Hi all,
Think we've figured this out, with much
help from you guys.
I believe the high percentage of kernel CPU
was due to the system swapping. I believe the root cause of the swapping was a
combination of:
a) an SGA that was too large
b) a sort_area_size that was set too
large (30Mb.)
c) an app that does a *lot* of
sorting
I believe each connection from the app
server (there were about 50-55 connections) would eventually grab 30Mb. of sort
space in it's PGA. According to Oracle, this memory never gets released to the
OS. So, that's 1.5-1.6Gb. of memory that apparently send us over the edge. Since
these are persistent connections from an app server, they never disconnect.
We greatly reduced the size of the java pool and brought sort_area_size down,
which - I think - fixed the problem.
Better to have a few disk sorts than have
your box start swapping!
Thanks again!
- Jerry
----- Original Message -----
From: "Connor McDonald" <<A
href="mailto:hamcdc_at_yahoo.co.uk"><FONT face="Courier New"
size=2>hamcdc_at_yahoo.co.uk<FONT face="Courier New"
size=2>>
To: "Multiple recipients of list ORACLE-L"
<<FONT face="Courier New"
size=2>ORACLE-L_at_fatcity.com<FONT face="Courier New"
size=2>>
Sent: Wednesday, August 29, 2001 5:27
AM
Subject: RE: OT : kernel using 75% of
CPU
> Agreed - and Sun doesn't
handle getting "close to the> edge" at all well imho. Recently
upgraded a db on> (2.6) server from 8.0 to 8.1.6 and it went from>
running fine to running like an absolute dog - kernel> thrashing exactly
like our initial poster reports...> > ... The problem?>
> java_pool_size (and its 20m default). Once the idiot> (me)
remembered to reset this to 32k, performance was> immediately better than
even the original 8.0. Just> an extra 20M freed up (on a 512M box)
and miracles> occurred ....> > Cheers>
Connor> > --- Christopher Spence <<A
href="mailto:cspence_at_FuelSpot.com"><FONT face="Courier New"
size=2>cspence_at_FuelSpot.com>
wrote:> > paging and swapping is the first thing that comes to>
> mind, look at vmstat.> > > > I think your
question is completely on topic.> > > > > >
"Do not criticize someone until you walked a mile in> > their shoes,
that way> > when you criticize them, you are a mile a way and>
> have their shoes."> > > > Christopher R. Spence
> > Oracle DBA > > Phone: (978) 322-5744 > >
Fax: (707) 885-2275 > > > > Fuelspot
> > 73 Princeton Street > > North, Chelmsford 01863 >
> > > > > -----Original Message----->
> Sent: Tuesday, August 28, 2001 11:20 AM> > To: Multiple
recipients of list ORACLE-L> > > > > > Hi
there,> > > > I have a Sun e4500, running Solaris 2.7
and Oracle> > 8.1.7.1.0. Everything> > looks normal from a
database perspective, but when I> > run "top" it show the> >
kernel being very hog-like:> > > > load averages:
14.38, 15.18, 15.18> > 07:16:21> > 126 processes: 118
sleeping, 4 running, 4 on cpu> > CPU states: 0.6% idle, 26.6%
user, 72.8% kernel, > > 0.0% iowait, 0.0% swap> >
Memory: 4096M real, 63M free, 216M swap in use,> > 5310M swap
free> > > > PID USERNAME THR PRI
NICE SIZE RES STATE TIME>
> CPU COMMAND> > 2286
oracle 1 0 0 1844M 1814M
run 9:44> > 13.90% oracle> > 11068
oracle 1 0 0 2056K 1536K
cpu0 0:02> > 1.53% top> > 11333
oracle 1 0 0 1150M 1124M
cpu1 0:01> > 1.39% oracle> >
5944 oracle 1 40 0 1820M 1789M
sleep 14:40> > 1.36% oracle> > 4797
root 1 50 0 2112K
1248K sleep 6:01> > 1.36% top> > 11346
oracle 1 0 0
110M 92M cpu0 0:01> > 1.26%
oracle> > 11114 oracle 1
0 0 1009M 984M cpu1 0:00>
> 0.66% oracle> > 11157 oracle
1 0 0 1009M 984M run
0:00> > 0.63% oracle> > 11368
oracle 1 33 0 1794M 1765M
sleep 0:00> > 0.29% oracle> > 19558
oracle 1 60 0 1797M 1751M
sleep 78:28> > 0.28% oracle> > 19554
oracle 1 60 0 1794M 1751M
sleep 38:05> > 0.20% oracle> > 11366
oracle 1 55 0 1793M 1763M
sleep 0:00> > 0.19% oracle> > 11292
oracle 1 26 2 2008K 1424K
run 0:00> > 0.19% dsql>
> > > Any ideas on what I, as a lowly DBA, would be
able> > to check? It's a bit out> > of my area and I'm
stumped...> > > > > > Thanks!>
> > > Jerry> > > > > > >
> > > =====> Connor McDonald> <A
href="
http://www.oracledba.co.uk"><FONT face="Courier New"
size=2>
http://www.oracledba.co.uk
(mirrored at > <FONT
face="Courier New" size=2>http://www.oradba.freeserve.co.uk<FONT
face="Courier New" size=2>)> > "Some days you're the pigeon, some
days you're the statue"> >
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-- > Author: =?iso-8859-1?q?Connor=20McDonald?=> INET:
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Received on Thu Aug 30 2001 - 09:13:39 CDT
