table of contentsgpcc.docs.pivotal.io/pdf/gp-wlm-170-user-guide.pdf · checking the health of...

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TableofContents

TableofContentsAboutGreenplumWorkloadManagerInstallingGreenplumWorkloadManagerManagingGreenplumWorkloadManagerServicesUsingtheGreenplumWorkloadManagerCommandLineUsingtheWorkloadManagerGraphicalInterface(gptop)UsingWorkloadManagerRulesUnderstandingRulesAddingRulesManagingRulesExampleRulesBestPracticesforRulesKnownIssuesQueryingWorkloadManagerRecordDataQueryingWorkloadManagerEventDataManagingResourceQueuesConfiguringWorkloadManagerComponentsTroubleshootingWorkloadManagerDatumReference

©CopyrightPivotalSoftwareInc,2013-2017 1 1.7.0

AboutGreenplumWorkloadManagerGreenplumWorkloadManagerisamanagementtoolforGreenplumDatabaseyoucanusetomonitorandmanagequeriesandtomanageresourcequeues.

YoucanuseGreenplumWorkloadManagertoperformtaskslikethese:

MonitorGreenplumDatabasequeriesandhostutilizationstatistics

Logwhenaqueryexceedsathreshold

ThrottletheCPUusageofaquerywhenitexceedsathreshold

Terminateaquery

Detectmemory,CPU,ordiskI/Oskewoccurringduringtheexecutionofaquery

Createdetailedrulestomanagequeries

Add,modify,ordeleteGreenplumDatabaseresourcequeues

WorkloadManagerArchitectureGreenplumWorkloadManagerisasetofGreenplumDatabase-specificpluginsdeployedonanextensiblePivotalframework.Alloftheapplicationlogicisisolatedintheseplugins.WorkloadManagerprovidesthefollowingplugins:

Agentplugins:

PublishinformationaboutactiveGreenplumDatabasequeries

Publishinformationaboutpostgresprocesses

Advertisequeryterminationcapability

Advertisequerythrottlingcapability

Advertisethresholdloggingcapability

Configurationmanagementplugins:

QuerythestateoftheGreenplumDatabaseclusterperiodically

InformtheframeworkoftheGreenplumDatabaseclusterstateandsizeallowing gp-wlm toautomaticallygrowwhenthedatabaseisexpanded.

Deployconfigurationsthroughoutthecluster.

Command-lineinterfaceplugins:

Add,modify,ordeleterules

Monitorqueriesandskew

ManageGreenplumDatabaseresourcequeues

Rulesengineplugins:

Provideextendedfunctionalityusedduringrulescreation

Theruntimeframeworkloadsthesepluginsatexecutiontime.


InstallingGreenplumWorkloadManager

PrerequisitesRedHatEnterpriseLinux(RHEL)64-bit5.5+or6,CentOS64-bit5.5+or6,orSUSE11

GreenplumDatabaseversion4.3.x

PivotalGreenplumCommandCenterinstallerforyourplatform

Note:TheGreenplumWorkloadManagerinstallersareincludedinthePivotalGreenplumCommandCenterinstalleryoudownloadfromPivotalNetwork .Theinstallerfile, gp-wlm-<version>-<platform>.bin ,isintheGreenplumCommandCenterinstallationdirectory, /usr/local/greenplum-cc-web ,bydefault.

RunningtheGreenplumWorkloadManagerInstallerGreenplumWorkloadManagerisinstalledontheGreenplumDatabasemasternode.Itautomaticallydistributesthesoftwaretoallsegmentserversinthedatabasecluster.TheinstallerdetectstheinstalledWorkloadManagerversion,ifany,andperformsanupgradeifnecessary.Runtheinstallerwiththe--force optiontoforcereinstallationofthecurrentversion.

Thepackageinstallerhasthefollowingsyntax:

./gp-wlm-<version>-<platform>.bin--help

./gp-wlm-<version>-<platform>.bin--install=<DIR>[--force][--install-concurrency=<COUNT>][--no-remove-old][--skip-health-check][--dbname-records=<database_name>][--tool-manifest=<FILE>]

Options

--help

DisplayscommandsyntaxfortheWorkloadManagerinstaller.

--install=DIR

The --install optionisrequired.ItspecifiesthedirectorywhereGreenplumWorkloadManagerwillbeinstalled,forexample /home/gpadmin .

--force

Ifthe --install optionpointstoanexistingGreenplumWorkloadManagerinstall,theinstallerwillcheckthecurrentlyinstalledversionandperformanupgradeonlyifthecurrentversionisolderthantheversionbeinginstalled.Ifthe --force optionisspecified,theinstallerwillallowinstallingthesameversionofGreenplumWorkloadManagerontopofitself.Notethat --force doesnotallowyoutodowngradeGreenplumWorkloadManagertoanearlierversion.

--install-concurrency=COUNT

Themaximumnumberofhoststobootstrapatonce.Thedefaultcountiscomputedbytheinstaller.Thisoptionplacesalimitonthenumberofprocessestheinstallercanfork.

--no-remove-old

Bydefault,theinstallerremovesallpreviousinstallationdirectoriesafteranupgrade.The --no-remove-old optionpreventstheinstallerfromremovingoldinstallationdirectories.

--skip-health-check

DonotperformaclusterhealthcheckafterWorkloadManagerinstallationcompletes.Thisoptionisnotrecommended.

--dbname-records

Thenameofthedatabasewherethe gp_wlm_records tableiscreated.Thedefaultispostgres.The template0 and template1 databasesmaynotbespecified.Thedatabasemustexistatinstalltime.ThesamedatabasemustbespecifiedwhenupgradingtoanewWorkloadManagerrelease.

--tool-manifestfilename

Theoptional --tool-manifest optionspecifiesatextfilecontainingalistofcommandsandtheirabsolutepaths.WorkloadManagernormallyfindsstandardsystemcommandsonthepath.Ifyourenvironmenthasincompatibleimplementationsofthesecommandsonthepath,createamanifestfilethatprovidestheabsolutepathtoastandardversion.


https://network.pivotal.io

Followingisanexampletoolsmanifestfile:

stat=/home/gpadmin/bin/statreadlink=/bin/readlinkssh=/home/me/bin/myssh

Theinstallercreatesa gp-wlm-data directoryintheinstallationdirectoryandinstallstheGreenplumWorkloadManagerreleaseintoit.Asymboliclinkgp-wlm intheinstallationdirectorylinkstothespecificGreenplumWorkloadManagerreleasedirectory.

1. LogintotheGreenplummasterhostasthe gpadmin user.

2. EnsurethattheGreenplumWorkloadManagerinstallerisexecutable.

$chmod+xgp-wlm-<version>-<platform>.bin

3. RuntheGreenplumWorkloadManagerinstaller.Specifytheabsolutepathtoaninstallationdirectorywhereyouhavewritepermission.Forexample:

$./gp-wlm-<version>-<platform>.bin--install=/home/gpadmin/

ThiscommandinstallsGreenplumWorkloadManagerinthe gp-wlm-data subdirectoryonallofthesegmentsandcreatesthe gp-wlm symboliclink.Forexample,theabovecommandinstallsWorkloadManagerin /home/gpadmin/gp-wlm-data/gp-wlm-release andcreatesthesymboliclink /home/gpadmin/gp-

wlm .

Note:Inrarecases,theinstallercanfailduringthe cluster-health-check phase.Iftheclusterisreportednothealthy,re-runtheinstallerwiththe --force option.

4. ToaddtheWorkloadManagerexecutablestoyourpath,source <INSTALL_DIR>/gp-wlm/gp-wlm_path.sh inyourshell.

$source<INSTALL_DIR>/gp-wlm/gp-wlm_path.sh

Youcanaddthe source commandtoyour ~/.bash_profile or ~/.bashrc scripttoincludetheWorkloadManagerexecutablesinyourpathwheneveryoulogin.

UninstallingGreenplumWorkloadManagerTouninstallGreenplumWorkloadManager,runthefollowingcommand:

$<INSTALL_DIR>/gp-wlm/bin/uninstall--symlink<INSTALL_DIR>/gp-wlm


ManagingGreenplumWorkloadManagerServicesGreenplumWorkloadManagerinstallsandrunsfourservicesonallsegmenthostsintheGreenplumcluster:

agent

cfgmon

rabbitmq

rulesengine

Theservicescanbemanagedusingthe INSTALLDIR/gp-wlm/bin/svc-mgr.sh command.Thecommandhasthefollowingsyntax:

INSTALLDIR/gp-wlm/bin/svc-mgr.sh\--service=SVCNAME\--action=ACTION

SVCNAME maybe agent , cfgmon , rabbitmq , rulesengine ,or all .If SVCNAME specifiesanindividualservice,onlythatserviceismodified.Specify alltomanipulateallservices.

The ACTION parameteraffectsonlythelocalsystem,unlessitisprefixedwith cluster- ,inwhichcaseitrunsonallhostsinthecluster.Theactionsare:

start / cluster-start –StartanyoftheWorkloadManagerservicesthatarenotrunning.

stop / cluster-stop –StopanyWorkloadManagerservicesthatarerunning.

status / cluster-status –Determineiftheservicesarerunning.

restart / cluster-restart –RestarttheWorkloadManagerservices.

enable / cluster-enable –EnableandstartWorkloadManagerservices.

disable / cluster-disable –StopanddisableWorkloadManagerservices.

Ifyousourcethe INSTALLDIR/gp-wlm/gp-wlm_path.sh fileinyourshell,theWorkloadManagerscriptsareinyourpath.Otherwise,youmustprovidethefullpathtotheutilityinthe gp-wlm/bin directory.

