From usidba@yahoo.com Thu, 30 Aug 2001 07:13:39 -0700 From: "Jerry C" Date: Thu, 30 Aug 2001 07:13:39 -0700 Subject: Re: OT : kernel using 75% of CPU - Summary and last post Message-ID: MIME-Version: 1.0 Content-Type: text/plain 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" <hamcdc@yahoo.co.uk> To: "Multiple recipients of list ORACLE-L" <ORACLE-L@fatcity.com> 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 <cspence@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> http://www.oracledba.co.uk (mirrored at > http://www.oradba.freeserve.co.uk)> > "Some days you're the pigeon, some days you're the statue"> > ____________________________________________________________> Do You Yahoo!?> Get your free @yahoo.co.uk address at http://mail.yahoo.co.uk> or your free @yahoo.ie address at http://mail.yahoo.ie> -- > Please see the official ORACLE-L FAQ: http://www.orafaq.com> -- > Author: =?iso-8859-1?q?Connor=20McDonald?=>   INET: hamcdc@yahoo.co.uk> > Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051> San Diego, California        -- Public Internet access / Mailing Lists> --------------------------------------------------------------------> To REMOVE yourself from this mailing list, send an E-Mail message> to: ListGuru@fatcity.com (note EXACT spelling of 'ListGuru') and in> the message BODY, include a line containing: UNSUB ORACLE-L> (or the name of mailing list you want to be removed from).  You may> also send the HELP command for other information (like subscribing).