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Oracle Database 12c
The Best Oracle Database 12c Tuning Features for Developers
and DBAs
Presentedby: AlexZaballa,OracleDBA
Alex Zaballa
http://alexzaballa.blogspot.com/
@alexzaballa206andcounting…https://www.linkedin.com/in/alexzaballa
Workedfor7 yearsinBrazil asanOracleDeveloper.2000- 2007
Workedfor8 yearsinAngolaasanOracleDBAfortheMinistryofFinance.2007- 2015
Oracle Database 12c
The Best Oracle Database 12c Tuning Features for Developers and DBAs
OracleOfficialDocumentation12.1.0.2
• http://docs.oracle.com/database/121/NEWFT/chapter12102.htm
OracleLearningLibrary(OLL)
• https://apexapps.oracle.com/pls/apex/f?p=44785:1:0
Articlesabout12c
• https://oracle-base.com/articles/12c/articles-12c
“Withmorethan500newfeatures,OracleDatabase12c isdesignedtogiveOraclecustomersexactlywhatthey’vetoldustheyneedforcloudcomputing,bigdata,security,andavailability.”
OracleAnnouncesBetaAvailabilityofOracleDatabase12cRelease2 - Oct26,2015
• PLUGGABLEDATABASESFrom252to4096
• HOTCLONINGDon’tneedtoputthesourceinread-onlyforcloning
• SHARDINGIt’slikepartitioninginasharednothingdatabaseThedataissplitintomultipledatabases
• In-MemoryIn-MemorycolumnStoreonActiveDataGuardHeatMap
• APPLICATIONCONTAINERPluggableDatabaseswillshareapplicationobjects
• Moreisolation,resourcemanagerwilllimitthememoryinadditiontoCPUandI/O.• AWRwillworkonActiveDataGuardDatabase:youcantuneyourreportingdatabase
AvailabilityofOracleDatabase12.2
Source:https://blogs.oracle.com/UPGRADE/entry/oracle_database_12_2_just
OracleDatabaseReleaseStatusMOSNote:742060.1
Multitenant
Source:OracleDocumentation
Multitenant
Is it a Tuning Feature?
Source:OracleDocumentation
Multitenant
Source:https://blogs.oracle.com/UPGRADE/entry/non_cdb_architecture_of_oracle
Multitenant
Source:https://blogs.oracle.com/UPGRADE/entry/non_cdb_architecture_of_oracle
Multitenant
Source:https://blogs.oracle.com/UPGRADE/entry/non_cdb_architecture_of_oracle
In-Memory
Source:OracleDocumentation
In-MemorySIMDVectorProcessing
Source:http://www.oracle.com/technetwork/database/in-memory/overview/twp-oracle-database-in-memory-2245633.html
In-Memory
Source:OracleDocumentation
Is it a Tuning Feature?
“Using Database In-Memory, businesses can instantaneouslyrun analytics and reports that previously took hours or days.”
In-Memory
In-MemoryArea– astaticpoolinSGA
In-Memory
Source:OracleBase.com
In-MemoryAltertablehr.EMPLOYEES inmemory;
ALTERTABLEsalesMODIFYPARTITIONSALES_Q1_1998INMEMORY;
ALTERTABLEsalesINMEMORYNOINMEMORY(prod_id);
CREATETABLESPACEtbs_testDATAFILE'+DG01SIZE100MDEFAULTINMEMORY;
In-Memory
Source:http://www.oracle.com/technetwork/database/in-memory/overview/twp-oracle-database-in-memory-2245633.html
SQLQueryRowLimitsandOffsets
SQLQueryRowLimitsandOffsets
SQLQueryRowLimitsandOffsets
Top-NQueries– Pré 12c
SQLQueryRowLimitsandOffsets
SQLQueryRowLimitsandOffsets
SQLQueryRowLimitsandOffsets
DEMO
ApproximateCountDistinct
ThisfunctionprovidesanalternativetotheCOUNT(DISTINCTexpr),withnegligibledeviationfromtheexactresult.
DEMO
PL/SQLFromSQLwith
functionIs_Number(xinvarchar2)returnvarchar2isPlsql_Num_Error exception;pragmaexception_init(Plsql_Num_Error,-06502);beginif(To_Number(x)isNOTnull)thenreturn'Y';elsereturn'';endif;exceptionwhenPlsql_Num_Error thenreturn'N';
endIs_Number;selectrownum,x,is_number(x)is_num fromt;
DEMO
SessionLevelSequences
Sessionlevelsequences areusedtoproduceuniquevaluesinasession.Oncethesessionends,thesequenceisreset.
GeneratingPrimaryKeysforaGlobalTemporaryTablewouldbeafieldwherethosekindsofsequencescouldbeused.
SessionLevelSequences
CREATESEQUENCEsequence_testSTARTWITH1INCREMENTBY1SESSION/
SessionLevelSequences
ALTERSEQUENCEsequence_testSESSION;
ALTERSEQUENCEsequence_testGLOBAL;
DEMO
SessionprivatestatisticsforGlobalTemporaryTables
Pre12c,statisticsgatheredforglobaltemporarytables(GTTs)werecommontoallsessions.