Whenaserviceisstopped,itwillnotberestarteduntilthe start actionisinvoked,orthelocalmachinereboots,whichevercomesfirst.

Whenaserviceisdisabled,itwillnotberestarteduntilthe enable actionisinvoked.Thisispersistentacrossreboot.

ThefollowingexamplechecksthestatusofallWorkloadManagerservicesonthelocalhost:

[gpadmin@mdw~]$svc-mgr.sh--service=all--action=statusRabbitMQisrunningoutofthecurrentinstallation.(PID=22541)agent(pid22732)isrunning...cfgmon(pid22858)isrunning...rulesengine(pid22921)isrunning...

CheckingtheHealthofGreenplumWorkloadManagerServicesAtanytime,thehealthofGreenplumWorkloadManagerservicescanbeverifiedacrosstheclusterbyinvokingthecluster-health-check utility.Thistoolconfirmsthatallservicesarerunningacrossthecluster,andthatmessagesarebeingreceivedfromeachmachineinthecluster.Followingisthesyntaxfor cluster-health-check :

INSTALLDIR/gpwlm/bin/cluster-health-check--symlink=/absolute/path/to/installation/symlink[--max-concurrency=N][--max-cluster-checks=N][--help]

Options: -c or --max-concurrency

The max-concurrency optionspecifiesthenumberofhoststocheckatonce.Thedefaultisacomputedvaluebasedonthenumberofhostsinthecluster:20iftherearefewerthan100hosts,50ifthereare100to199hosts,and75ifthereare200ormorehosts.

-m or --max-cluster-checks

Thenumberoftimestocheckforahealthycluster.Thedefaultis1.


-s or --symlink

Theabsolutepathtothe gp-wlm directorylinkedtotheinstalledWorkloadManagerrelease.Required.

-h or --helpDisplaycommandusageinformationandexit.

Ifthecommandreportsanerrorcommunicatingwithoneormoreservices,theclustermayberestartedwiththiscommand:

INSTALLDIR/gp-wlm/bin/svc-mgr.sh--action=cluster-restart--service=all

ThiscommandstopsandthenrestartseachoftheWorkloadManagerservicesoneachsegmenthost.


UsingtheGreenplumWorkloadManagerCommandLineTheGreenplumWorkloadManagercommandlineutility, gp-wlm ,providesaccesstoWorkloadManagercapabilities.Theutilitymayberunbyenteringcommandsinteractivelyorbyspecifyingequivalentactionsusingcommand-lineoptions.Thecommand-lineoptionsareusefulforscripting,sincetheyrequirenointeractiveuserinput.

Togethelpininteractivemode,issuethecommand: help

Togethelpforcommandlineinvocation,issuethecommand: gp-wlm--help

Belowisthe gp-wlm commandsyntax:

Usage:gp-wlm[-g|gptop][--rq-add=<queue-name>with<queue-settings>][--rq-delete=<queue-name>][--rq-modify=<queue-name>with<queue-settings>][--rq-show=all][--rq-useradd=<user>to<queue-name>][--rq-userdel=<user>from<queue-name>][--rule-add=[transient]<name><rule>][--rule-delete=all|<name>][--rule-dump=<path>][--rule-import=<path>][--rule-modify=[transient]<name><rule>][--rule-restore=<path>][--rule-show=all|<name>[<host><domain>]][--describe=<datum>][--config-show<component><setting>][--config-describe<component><setting>][--config-modify<component><setting>=<value>][--set-domain=<domain>][--set-host=<host>][--schema-path=<path>][--version][--help][--usage]

The gp-wlm command-lineoptionshaveparallelcommandsinthe gp-wlm interactivemode.Theoptiondescriptionsbelowlinktotheinteractivemodecommandsforadditionalusageinformationandexamples.

Options

-g or --gptopStartsthe gptop graphicaluserinterface.SeeUsingtheWorkloadManagerGraphicalInterface(gptop)formoreabout gptop .

--rq-addAddsaresourcequeuewiththespecifiednameandsettings.SeeResourceQueueSettingsfortheformatandcontentofthe<queue-settings>argument.

--rq-deleteDeletestheresourcequeuewiththespecifiedname.SeeDeletingaResourceQueueforinformationaboutdeletingresourcequeues.

--rq-modifyChangesthesettingsfortheresourcequeuewiththespecifiednametothespecifiedsettings.SeeResourceQueueSettingsfortheformatandcontentofthe<queue-settings>argument.

--rq-show=allOutputsalistofresourcequeuesandsettings.SeeDisplayingResourceQueuesforanexampleoftheoutput.

--rq-useraddAddsadatabaseroletoaresourcequeue.Arolecanbelongtooneresourcequeueatatime.SeeAddingUserstoResourceQueuesfordetailsandexamples.

--rq-userdelDeletesadatabaserolefromaresourcequeue.SeeDeletingaUserfromaResourceQueuefordetailsandexamples.

--rule-addAddsaruletotherulesengine.SeeAddingRulesfordetailsaboutthepartsofaruleandexamples.

--rule-deleteDeletesarulewithaspecifiednameor,byusingthereservedname all ,allcurrentrules.SeeDeletingRulesfordetailsandexamples.

--rule-dumpSavesthecurrentsetofpermanentrulestoanamedfile.SeeSavingRulestoDiskfordetailsandexamples.


--rule-importAddsrulessavedinanexternalfiletothecurrentruleset.SeeImportingRulesfordetailsandexamples.

--rule-modifyModifiesarulebyreplacingtheruleexpressionormakingatransientrulepermanent.SeeModifyingRulesfordetails.

--rule-restoreRestorerulesfromanexternalfile,replacingthecurrentrulesintherulesengine.SeeRestoringRulesfordetails.

--rule-showDisplayarulebynameor,byusingthereservedname all ,allcurrentrules.SeeDisplayingRulesfordetailsandexamples.

--config-showShowthecurrentvalueofasettingforaWorkloadManagercomponent.SeeConfiguringWorkloadManagerComponentsfordetailsabouttheconfigurationcommands.

--config-describeDescribethepurposeofasettingforaWorkloadManagercomponentanditsvalueconstraints.

--config-modifyOverridethevalueofasettingforaWorkloadManagercomponent.Thecomponentisautomaticallyrestartedafterasettingisupdated.

--set-domainSetthedomain,orclustername,forthe gp-wlm interactivesession.Itisrecommendedtousethedefaultdomain.

--set-hostSetthehostwherethe gp-wlm sessionruns.Thedefaultisthemachinewhereyourun gp-wlm .Itisrecommendedtoonlyrun gp-wlm ontheGreenplummasterhost.

--schema-pathThepathtotheschemafiles.Thedefaultpath, INSTALLDIR/schema ,shouldnotbechanged.

--usageDisplaysusageinformationforthe gp-wlm command.

--helpDisplaysonlinehelpforthe gp-wlm command.

--describeDisplaysadescriptionofadatum.Forexample:

$gp-wlm--describe=datid:numbackends

--version or -vDisplaysthe gp-wlm version.

Usinggp-wlminInteractiveMode1. Startgp-wlmatthecommandline:

$gp-wlm

The gp-wlm commandpromptdisplaysthenameofthehostwhere gp-wlm isrunningandthenameoftheGreenplumDatabaseclusterordomain.Enter help attheinteractivepromptforausagemessage.

Whenusingthe gp-wlm command-line:

Entereachcommandonasingleline.Commandsareexecutedimmediately.

Enterthe help commandtoviewalistofWorkloadManagercommands.

Enter describe <datum> toviewadescriptionofadatum.

Whileenteringacommand,gethelpwithcommandsyntaxbypressingthetabkeytoshowvalidoptions.Thisisespeciallyusefulwhenconstructingarule.Inthefollowingpartialexample,userentryisinbold.


mdw/gpdb-cluster>rule<tab>adddeletedumpmodifyrestoreshowmdw/gpdb-cluster>ruleadd<tab><rule-name>transientmdw/gpdb-cluster>ruleaddtransient<tab><rule-name>mdw/gpdb-cluster>ruleaddtransientmyrule<tab>gpdb_recordhost:pg_terminate_backendmdw/gpdb-cluster>ruleaddtransientmyrulegpdb_record(<tab><dt>)gpdb_segment_rolemessagequery_startusename</dt>current_queryhostpidsession_id...

Enterthequitcommandattheprompttoexitthe gp-wlm interactivemode.

SettingtheWorkloadManagerTargetHostandDomainUsethe sethost and setdomain commandstosetthedefaulthostanddomainfortheWorkloadManagersession.

Itisrecommendedtoonlyrunthe gp-wlm toolontheGreenplumDatabasemasternodeandtoleavethehostanddomainattheirdefaultvalues.

Thedefaulthostisthenameofthemachinewhereyouexecute gp-wlm .ThehostnamemustberesolvableinDNS.Youcanspecifydifferenthostandclusternamesonthe gp-wlm commandlinebysupplyingthe --set-host and --set-domain commandlineoptions.

Example:

mdw/gpdb-cluster>sethostsmdwsmdw/gpdb-cluster>setdomaingpdbsyssmdw/gpdbsys>


UsingtheWorkloadManagerGraphicalInterface(gptop)TheWorkloadManagerGraphicalinterface, gptop ,isacursesinterfacethatyoucanusetomonitorlivedatafortherulesengine,hoststatistics,activeGreenplumDatabasequeries,anddatabaseskew.

Youcanstart gptop fromthecommandlinebyrunning gptop inaterminal.Ifyouarealreadyusinginteractive gp-wlm ,enterthe gptop commandtoenterthemonitor.

