Tuning Networks.docx

Tuning Networks.docx

《Tuning Networks.docx》由会员分享，可在线阅读，更多相关《Tuning Networks.docx（16页珍藏版）》请在冰豆网上搜索。

TuningNetworks

TuningNetworks

Thischapterdescribesdifferentconnectionmodelsandintroducesnetworkingissuesthataffecttuning.

Thischaptercontainsthefollowingsections:

∙UnderstandingConnectionModels

∙DetectingNetworkProblems

∙SolvingNetworkProblems

UnderstandingConnectionModels

Thetechniquesusedtodeterminethesourceofproblemsvarydependingontheconfiguration.Youcanhaveasharedserverconfigurationoradedicatedserverconfiguration.

∙Ifyouhaveasharedserverconfiguration,thenLSNRCTLserviceslistsdispatchers.

∙Ifyouhaveadedicatedserverconfiguration,thenLSNRCTLserviceslistsdedicatedservers.

Itispossibletoconnecttodedicatedserverwithadatabaseconfiguredforsharedserversbyplacingtheparameter（SERVER=DEDICATED）intheconnectdescriptor.

SharedServerConfiguration

Thissectiondiscussesthesetupsforthesharedserverconfiguration.

RegisteringtheDispatchers

TheLSNRCTLcontrolutility'sservicesstatementlistseverydispatcherregisteredwithit.ThislistincludesthedispatchersprocessID.Youcancheckthealertlogtoconfirmthatthedispatchershavebeenstartedsuccessfully.

Note:

RememberthatPMONcantakeaminutetoregisterthedispatcherwiththelistener.

LSNRCTL>services

Connectingto

（DESCRIPTION=（ADDRESS=（PROTOCOL=tcp）（HOST=helios）（PORT=1521）））

ServicesSummary...

Service""has1instance（s）.

Instance"sales",statusREADY,has3handler（s）forthisservice...

Handler（s）:

"DEDICATED"established:

0refused:

0state:

ready

LOCALSERVER

"D000"established:

0refused:

0current:

0max:

10000state:

ready

DISPATCHER

helios,pid:

1689>

（ADDRESS=（PROTOCOL=tcp）（HOST=helios）（PORT=52414））

"D001"established:

0refused:

0current:

0max:

10000state:

ready

DISPATCHER

helios,pid:

1691>

（ADDRESS=（PROTOCOL=tcp）（HOST=helios）（PORT=52415））

Thecommandcompletedsuccessfully.

SeeAlso:

OracleNetServicesAdministrator'sGuideforinformationonsettingtheoutputmode

ConfiguringInitializationParametersforSharedServers

Thefollowinglistprovidesinformationonconfiguringinitializationparametersforsharedservers.

∙MakesurethattheDISPATCHERSlineiscorrectlyset.Forexample:

∙DISPATCHERS="（DESCRIPTION=（ADDRESS=（PROTOCOL=TCP）

∙（HOST=hostname）（PORT=1492）（queuesize=32）））

∙（DISPATCHERS=1）

∙（LISTENER=alias）

∙（SERVICE=servicename）

∙（SESSIONS=1000）

∙（CONNECTIONS=1000）

∙（MULTIPLEX=ON）

∙（POOL=ON）

∙（TICK=5）"

∙

One,andonlyone,ofthefollowingattributesisrequired:

∙PROTOCOL

∙ADDRESS

∙DESCRIPTION

ADDRESSandDESCRIPTIONprovidesupportforthespecificationofadditionalnetworkattributesbeyondPROTOCOL.Inthepreviousexample,theentireDISPATCHERSlinecanbe（PROTOCOL=TCP）.TheattributesDISPATCHERS,LISTENER,SERVICE,SESSIONS,CONNECTIONS,MULTIPLEX,POOL,andTICKSarealloptional.

MakesurethattheoptionalMAX_DISPATCHERSlineiscorrectlyset.Forexample:

MAX_DISPATCHERS=4

Thislineshouldreflectthetotalnumberofdispatchersyouwanttostart.

MakesurethattheoptionalMAX_SHARED_SERVERSlineiscorrectlyset.Forexample:

MAX_SHARED_SERVERS=5

ThislinesetstheupperboundonthetotalnumberofsharedserversPMONcancreate,basedonthepeakloadofthesystem.Thisshouldbesethighenoughsothatallrequestscanbeserviced,butnotsohighthatthesystemswapsiftheyarereached.Thepurposeofthisparameteristopreventtheserverfromswapping.Runthefollowingscripttoseewhatthehighwatermarkisforthenumberofserversrunning,andthensetMAX_SHARED_SERVERStomorethenthis.

SELECTmaximum_connections"MAXCONN",servers_started"STARTED",servers_

terminated"TERMINATED",servers_highwater"HIGHWATER"FROMV$SHARED_SERVER_

MONITOR;

∙MakesurethattheoptionalSHARED_SERVERSlineiscorrectlyset.Forexample:

∙SHARED_SERVERS=5

∙

Thisisthetotalnumberofsharedserversstartedwhenthedatabaseisstarted.ItalsorepresentsthetotalnumberofsharedserversPMONtriestokeep.Itshouldbethetotalnumberofserversexpectedtobeusedwhenthedatabaseisactive.MAX_SHARED_SERVERSisintendedtohandlepeakload.

CheckingtheConnections

UsetheLSNRCTLcontrolutility'sservicescommandtoseeifthereareexcessiveconnectionrefusals.Checkthelistener'slogfiletoseeifthisisaconnectionproblem.Forexample:

LSNRCTL>services

Connectingto

（DESCRIPTION=（ADDRESS=（PROTOCOL=tcp）（HOST=helios）（PORT=1521）））

ServicesSummary...

Service""has1instance（s）.