SessionprivatestatisticsforGlobalTemporaryTables
On12c,bydefaultsession-privatestatisticsareenabled
SELECTDBMS_STATS.get_prefs('GLOBAL_TEMP_TABLE_STATS')FROMdual;
STATS------------------------------------------------------------------------------SESSION
SessionprivatestatisticsforGlobalTemporaryTables
Howtochange?
Behaviorpre12c:BEGINDBMS_STATS.set_global_prefs (pname =>'GLOBAL_TEMP_TABLE_STATS',pvalue =>'SHARED');
END;/
Backtodefaulton12c:BEGINDBMS_STATS.set_global_prefs (pname =>'GLOBAL_TEMP_TABLE_STATS',pvalue =>'SESSION');
END;/
SessionprivatestatisticsforGlobalTemporaryTables
Howtochangeforonetable?
BEGINdbms_stats.set_table_prefs('SCOTT','GTT_TEST','GLOBAL_TEMP_TABLE_STATS','SHARED');END;
BEGINdbms_stats.set_table_prefs('SCOTT','GTT_TEST','GLOBAL_TEMP_TABLE_STATS’,’SESSION');END;
DEMO
TemporaryUndo
GlobalTemporaryTables(GTT)holdthedatainatemporarytablespace.ThedatainGTTsareeitherdeletedaftercommitorkeptuntilthesessionisconnecteddependingofthedefinitionoftheGTT.(ONCOMMITPRESERVEORDELETEROWS).
DMLsinaGlobalTemporaryTablesdonotgenerateREDO,butgenerateUNDO andthiswillresultinREDOgenerating.
TemporaryUndo
altersessionsettemp_undo_enabled=true;
altersystemsettemp_undo_enabled=true;
**youcanchangeforthesessionorforthedatabase.*defaulttrue
DEMO
MultipleIndexesonthesamesetofColumns
Pre12c:
ORA-01408:suchcolumnlistalreadyindexederror.
MultipleIndexesonthesamesetofColumns
Istheabilitytocreatemorethanoneindexonthesamesetofcolumnsin12c.
**Onlyoneoftheseindexescanbevisibleatatime
MultipleIndexesonthesamesetofColumns
Whywouldyouwanttodothat?
• Uniqueversusnonunique
• B-treeversusbitmap
• Differentpartitioningstrategies
DEMO
LimitthePGA
SQL>showparameterpga
NAME TYPEVALUE-------------------------- ------------- ----------------------pga_aggregate_limit biginteger2G
pga_aggregate_target ****
LimitthePGA
PGA_AGGREGATE_LIMIT issettothegreaterof:
- 2GB(defaultvalue)- 200%ofPGA_AGGREGATE_TARGET- 3MBtimesthePROCESSESparameter
StatisticsDuringLoads
Theabilitytogatherstatisticsautomaticallyduringbulkloads:
- CREATETABLEASSELECT
- INSERTINTO...SELECTintoanemptytableusingadirectpathinsert
DEMO
PartialIndexesforPartitionedTable
• Youcancreatelocalandglobalindexesonasubset ofthepartitionsofatable,enablingmoreflexibilityinindexcreation.
• Thisfeatureisnotsupportedforuniqueindexes,orforindexesusedforenforcinguniqueconstraints.
PartialIndexesforPartitionedTable
DEMO
FullDatabaseCaching
Canbeusedtocachetheentiredatabaseinmemory.Itshouldbeusedwhenthebuffercachesizeofthedatabaseinstanceisgreaterthanthewholedatabasesize.
AdaptiveQueryOptimization
ê
AdaptivePlans
ê
AdaptiveJoinMethod
AdaptiveJoinMethod
OptimizercanchangejoinfromNestedLooptoHashJoinandviceversa.
Why?Optimizermistakes§ EstimatedRowsandActualrowsaredifferent
Before12crequiresDBA/Developerintervention
AdaptiveJoinMethod
Source:OracleDocumentation
AdaptiveJoinMethod
ParametersthatcontrolAdaptivePlans:
Name Type Valueoptimizer_adaptive_features boolean TRUE
optimizer_adaptive_reporting_only boolean FALSEoptimizer_features_enable string 12.1.0.1
ExplainPlancommandshowsthedefaultplan
Source:OracleDocumentation
DBMS_XPLAN.DISPLAY_CURSORshowsthefinalplan
Source:OracleDocumentation
DEMO
Real-TimeSQLMonitoring
• Sql MonitoringrequiresbothDiagnosticsandTuningPacklicenses
Real-TimeSQLMonitoring
• MONITORHintSELECT/*+MONITOR*/
• Allparallelstatements
• After5secondsofCPU/IOtimespentforserialqueries
Real-TimeSQLMonitoring
Real-TimeSQLMonitoring
Real-TimeSQLMonitoring
Real-TimeSQLMonitoring
Real-TimeSQLMonitoring
Real-TimeSQLMonitoring
Real-TimeSQLMonitoring
Real-TimeSQLMonitoringSPOOL/tmp/report_sql_monitor.htm
SELECTDBMS_SQLTUNE.report_sql_monitor(sql_id =>'5dhu4w0j59yp7',type=>'HTML',report_level =>'ALL')ASreportFROMdual;
SPOOLOFF
Real-TimeSQLMonitoring
DEMO
SQLcl
http://www.oracle.com/technetwork/developer-tools/sql-developer/downloads/index.html
ThankYou
SlidesAvailable:http://www.slideshare.net/