Note:IfyouusethePuTTYssh/telnetclientforWindowstorun gptop ,youmayexperienceproblemswithfunctionkeysandline-drawingcharacterswiththedefaultsettings.Tosupportfunctionkeys,inthePuTTYConfigurationwindow,chooseConnection>Dataandenter xterm-color or putty intheTerminal-typestringfield.Toenablecorrectline-drawingcharacters,chooseWindow>TranslationandsetRemotecharactersettoUsefontencoding.

Whenyoufirststart gptop ,theGPDBQueriespane(seebelow)isselected.Atanytime,youcanpresstheF2keytogetapaneselectionmenu.UsetheTab,Left-Arrow,orRight-Arrowkeystomakeaselection.PressF2tocloseanopenmenuwithoutmakingaselection.

Anasterisk( * )nexttoacolumnheadingindicatesthattherowsaresortedbythatcolumn.Tochangethesortorder,presstheF3key,thenchoosethenumberofthecolumnyouwanttosortbyfromthepop-upmenu.

Press q orchooseFile>Exittoleave gptop .

The gptop monitoringfeaturesareundertheMonitormenu.TheMonitormenuhasfouroptions:

GPDBQueries–ShowsactiveGreenplumDatabasequeries

GPDBSkew–Showsskewstaticsforactivequeries

Hydra–Showsstatisticsfromtherulesengine

SysData–Showsperformancestatisticsforeachhostinthecluster

GPDBQueriesTheGPDBQueriesmonitordisplaysalineforeachactiveGreenplumDatabasequery.

SessIDThesessionidforthequery.

TimeThenumberofsecondssincethequerybeganexecuting.

UserThenameoftheGreenplumDatabaserolethatsubmittedthequery.

ClientAddrThenetworkaddressfromwhichthequerywassubmitted.

DatNameThedatabasenamethequeryisrunningagainst.

QueryThetextofthequery.

GPDBSkewTheGPDBSkewmonitorshowscalculatedskewstatisticsforactiveGreenplumDatabasequeries.Statisticsarecalculatedoneachhostinthesystemandthensenttothemasterwheretheyaresummarized.YoucanselectahostandpressEntertoseestatisticsforthehost.Thecalculatedskewvalueisthecubedstandarddeviationacrossthecluster.Valuescloserto0.0indicatelessskew.TheGPDBSkewmonitorshowsthefollowingcolumnsforeachactivequery:

SessIDTheGreenplumDatabasesessionIDforthequery.


TimeThenumberofsecondssincethequerystarted.

UserTheGreenplumDatabaserolethatsubmittedthequery.

CPU-SkewAmeasureofCPUskewcalculatedasthecubedstandarddeviationofthetotalCPUforeachhostforthequery.

MEM-SkewAmeasureofmemoryskewcalculatedasthecubedstandarddeviationofthetotalresidentsizepercentforeachhostforthequery.

READ-SkewAmeasureofdiskreadI/Oskewcalculatedasthecubedstandarddeviationofthebytesreadpersecondforeachhostforthequery.

WRITE-SkewAmeasureofdiskwriteI/Oskewcalculatedasthecubedstandarddeviationofthebyteswrittenpersecondforeachhostforthequery.


UsingWorkloadManagerRulesRulestriggeractionswhentheymatchevents.Theagentpluginsonthesegmenthostscollectstatisticsandassociateddata.Therulesenginematchesthemtorules,andperformsthespecifiedactionsintheagentplugins.

UnderstandingRules

AddRuleCommandSyntax

ManagingRules

ExampleRules

BestPracticesforRules

KnownIssues


UnderstandingRulesThistopicprovidesanintroductiontoWorkloadManagerrulesincludinghowtowritethemandhowtheybehaveinaGreenplumDatabaseclusterwithWorkloadManager.

RulesOverviewAWorkloadManagerrulespecifiesanactiontoexecutewhenaspecifiedconditionisdetectedintheGreenplumDatabasecluster.AdministratorswriteWorkloadManagerrulestoinvestigateproblemqueries,throttlequeriesthatconsumetoomuchCPU,orsimplyterminatequeriesthatcoulddisruptthedatabasesystem.

The rulesengine serviceoneachGreenplumhostevaluatesrulesagainstfacts,calleddatums,collectedfromtheGreenplumhostoperatingsystemsanddatabaseprocesses.Atregularintervals,datumsarecollectedandsubmittedtothe rulesengine serviceoneachhost.Whentherulesenginematchesarule,itperformsitsaction.

Arulehasanactionexpressionandaconditionexpressionseparatedbythe WHEN keyword.Itcanbereadas“do<action-exp>WHEN<condition-exp>”.

Hereisarulethatterminatesanysessionthathasrunforover120seconds:

pg_terminate_backend()whensession_id:host:pid:runtime>120

Intheaboverule,theactionexpressionis pg_terminate_backend() andtheconditionexpressionis session_id:host:pid:runtime>120

.

Theterm session_id:host:pid:runtime isascopeddatum; runtime isthenameofthedatumand session_id:host:pid isthescope.Thisscopeddatumspecifiestheelapsedexecutiontimeforaqueryexecutorprocessonasegmenthost.Thecolon-delimitedsectionsofthescopeanddatumidentifythesourceofthevalue:

session_id –IDofaGreenplumDatabasequery

host –thenameofasegmenthost

pid –processIDofaqueryexecutorprocessrunningonthehost

runtime –elapsedtimesincethequeryexecutorprocessstarted

Youcreaterulesusingthe ruleadd commandinaninteractive gp-wlm sessionorwiththe --rule-add command-lineoption.Eachrulehasauniquenameusedformanagingtherulewithcommandssuchas rulemodify or ruledelete .

Arulemayalsobelabeled transient ,whichmeanstheruleisactiveonlyuntilitisdeletedorWorkloadManagerisrestarted.

Fordetailsaboutthe ruleadd commandsyntaxandusageseeAddRules.

ForreferenceinformationaboutWorkloadManagercommandsthatmanageexistingrules(modify,delete,dump,import,andrestore),seeManagingRules.

Thenextsectionsprovidemoredetailedinformationaboutthecomponentsofarule:actionexpressions,conditionexpressions,datums,andscopes.

ActionExpressionTheactiontoperformwhenaruleistriggeredisspecifiedwithoneofthefollowingWorkloadManageractions:

gpdb_record –recordacustommessageanddetailsofthedatabasequeryprocessinthe gp_wlm_records databasetable.

host:throttle_gpdb_query –throttleaGreenplumDatabasequeryonaspecifiedhost.

host:pg_cancel_backend –cancelthecurrentqueryinasessiononahostbycallingthePostgreSQLpg_cancel_backend() function.

pg_terminate_backend –terminateasessionbycallingthePostgreSQL pg_terminate_backend() function.

Arule’sconditionexpressionalwaysidentifiesasinglequeryexecutorprocessonasingleGreenplumsegmenthost.Whenarule’sactionexecutes,itwillhaveinitscontextthequery’ssessionID,asegmenthostname,andtheprocessIDofasinglequeryexecutorprocessonthehost.

EachoftheactionsrespondstothesingleGreenplumDatabasequeryexecutorprocessidentifiedbytheconditionexpression.SeeRuleActionsforreferenceinformationfortheactions.


Actionexpressionsarewrittenasfunctionsandcanhavezeroormorearguments,specifiedwith key=value pairsinparenthesesaftertheactionname:

<action-name>(<arg1>=<value1>,<arg2>=<value2>,...)

gpdb_recordThe gpdb_record actionwritesthetextspecifiedinits message argumenttoalogfile,alongwithdetailsofthedatabasequeryprocessidentifiedintherule’sconditionexpression.Forexample,the gpdb_record actioncanlogamessagewhenanyqueryprocessexceeds120seconds:

gpdb_record(message='queryruntimeexceeds120seconds')whensession_id:host:pid:runtime>120

The gp_wlm_records externalGreenplumDatabasetableprovidesSQLqueryaccesstotheloggedrecords.(SeeQueryingthegp_wlm_recordsTable formoreinformation.)

The gpdb_record actionhasseveralarguments,butonlythe message argumentisrequiredtobespecifiedintherule.Hereisthefulllistofargumentsforthisaction:

message –Informativestringdescribingthereasonforrecording

current_query -Thetextofthecurrentquery

gpdb_segment_role -Roleofthedatabaseinstance: GPDB_MASTER or GPDB_SEGMENT

host -Thehostnameofthesegment

pid -Thepostgresprocessassociatedwiththequery

query_start -Querystarttime

session_id -Sessionidofthequery

usename -Nameoftheuserloggedintothisbackend

Withtheexceptionof message ,avalueforeachoftheseargumentsisinferredfromthematchedqueryprocess. gpdb_record logsarecordthatincludesthesuppliedmessage,alloftheseinferredvalues,thetextoftherule,andcontextvaluesfromtheconditionexpression.

host:throttle_gpdb_queryThe host:throttle_gpdb_query actionholdsaquerytoamaximumshareofCPUonahost,specifiedinthemax_cpu argumentasapercentageofCPUutilization.

The host: prefixonthe host:throttle_gpdb_query actionisascope.The host: scopeindicatesthattheactionwillbeperformedonlyonthehostmachineswheretherule’sconditionismatched.The host:throttle_gpdb_query actioniscurrentlytheonlyscopedaction.(Datumsusedintheconditionexpressionareallscoped.SeeDatumsandScopesbelowfordetails.)

This host:throttle_gpdb_query rulethrottlesaqueryonahostto30%CPUutilization:

host:throttle_gpdb_query(max_cpu=30)whensession_id:host:total_cpu>20

The session_id:host:total_cpu scopeddatumisthetotalpercentageofCPUusedbyallqueryexecutorprocessesonahostworkingonthesamequery.