Instance"sales",statusREADY,has2handler（s）forthisservice...

Handler（s）:

"DEDICATED"established:

11refused:

0state:

ready

LOCALSERVER

"D000"established:

565refused:

4current:

155max:

10000state:

ready

DISPATCHER

helios,pid:

5673>

（ADDRESS=（PROTOCOL=tcp）（HOST=helios）（PORT=38411））

Thecommandcompletedsuccessfully.

Undernormalconditions,thenumberrefusedshouldbezero.Shutdownthelistenerandrestartittoerasethesestatistics.Iftherefusedcountisincreasingafterthelistenerrestarts,thentheconnectionsarebeingrefused.Iftherefusedcountstaysatzero,andiftheproblemyouaretroubleshootingisoccurring,thenyourproblemisnotwiththeconnectionsbeingrefused.

CheckingtheConnect/SecondRate

Connectionrefusalscanoccurformanyreasons.Examinethelistenerlogtoseewhattheconnectrateis.Runthelistenerloganalyzerscripttocheck.

Thelistenerisaqueue-basedprocess.Itreceivesconnectrequestsfromthelowerlevelprotocolstack.Ithasalimitedqueuestackwhichisconfigurabletotheoperatingsystemmaximum.Itcanonlyprocessoneconnectionatatime,andthereisalimittothenumberofconnectionsasecondtheprocesscanhandle.

Iftherateatwhichtheconnectrequestsarriveexceedsthatlimit,thentherequestsarequeued.Thequeuestackisalsolimited,butyoucanconfigureit.Iftherearemorelistenerprocesses,thentherequestsmadeagainsteachindividualprocessarefewerandarehandledmorequickly.

Increasingthelistenerqueueisdoneinthelistener.orafile.Thelistener.orafilecancontainmanylisteners,eachbyadifferentname.Itisassumedthatonlyoneofthoselistedishavingaproblem.Ifnot,thenapplythismethodtoallapplicablelisteners.Toincreasethelistenerqueue,add（queuesize=number）tothelistener.orafile.Forexample:

listener=

（address=

（protocol=tcp）

（host=sales-pc）

（port=1521）

（queuesize=20）

）

SeeAlso:

OracleNetServicesAdministrator'sGuide

Stopandrestartthelistenertoinitializethisnewparameter.Ifyouarenotcurrentlyrunningasharedserverconfiguration,thenconsiderdoingso.Itisfasterforthelistenertohandleaclientrequestinasharedserverconfigurationthanitisinadedicatedserverconfiguration.

Note:

Sharedserverdispatchersalsoreceiveconnectrequestsandcanalsobenefitfromtuningthequeuesize.

Themaximumqueuesizeissubjecttothemaximumsizepossibleforaparticularoperatingsystem.

DetectingNetworkProblems

Thissectionencompasseslocalareanetwork（LAN）andwideareanetwork（WAN）troubleshootingmethods.

UsingDynamicPerformanceViewsforNetworkPerformance

Networksentailoverheadthataddsacertainamountofdelaytoprocessing.Tooptimizeperformance,youmustensurethatyournetworkthroughputisfast,andyoushouldtrytoreducethenumberofmessagesthatmustbesentoverthenetwork.Itcanbedifficulttomeasurethedelaythenetworkadds.

Threedynamicperformanceviewsareusefulformeasuringthenetworkdelay:

∙V$SESSION_EVENT

∙V$SESSION_WAIT

∙V$SESSTAT

InV$SESSION_EVENT,theAVERAGE_WAITcolumnindicatestheamountoftimethatOraclewaitsbetweenmessages.Youcanusethisstatisticasayardsticktoevaluatetheeffectivenessofthenetwork.

InV$SESSION_WAIT,theEVENTcolumnliststheeventsforwhichactivesessionsarewaiting.The"sqlnetmessagefromclient"waiteventindicatesthatthesharedorforegroundprocessiswaitingforamessagefromaclient.Ifthiswaiteventhasoccurred,thenyoucanchecktoseewhetherthemessagehasbeensentbytheuserorreceivedbyOracle.

Youcaninvestigatehang-upsbylookingatV$SESSION_WAITtoseewhatthesessionsarewaitingfor.Ifaclienthassentamessage,thenyoucandeterminewhetherOracleisrespondingtoitorisstillwaitingforit.

InV$SESSTATyoucanseethenumberofbytesthathavebeenreceivedfromtheclient,thenumberofbytessenttotheclient,andthenumberofcallstheclienthasmade.

UnderstandingLatencyandBandwidth

Themostcriticalaspectsofanetworkthatcontributetoperformancearelatencyandbandwidth.

∙Latencyreferstoatimedelay;forexample,thegapbetweenthetimeadevicerequestsaccesstoanetworkandthetimeitreceivespermissiontotransmit.

∙Bandwidthisthethroughputcapacityofanetworkmediumorprotocol.Variationsinthenetworksignalscancausedegradationonthenetwork.Sourcesofdegradationcanbecablesthataretoolongorwrongcabletype.Externalnoisesources,suchaselevators,airhandlers,orflorescentlights,canalsocauseproblems.

CommonNetworkTopologies

LocalAreaNetworkTopologies:

∙Ethernet

∙FastEthernet

∙1GigabitEthernet

∙TokenRing

∙FDDI

∙ATM

WideAreaNetworkTopologies:

∙DSL

∙ISDN

∙FrameRelay

∙T-1,T-3,E-1,E-3

∙ATM

∙SONAT

Table 11-1liststhemostcommonratingsforvarioustopologies.

Table11-1 BandwidthRatings

TopologyorCarrier

Bandwidth

Ethernet

10Megabits/second

FastEthernet

100Megabits/second

1GigabitEthernet

1Gigabits/second

TokenRing

16Megabits/second

FDDI

100Megabits/second

AT