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Re: ROW CACHE HIGH - Priority 1

From: Tanel Poder <tanel.poder.003_at_mail.ee>
Date: Fri, 26 Sep 2003 03:14:48 -0800
Message-ID: <F001.005D12DC.20030926031448@fatcity.com>


> sql parsing would be reflected in Library cache not rowcache
>
> Basic stuff

Not that basic. Rowcache will get hit during any hard parse, since you need to get information about objects from DD. And if objects information isn't cached yet, it has to be loaded into row cache.

Btw, row cache locks might come from LMT extent (de)allocation. Now, if both RAC instances start allocating or deallocating extents in a datafile, they need to access the same bitmap blocks, which results in GC traffic or pings, maybe that's the problem?

Tanel.

>
> Sam
> ----- Original Message -----
> To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
> Sent: Wednesday, September 24, 2003 1:14 PM
>
>
> > General answer: upgrade to 9.2.0.4 and hope that the bug has been fixed.
> > Row cache locks are data dictionary locks. You can see the contents of
row
> > cache
> > by inspecting v$rowcache. You may need to increase shared pool.
> > Last but not least, how fast is your private network connection between
> the
> > two nodes? 100mbit/sec is not nearly fast enough. You need at least a
> > gigabit
> > switch. Also check your SQL for hard parsing (see the executions and
> > invalidations in
> > v$sqlarea), ad-hoc DDL and that kind of stuff.
> > And no, it's not my priority 1.
> >
> >
> > --
> > Mladen Gogala
> > Oracle DBA
> >
> >
> >
> > > -----Original Message-----
> > > From: ml-errors_at_fatcity.com [mailto:ml-errors_at_fatcity.com] On
> > > Behalf Of Muqthar Ahmed
> > > Sent: Wednesday, September 24, 2003 3:50 PM
> > > To: Multiple recipients of list ORACLE-L
> > > Subject: ROW CACHE HIGH - Priority 1
> > >
> > >
> > > Hi,
> > >
> > > I have Oracle 9.2.0.2.0 RAC (two nodes) on IBM AIX.
> > > Currently I am seeing very high number for ROW CACHE LOCK in
> > > statspack.
> > >
> > > Top 5 Timed Events
> > > ~~~~~~~~~~~~~~~~~~
> > > % Total
> > > Event Waits
> > > Time (s) Ela Time
> > > -------------------------------------------- ------------
> > > ----------- --------
> > > row cache lock 11,310 5,441
> > > 86.97
> > > CPU time
> > > 522 8.34
> > > global cache cr request 32,513 71
> > > 1.14
> > > global cache null to x 21,507 57
> > > 91
> > > log file sync 22,689 49
> > > .78
> > >
> > > -------------------------------------------------------------
> > >
> > > Get
> > > Spin &
> > > Latch Name Requests Misses
> > > Sleeps Sleeps 1->4
> > > -------------------------- --------------
> > > ----------- ----------- ------------
> > > library cache 7,094,208 31,499
> > > 1,480 30031/1456/12/0/0
> > > shared pool 2,385,408 6,739
> > > 527 6212/527/0/0/0
> > > ges enqueue table freelist 1,492,275 1,903
> > > 124 1780/122/1/0 /0
> > > library cache pin 3,201,008 1,437
> > > 130 1307/130/0/0/0
> > > row cache objects 1,400,498 1,020
> > > 56 964/56/0/0/0
> > > row cache enqueue latch 1,292,843 715
> > > 19 696/19/0/0/0
> > >
> > > It is holding row cache lock (v$session_wait), other sessions
> > > are in the queue....due to this, number of concurrent
> > > sessions will increase from 100 to 350 sessions on each node.
> > > In less than one minute everything will be cleared ( OLTP database)
> > >
> > > I have already opened a TAR with Priority 1. Do you have any
> > > suggestions.
> > >
> > > Thanks
> > > Muqthar Ahmed
> > > DBA
> > >
> > > --
> > > Please see the official ORACLE-L FAQ: http://www.orafaq.net
> > > --
> > > Author: Muqthar Ahmed
> > > INET: Muqthar.Ahmed_at_decoratetoday.com
> > >
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> > --
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> > --
> > Author: Mladen Gogala
> > INET: mladen_at_wangtrading.com
> >
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> --
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> Author: Sam Roberts
> INET: rabbit_at_emirates.net.ae
>
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Tanel Poder
  INET: tanel.poder.003_at_mail.ee

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Received on Fri Sep 26 2003 - 06:14:48 CDT

Original text of this message

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