Supercharge your Code to get OpAmal Database Performance · Supercharge your Code to get OpAmal Database Performance Gerald Venzl Senior Principal Product Manager Oracle Database

Copyright©2016,Oracleand/oritsaffiliates.Allrightsreserved.|

SuperchargeyourCodetogetOpAmalDatabasePerformanceGeraldVenzlSeniorPrincipalProductManagerOracleDatabaseDevelopment@GeraldVenzl


SafeHarborStatementThefollowingisintendedtooutlineourgeneralproductdirecAon.ItisintendedforinformaAonpurposesonly,andmaynotbeincorporatedintoanycontract.Itisnotacommitmenttodeliveranymaterial,code,orfuncAonality,andshouldnotberelieduponinmakingpurchasingdecisions.Thedevelopment,release,andAmingofanyfeaturesorfuncAonalitydescribedforOracle’sproductsremainsatthesolediscreAonofOracle.

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Gerald’sSafeHarborStatement

Nothingsaidhereisaguaranteeforsolvingyourpar6cularproblem.WhilethetechniquespresentedherecanhaveahugeposiAveimpactonperformanceitisnotguaranteedthattheywillfixyourparAcularproblem.

Performanceisrela6ve.Itdependsonahugeamountofdifferentfactorsandcan’tbecompared1:1.ThenumbersinthisdeckreflectaAny2GBVirtualBoxenvironmentwithonlyonevirtualCPU,keepthatinmind.

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ProgramAgenda

IntroducAon

Whatisperformance

OracleDatabasePerformanceStaAsAcs

Commits–saverofyourdata

Rowbyrow=slowbyslow

Bindvari…–WHAT?

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ProgramAgenda

IntroducAon

Whatisperformance



Rowbyrow=slowbyslow

Bindvari…–WHAT?

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IntroducAon

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IntroducAon

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IntroducAon

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IntroducAon

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IntroducAon

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IntroducAon

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IntroducAon

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IntroducAon

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IntroducAon

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ProgramAgenda

IntroducAon

Whatisperformance



Rowbyrow=slowbyslow

Bindvari…–WHAT?

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Whatisperformance

Performance=?

Asimpleformula

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Whatisperformance

Performance=latencyxthroughput

Asimpleformula

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Whatisperformance

•  Latency:TheAmetoprocessaunitofwork•  Throughput:Theamountofunitsofworkthatcanbeprocessedinparallel• Aunitofworkiseitherprocessed(CPU)orhastowait(I/O)• Goalsare:– Processaunitofworkasefficientaspossible– Reducewait6measmuchaspossible– Avoidunnecessaryresourceconsump6on(CPU&I/O)

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Whatisperformance


10,000workunits/s=?

Asimpleformula

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Whatisperformance


10,000workunits/s=1msx10wu

Asimpleformula

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Whatisperformance


10,000workunits/s=10msx100wu

Asimpleformula

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Whatisperformance

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Whatisperformance

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ProgramAgenda

IntroducAon

Whatisperformance



Rowbyrow=slowbyslow

Bindvari…–WHAT?

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Thedatabaseasa

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Thedatabaseasablackbox

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Adatabaseiseither

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Adatabaseiseitherworking

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Adatabaseiseitherworkingoridle

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Theworkingstatesofthedatabase

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Busy



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Wai6ng



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TheworkingstatesoftheOracleDatabase

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=Sta6s6cs


TheworkingstatesoftheOracleDatabase

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=Sta6s6cs

=WaitClasses


OracleDatabasestaAsAcs•  1804staAsAcsintotalinOracleDB12.2.0.1•  Query:v$sysstat,v$mystat,v$sesstat(v$statname)

•  Forexample:SELECT n.name, s.value FROM v$mystat s, v$statname n WHERE s.statistic#=n.statistic# AND value > 0 ORDER BY n.name;

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Oracledatabasewaitclasses•  Administra6ve:WaitsresulAngfromDBAcommandsthatcauseuserstowait(indexrebuild,etc.)

