Use the Oracle Logminer to protect your data and move to the...

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UsetheOracleLogminertoprotectyourdataandmovetotheCloud!

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KonstantinKerekovski,RaymondJamesFinancial

April2-6,2017inLasVegas,NVUSA#C17LV

BIO

KonstantinRomanovKerekovski

WorkExperience:• AmericanExpress– OracleDBA11g,12c,RAC,GG,DG• RaymondJamesFinancial– OracleDBA11g,12c,Exadata,ODA

ExperiencewithReplicationTechnologies:• Goldengate11g,12c• Dataguard11g,12c• Logminer11g,12c

WhatistheLogminer?

• Asuiteofpackagesandviews• Atooltoanalyzeyourarchivedlogs


RecommendedSettings

• MinimumDatabaseSupplementalloggingenabled.

• (Optional)SupplementalloggroupsontablesinvolvedinanyLogminerreplication.


WhatisSupplementalLogging?

• Extraredologgingotherthanwhatisrequiredtorecoverdatabasechangesviamediarecovery(RMAN).

Examples:• Sessionlevelinformation• Beforeimagesofcolumns


WhyisSupplementalLoggingimportant?

• LogminercannotreturnvalidSQLstatementswithoutsupplementallogging.• Logminerwillnotbeusableforanyauditingpurposesduetomissingredodata.


AddingDatabaseMinimumSupplementalLogging

SQL> alter database add supplemental log data;

Database altered.


AddingDatabaseMinimumSupplementalLogging(cont’d)


OtherLevelsofDBSupplementalLogging


DatabaseSupplementalLoggingconsiderations

• In12c,supplementalloggingdoneatCDB$ROOTenablessupplementalloggingonallPDBs.• IncreasesamountofREDOgeneratedbyALLtransactions.


Whyistable-levelSupplementalLoggingneeded?

• Tostorebefore-imagesofkeycolumnsintoredostream.

• ToensureSQLretrievedfromSQL_REDOcolumnhastheproperpredicatesinwhereclause.

• ToavoidusingROW_ID’swhenrerunningSQL_REDOdata.


Addingtable-levelSupplementalLogging

IdentificationKeyLogging


Addingtable-levelSupplementalLogging

CustomLogGroups


SupplementalLogTestCase


Whathappenswithnotable-levelSupplementalLogging?


Whathappenswithnotable-levelSupplementalLogging?(cont’d)


NoSupplementalLoggingwhatsoever


WhathappenswithallcolumnSupplementalLogging?


WhathappenswithallcolumnSupplementalLogging?(cont’d)


WhathappenswithPKSupplementalLogging?


WhathappenswithPKSupplementalLogging?(cont’d)


WhyPrimaryKey IdentificationKeySupplementalLoggingissafer


WhyPrimaryKey IdentificationKeySupplementalLoggingissafer(cont’d)


DatabaseObjectsofinterest

• DBMS_LOGMNR_D

• DBMS_LOGMNR

• V$LOGMNR_CONTENTS


DBMS_LOGMNR_D

• DatabasePackage• Usedtostoredatadictionaryinflatfilesortheredologs.


TheDataDictionary

• MapsObjectIDstoObjectNames,aidsinDDLtracking.

• Canbeaccessedin3differentways1. Fromstoredversioninredologs2. Fromstoredversionaflatfile3. Fromthedatabaseitself.


Whyyoushoulduse1ofthe3datadictionaryoptions


DBMS_LOGMNR

• Startsandendslogminingsessions.

• Specifieswhichredologsaretobeanalyzed.

• SpecifieshowtodisplaySQL_REDOandSQL_UNDOviaOPTIONSargumentinSTART_LOGMNR


START_LOGMNROptions

• NO_SQL_DELIMITER• NO_ROW_ID_IN_STMT• COMMITTED_DATA_ONLY• CONTINUOUS_MINE

• DDL_DICT_TRACKING• DICT_FROM_ONLINE_CATALOG• DICT_FROM_REDO_LOGS


COLUMN_PRESENTandMINE_VALUE


COLUMN_PRESENTandMINE_VALUE(cont’d)


V$LOGMNR_CONTENTS

• ViewexposingREDOandUNDOminedviaDBMS_LOGMNR• SystemPrivilegeNeeded(12c)

• LOGMINING• SELECT_CATALOG_ROLE

• SystemPrivilegeNeeded(11g)• SELECTANYTRANSACTION• SELECT_CATALOG_ROLE


WhathappenswhenV$LOGMNR_CONTENTSisqueried?

• RedoisanalyzedaccordingtoSTARTSCN/ENDSCNorSTARTTIME/ENDTIME.• Logfiles aredynamicallyaddedtologminingsessionifCONTINUOUS_MINEwasspecified.• REDOandUNDOdataisreturnedintheformofROWS.• ChangerecordsreturnedinascendingSCNorderunlessotherwisespecifiedinSQLstatement.


Additionalinterestingviews• V$LOGMNR_LOGS- ContainsadditionalinformationonARCHIVELOGS.

• V$LOGMNR_PARAMETERS– Informationoncurrentlogminingsession.


AlittlemoreonV$LOGMNR_PARAMETERS

AuditingDatabaseActivity


Databasechangecausesoutage

• Databasesuddenlybecomesunresponsive.

• Databaseserverisunabletocreateanynewprocessesandneedstoberebooted.

• Everyoneispanickingandmanagementisverydispleased.


Whatdoweknow?

1. Aheavilyusedindex(HR.EMP_EMP_ID_PK)wasrecentlyalteredtoPARALLEL99.

2.Thedatabaseisauditingchangestoindexes.

3.DBA_AUDIT_TRAILhasnoauditrecordsforindex!


DBMS_LOGMNRtotherescue!


Verifyingoursuspicions

RecoveringfromLogicalCorruption


BotchedUpdateScript

SQL> !cat update_salary.sql

set echo on;

update hr.employees set salary = 100000;

where employee_id =100;

commit;


OutcomeSQL> @update_salary.sql

SQL> update hr.employees set salary = 100000;

107 rows updated.

SQL> where employee_id =100;

SP2-0734: unknown command beginning "where empl..." - rest of

line ignored.

SQL> commit;

Commit complete.


DBMS_LOGMNRtotherescue!


RetrievingtheSQL_UNDO

References

https://github.com/kerekovskik/COLLABORATE_2017https://github.com/kerekovskik/COLLABORATE_2017/wikihttps://docs.oracle.com/database/121/SUTIL/toc.htmhttps://docs.oracle.com/database/121/ARPLS/d_sql.htm

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