Notethatthisruleestablishesarangebetween20%and30%CPUutilization.ThrottlingonahostbeginswhentotalCPUutilizationforthequeryexceeds20%andendswhenitdropsbelow20%.ThrottlingkeepstheCPUutilizationfromexceeding30%.Setting max_cpu argumenthigherthantherule’striggerthresholdpreventsrapidlyalternatingbetweenthrottlingenabledandthrottlingdisabledstatesthatcouldoccurifthethresholdandmaximumCPUareequal.

pg_cancel_backendThe host:pg_cancel_backend actioncancelsaqueryonahost.Itexecutesthe pg_cancel_backend() PostgreSQLfunctiononthesessionmatchedbytheconditionexpression.

Thefollowingrulecancelsthecurrentqueryinasessionthatexceeds75%totalCPUutilizationonanysegmenthostandhasrunformorethanfiveminutes:


http://docs-gpcc-staging.cfapps.io/300/gp-wlm/topics/rules/gp-wlm-records.html

host:pg_cancel_backend()whensession_id:host:total_cpu>75andsession_id:host:pid:runtime>300

Whenarulecancelsaquery,WorkloadManagerlogstheeventinalogfileonthesegmenthost.Theseeventrecordscanbequeriedusingthegp_wlm_events databaseview.TheviewdependsonGreenplumexternaltablesoneachsegmenthostandmustfirstbesetupusing manage-event-tables.sh

script.SeeQueryingWorkloadManagerEventDatafordetails.

pg_terminate_backendThe pg_terminate_backend actionexecutesthePostgreSQL pg_terminate_backend() functiononthesessionmatchedbytheconditionexpression.Thisisanunscopedactionbecauseasessionmustbeterminatedonallsegments.

Thefollowingruleterminatesasessionthatexceeds75%totalCPUutilizationonanysegmenthostandhasrunformorethanfiveminutes:

pg_terminate_backend()whensession_id:host:total_cpu>75andsession_id:host:pid:runtime>300

Whenaruleterminatesaquery,WorkloadManagerlogstheeventinalogfileoneachsegmenthost.Theseeventrecordscanbequeriedusingthegp_wlm_events databaseview.TheviewdependsonGreenplumexternaltablesoneachsegmenthostandmustfirstbesetupusing manage-event-tables.sh

script.SeeQueryingWorkloadManagerEventData fordetails.

ConditionExpressionTheconditionexpression(predicate)ofaruleisaBooleanexpressionthatidentifiesGreenplumDatabasequeriesyouwanttoactupon.

Datumscanbecomparedtovaluesusingthefollowingoperators.

Operator ValueFormat Description

=Anumberfornumericdatumsoraquotedstringforstrings.

Matchesonlywhenthevaluesareexactlyequal.

!=Anumberfornumericdatumsoraquotedstringforstrings. Matcheswhenthevaluesarenotequal.

=~Regularexpressionontherightsideenclosedinslashes( / ). datum =~ /sel.*by/

Performsaregularexpressionmatchbetweenthestringvalueandthespecifiedregex.Posixregularexpressionsyntaxisused.

> Number Greaterthan

< Number Lessthan

>= Number Greaterthanorequalto

<= Number Lessthanorequalto

Expressionscanbearbitrarilycomplex,joiningmultiplecomparisonswithBooleanANDandORoperatorsandparenthesestoenforceprecedence.Forexample:

host:pid:cpu_util>50or(host:pid:cpu_util>30andsession_id:host:pid:usename="fred")

IncludingClauseThe including keywordintroducesacomma-separatedlistofdatumstoaddtothecontextwhenaruletriggers.Anydatumreferencedintheconditionexpressionisautomaticallyaddedtothecontext.Toaddcontextvaluesfordatumsnotusedintheconditionexpression,listthedatumsaftertheincluding keyword.

Datumsinthe including clausearespecifiedwithoutscopes.Iftherulescompilercannotinferthescopefromscopesalreadyboundintherule,therulefailscompilationwithanerrormessage.

Thefollowingruleaddsthe host:pid:long_name and host:pid:avg_cpu_util datumstothecontext:

gpdb_record(message="CPUover50%")whenhost:pid:cpu_util>50includinglong_name,avg_cpu_util


http://docs-gpcc-staging.cfapps.io/300/gp-wlm/topics/kevents.html

The host:pid:cpu_util datumisinthecontextbecauseitisreferencedintheconditionclause.

Whena gpdb_record actiontriggers,thecontextdatumsareaddedtothe context_args columnofthe gp_wlm_events table.Whena host:pg_cancel_backend orpg_terminate_backend actiontriggers,thecontextdatumsareaddedtothe context columnofthe gp_wlm_events view.

Theadditionaldatumvaluescanprovideusefulinformationwheninvestigatingrecordedmessagesandterminationevents.

DatumsandScopesDatumsaredataitemscollectedbytheagent,andincludeoperatingsystemstatistics,OSprocessstatistics,anddatabasequerydata.

WorkloadManagerprovidesarichsetofdatumstouseinconditionexpressionssothatyoucantargetqueriesandqueryprocesseswithveryspecificcharacteristics.Forexample,arulecouldtargetqueriesexecutedwithacertaindatabaserolethataccessacertaintableanduseover30%ofCPUonanyhost.

Thenameofadatumisprefixedbyitsscope,whichprovidescontextforthedatum.Thehost:pid scopeofthe host:pid:cpu_util datum,forexample,meansthatthe cpu_util datumisthepercentageofCPUusedbyanOSprocess( pid )executingonaspecifichost( host ).The session_id:host:pid scopeforthesession_id:host:pid:usename datumindicatesthatthe usename datumisthedatabaseroleexecutingaGreenplumDatabasesegmentqueryprocess.Thesession_id istheidofthequeryand host isthesegmenthostwherethequeryexecutorprocess, pid ,isexecuting.

Datumsinthe including listofarulearespecifiedwithoutscopes.Therulescompilersearchesforincludeddatumsinscopesalreadyboundintheconditionexpressionandfailsifthescopecannotbeinferred.

Rulesmustbewritteninawaytoidentifyasinglequeryexecutorprocessonahost.Thefollowingrulerecordsamessagewhentheresidentmemorysizeforanyprocessexceeds20%.The host:pid scopedoesnotincludea session_id ,soanadditionalrexexptermisaddedtotheconditionexpressionmatchanyquery.Thisensuresthatthe host:pid:resident_size_pct datumisfromaqueryexecutorprocessandthattheactionhasaknownquerywhenitexecutes.Withoutthe session_id:host:pid:usename comparison,thisrulewouldfailtocompile.

ruleaddmem_high_segment_useage_20gpdb_record(message="MEM:highsegmentpctusage-20%")whenhost:pid:resident_size_pct>20andsession_id:host:pid:usename=~/.*/

WorkloadManagerDatumReferencelistsallofthedatums,theirscopes,andtheirdataformats.

datid ScopeThe datid scopeisfordatumsthatarevaluesfromasingledatabaseintheGreenplumDatabasesystem.Thedatid:datname datum,forexample,canbeusedtorestrictaruletoaspecificdatabase:

...anddataid:datname='my_db'

Datumswith datid scopemustbecombinedintheconditionexpressionwithotherdatumsthatidentifyaqueryprocess.

gpdb ScopeThe gpdb scopeisfordatumsfromtheentireGreenplumDatabasesystem.Thereiscurrentlyjustonesuchdatum:gpdb:total_master_connections ,whichisthetotalnumberofclientconnectsforalldatabasesinthesystem.Thisdatumcouldbeusedtopreventarulefromtriggeringuntilaspecifiednumberofconnectionsisexceeded.

host ScopeThe host scopeappliestodatumsthatarevaluesfromasinglehostintheGreenplumcluster.Theseincludethecurrentdateandtimevaluesfromthehostandthehost’stotalCPUutilization.

host:segment_id ScopeThe host:segment_id ScopeisusedfordatumsfromasingleGreenplumsegment.Itisusedfordatumsthatreportthevirtualmemory(vmem)usageforasegment.

host:pid ScopeThe host:pid scopeisfordatumsreferringtoanyoperatingsystemprocessonahost.Thesedatumsincludethememory,CPU,andI/OstatisticsavailablefromLinuxforOSprocesses.Datumswith host:pid scopecanbeusedtonarrowaruletoqueryprocessesusingmorehostresourcesthanexpected.

session_id ScopeA session_id istheGreenplumcluster-wideIDforadatabasequery.Thedatumswith session_id scopeareCPUanddiskI/OskewstatisticsforasinglequerythatWorkloadManagercalculatesfromthe host:pid datumsfromallqueryexecutorprocessesonallsegmenthostsforthe


query.

session_id:host ScopeThe session_id:host scopeincludesdatumsthatareaggregatedmemory,CPU,andI/Ostatisticsforallprocessesonallhostsrunningaquery.

session_id:host:segment_id ScopeThe session_id:host:segment_id scopeincludesdatumsthatreporttheamountofvirtualmemory(vmem)consumedbyaGreenplumsegmentforasession.

session_id:host:pid ScopeThe session_id:host:pid scopeisusedfordatumsthattakevaluesfromaqueryexecutorprocessonasinglesegmenthost.


AddingRules

AddRuleCommandSyntaxThe ruleadd commandaddsarule.Hereisthesyntaxfortheruleaddcommand:

ruleadd[transient]<name><action-name>(<action-args>)when<expression>[including<datum_list>]

transientRulesmaybepersistentortransient.Apersistentruleremainsactiveuntilitisdeleted,whileatransientruledisappearswhentherulesengineserviceisshutdownonallhosts.Rulesarepersistentbydefault;youmustincludethe transient keywordtocreateatransientrule.

