Xref: alice comp.databases.oracle.server:24166 Path: alice!news-feed.fnsi.net!priori!logbridge.uoregon.edu!nntp2.dejanews.com!nnrp1.dejanews.com!not-for-mail From: mkhawaji@hotmail.com Newsgroups: comp.databases.oracle.server Subject: Re: db_writers: Determining appropriate value Date: Tue, 07 Jul 1998 18:44:20 GMT Organization: Deja News - The Leader in Internet Discussion Lines: 54 Message-ID: <6ntqa4$qod$1@nnrp1.dejanews.com> References: <35993567.25312310@news.dvol.com> X-Article-Creation-Date: Tue Jul 07 18:44:20 1998 GMT X-Http-User-Agent: Mozilla/3.04 (X11; I; SunOS 4.1.4 sun4m) We have a Solaris server with 4 cpus and multiple instances. When changing the db_writers in the init.ora file and startup the database, it startups with no problems. But, when I go to the OS and do ps -ef |grep ora_dbwr , I got always one no matter what is the db_writers is in the init.ora. What could be the problem?. Thank you Mamdou Khawaji DBA In article , joelga@nospam.pebble.org wrote: > > On Tue, 30 Jun 1998 19:05:44 GMT, Chuck Hamilton wrote: > >I'm running Oracle 7.3.2.3 on HPUX 10.10. What can I query to see if I > >need additional db writers? Perhaps something from v$waitstat or > >v$sysstats? > > From docs Tuning Oracle on Solaris book: select * from v$system_event; > If there is a value in total_wait, DBWR is a bottleneck. Add writers > until there isn't a bottleneck anymore. I don't have an HP system just > now, can't verify this applies. > > From Ault's O8 book: watch free buffer waits from v$sysstat for spikes > when system is busy. Set the DB_WRITERS to the number of disks used by > Oracle. Increase _DB_BLOCK_WRITE_BATCH if DBWR performance is still poor, > be sure _DB_BLOCK_MAX_SCAN_CNT is 30 or greater. > > > > >Oracle Education needs to add this to the tuning class. They tell you > >to use multiple async i/o or multiple db writers - but they don't tell > >you how to determine how many. > > Because it's platform specific, application dependent and Async is preferable, > I suppose. > > >-- > >Chuck Hamilton > >chuckh@dvol.com > > > >If at first you don't succeed, sky diving isn't for you. > > -- > These opinions are my own and not necessarily those of Information Quest or > Pebble In The Sky http://www.informationquest.com mailto:jgarry@nospameiq.com > http://ourworld.compuserve.com/homepages/joel_garry Remove nospam to reply. > mailto:joel_garry@compuserve.nospam.com "See your DBA?" I AM the @#%*& DBA! > -----== Posted via Deja News, The Leader in Internet Discussion ==----- http://www.dejanews.com/rg_mkgrp.xp Create Your Own Free Member Forum