Re: Re: linux system load
- From: "biti_rainy" <biti_rainy@xxxxxxxxx>
- To: "gogala@xxxxxxxxxxxxx" <gogala@xxxxxxxxxxxxx>, "oracle-l" <oracle-l@xxxxxxxxxxxxx>
- Date: Sat, 20 Nov 2004 22:47:39 +0800
hi,Mladen Gogala
thanks for your repply.
i do not do many statspack snapshot frequencly , the job is
what => statspack.snap;
interval => trunc(sysdate) +
decode(to_char(sysdate,'hh24'),8,9.5,9,10.5,10,15,15,16,16,17,17,23,32.5)/24
i check the statspack report , system load ,cpu load,io,net,swap from
8:30 AM to 9:30 AM every day, and i checked more than 30 days.about
scatter 10 days's load-1 are out of ways ,but the statspack reports
show nothing. all the loadprofile , top 5 event ,cpu time,top sqls,eplasd
time ... are almost the same . and at that time (from 8:30 am to
9:30 AM) i check active session and the runing sql ,i find nothing
special. so i am puzzle.
we are using mrtg to monitoring the os and db stat with web chart.
i use both sar and top, from top output , about 15 process's cpu% are
close to 1.5%, the other days this may be close to 1% . may be this
is the point, but the statspack reports show that the cpu_time ,
eplasd time ,wait time ,executions are the same.only the system
load(load-1 / load-5 /load-15) is strange.
Best regards
msn: biti_rainy@xxxxxxxxxxx
a dba from alibaba(china)
---- from the mail-----
>
>Do more statspack reports at level 9. Do it every minute. That will
>lighten the
>load. You never have to actually view the report. What do you expect to
>find out from statspack? Statspack will give you the immensely useful
>information with regard to the numbers of db block gets, number of
>sorts, the hit ratio for your dictionary, library and buffer cache, but
>will not tell you a thing about your run queue. So, let's stop and
>think for a moment. Are you using the right tool? Will sar and
>statspack help you to find out what's happening and will
>they give the SPIDs of the processes to watch? Methinks not. So, you
>need a tool which will show you the activity of each process, not
>a statistical value sampled, chewed and regurgitated and then given to
>you, after a period of time. This information is worth as much as my
>description tries to imply. The same applies to statspack. Please,
>don't let me dissuade you from printing statspack
>reports. I have few shares of the International Paper (ticker: IP) and
>I like people who print STATSPACK reports. You must be aware that
>printing statspack reports will do more good to me then to you. What
>you want is called "top". NO! Stop! Don't read the source code! Your
>problem is shortage of CPU resources. Top will tell you the most active
>process. You must see what is it doing and why is it doing so. CPU
>exhaustion is frequently a reward for a good BCHR. SQL statement like
>
>select count(*) from emp,emp,emp,emp,emp,emp,emp,emp,emp;
>
>will consume huge amount of CPU and propel your BCHR close to mach 10,
>before even NASA manages to get there. It is the hardest problem of
>them all: the method that uses the wait interface tells you to see what
>are the processes waiting for. Your problem are processes that are NOT
>waiting. Processes that are spinning like crazy are not waiting - they
>are running, by the very definition of the term. What you have to do is
>to analyze what are they doing and is there a method (usually, a change
>in the algorithm) to do it cheaper. And, please, don't use statspack.
>
>
>
>
>>=20
>> i am vary puzzle.
>
>Oh, so am I. Variations are wild.
>
>> i want to know what is the formula of load-1 and load-5
>>=20
>> i read the sar's source code and find that it read the
>> /proc/LOADAVG
>> i do not read the linux source code
>
>Reading the whole Linux source code is useful for some things,
>but tuning oracle database is not one of them. The same applies to sar.
>Always look at the bright side of life. For life's quite absurd, and
>manual is the final word, you must always face the curtain with a bow.
>So, instead of reading the source code, here is what the fine manual
>says:
>
> -q Report queue length and load averages. The following
>values are
> displayed:
>
> runq-sz
> Run queue length (number of processes waiting for
>run
> time).
>
> plist-sz
> Number of processes in the process list.
>
> ldavg-1
> System load average for the last minute.
>
> ldavg-5
> System load average for the past 5 minutes.
>
> ldavg-15
> System load average for the past 15 minutes.
>
>
>
>>=20
>> Best regards
>> msn: biti_rainy@xxxxxxxxxxx
>> a dba from alibaba(china)
>
>--=20
>Mladen Gogala
>Oracle DBA
>
>
>
>
>
>--=20
>Mladen Gogala
>Oracle DBA
>
>
>--
>//www.freelists.org/webpage/oracle-l
>
--
//www.freelists.org/webpage/oracle-l
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