<name>Auniquenamefortherule.Thename all isreserved.

<action-name>Theactiontoperform.Oneofthefollowing:

host:throttle_gpdb_query –specifyamaximumallowedCPUutilizationpercentageforaGreenplumDatabasequery.

host:pg_cancel_backend -cancelthecurrentqueryonahostbycallingthePostgreSQLhost:pg_cancel_backend() function.

pg_terminate_backend –terminateasessionbycallingthePostgreSQL pg_terminate_backend() function.

gpdb_record –recordaneventaboutaqueryinthe gp_wlm_records table.

<action-args>Argumentsthatpassvaluestotheaction,ifneeded.Anargumentisspecifiedasan arg-name=value pair.Multipleargumentsareseparatedbycommas.

<expression>ABooleanexpressionthatfilterstargetsfortheaction.Theexpressionreferencesoneormoredatumstofilterthefactsthattriggertheaction.TheexpressionmaycontainPosixregularexpressions(regex).

including<datum-list>Anoptional,comma-separatedlistofdatumstoaddtothecontextwhentheruletriggers.Withoutan including clause,theactioncontextcontainsonlyvaluesfordatumsreferencedinthe expression clause.Addthe including clausetoaddvaluesforadditionaldatumstotheactioncontext.

Datumsinthe<datum_list>arespecifiedwithoutscopeprefixes.IftheWorkloadManagerrulecompilercannotfindadatuminanycurrentlyboundscope,addingtherulefailswithanerrormessage.

When gpdb_record , host:pg_cancel_backend ,and pg_terminate_backend actionsaretriggered,thedatumsin<datum-list>areaddedtothecontextargumentscolumnsinthe gp_wlm_records tableor gp_wlm_events view.

RuleActions

host:throttle_gpdb_queryThrottleaGreenplumDatabasequeryonaspecifiedhost.

Arguments:

max_cpu -HoldprocesstoamaximumofthispercentageCPUutilization.

pid -Theprocesstothrottle.

session_id -Thesessiontothrottle.

The max_cpu argumentisrequired.The pid and session_id argumentscanbeinferredfromthesession_idinthewhenclauseandarenormallyomitted.


host:pg_cancel_backendCancelaqueryonahost.ThisactioncallsthePostgreSQLpg_cancel_backend administrativefunction.

Arguments:

session_id –ThesessionIDofthequerytoterminate.

Theargumentisnormallyomitted,allowingthesessionIDtobeinferredbyusingthesession_idintherule’swhenclause.WorkloadManagerthendetermineswhichsessiontocancel.TheactionsendsaSIGINTsignaltothesessionprocess,whichcancelsthecurrentquery.Seehttp://www.postgresql.org/docs/9.3/static/functions-admin.html formoredetails.

Thefollowingexamplecancelsthecurrentqueryinanysessionthathasbeenexecutingformorethan20seconds:

mdw/gpdb-cluster>ruleaddcancel_queryhost:pg_cancel_backend()whensession_id:host:pid:runtime>20

pg_terminate_backendTerminateasessiononallhosts.ThisactioncallsthePostgreSQLpg_terminate_backend administrativefunction.

Arguments:

session_id –ThesessionIDtoterminate.

Theargumentisnormallyomitted,allowingthesessionIDtobeinferredbyusingthesession_idmatchedbyrule’swhenclause.WorkloadManagerthendetermineswhichpidtoterminate.Seehttp://www.postgresql.org/docs/9.3/static/functions-admin.html formoredetails.

Thefollowingexampleterminatesanysessionthathasbeenexecutingformorethan20seconds:

mdw/gpdb-cluster>ruleaddcancel_sessionpg_terminate_backend()whensession_id:host:pid:runtime>20

gpdb_recordLogsamessagetothe gp_wlm_records tablewhenaruleismatched.

Arguments:

current_query -Thetextofthecurrentquery

gpdb_segment_role -Roleofthedatabaseinstance: GPDB_MASTER or GPDB_SEGMENT

host -Thehostnameofthesegment

message –Informativestringdescribingthereasonforrecording.

pid -Thepostgresprocessassociatedwiththequery

query_start -Querystarttime

session_id -Sessionidofthequery

usename -Nameoftheuserloggedintothisbackend

Onlythemessageargumentmustbesupplied;allotherargumentscanbeinferredfromtherule’swhenclause.

Thefollowingexamplelogsallqueries:

mdw/gpdb_cluster>ruleaddrecord_querygpdb_record(message="all")whensession_id:host:pid:usename=~/.*/

SeeQueryingthegp_wlm_recordsTable forinformationaboutthe gp_wlm_records table.


https://www.postgresql.org/docs/9.3/static/functions-admin.html

https://www.postgresql.org/docs/9.3/static/functions-admin.html

http://docs-gpcc-staging.cfapps.io/300/gp-wlm/topics/rules/gp-wlm-records.html#section_grd_vf3_ft

ManagingRulesUsingcommandsdescribedinthistopic,rulescanbedisplayed,deleted,modified,andsavedtoorrestoredfromdisk.Eachofthecommandshasagp-wlm command-lineequivalent.

DisplayingRulesUsethe rule

showcommandtoseeexistingrules.Youcanshowallexistingrulesorspecifyasinglerulebyname.

ruleshow{all|rule-name}

The ruleshowall

commandinthisexamplelistsallregisteredrules:

mdw/gpdb-cluster>ruleshowall---Name--------------Expression-----------record_querygpdb_record(message="all")whensession_id:host:pid:usename=~/.*/cancel_querypg_terminate_backend()whensession_id:host:pid:runtime>20throttle_queryhost:throttle_gpdb_query(max_cpu=20)whensession_id:host:pid:current_query=~/.*selectcount.*/

Thisexamplelistsasinglerulebyname:

mdw/gpdb-cluster>ruleshowthrottle_query---Name--------------Expression-----------throttle_queryhost:throttle_gpdb_query(max_cpu=20)whensession_id:host:pid:current_query=~/.*selectcount.*/

DeletingRulesTheruledeletecommandremovesarule.

ruledeleterule-name

Todeleteallrulesatonce,use ruledeleteall :

ruledeleteall

Iftherearenorules,thiscommandreturnsanerror.

ModifyingaRuleUsethe rulemodify commandtoaltertheexpressionforanexistingrule.Youmayalsoremovethetransientkeywordfromtheruledeclarationtoconvertittoapersistentrule.Conversionfrompersistenttotransientisnotcurrentlysupported.

rulemodify[transient]nameaction-name(action-args)whenexpression

Thisexamplemodifiesthe cancel_query ruletoalterthenumberofsecondsaqueryrunsonahosttotriggertherulefrom20to25:

mdw/gpdb-cluster>rulemodifycancel_querypg_terminate_backend()whensession_id:host:pid:runtime>25

SavingRulestoDiskThe ruledump commandsavesallpersistentrulesintheclustertoatextfile,oneruleperline.


ruledumppath

Ifyoudonotprovidethefullpathtothefile,thefileiswrittenrelativetothedirectorywhereyoustartedthe gp-wlm session.Theuserrunning gp-wlmmusthavepermissiontowritethefileatthespecifiedlocation.Ifthefileexists,the ruledump commandoverwritesit.

Thefollowingexamplesavesrulestothe /home/gpadmin/rules/20150910-1 file.Ifthe /home/gpadmin/rules directorydoesnotexist,anerrorisreported.

mdw/gpdb-cluster>ruledump/home/gpadmin/rules/20150910-1

ImportingRulesfromDiskThe ruleimport commandimportsrulesfromafileintotheactivesetofrules.Importedrulesreplaceexistingruleswiththesamenames.Existingruleswithnamesnotpresentinthefileareunchanged.

ruleimportpath

RestoringRulesfromDiskThe rule

restorecommandrestoresallrulesfromafile,replacinganyexistingrules.Itisequivalentto rule

delete=allfollowedby ruleimport

path.

rulerestorepath


ExampleRulesThissectionprovidesexamplesofruleswrittenforvariouspurposes.

Note:Rulesmustbeenteredonasingleline,buttherulesshowninthissectionarewrappedforreadability.

RecordhighcpuutilizationqueriesThefollowingruleinvokesthe gpdb_record actionwhenthegpadminuserrunsaqueryanditstotalcpuutilizationonahostexceeds100%.

ruleaddsimplegpdb_record(message="Toomuchcpuforgpadmin")whensession_id:host:total_cpu>100andsession_id:host:pid:usename='gpadmin'

ThrottlethecpuutilizationofaqueryThisruleinvokesthe host:throttle_gpdb_query actionwhenthecpuutilizationofaprocessexceedsathresholdandthequeryhasrunformorethan20seconds.

ruleaddthrottlehost:throttle_gpdb_query(max_cpu=30)whenhost:pid:cpu_util>20andsession_id:host:pid:usename='gpadmin'andsession_id:host:pid:runtime>20

Cancelanyquerywherethesessionhasrunlongerthan120secondsThisruleinvokesthe host:pg_cancel_backend actionwhena session_id:host:pid:runtime exceedstwominutes.

ruleaddkill_longhost:pg_cancel_backend()whensession_id:host:pid:runtime>120

ThrottleandevenoutskewThisruleinvokes host:throttle_gpdb_query whenthetotalcpuusageofaqueryonahostexceeds90%andthecurrentqueryisaselectontheskewtesttable.

ruleaddskewrulehost:throttle_gpdb_query(max_cpu=50)whensession_id:host:total_cpu>100andsession_id:host:pid:current_query=~/select.*skewtest/

Youcanobservetheeffectsofthisruleinthe gptop GPDBSkewpage.