•  Applica6on:WaitsresulAngfromuserapplicaAoncode(lockwaitscausedbyrowlevellockingorexplicitlockcommands)

•  Cluster:WaitsrelatedtoOracleRealApplicaAonClustersresources(globalcacheresourcessuchas'gccrblockbusy')

•  Commit:Thiswaitclassonlycomprisesonewaitevent-waitforredologwriteconfirmaAonaneracommit(thatis,'logfilesync')

•  Concurrency:Waitsforinternaldatabaseresources(latches,cursorpins,etc.)

•  Configura6on:WaitscausedbyinadequateconfiguraAonofdatabaseorinstanceresources(undersizedlogfiles,sharedpool,etc.)

•  Idle:WaitsthatsignifythesessionisinacAve,waiAngforwork('SQL*Netmessagefromclient')

•  Network:Waitsrelatedtonetworkmessaging('SQL*Netmoredatatodblink’)

•  Other:Waitswhichshouldnottypicallyoccuronasystem(forexample,'waitforEMONtospawn')

•  Queueing:DelaysinobtainingaddiAonaldatainapipelinedenvironment.(parallelqueries,orDBMS_PIPEPL/SQLpackages)

•  Scheduler:ResourceManagerrelatedwaits('resmgr:becomeacAve’,etc.)

•  SystemI/O:WaitsforbackgroundprocessI/O(forexample,DBWRwaitfor'dbfileparallelwrite')

•  UserI/O:WaitsforuserI/O(forexample'dbfilesequenAalread')

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Oracledatabasewaitclasses•  Forexample:•  SELECT sid, event, p1, p2, p3 FROM v$session_wait ORDER BY sid, event;

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ProgramAgenda

IntroducAon

Whatisperformance



Rowbyrow=slowbyslow

Bindvari…–WHAT?

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Commits–saverofyourdataHowdoesOraclemakesureyourdataisstoredondisk?

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DML(s)



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DML(s) COMMIT



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INSERTINTOpurchase(…)

VALUES(:1,:2,:3,…);



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VALUES(:1,:2,:3,…);



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VALUES(:1,:2,:3,…);

BufferCache



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VALUES(:1,:2,:3,…);COMMIT

BufferCache



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BufferCache



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BufferCache REDOlogs


Commits–saverofyourdataWhathappensonaCOMMIT?

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DML(s) COMMIT



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GenerateSCN



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GenerateSCN

LGWRwritestoREDOlogs



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GenerateSCN


Releaselocksontables



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GenerateSCN



Removesafe-points



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GenerateSCN



Removesafe-points

Performcommitcleanout



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GenerateSCN



Removesafe-points


MarkTXN

complete



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GenerateSCN



Removesafe-points


MarkTXN

complete

Copyright©2016,Oracleand/oritsaffiliates.Allrightsreserved.| 63

PreparedStatementstmt=conn.prepareStatement( "INSERTINTOTEST(id,text,created_tms,last_upd_tms)VALUES (?,?,SYSDATE,SYSDATE)");

longstart=System.currentTimeMillis();

for(inti=1;i<=rows;i++){stmt.setInt(1,i);stmt.setString(2,"Thisistherowwiththevalueof"+i);stmt.executeUpdate();conn.commit();

}

longend=System.currentTimeMillis();System.out.println("Elapsedtime(ms)forcommitaftereveryrow:"+(end-start));





for(inti=1;i<=rows;i++){stmt.setInt(1,i);stmt.setString(2,"Thisistherowwiththevalueof"+i);stmt.executeUpdate();

}conn.commit();

longend=System.currentTimeMillis();System.out.println("Elapsedtime(ms)forcommitattheend:"+(end-start));



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Commiteveryrow

Commitatend

•  ThreetestrunsinserAng10krows

•  DarkblueaxisshowselapsedAmewhencommitnganereveryrow

•  LightblueaxisshowselapsedAmewhencommitngonlyonceaneralldataisloaded

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• Commitwhenyourbusinesslogicrequiresyouto– Nonrestart-ableworkunitsusuallyrequirecommit•  Paymentprocessing,orderconfirmaAon,ATMwithdrawal,etc.

