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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Tuning I/O-related wait - Metalink Note: 223117.1
Thanks=20y'all!
-----Original=20Message-----
From:=20Bobak,=20Mark=20[mailto:Mark.Bobak_at_il.proquest.com]
Sent:=20Tuesday,=20November=2009,=202004=203:38=20PM
To:=20Roger=20Xu;=20oracle-l_at_freelists.org
Subject:=20RE:=20Tuning=20I/O-related=20wait=20-=20Metalink=20Note:=202231=
17.1
Starting=20w/=209i,=20Oracle=20renamed=20"Top=205=20wait=20events"=20as=20=
"Top=205=20timed=20events"=20and=20included=20CPU=20Time=20in=20the=20list= .
I=20have=20no=20idea=20what,=20if=20any,=20performance=20problem=20your system=20has,=20based=20on=20the=20data=20you've=20presented.
First=20of=20all,=20does=20the=20system=20actually=20have=20any=20performa=
nce
problems?=20=20If=20not,=20looking=20at=20StatsPack=20reports=20is=20not
likely=20to=20be=20a=20very=20rewarding=20exercise.
Next,=20it=20looks=20like=20the=20statspack=20snapshot=20window=20was=20ar=
ound=20
13=201/4=20hours.=20=20That's=20about=2013=20hours=20too=20long.=20=20Try=20=
to=20take
short,=2010-15=20minute=20snapshots,=20at=20performance=20critical=20times=
.
Finally,=20StatsPack=20isn't=20particularly=20useful=20for=20determining=20=
what=20
your=20problem=20is.=20=20A=20much=20better=20approach=20is=20to=20identif=
y=20the=20most
business=20critical=20processes=20and=20monitor=20their=20performance.=20=20=
If=20any=20of=20them=20have=20problems,=20trying=20tracing=20the=20session=
=20with=20
a=2010046=20level-8=20trace.=20=20that=20will=20go=20much=20farther=20than=
=20a=20
StatsPack=20report=20in=20finding=20the=20root=20cause=20of=20a=20performa=
nce=20problem.
Hope=20that=20helps,
-Mark
>=20-----Original=20Message-----
>=20From:=20oracle-l-bounce_at_freelists.org
>=20[mailto:oracle-l-bounce_at_freelists.org]On=20Behalf=20Of=20Roger=20Xu
>=20Sent:=20Tuesday,=20November=2009,=202004=204:20=20PM
>=20To:=20oracle-l_at_freelists.org
>=20Subject:=20RE:=20Tuning=20I/O-related=20wait=20-=20Metalink=20Note:=20=
223117.1
>=20
>=20
>=20Why=20there=20is=20no=20"Top=205=20Wait=20Events"=20in=20our=20statspa=
ck=20report?
>=20But=20we=20have:
>=20Top=205=20Timed=20Events
>=20~~~~~~~~~~~~~~~~~~=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20
>=20=20=20=20=20=20=20=20=20=20%=20Total
>=20Event=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
Waits=20=20=20=20
>=20Time=20(s)=20Ela=20Time
>=20--------------------------------------------=20------------=20
>=20-----------=20--------
>=20CPU=20time=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20
>=20=2020,014=20=20=20=2041.90
>=20db=20file=20sequential=20read=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20=2012,629,049=20=20=20=20=20
>=20=2017,830=20=20=20=2037.33
>=20log=20file=20sync=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20223,490=20=20=20=20=
=20
>=20=20=204,221=20=20=20=20=208.84
>=20enqueue=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=204,= 977=20=20=20=20=20
>=20=20=202,711=20=20=20=20=205.68
>=20db=20file=20parallel=20write=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20=20=20=20=20=20=2027,227=20=20=20=20=20
y=20comments?
a=20Statspack=20report
>=20=20=20=203,268=20=20=2015.70
>=20control=20file=20parallel=20write=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20=20=20=20=20=20893=20=20=20=20=20
>=20=20=20=20=20=20198=20=20=20=20=20.95
>=20db=20file=20parallel=20write=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=2040=20=20=20=20=20=
>=20=20=20=20=20=20131=20=20=20=20=20.63
>=20=20=20=20=20=20=20=20=20=20
>=20-------------------------------------------------------------=20=20=20=
=20=20=20=20=20
>=20
>=20Based=20on=20this=20listing=20we=20may=20be=20tempted=20to=20immediate=
ly=20start=20
>=20looking=20at=20the
>=20causes=20between=20the=20'direct=20path=20read'=20and=20'db=20file=20s=
cattered=20
>=20read'=20waits=20and
>=20to=20try=20to=20tune=20them.=20This=20approach=20would=20not=20take=20=
into=20
>=20account=20'Service=20Time'.