ComplexruleThisruleinvokes gpdb_record foraquerythatmeetsthefollowingcriteria:

aqueryhastotalCPUusagegreaterthan90%onahostandhasbeenrunningformorethan45seconds,or

hascpuskewgreaterthan20%,and

isaselectonatablethatcontains“test”initsname.

ruleaddcomborulegpdb_record(message="MyMessage")when((session_id:host:total_cpu>90andsession_id:host:pid:runtime>45)orsession_id:cpu_skew>20)andsession_id:host:pid:current_query=~/select.*test/


TheruleshowshowyoucangroupBooleanexpressionswithparentheses.

RecordquerieswithhighmemoryusageThisrulerecordsamessagewhenaqueryprocessexceeds20%oftheresidentmemoryonahost.

ruleaddtransientmem_high_segment_useage_20gpdb_record(message=”MEM:highsegmentpctusage-20%”)whenhost:pid:resident_size_pct>20andsession_id:host:pid:usename=~/.*/

Recordquerieswithmemory(rss)skewabove10%Thisrulecallsthe gpdb_record actiontologwhenmemoryskewexceeds10%onahost.

ruleaddmem_skew_10gpdb_record(message="MEM:queryskew10")whensession_id:resident_size_pct_skew>10andsession_id:host:pid:usename=~/.*/


BestPracticesforRules1. Avoidcreatingrulesthatmodifytheconditiontherule’sexpressionismatching.Forexample,considerthisrule:

host:throttle_gpdb_query(max_cpu=20)whenhost:pid:cpu_util>30andsession_id:host:pid:runtim>0

IfCPUusagegoesabove30%,theruletriggersandreducestheusageto20%.Whentheusagefallsbelow30%,theruleisnolongermatched,sothethrottlingendsandusagecanagainclimbto30%.Thiscreatesanundesirablecyclicbehavior.Instead,createarulelikethefollowing:

host:throttle_gpdb_query(max_cpu=30)whenhost:pid:cpu_util>20andsession_id:host:pid:runtime>0

Thisruletriggersat20%CPUutilizationandthrottlestheCPUto30%utilization.Thethrottlingcontinuesuntilutilizationdropsbelow20%.Thesession_id:host:pid:runtime conditionistrueforanyrunningqueryandprovidesthenecessary session_id forthe throttle_gpdb_query action.

2. Avoidcreatingrulesthatterminateaquerybasedonskewalone.Considerthefollowingrule:

pg_terminate_backendwhensession_id:resident_size_pct_skew>10

Thisisapoorrulefortworeasons.First,itterminatesallquerieswhenskewisabove10,includingqueriesthatwerenotcontributingtoskew.Second,wellbehavedqueriescantemporarilyexperienceskewhighenoughtoachievethiscondition.Forexample,ifthesegmentsdonotcompleteaqueryatthesametime,skewcanappearneartheendofexecution.Aquerycouldrunnormallyacrossseveralnodesandthen,aseachnodecompletesitsportionofthequery,itsresourceutilizationdrops,causingatemporaryincreaseinskewwhileothernodesarestillrunning.

3. Rulesthatmatchdatawith datid: scopewilltriggerforanydatabaseintheclusterunlessapredicateisaddedtoconfinethematchtoatargetdatabase.Forexample,thisruletriggerswheneverthenumberofconnectionstoanysingledatabaseexceeds10:

gpdb_record(message="exceeded10connections")whensession_id:host:pid:runtime>0anddatid:numbackends>10

Addapredicatetofilterforthedatabaseassociatedwiththesession:

gpdb_record(message="exceeded10connectionsonfoo")whensession_id:host:pid:runtime>0anddatid:datname="foo"anddatid:numbackends>10


KnownIssuesTowritearulethatperformsaGreenplumDatabaseaction( gpdb_record , pg_terminate_backend , host:throttle_gpdb_query ),theconditionmustincludeasession_id ,evenwhentheintendedconditionisbasedsolelyonprocessinformation.Forexample,thefollowingruleappearstoterminateanyquerythatusesmorethan20%ofsystemmemory:

pg_terminate_backend()whenhost:pid:resident_size_pct>20

However,becausethisrulecontainsno session_id ,WorkloadManagercannotinferthequerytoterminate,andtherulewillnotbeadded.Togetthedesiredbehavior,addanalways-true session_id conditiontotherule,forexample:

pg_terminate_backend()whenhost:pid:program_size_pct>20andsession_id:host:pid:runtime>0


QueryingWorkloadManagerRecordDataThe gp_wlm_records tablecontainsarecordofeventsdescribingwhere,why,andhowthe gpdb_record actionwastriggeredbyaruleontheGreenplumcluster.

The gp_wlm_records tableiscreatedinthe postgres databasebydefault.Adifferentdatabasecanbespecifiedatinstallationtimewithwiththe--dbname-records installationoption.

Thetablehasthefollowingstructure:

Column Type

time text

state text

ident text

hostname text

query_start text

message text

pid integer

session_id integer

gpdb_segment_role text

usename text

current_query text

rule text

context_args text

Theprimaryidentifierofeachentryinthetableisthe ident column.Thiscolumnstoresauniqueidentifierthatrepresentsaspecificrulethattriggeredonaspecificnodeinthecluster.Ifaruletriggersonmorethanonenodeintheclusteratthesametime,eachnodeistreatedasaseparateeventandreceivesauniqueidentifier.

Followingaretwosampleentriesfromthe gp_wlm_records table.Inthisexample,arulewascreatedtotrackwhenaqueryrunsformorethan120seconds:

=#\xonExpandeddisplayison.=#select*fromgp_wlm_records;-[RECORD1]-----+-----------------------------------------------------------------------------------------time|FriJun1714:30:272016state|BEGINident|36b3369d-0be8-4d98-b116-6d55f1caf122hostname|sdw2query_start|2016-06-1714:28:24.162044-07message|Queryexceeds120seconds.pid|98885session_id|1112gpdb_segment_role|GPDB_SEGMENTusename|gpadmincurrent_query|deletefromtestwheref1();rule|gpdb_record(message="Queryexceeds120seconds.")whensession_id:host:pid:runtime>120context_args|runtime=121-[RECORD2]-----+-----------------------------------------------------------------------------------------time|FriJun1714:31:072016state|ENDident|36b3369d-0be8-4d98-b116-6d55f1caf122hostname|query_start|message|pid|session_id|gpdb_segment_role|usename|current_query|rule|context_args|

Intheaboveexample,the state columnrepresentswhenaquerybegantriggeringaruleonagivennodeandwhenitstopped.Thehostname columnstoresthehostonwhichtheruletriggered.


QueryingWorkloadManagerEventDataWhenaWorkloadManagerrulesuccessfullyexecutesa pg_terminate_backend() or host:pg_cancel_backend() actiontocancelaGreenplumDatabasequery,theeventisloggedtoafileonthehost.

The manage-event-tables.sh utilityscriptcreatesexternaltablestoaccessthelogfilesandaviewtoconsolidatetheexternaltablessothatyoucanquerytheseeventrecordsfromwithinadatabase.Theexternaltablesandviewmustfirstbecreatedusingthe manage-event-tables.sh script.Theexternaltablesarecreatedinthepostgresdatabasebydefault,butyoucanspecifyadifferentdatabasewhenyoucreatethetables.

SettingUpthegp_wlm_eventsViewThe manage-event-tables.sh scriptcreates,recreates,ordropstheexternaltablesand gp_wlm_events view.

Toseethesyntax,logintotheGreenplummasterhostasthegpadminuserandrunthescriptwiththe -h ( --help )option:

$<INSTALL_DIR>/bin/manage-event-tables.sh--helpManagethegp-wlmexternaleventtables.Commands:--createCreatetheexternaltableandviews.--dropDroptheexternaltableandviews.-h,--helpDisplaythismessage.Options:-d,--dbname=NAMEUsedatabaseNAME.Defaultispostgres.-q,--quietSilencestdout.

Tocreate(orrecreate)theexternaltablesandthe gp_wlm_events view,runthescriptwiththe --create flag.Ifyouwanttocreatethetablesandviewinadatabaseotherthanpostgres,includethe --dbname option.

<INSTALL_DIR>/bin/manage-event-tables.sh--create--dbname=<database-name>

Todeletethetablesandviewsfromadatabaseotherthanpostgres,youmustincludethe --dbname optionwiththe --drop option.

Usingthegp_wlm_eventsViewThe gp_terminate_backend and pg_cancel_backend eventsareloggedandaccessibleinthe pg_wlm_events view.

Thefollowingtabledescribesthecontentsofthe gp_wlm_events view.

Columnname Type Description

ident text Auniqueidentifierforeachrow.

time timestamp Thetimetheeventrecordwascreated.

rulename text Thenameofthetriggeredrule.

action text Thecomponentthattriggeredtheevent.

sess_id integer TheIDofthesessionthatmatchedthisruletrigger.

hostname text Thehostonwhichtheeventoccurred.

usename text Therolenamefromthesessionthatmatchedthisruletrigger.

current_query text Thetextofthecurrentqueryinthesession.

datname text Thedatabasenameofthesession.

application_name text Thenameoftheclientapplicationofthesessionthatmatchedthisruletrigger.

context text Acomma-delimitedlistofrule-specificcontextualdatums.

rule text Theruleexpression.

The sess_id , usename , current_query , datname ,and application_name columnsmatchcolumnswiththesamenamesinthe pg_stat_activity systemviewrowfortheprocessthatmatchedtheruletrigger.Seepg_stat_activity .

