are enforced.

  • Performs an object relationship check, which verifies that parent-child relationships between dictionary objects are enforced.

  The Dictionary Integrity Check operates on the following dictionary objects:

  tab$, clu$, fet$, uet$, seg$, undo$, ts$, file$, obj$, ind$, icol$, col$, user$, con$, cdef$, ccol$, bootstrap$, objauth$, ugroup$, tsq$, syn$, view$, typed_view$, superobj$, seq$, lob$, coltype$, subcoltype$, ntab$, refcon$, opqtype$, dependency$, access$, viewcon$, icoldep$, dual$, sysauth$, objpriv$, defrole$, and ecol$.

END