– Restart-ableworkunitsnormallydon’trequireacommit•  Batchloads,datatransformaAon,etc.

• Commitmeansaroundtriptothedatabase• Remember:Autocommitissettotruebydefaultinalotofdrivers

Whentocommit?

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ProgramAgenda

IntroducAon

Whatisperformance



Rowbyrow=slowbyslow

Bindvari…–WHAT?

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Rowbyrow–Quiz• Whatwouldyouratherdoonatablewith10millionrows:

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Rowbyrow–Quiz• Whatwouldyouratherdoonatablewith10millionrows:PreparedStatementstmt=conn.prepareStatement(

"SELECTvalueFROMPURCHASEWHEREtms>'2016-09-01'");ResultSetrslt=stmt.executeQuery();while(rslt.next()){

val+=rslt.getInt(1);}

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val+=rslt.getInt(1);}PreparedStatementstmt=conn.prepareStatement(

"SELECTSUM(value)FROMPURCHASEWHEREtms>'2016-09-01'");ResultSetrslt=stmt.executeQuery();rslt.next();val=rslt.getInt(1);

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val+=rslt.getInt(1);}PreparedStatementstmt=conn.prepareStatement(

"SELECTSUM(value)FROMPURCHASEWHEREtms>'2016-09-01'");ResultSetrslt=stmt.executeQuery();rslt.next();val=rslt.getInt(1);

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Rowbyrow=Slowbyslow

• Databasesworkbestwithsetbasedprocessing• Processasmuchaspossibleonthesidewhereitmakesmostsense• GenerallyasingleSQLstatementexecuAonisfastest• Avoidunnecessaryroundtrips

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for(inti=1;i<=rows;i++){stmt.setInt(1,i);stmt.setString(2,"Thisistherowwiththevalueof"+i);stmt.executeUpdate();

}conn.commit();

longend=System.currentTimeMillis();System.out.println("Elapsedtime(ms)forrowbyrowinsert:"+(end-start));

Rowbyrow=Slowbyslow




for(inti=1;i<=rows;i++){stmt.setInt(1,i);stmt.setString(2,"Thisistherowwiththevalueof"+i);stmt.addBatch();

}stmt.executeBatch();conn.commit();

longend=System.currentTimeMillis();System.out.println("Elapsedtime(ms)forsetbasedinsert:"+(end-start));

Rowbyrow=Slowbyslow


2701628986

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Inserteveryrow

Setbasedinsert

•  ThreetestrunsinserAng10krows

•  DarkblueaxisshowselapsedAmeofindividualinserts

•  LightblueaxisshowselapsedAmeofsetbasedinserts

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Rowbyrow=Slowbyslow


Rowbyrow=Slowbyslow

• UseDMLerrorlogging– Errorsdon’tabortbatch– Errorsareloggedintoseparateerrortableincludingtheinputdata

•  SQLsyntax:INSERTINTOTEST…LOGERRORS;

Whatabouterrors?

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ProgramAgenda

IntroducAon

Whatisperformance



Rowbyrow=slowbyslow

Bindvari…–WHAT?

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Bindvari…–WHAT?

•  SQLstatementsarestrings• ButdatamanipulatedviaSQLmaybeofadifferenttypes(Number,Date,…)• Abindvariableallowsyoutobinddatatoanexplicitdatetype– Withouthavingtoconvertthedatatypefromstring– AndwithouthavingtoparsetheSQLstatementagain

Whatarebindvariables

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SQLprocessingHowdoesOracleactuallyprocessyourSQLs?