Sincetheviewisbasedonexternaltables,eachtimeyourunaquery,theviewisrefreshedfromtheeventlogsontheGreenplumhosts.


http://gpdb.docs.pivotal.io/latest/ref_guide/system_catalogs/pg_stat_activity.html

ManagingResourceQueuesUse rq commandstoshow,create,remove,andmodifyresourcequeues,andtomanagetherolesthatareassignedtoresourcequeues.

The queue-settings argumentcancontainthefollowingproperties:

PropertyName Type Description

active_statements IntegerLimitsthenumberofqueriesthatcanbeexecutedbyrolesassignedtotheresourcequeue.Eithertheactive_statements or max_cost propertymustbesetoneachresourcequeue.

max_cost FloatSetsamaximumlimitonthetotalcostofqueriesthatcanbeexecutedbyrolesassignedtotheresourcequeue.Thecostofaqueryisestimatedbythequeryplannerandismeasuredinunitsofdiskpagefetches.Eitherthe active_statements or max_cost propertymustbesetoneachresourcequeue.

min_cost FloatSetstheminimumestimatedquerycostforaquerytobemanagedbytheresourcequeue.Querieswithestimatedcostsbelowthisthresholdareexecutedimmediately.

cost_overcommit BooleanIfaresourcequeueislimitedbasedon MAX_COST ,aquerythatexceedsthe MAX_COST limitisallowedtoexecuteifthesystemisidleand COST_OVERCOMMIT is true .If COST_OVERCOMMIT issetto false ,queriesthatexceed MAX_COST arealwaysrejected.

priority EnumerationSetstherelativepriorityofqueriesexecutedbyrolesassignedtotheresourcequeue.Theallowedvalues,inorderofincreasingpriority,are MIN , LOW , MEDIUM , HIGH ,and MAX .

memory_limitInteger(kilobytes)

Setsthetotalamountofmemorythatallactivestatementssubmittedtothequeuemayconsume.Theminimumis10240KB.Thereisnomaximum,butwhenaqueryexecutesitislimitedbythesegmenthost’sphysicalmemory.Settheparameterto-1fornolimit.

:Table1.ResourceQueueProperties

Specifytheresourcequeuepropertiesina parameter-name=value format,forexample:

mdw/gpdb-cluster>rqmodifymyrqwithactive_statements=10

Separatemultiplequeuesettingswithacomma.The queue-settings argumentmustnotcontainspaces.Thisexamplesetsthreeproperties:

mdw/gpdb-cluster>rqaddETLwithactive_statements=3,priority=LOW,memory_limit=524288

AGreenplumDatabaserole(loginuser)isassociatedwithasingleresourcequeue.Newlycreatedrolesareaddedtothe pg_default queueifanotherresourcequeueisnotspecified.

Queriessubmittedbyusersassociatedwitharesourcequeuearemanagedbythequeue.Thequeue’ssettingsdeterminewhetherqueriesareacceptedorrejected,iftheyrunimmediatelyorwaitforresourcestobereturnedtothequeue,howmuchmemorytoallocatetothequery,andtherelativeamountofCPUthequerywillhave.

Resourcequeuessharethememoryallocatedtoeachsegment.Addinganewresourcequeueoralteringaqueue’ssettingsmayrequireadjustingotherresourcequeuestoavoidover-allocatingtheavailablememoryandcausingqueriestofail.SeetheWorkloadManagementsectionintheGreenplumDatabaseAdministratorGuideforguidelinesonconfiguringresourcequeues.

AddingaNewResourceQueue

DeletingaResourceQueue

ModifyingaResourceQueue

DisplayingResourceQueues

AddingUserstoResourceQueues

DeletingaUserfromaResourceQueue

AddingaNewResourceQueueThe rqadd commandcreatesanewresourcequeue.Thecommandhasthefollowingsyntax:


rqaddqueue-namewithqueue-settings

Youmustsetoneorbothofthethresholdproperties— active_statements or max_cost —whenyoucreateanewresourcequeue.

ThefollowingexamplecreatesanETLqueuethatcanrunthreeconcurrentqueriesatlowCPUpriorityrelativetootherqueries.

mdw/gpdb-cluster>rqaddetlwithactive_statements=3,priority=low

DeletingaResourceQueueDeleteanexistingresourcequeuebynameusingthe rqdelete command:

rqdeletequeue-name

Itisnotpossibletodeleteaqueuethathasrolesassignedtoit.

ModifyingaResourceQueueUsethe rqmodify commandtoalterqueuesettings.Youcanaddnewsettingsorupdateexistingsettingsbyspecifyingpropertiesinthe queue-settingsargument.

rqmodifyqueue-namewithqueue-settings

ThefollowingexamplemodifiestheETLqueuetoruntwoconcurrentquerieswithamaximumof524288KB(512MB)ofmemory.Eachquerywillbeallocated256MBofmemory.

rqmodifyetlwithactive_statements=2,memory_limit=524288

DisplayingResourceQueuesUsethe rqshow

allcommandtodisplayresourcequeues.Thisexampledisplayssettingsforthe etl and pg_default resourcequeues.

mdw/gpdb-cluster>rqshowallrsqnameresnameressettingrestypeidetlactive_statements21etlmax_cost-12etlmin_cost03etlcost_overcommit14etlprioritylow5etlmemory_limit5242886pg_defaultactive_statements101pg_defaultmax_cost-12pg_defaultmin_cost03pg_defaultcost_overcommit04pg_defaultprioritymedium5pg_defaultmemory_limit-16

AddingUserstoResourceQueuesThe rq

useraddcommandaddsausertoaresourcequeue.Theuserisremovedfromtheirpreviousresourcequeueasusersareassociatedwithonlyone

resourcequeue.Theuser’ssubsequentqueriesaremanagedbythenewresourcequeue.

rquseraddusertoqueue-name


DeletingaUserfromaResourceQueueThe rquserdel commanddeletesarolefromaresourcequeue.Theuserwillbeassociatedwiththedefaultqueue, pg_default .

rquserdeluserfromqueue-name


ConfiguringWorkloadManagerComponentsYoucanusetheGreenplumWorkloadManager config commandtoview,override,anddescribecertainWorkloadManagerconfigurationsettings.Theconfig commandmayberuninteractivelyina gp-wlm sessionorinbatchmodeatthecommandline.ThecommandmustberunontheGreenplummasterhost.

SeeUsingtheGreenplumWorkloadManagerCommandLinefor gp-wlm command-linesyntaxandusage.

NoteThe config commandworksonlywithsettingsthatcanbechangedbyusers.

Whenviewing,describing,orsettingthevalueofaconfigurationsetting,youmustspecifyitsWorkloadManagercomponent.Acomponentcanbeanindividualservice,plugin,orcommand-linetoolthatisapartoftheWorkloadManagersystem.

Ininteractivemode,youcandouble-tapthetabcharactertoseewhichcomponentsandsettingsareavailablefortheshow,describe,andmodifycommands.

ViewingConfigurationValuesToviewthecurrentvalueofaconfigurationsettingwhileina gp-wlm session,usethefollowingsyntax:

>configshow<component><setting>

Forexample,thefollowingcommandshowstheloggingleveloftherulesengineservice:

>configshowrulesenginelogging:log_level

Fromthecommandline,usethe --config-show option:

$gp-wlm--config-show='<component><setting>'

Forexample:

$gp-wlm--config-show='rulesenginelogging:log_level'

DescribingConfigurationValuesUsethe describe commandtoseeadescriptionofasettingandconstraintsforthesetting’svalues.

Ina gp-wlm session,thesyntaxis:

>configdescribe<component><setting>

Onthe gp-wlm commandline,usethe config-describe command-lineoption:

$gp-wlm--config-describe='<component><setting>'

Forexample,todescribetheloggingleveloftherulesengineinaninteractive gp-wlm session,usethiscommand:

>configdescriberulesenginelogging:log_level

Theoutputofthecommandlookslikethefollowing:

component:rulesenginesetting:logging:log_leveldescription:Thelogverbosityoftherulesenginedaemonvalidvalues:err,warn,info,debug,trace


Hereisthesamecommandinbatchmodeatthecommandline:

$gp-wlm--config-describe='rulesenginelogging:log_level'

ModifyingConfigurationValuesUsethe configmodify commandtochangethevalueofaWorkloadManagerconfigurationsetting.Changingaconfigurationsettingautomaticallychangesthesettingonallhostsinthecluster.

Inaninteractive gp-wlm session,usethissyntax:

>configmodify<component><setting>=<value>

Atthecommandline,usethe gp-wlm --config-modify option,withthefollowingsyntax:

$gp-wlm--config-modify='<component><setting>=<value>'

Thenewsettingispersisted,andwillbepreservedduringfutureWorkloadManagersoftwareupgrades.

Whenasettingforaserviceismodified,theaffectedserviceisautomaticallyrestartedoneveryhostinthecluster.However,thiscanonlyoccurautomaticallyifthecfgmonserviceisrunningontheGreenplummasteratthetimethesettingischanged.Ifthecfgmonserviceisnotrunning,thesettingisstillupdatedpersistently,butthenewvalueisnotbroadcasttotherestoftheclusteruntilthecfgmonserviceisstarted.Thecfgmonserviceisalwaysrunning,bydefault.

ConfigurableWorkloadManagerSettingsThefollowingtablelistssettingsthatcanbeviewed,described,andconfiguredusingthe config command.

