Hi Zhu Chao, There's one material called *SQL Memory Management in Oracle9i, *wroted by Benoît Dageville & Mohamed Zait, it describes how Oracle manage PGA. You may refere to it. 2008/10/7 Zhu,Chao <zhuchao@xxxxxxxxx> > hi, everyone, > I think many people using this parameter instead of very old > *_area_size these days and it just works well for most sites; > We are running into a different problem. With more and more traffic/SQL > execution, we are having more and more connections to the database. > Excessive session# is leading to excessive total PGA usage; and we have to > continuously reduce the SGA to accomedate the increasing PGA size, or > convert to MTS (but MTS comes with very high CPU overhead with high > connection# too). > Just wondering whether it is helpful to use this parameter to control > the total PGA caused by the excessive connection. This parameter helps make > oracle distribute the tunable pga size between processes. But I am not sure > how to estimate the tuneable/un-tunable pga size? > v$pgastat/sum(v$process.pga_max_size) is showing 5gb - 7gb pga usage but os > stats shows around 10gb-15gb pga usage; > Our platform is solaris 10/oracle 10.2 on Sparc. > > any comment is welcome. thx. > > -- > Regards > Zhu Chao > www.cnoug.org > > -- Regards, Yaping Chen http://yaping123.wordpress.com