>=20
>=20Here=20is=20the=20statistic=20that=20measures=20'Service=20Time'=20fro=
m=20the=20
>=20db=20file=20scattered=20read=20=20=20=20=20=20=3D=20=201.65%
>=20direct=20path=20write=20=20=20=20=20=20=20=20=20=20=20=3D=20=200.86%
>=20control=20file=20parallel=20write=20=3D=20=200.05%
>=20db=20file=20parallel=20write=20=20=20=20=20=20=3D=20=200.03%
>=20
>=20It=20is=20now=20obvious=20that=20the=20I/O-related=20Wait=20Events=20a=
re=20not=20
>=20really=20a=20significant
>=20component=20of=20the=20overall=20Response=20Time=20and=20that=20subseq=
uent=20
>=20tuning=20should=20be
>=20directed=20to=20the=20Service=20Time=20component=20i.e.=20CPU=20consum=
ption.
>=20
>=20Incidentally,=20the=20improved=20"Top=205=20Timed=20Events"=20section=20=
in=20
>=20Statspack=20starting
>=20with=20Oracle9i=20Release=202=20would=20show=20output=20similar=20to=20=
our=20
>=20calculated=20listing.
>=20
>=20<End=20quote>
>=20
>=20Can=20sombody=20please=20expalin=20:
>=20
>=20How=20did=20he=20come=20out=20with
>=20CPU=20time=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=
=3D=2094.52%
>=20direct=20path=20read=20=20=20=20=20=20=20=20=20=20=20=20=3D=20=202.85%=
=20=20.........
>=20
>=20
>=20--
>=20Regards=20&=20Thanks
>=20BN
>=20--
>=20http://www.freelists.org/webpage/oracle-l
>=20
>=20For=20technical=20support=20please=20email=20tech_support_at_dp7uptx.com=20=
or=20you=20can
>=20MessageLabs=20Email=20Security=20System.
>=20
>=20
>=20
>=20This=20e-mail=20is=20intended=20solely=20for=20the=20person=20or=20ent=
ity=20to=20
>=20which=20it=20is=20addressed=20and=20may=20contain=20confidential=20and=
/or=20
>=20privileged=20information.=20Any=20review,=20dissemination,=20copying,=20=
>=20printing=20or=20other=20use=20of=20this=20e-mail=20by=20persons=20or=20=
entities=20
>=20other=20than=20the=20addressee=20is=20prohibited.=20If=20you=20have=20=
received=20
>=20this=20e-mail=20in=20error,=20please=20contact=20the=20sender=20immedi=
ately=20
>=20and=20delete=20the=20material.=20
>=20____________________________________________________________________
>=20This=20email=20has=20been=20scanned=20for=20all=20viruses=20by=20the=20=
>=20MessageLabs=20Email=20Security=20System.=20Any=20questions=20please=20=
call=20
>=20972-721-8257=20or=20email=20your=20request=20to=20tech_support_at_dp7uptx=
.com.
>=20--
>=20http://www.freelists.org/webpage/oracle-l
>=20
For=20technical=20support=20please=20email=20tech_support_at_dp7uptx.com=20or=
=20you=20can
call=20(972)721-8257.=20
This=20email=20has=20been=20scanned=20for=20all=20viruses=20by=20the=20Mes=
sageLabs=20Email=20Security=20System.
This=20e-mail=20is=20intended=20solely=20for=20the=20person=20or=20entity=20= to=20which=20it=20is=20addressed=20and=20may=20contain=20confidential=20an= d/or=20privileged=20information.=20Any=20review,=20dissemination,=20copyin=g,=20printing=20or=20other=20use=20of=20this=20e-mail=20by=20persons=20or=20= entities=20other=20than=20the=20addressee=20is=20prohibited.=20If=20you=20= have=20received=20this=20e-mail=20in=20error,=20please=20contact=20the=20s= ender=20immediately=20and=20delete=20the=20material.=20
This=20email=20has=20been=20scanned=20for=20all=20viruses=20by=20the=20Mes= sageLabs=20Email=20Security=20System.=20Any=20questions=20please=20call=20= 972-721-8257=20or=20email=20your=20request=20to=20tech_support_at_dp7uptx.com=.
-- http://www.freelists.org/webpage/oracle-lReceived on Tue Nov 09 2004 - 15:42:20 CST
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