Component Setting Description Type Constraints Default

agent logging:log_level Logverbosityofagent String ValidValues:err,warn,info,debug,trace

info

cfgmon logging:log_level Logverbosityofcfgmon String ValidValues:err,warn,info,debug,trace

info

gpdb_stats collect_frequency HowoftentocollectGPDBstatisticsinformation Float Validrange:0.1-60.0seconds 1.0

publish_frequency HowoftentopublishGPDBstatisticsinformation Float Validrange:0.1-60.0seconds 4.0

publish_idle_sessions PublishinformationaboutidleGreenplumDatabasesessions

Boolean ‘true’or'false’ 'true’

rulesengine engine:rule_frequency Frequencyofruleevaluationinseconds Float Validrange:0.1-60.0seconds 2.0

logging:log_level Logverbosityofrulesengine String ValidValues:err,warn,info,debug,trace

info

systemdata logging:log_level Logverbosityofsystemdataplugin String ValidValues:err,warn,info,debug,trace

info

publish_idle_processes PublishinformationaboutidleGreenplumDatabasesessions

Boolean 'true’or'false’ 'true’


TroubleshootingYoumaycollectalllogsacrosstheclusterusingasinglecommand.Tocreateatarballofalllogsinthecurrentdirectory,invoke:

bin/gather-cluster-logs.sh--symlink<LN>

where LN isthepathtothe gp-wlm symboliclinktotheGreenplumWorkloadManagerinstallationdirectory.


WorkloadManagerDatumReferenceThistopicliststhedatumscollectedbyGreenplumWorkloadManager.ThesedatumscanbeusedinWorkloadManagerrulestoselectfactsthattriggeranaction.Inrules,prefixdatumswiththeirscope,forexample:

host:cpu_util>35

Thiswillmatchanyhostwithgreaterthan35%CPUutilitization.Thefollowingexpressionmatchesasingle postgres processonanyhostusingmorethan35%CPU:

host:pid:cpu_util>35andhost:pid:name='postgres'

Thedatumsarearrangedinthefollowingcategories:

Connections–numberofbackendconnectionsandconnectionstothemaster

Identification–namesofusers,hosts,databases,ports,processes,andsoon

Transactions–informationaboutthecurrenttransaction,querieswithintransactions,andnumbersoftransactionscommittedandrolledbackinthedatabase

Date/Time–dateandtimedatumsforahost

CPU–CPUutilitizationforhosts,processes,andsessions

Memory–memoryutilitizationforprocessesandqueries

Spill–numberofspillfilescreatedandtotalspillfilesizeforaquery

I/O–diskread/writestatisticsfordatabases,processes,andqueries

Skew–diskread/writeskewandmemoryskewforqueries

ConnectionsScope Datum Datatype Description

datid numbackends integer Numberofbackends

gpdb total_master_connections integer Totalnumberofconnectionstothemastersegmentacrossalldatabases

Identification

Scope Datum Datatype Description

session_id:host:pid usename string Nameoftheuserloggedintothisbackend

datid datname string Nameofthisdatabase

host:pid long_name stringBydefault,thisistheabsolutepathtotheprocessexecutable,butmaybeoverriddenbytheprocessitselftostatusinformationinutilitieslikeps(1)

host:pid name string Thefilenameoftheexecutable

host:pid state string Kernelstateofthisprocess;seethemanpageforproc(5)formoreinformation

session_id:host:pid application_name string Nameoftheapplicationthatisconnectedtothisbackend

session_id:host:pid client_addr string IPaddressoftheclientconnectedtothisbackend

session_id:host:pid client_port integer TCPportnumberthattheclientisusingforcommunicationwiththisbackend

session_id:host:pid datid integer OIDofthedatabasethisbackendisconnectedto

session_id:host:pid datname string Nameofthedatabasethisbackendisconnectedto

session_id:host:pid gpdb_segment_role string ThecurrentroleofthisGreenplumDatabasesegment(MASTER,SEGMENT,MIRROR)

session_id:host:pid usesysid integer OIDoftheuserloggedintothisbackend


TransactionsScope Datum Datatype Description

datid xact_commit integer Numberoftransactionsinthisdatabasethathavebeencommitted

datid xact_rollback integer Numberoftransactionsinthisdatabasethathavebeenrolledback

session_id:host:pid backend_start string Timewhenthisprocesswasstarted,i.e.,whentheclientconnectedtotheserver

session_id:host:pid current_query string Textofthisbackend’scurrentquery.

session_id:host:pid query_start string Timewhenthecurrentlyactivequerywasstarted

session_id:host:pid runtime integer Timeelapsedsincethequerystarted

session_id:host:pid xact_start string Timewhenthisprocess’currenttransactionwasstarted

Date/TimeScope Datum Datatype Description

host day integer Dayas0-30

host day_of_week integer Dayas0-6

host day_of_week_string string Mon,Tue,…

host month integer Monthas0-11

host year integer Numericyear

host hour integer Houras0-23

host minute integer Minuteas0-59

CPU


host node_cpu_util float CurrentCPUutilizationonthishost,normalizedbynumberofactiveCPUs

host:pid avg_cpu_util float AverageCPUutilizationconsumedbythisprocessoverthelasttwopollingintervals

host:pid cpu_util float PercentageoftotalCPUutilizationconsumedbythisprocess

session_id cpu_skew floatCPUutilizationskewacrossthecluster.Calculatedasthecubedstandarddeviationofsession_id:host:total_cpufromallhostsrunningacertainquery

session_id:host total_cpu float Totalcpuutilizationofallprocessesrunningacertainqueryonahost

Memory


host mem_avail integer Totalavailablememoryonthishost(free+buffers+cached)(kB)

host mem_avail_pct float Availablememoryonthishostaspercentageoftotal

host mem_buffers integer Memoryinbuffersonthishost(kB)

host mem_cached integer Cachedmemoryonthishost(kB)

host mem_free integer Freememoryonthishost(kB)

host mem_free_pct float Freememoryonthishostaspercentageoftotal

host mem_total integer Totalmemoryonthishost(kB)

host:pid data_size_bytes integer Thesizeofdata+stackmemoryregioninthisprocess(bytes)

host:pid dirty_size_bytes integer Thesizeofdirtypagesusedinthisprocess(bytes)

host:pid library_size_bytes integer Thesizeoflibrarymemoryregioninthisprocess(bytes)


host:pid program_size_bytes integer Thetotalprogramsize(bytes)host:pid program_size_pct float Thesizeofthisprocessasapercentageoftotalsystemmemory

host:pid resident_size_bytes integer Thesizeofresidentmemoryconsumedbythisprocess(bytes)

host:pid resident_size_pct float Thesizeofthisprocess’residentmemoryasapercentageoftotalsystemmemory

host:pid shared_size_bytes integer Thesizeofallsharedpagesusedbythisprocess(bytes)

host:pid text_size_bytes integer Thesizeofcodememoryregioninthisprocess(bytes)

host:segment_id total_vmem_size_mb integer TotalvmemusageforthisGreenplumsegmentinmegabytes

host:segment_id total_vmem_size_pct float TotalvmemusageforthisGreenplumsegmentasapercentageoftotal

session_id:host:segment_id vmem_size_mb integer Totalvmemusedbythesessiononthissegment

session_id:host:segment_id vmem_size_pct floatThepercentageofthissegment’s vmem_protect_limit consumedbythissession

session_id:host total_resident_size_pct floatTotalresidentmemorypercentageofallprocessesrunningacertainqueryonahost


SpillScope Datum Datatype Description

session_id:host:pid spillfile_count_across_cluster integer Totalnumberofspillfilescreatedforthisqueryacrossthecluster

session_id:host:pid spillfile_size_across_cluster integer Totalsizeofspillfilescreatedforthisqueryacrossthecluster

I/OScope Datum Datatype Description

datid blks_hit integer NumberoftimesdiskblockswerefoundalreadyinthePostgreSQLbuffercache

datid blks_read integer Numberofdiskblocksreadinthisdatabase

host:pid disk_read_bytes integer Totalnumberofbytesreadfromdiskbythisprocess

host:pid disk_read_bytes_per_sec float Thenumberofbytesreadfromdiskpersecondbythisprocess

host:pid disk_write_bytes integer Totalnumberofbyteswrittentodiskbythisprocess

host:pid disk_write_bytes_per_sec float Thenumberofbyteswrittentodiskpersecondbythisprocess

host:pid read_bytes integer Totalnumberofbytes(disk,network,IPC)readbythisprocess

host:pid read_bytes_per_sec float Thenumberofbytesreadpersecond(disk+net+IPC)bythisprocess

host:pid reads integer Totalnumberofreadsystemcallsmadebythisprocess

host:pid reads_per_sec float Thenumberoftotalread(2)callspersecondbythisprocess

host:pid write_bytes integer Totalnumberofbytes(disk,network,IPC)writtenbythisprocess

host:pid write_bytes_per_sec float Thenumberofbyteswrittenpersecond(disk+net+IPC)bythisprocess

host:pid writes integer Totalnumberofwritesystemcallsmadebythisprocess

host:pid writes_per_sec float Thenumberoftotalwrite(2)callspersecondbythisprocess

session_id:host total_disk_read_bytes_per_sec integer Totaldiskreadbytes-per-secondofallprocessesrunningacertainqueryonahost

session_id:host total_disk_write_bytes_per_sec integer Totaldiskwritebytes-per-secondofallprocessesrunningacertainqueryonahost

Skew


session_id disk_read_bytes_per_sec_skew floatDiskreadskewacrossthecluster.Calculatedasthecubedstandarddeviationofsession_id:host:total_disk_read_bytes_per_secfromallhostsrunningacertainquery

session_id disk_write_bytes_per_sec_skew floatDiskwriteskewacrossthecluster.Calculatedasthecubedstandarddeviationofsession_id:host:total_disk_write_bytes_per_secfromallhostsrunningacertainquery


session_id resident_size_pct_skew floatResidentmemoryutilizationskewacrossthecluster.Calculatedasthecubedstandarddeviationofsession_id:host:total_resident_size_pctfromallhostsrunningacertainquery



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