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Parsing



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Parsing Execu6on



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SodParsingHardParsing Execu6on


SQLprocessing–ParsingHowdoesOracleactuallyprocessyourSQLs?

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SyntaxCheck

IstheSQLsyntaxcorrect?

I.e.didyoutypeFROMandcocorrectly?



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SyntaxCheck

Seman6cCheck

Doesthetablesexist;

doyouhavepermissions,…



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SyntaxCheck

Seman6cCheck

SharedPoolCheck

CreateSQLIDandcheck

whetherithasalreadybeenexecutedbefore



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SyntaxCheck

Seman6cCheck

SharedPoolCheck

AlwayshappensforanygivenqueryVeryfast!

Donebyyoursessionprocess(happensconcurrentlyforeachsession)

Sodparse



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SharedPoolCheck

SQLalreadyexists?

Execu6onYes



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SharedPoolCheck

Execu6on

SQLalreadyexists? No



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SharedPoolCheck

Op6miza6on

Execu6on

SQLalreadyexists?



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SharedPoolCheck

Op6miza6onRowsource

(execu6onplan)genera6on

Execu6on

SQLalreadyexists?



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SharedPoolCheck

Op6miza6onRowsource

(execu6onplan)genera6on

Execu6on

•  CPUintensive•  Checkdatadic6onary•  Checklibrarycache•  Useslatchestoserializeonthosecaches

Hardparse


SQLprocessing–BindvariablesHowdoesOracleactuallyprocessyourSQLs?

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SELECTtext

FROMTEST

WHERE

id=453;

SQLID:5mwwhtqv204ba



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SELECTtext

FROMTEST

WHERE

id=453;

SQLID:5mwwhtqv204ba

SQLID:06jc0z1kcuu6b

SELECTtext

FROMTEST

WHERE

id=879;



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SQLID:cknumntjbx8u3

SELECTtext

FROMTEST

WHERE

id=?;



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SELECTtext

FROMTEST

WHERE

id=?;

SQLID:cknumntjbx8u3

SELECTtext

FROMTEST

WHERE

id=?;



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SELECTsql_id,sql_text

FROMv$sql

WHEREsql_text

LIKE'%TEST%';

SQL_ID SQL_TEXT

cknumntjbx8u3 SELECTtextFROMTESTWHEREid=:1

5mwwhtqv204ba SELECTtextFROMTESTWHEREid=453

06jc0z1kcuu6b SELECTtextFROMTESTWHEREid=879

3y3unjhrpp9nm SELECTsql_id,sql_textFROMv$sqlWHEREsql_textLIKE'%TEST%'


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Selectusingliterals

Selectusingbindvar

•  ThreetestrunsselecAng1krows

•  DarkblueaxisshowselapsedAmeofSELECTusingliterals

•  LightblueaxisshowselapsedAmeofSELECTusingbindvariable

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Bindvari…-WHAT?


Usefulresources

• PerformanceTuningGuide•  SQLTuningGuide• DatabaseDevelopmentGuide•  JDBCDeveloper’sGuide• UniversalConnecAonPoolforJDBCDeveloper’sGuide

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Whereisthesource?

github.com/gvenzl/Oracle-JavaOneSuperchargeCodeOp6malDBPerf

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SafeHarborStatementTheprecedingisintendedtooutlineourgeneralproductdirecAon.ItisintendedforinformaAonpurposesonly,andmaynotbeincorporatedintoanycontract.Itisnotacommitmenttodeliveranymaterial,code,orfuncAonality,andshouldnotberelieduponinmakingpurchasingdecisions.Thedevelopment,release,andAmingofanyfeaturesorfuncAonalitydescribedforOracle’sproductsremainsatthesolediscreAonofOracle.

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Documents

Supercharge your Code to get OpAmal Database Performance · Supercharge your Code to get OpAmal Database Performance Gerald Venzl Senior Principal Product Manager Oracle Database